Monday Morning, April 20, 2015 Plenary Lecture Room: Town & Country - Session PL Plenary Lecture 8:00am PL1 Connecting Residual Stress and Thin Film Growth Processes: Real-time Experiments and a Kinetic Model, Eric Chason ([email protected]), Brown University, USA INVITED Polycrystalline thin films often develop residual stress during growth. Since it can be large enough to impact performance or cause failure, there is a need to understand and control it. Stress evolution can be measured in realtime during film growth using wafer curvature techniques. A large number of studies have been performed that quantify the dependence of the stress on deposition rate, grain size, temperature and microstructure in numerous materials systems. These show that the residual stress may depend strongly on the processing conditions, e.g., electrodeposited Ni films can be 400 MPa (tensile) if the film is grown rapidly and -500 MPa (compressive) if the film is grown slowly. The stress can also go through a series of states during deposition, even changing sign as the microstructure evolves from individual islands to a continuous film. But why do they develop stress at all, since strained films have higher energy than relaxed ones? To understand the non-equilibrium state of the film, we consider the kinetic processes that occur during thin film growth. We have developed a model that explains the stress evolution in terms of competing mechanisms that operate as the boundary forms between adjacent grains. The stress changes because the balance between these mechanisms changes with different processing conditions or with the evolving microstructure. The model predicts a dependence on the dimensionless parameter D/LR where D is the diffusivity, R is the growth rate and L is the grain size. We compare the calculations from the model with measurements on different films as a function of growth rate, temperature and grain size. More recently, studies of stress in patterned films have been performed in which the microstructure of the film is known precisely, allowing for direct comparison with the model.

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Monday Morning, April 20, 2015 Hard Coatings and Vapor Deposition Technology Room: Golden West - Session B2-1

11:00am B2-1-4 Microstructural Investigation of CVD Titanium Aluminium Nitride Multilayer Coatings, S. Mousavi Nik ([email protected]), Chalmers University of Technology, Sweden, D. Stiens, T. Manns, S. Ruppi, Walter AG, Germany, Mats Halvarsson, Chalmers University of Technology, Sweden Coatings of alumina and TiN are widely used in metal cutting applications. Alumina is an excellent material due to its chemical inertness and hothardness and is generally deposited by CVD (Chemical Vapour Deposition). Various phases, such as alpha, kappa and gamma can be produced. With the addition of Al to TiN, the material is capable of forming an alumina scale for oxidation resistance, and improved wear behaviour is observed in many applications. Such TiAlN coatings are commonly produced with different PVD (Physical Vapour Deposition) techniques. More recently also CVD has been used for deposition of TiAlN coatings. The desired fcc phase of TiAlN is metastable and can be produced by CVD processes using ammonia (NH3) as a precursor. The maximum Al/Al+Ti ratio in TiAlN is around 0.7 for PVD, while values up to 0.9 or even higher is possible by CVD. This is thought to be beneficial for the oxidation resistance and performance of such coatings in metal cutting applications. In the present work CVD TiAlN multilayer coatings were produced on standard WC/Co cemented carbide substrates. The coatings were characterized by X-ray diffraction (XRD), scanning and transmission electron microscopy (STEM and TEM) and energy dispersive X-ray analysis (EDX). The detailed microstructure, such as grain size, grain shape and possible twinning is reported. The texture and presence of local epitaxy between layers are described using XRD pole figures and electron diffraction techniques, such as selected area electron diffraction (SAED) and convergent beam electron diffraction (CBED). The local composition changes are described using EDX linescans and maps. The possible grain boundary changes in TiAlN due to prolonged deposition times are also investigated.

CVD Coatings and Technologies Moderator: Elisabeth Blanquet, University of GrenobleAlps, France, Masaharu Shiratani, Kyushu University, Japan 10:00am B2-1-1 Chemical Vapor Deposition of Diamond Coatings on Cu-W Alloys, Boqian Wan, Y. Li, Q. Yang ([email protected]), X. Sun, University of Saskatchewan, Canada Due to the large difference of thermal expansion coefficient between diamond and copper, diamond thin films on Cu substrate surfer from cracking and delamination. In this study, three Cu-W alloys containing 30 ~ 50 wt % Cu were synthesized by powder metallurgy and used as substrates for diamond coating in a microwave plasma enhanced chemical vapor deposition reactor. Optical microscopy, scanning electron microscopy, Raman spectroscopy, X-ray diffraction, synchrotron X-ray absorption spectroscopy, and indentation testing were used to investigate the morphology, composition, microstructures and adhesion of diamond films. The results show that the adhesion of diamond coatings on these Cu-W alloy substrates are much higher than on Cu substrate. The adhesion improvement is primarily attributed to the reduced thermal expansion coefficient mismatch and the formation of WC phase on the sub-surface of the substrate which strengthens the coating-substrate interfacial bonding. 10:20am B2-1-2 Advanced CVD-Diamond Coatings on Cutting Tools for Machining of CFRP, Michael Woda ([email protected]), B. Mesic, M. Frank, C. Schiffers, W. Kölker, O. Lemmer, CemeCon AG, Germany Composite materials - carbon reinforced fiber plastics (CFRP) and CFRP stacked with aluminum and titanium - are used in aerospace and automotive industry as an important and emerging material. Milling and drilling of the workpiece material CFRP is facing new challenges for high-end cutting tools including fiber delamination, parasitic chatter-marks and rapid tool wear due to the abrasive behavior of CFRP. Diamond coated tools made of cemented carbides are well suited to enable sufficient tool performance. In particular multilayer nano-crystalline diamond layers grown by Hot Filament CVD (HF-CVD) with very smooth surfaces and excellent adhesion reveal beneficial properties for CFRP cutting applications.

11:20am B2-1-5 Amorphous Phase Mixed α-Al2O3 Hard Coatings by Plasma-Enhanced Chemical Vapor Deposition, Naoyuki Iwasaki ([email protected]), S. Tatsuoka, K. Sato, K. Yamaguchi, Mitsubishi Materials Corporation, Japan Chemical Vapor Deposition (CVD) method has been used for the industrial production of wear resistant coatings on cutting tools and Al2O3 coatings have been widely used to maintain high hardness and excellent oxidation resistance under such a severe cutting condition. We have reported that growth mechanism of amorphous phase mixed α-Al2O3 thin films deposited by thermal CVD using gas mixtures of trimethylaluminium, as aluminum precursor and O2 instead of conventional gas mixtures, such as AlCl3 and CO2 [1]. In this work, we investigated growth mechanism of amorphous phase mixed α-Al2O3 thin films deposited by Plasma-Enhanced Metal Organic CVD (MOCVD) using gas mixtures of trimethylaluminium, as aluminum precursor and O2. Due to the plasma activation, high growth rate of 15μm/h for amorphous phase mixed α-Al2O3 and 45μm/h for amorphous-Al2O3 are obtained. Plasma-Enhanced MOCVD Al2O3 film shows unique lenticular morphology and much higher deposition rate makes more amorphous-like Al2O3. [1] S. Tatsuoka, et al., ICMCTF2014, B2-12.

10:40am B2-1-3 Surface Reactions during Ammonia-Plasma-Assisted Atomic LayerDeposition of Silicon Nitride, Sumit Agarwal ([email protected]), R. Ovanesyan, Colorado School of Mines, USA, D. Hausmann, Lam Research Corporation, USA The advent of FinFETs with high-aspect-ratio 3-D geometries increases demands on conformality of SiNx films. These stringent requirements on conformality and low thermal budget can be simultaneously met usingatomic layer deposition (ALD). While there are a few reports in the literature that show that SiNxcan beconformally deposited via ALD at 6 μm) on AISI D2 tool steel substrates and to investigate the properties of ZrN coatings with different thickness. ZrN coatings were prepared using dc unbalanced magnetron sputtering, where the opening of gate valve between turbomolecular pump (TP) and deposition chamber and the pumping speed of TP being the major controlling parameters. The hardness, adhesion strength and wear resistance were assessed by nanoindentation, scratch test and pin-on-disk test, respectively. The microstructure of the thick ZrN coatings was correlated to the deposition parameters, and the mechanical properties were also associated with the surface roughness and microstructure. The residual stress in the coating was determined by both cos2αsin2ψ X-ray diffraction (XRD) and laser curvature methods. In addition, the stress distribution in coatings was measured using cos2αsin2ψ XRD method at different incident angles, which may facilitate the understanding of the relation between mechanical properties and stress distribution in the coatings.

10:40am F5-3 Failure Behaviour of AZO/Ag/AZO Multilayers on Pen Substrates for Flexible Electronic Devices, D. Mohammed, University of Birmingham, UK, S. Elhamali, D. Koutsogeorgis, Nottingham Trent University, UK, J. Bowen, Stephen Kukureka ([email protected]), University of Birmingham, UK Requirements of transparent conductive oxide (TCO) films for optoelectronic applications are mainly focussed on their low electrical resistivity, optical transmittance of above 85% in the visible region and mechanical stability on flexible polymer substrates. Examples of applications include flat-panel displays, solar cells and thin-film transistors (TFTs). Indium tin oxide is widely used in transparent conductive electrodes in such devices, but high costs and brittleness have limited its applications. The electrical conductivity and mechanical stability of a single aluminium-doped zinc oxide (AZO) layer for flexible optoelectronic applications are still relatively limited. In this study we prepared AZO (35 nm)/Ag/AZO (35 nm) films using RF magnetron sputtering at room temperature. In order to satisfy the requirements of TCO films for flexible electronic device applications, Ag thin films with thicknesses 8, 10 and 12 nm were used as intermediate metal layers. The effect of Ag thickness on the electrical and optical properties is reported and discussed. The mechanical properties of AZO/Ag/AZO multilayer film compared with the single-layered AZO sample were investigated using cyclic bending fatigue and twisting tests. Changes in electrical resistance were monitored in situ. Scanning electron microscopy and atomic force microscopy were used to provide surface characterisation of the mechanically-tested samples. The effective embedment of the Ag layer between upper and lower AZO films led to metallic conductivity, high optical transparency and superior flexibility to the single AZO electrode, due to the high failure strain of the

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of Al2O3 to provide a hydrophilic effect to the “teflon” material. Other examples demonstrate the ability of ALD to introduce catalytic sites in mesoporous silica materials [2]. [1] Puurunen, J. Appl. Phys. 97, 121301 (2005). [2] Detavernier et al., Chem. Soc. Rev. 40, 5242 (2011). [3] Profijt et al., J. Vac. Sci. Technol. A 29, 050801 (2011). [4] Musschoot et al., Surf. Coat. Technol. 206, 4511 (2012). [5] Dendooven et al., Chem. Mater. 24, 1992 (2012).

ductile Ag layer. Furthermore, AZO/Ag/AZO showed similar performance compared with ITO films. These results indicate that flexible AZO/Ag/AZO multilayer electrodes grown by RF magnetron sputtering are a promising candidate for use as an indium-free flexible anode for optoelectronic devices. 11:00am F5-4 Electro-mechanical Characterization of Directly Written Ag Patterns on Compliant Substrates for Optoelectronic Devices, Maria A. Torres Arango, S. Konstantinos ([email protected]), West Virginia University, USA There is currently a great interest in developing flexible conducting electrodes. Such electrodes are used in most electronic devices ranging from displays to solar cells to flexible bio-sensors. To date most of these electrode components are fabricated using expensive vacuum based techniques such as sputtering, and are based on transparent conducting oxides (TCO’s). These oxides are not entirely compatible with flexible substrates under the application of relatively large mechanical stresses. Therefore, there is a need to explore novel low-cost and large-area fabrication methods to deposit ductile conducting materials alternative to brittle TCO’s. This work focuses on Ag patterns fabricated on flexible polyethylene naphthalate substrates utilizing a nozzle-based robotic printing approach. Such lithography-free method minimizes material waste by printing exact amounts of solution-derived inks on digitally predefined substrate locations. Additionally, it allows a broad feature size range, from a few μm to a few mm, and a variety of ink viscosities allowing control of printed shapes. In this study, we investigate the synthesis and direct writing of Ag inks, patterned-on-flex as lines and grid lattices of various sizes in the μm scale. Microstructural characterization is performed using microscopy, and X-ray diffraction. The optical, electrical, and mechanical properties of the patterns are assessed as a function of processing parameters and ink properties. Specifically, optical transmission measurements are correlated to line/grid spacing. Electrical properties are assessed through Hall effect measurements and are linked to ink heat treatment temperatures. The mechanical performance of the flexible patterns is investigated using a micromechanical tester under monotonic and cyclic tensile loading conditions up to a few thousand cycles. During mechanical characterization, the patterns’ electrical resistance is monitored in-situ using a digital multimeter. Resulting variations are associated with potential mechanical failure modes observed. It is believed that direct writing of solution-based conductive patterns on compliant substrates may hold the key in developing the next generation of truly flexible optoelectronic devices.

12:00pm F5-7 Effects of Electrolyte Composition on the Process of Conversion of Aluminium Foil into Alumina Ceramics by Plasma Electrolytic Oxidation, Husein Meshreghi, A. Yerokhin ([email protected]), A. Matthews, The University of Sheffield, UK Alumina thick and thin films can be used for a variety of purposes, including the semiconductors, electronics, substrate and dielectric, piezoelectric and ferromagnetic devices. The films can be produced by conventional methods such as tape casting and roll compaction from ceramic slurry. However, these methods offer limited part geometries and cause defects in the film structure. Plasma electrolytic oxidation is a novel surface engineering technology, allowing relatively thin and thick oxide coatings to be formed on metals. Alumina ceramics were produced by conversion of a rectangular shape aluminium foil (15 × 15 × 0.05 mm) using a plasma electrolytic oxidation technique. To achieve better understanding of the coating formation on the foil substrates the PEO process was carried out for 6 minutes in electrolytes containing various proportions of alkali, silicate and phosphate salts. The coating thickness, morphology and phase composition were analysed using SEM and XRD techniques. The effect of the electrolyte contents on the current density, surface morphology and phase composition of oxide layers were studied. Preliminary results indicate that the percentage of conversion to alumina reaches ~46%. The increase of potassium hydroxide concentration leads the discharge phenomena to occur at lower voltages. Moreover the addition of silicate in the electrolyte can increase the activity of discharge as well as coating surface roughness. It was found that the pore size increases with increasing the electrolyte concentration, which may affect coating properties. Oxide layers generated in phosphate solutions show pancakelike morphology, while the volcano-like structures are observed in the coatings prepared in silicate rich electrolytes.

Topical Symposia Room: Sunset - Session TS1

11:20am F5-5 Conformal Coating of Fibrous and Porous Substrates by ALD, Jolien Dendooven ([email protected]), D. Deduytsche, J. Musschoot, A.K. Roy, C. Detavernier, Ghent University, Belgium INVITED The Atomic Layer Deposition (ALD) technique enables the deposition of ultrathin coatings by sequential exposure of a solid surface to pulses of precursor vapor and a reactant gas [1]. The self-limiting nature of the surface reactions ensures precise film thickness control and excellent conformality, even on complex 3D substrates [2]. These unique advantages render ALD a promising technique for applications where nanoscale coatings are required on fibrous or porous substrates, such as fuel cells, batteries, catalytic surfaces, filtration devices, membranes, etc. The successful conformal coating of 3D substrates requires, however, a careful optimization of the growth parameters. This is especially true for plasma enhanced (PE-)ALD processes. In PE-ALD, the reactant gas is activated in a plasma, generating radicals that are more reactive towards the growing film [3]. Consequently, PE-ALD often allows for deposition in a lower temperature range, and results in higher growth rates and improved film purity. However, because radicals can recombine on the sidewalls of high aspect ratio features, good conformality is often indicated as a challenge for PE-ALD. This work explores the conformality of thermal and PE-ALD on fibrous and nanoporous materials. In a first study, we deposited Al2O3 on nonwoven polyester fibers and evaluated the conformality as a function of precursor exposure time and fiber density [4]. While longer exposure times resulted in deposition deeper inside the nonwoven for the thermal ALD process, the O 2 plasma-based process was found to have a very limited penetration. In a second study, we investigated ALD of TiO2 in mesoporous titania films with sub-10 nm pore sizes [5]. Novel in situ synchrotron-based x-ray fluorescence and scattering techniques were developed to obtain cycle-percycle information on the material uptake and densification of the porous film. The results demonstrated the ability of thermal ALD to tune the diameter of nanopores down to the molecular level. In addition, results will be presented where the unique advantages of ALD are exploited to functionalize the surface of porous polymers and inorganic materials. A first example concerns the modification of PTFE by PE-ALD

Monday Morning, April 20, 2015

Mechanical Aspects of Biointerfaces Moderator: Jinju Chen, Newcastle University, UK, Sandra E. Rodil Posada, Universidad Nacional Autónoma de México, México 10:00am TS1-1 Influence of Surface Topography and Roughness on Initial Formation of Biofilm, Yasmine Ammar ([email protected]), D. Swailes, B. Bridgens, J. Chen, Newcastle University, UK Surface roughness is an important factor affecting cellular attachment to surfaces prior to biofilm formation. The presence of nanoscale asperities reduce the physicochemical potential barrier encountered by a bacterial cell when it approaches the surface. More recently, the effect of the surface topography on biofilm development has also been qualified . Local zones of flow recirculation introduced by the surface shapes are responsible for modifying the deposition rate defined as the ratio of the particle flux towards the wall over the wall concentration. This work is to study the initial deposition of activated sludge bacteria from a wastewater treatment plant. The objective of the study presented here is two-fold: (1) to specify the boundary conditions of a convection diffusion equation, which are appropriate for bacterial deposition in laminar viscous flows and can be easily implemented in a Computational Fluid Dynamics (CFD) code; (2) to assess the bacterial deposition rate for different surface features, which would guide the design of appropriate material topography for wastewater treatment. Here, bacteria are treated as inert colloidal particles that attach to surfaces according to the extended Derjaguin-Landau-Verwey-Overbeek (DLVO) theory. The deposition model accounts for bacterial cell surface structures, hydrophobicity and motility which are known to increase activated sludge bacterial adhesion. The surface asperities are modelled by a lognormal size distribution with mean μ~50 nm and standard deviation σ~3. The model is

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validated by comparing deposition measured in a parallel flow chamber to the CFD results for different ionic strengths and surface properties. Based on CFD simulations, the relationship between the deposition rate and the surface topography has been established.

Topical Symposia Room: Royal Palm 1-3 - Session TS6 Atmospheric Plasma Applications Moderator: Hana Baránková, Uppsala University, Sweden

10:20am TS1-2 Phase Field Model of Biofilm-Flow Interaction, Tianyu Zhang ([email protected]), Montana State University, USA INVITED We derive a set of phase field models for biofilms using the one-fluid twocomponent formulation in which the combination of extracellular polymeric substances (EPS) and the bacteria are effectively modeled as one fluid component while the collective ensemble of nutrient and the solvent are modeled as the other. The biofilm is assumed an incompressible continuum. Numerical simulations are carried out in one and two space dimension using a velocity-corrected projection method for incompressible flows. Biofilm growth, expansion, streaming, rippling, and detachment are simulated in shear cells numerically. Viscoelastic properties of the biofilm is investigated as well.

10:00am TS6-1 Incorporation of Amine Moieties onto Ultra-high Molecular Weight Polyethylene (UHMWPE) Surface via Plasma Polymerization and Grafting of Allylamine, Gaelle Aziz ([email protected]), R. Morent, N. De Geyter, H. Declercq, R. Cornelissen, Ghent University, Belgium The ultimate aim in medicine, besides prevention, is the healing of diseases and repairing damage after injuries. In reconstructive surgery, the task of engineers, material scientists and physicists is to provide an optimal system for each application. One particular application is the replacement of joints such as knee, shoulder and hip prosthesis in which ultra-high molecular weight polyethylene (UHMWPE) polymer is used. Since the interaction between the biological environment and biomaterial takes place on the material surface, the success of an implant is determined to a large extent by its surface properties. However, UHMWPE is non-polar and thus not optimal for cell adhesion and proliferation; its hydrophobic nature also limits its lubrication by synovial fluid in the joint increasing its friction and wear leading to a decreased longevity. Plasma technology (plasma polymerization and plasma surface treatment) is widely used to alter the surface properties of polymers by incorporation of functional groups on their surfaces without affecting their bulk properties. Among others, nitrogen functional groups are known to increase surface wettability and promote cell adhesion and proliferation. In this research, plasma polymerization (continuous and pulsed plasma), and plasma post-irradiation grafting were used in order to deposit allylamine polymer thin films onto the surface of UHMWPE. Different process parameters such as power, monomer concentration, pressure and treatment time were varied for optimization. After treatment, surfaces were characterized via different physical and chemical characterization techniques such as: water contact angle measurements (WCA), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) and optical reflectance spectroscopy (OPS). Moreover, films stability and ageing behaviors were investigated by soaking the substrates in a phosphate buffer solution at 37°C while agitating and by storing the substrates at ambient temperature respectively for 7 days. Cell culture tests were also done on the treated surfaces in order to evaluate their biocompatibility. Eventually, a comparison between the different methods and different process parameters on the film properties and biocompatibility has been made.

11:00am TS1-4 Nanomechanical and Microstructure Analysis of Extracellular Matrix of Immortalized Cell Line Y201 from Human Mesenchymal Stem Cells, Pengfei Duan, J. Chen ([email protected]), Newcastle University, UK Human Mesenchymal stem cells (MSCs) have been used as primary cell lines for musculoskeletal tissue engineering. However, the translation of MSCs preclinical results has serious problems to be solved due to the significant variability of MSCs preparations and limited life-span of MSCs. To circumvent such issues, it has been suggested to immortalize these cells by genetic manipulation. Various work has demonstrated that such immortalized cells grow fast and are able to produce significant amount of extracellular matrix. However, it remains elusive how good these extracellular matrix could be. In this study, the nanoindentation technique was adopted to evaluate the mechanical properties of the matrix formed on glass coverslips by immortalized cell line Y201 from human MSCs at different cell culture conditions. However, for the extracellular matrix formed the implant or other surfaces are often highly inhomogeneous and have a rough surface and non-uniform thickness. This would make data interpretation of nanoindentation complicated. Therefore, different nanoindentation test protocols have been designed. It has shown that multicyling test protocols are more suited to such inhomogeneous materials. Statistical analysis has revealed that the matrix produced by cells on day 14 is stronger compared to other culture periods possibly due to the denser microstructure. When the cell culture exceeds 21 days, the local cell detachment tends to affect the measured mechanical properties. In addition, surface chemistry analysis has shown that little minerals have been produced regardless fast cell growth.

10:20am TS6-2 Modification of TiO2 Powder via Atmospheric Dielectric Barrier Discharge Treatment for High Performance Lithium-ion Battery Anodes, Shang-I Chuang, H. Yang, H.W. Chen, J.G. Duh ([email protected]), National Tsing Hua University, Taiwan The main objective of this research is to improve the electrochemical performances of TiO2 Li-ion anode material by introducing plasma treatment of TiO2 powder. A specially designed atmospheric dielectric barrier discharge (DBD) plasma generator that are feasible to treat powders is proposed. TiO2 powder underwent N2 and H2 mixed argon plasma treatment for 5, 10, 20, and 40 min. The rate capability of 20 min plasma treated TiO2 anode had the best performance. As-treated TiO2 reached a maximum nitrogen doping content 1.0% which was analyzed from x-ray photoelectron spectroscopy (XPS) peak analysis. In addition, Ti (IV) was partially reduced to Ti (III). The effectiveness of plasma treatment was evaluated by diagnosing plasma using optical emission spectroscopy (OES). Significant amount of excited argon was presented. Excitation of nitrogen second positive system, and presence of hydrogen excited spectrum were also identified. Although results of scanning and transmission electron spectroscopy (SEM, and TEM) did not show noticeable surface morphology and microstructure change, it is still believed that hydrogen contributed TiO2 reduction causing oxygen vacancy. These oxygen vacancy further provides the chance to let excited nitrogen doped onto surface of TiO 2 particle. Electrochemical properties of TiO2 is raised due to the production of oxygen vacancy and nitrogen doping. These findings enhance the understanding of the atmospheric plasma treatment on the potential application of TiO2 anode material in Li-ion battery.

11:20am TS1-5 3D Monolayer Stress Cytometry, R. Serrano, A. Aung, S. Varghese, University of California San Diego, USA, Juan Carlos del Alamo ([email protected]), University of California San Diego INVITED Many important biological processes, such as endothelial mechanotransduction of hemodynamic forces and neutrophil extravasation, involve the transmission of stresses across a cell monolayer. During these processes, the monolayer undergoes both lateral distortion due to the inplane traction forces generated by the cells, and bending due to the out-ofplane component of the traction forces. However, the contribution of this bending to the monolayer stresses has been neglected in the literature. Here, we present a novel technique to determine monolayer stresses that considers both lateral distortion and bending. To illustrate the method, and to quantify the relative importance of the lateral and bending stresses, we measure the monolayer stresses in micropatterned endothelial cell islands of varying sizes and shapes. The cell islands are cultured on flexible polyacrylamide gels embedded with fluorescent beads, which deform due to traction forces exerted by the cells. We measure the three-dimensional gel deformation using previously established 3D Traction Force Microscopy methods, and recover the monolayer stresses from the measured deformation using Kirchoff-Love thin plate theory. The equations are solved numerically in an efficient manner using a Fourier pseudo-spectral method. The boundary conditions corresponding to the geometry of the cell islands are enforced within the Fourier framework using a relaxation iterative method. Our results indicate that, regardless of island shape, the three-dimensional bending stresses are dominant at the center of the island while the lateral stresses are more important near the island edge. Also, comparing the results from islands of different sizes shows that the relative importance of the bending stresses increases with decreasing island size. These results suggest that it is necessary to resolve bending stresses to accurately determine the monolayer stresses, and reveal that the transmission of forces across cell junctions is three-dimensional and more complex than previously believed.

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10:40am TS6-3 Development of Cold Atmospheric Pressure Plasma Jets for Material Processing and Surface Decontamination, Konstantin Kostov ([email protected]), Universidade Estadual Paulista - UNESP, Brazil, M. Machida, UNICAMP, Brazil, V. Prysiaznhyi, R.Y. Honda, T. Nishime, A. Castro, Universidade Estadual Paulista - UNESP, Brazil INVITED In the past decade cold atmospheric pressure plasma jets (APPJs) have attracted much attention due to their simple construction, versatility, easy scalability, low production costs and most importantly because they can produce very reactive chemistry at room temperature. A very interesting feature of APPJs is their ability to penetrate inside small holes and propagate along flexible dielectric tubes. This property makes the plasma jets very attractive tools for biomedical applications such as generation and propagation of plasma through catheters, endoscopic tubes, tooth channels etc. However, for each specific medical application usually a different kind of plasma source is needed. Therefore, it is very important to continuously developed new plasma jet prototypes that can be tested for different applications. In this work we address three major issues for the design and development of APPJs. First of them is the precise power determination of a plasma jet, which is essential for biomedical applications. Most commonly used techniques are the direct integration of current - voltage waveforms and the Lissajous figure method. We compare these approaches, discuss their advantages and drawbacks and also determine the range of their applicability. An important concern in plasma medicine, where clinical treatments are performed by APPJs, is the precise control of the device power. A manner for fine power adjustment of plasma jets is the use of burst mode operation of a conventional AC power supply. As we will show in this way very stable and cold plasma jets can be generated. Finally we describe a novel method for generation of cold atmospheric pressure plasma jet at the downstream end of a long flexible plastic tube without igniting plasma inside it. The device consists of a closed chamber where dielectric barrier discharge (DBD) is ignited. The discharge is driven by a conventional AC low frequency power supply. The exit of DBD reactor is connected to a long (up to 4 meters) commercial flexible plastic tube with a thin floating Cu wire passing through it. The gas flow is guided by the plastic tube while the metal wire, when there is plasma inside the DBD reactor, acquires the plasma potential. There is no discharge inside the plastic tube however under certain conditions a small plasma jet can be extracted from the downstream tube end. The jet obtained by this method is cold enough to be put in direct contact with human skin without electric shock. Therefore, by using this approach a cold plasma jet is generated far from the discharge generation region and the produced active species can be used for medical treatment and decontamination.

atmospheric pressure plasma technology can lead to an implant with improved quality and a subsequent longer lifespan. 11:40am TS6-6 Plasma Discharge Process for the Nitrogenfunctionalization of CNTs and their Electrocatalytic Activities, SangYul Lee ([email protected]), S.M. Kim, A.R. Cho, Korea Aerospace University, Korea, J.W. Kim, Incheon University, Korea Functionalization of carbon nanotubes (CNTs) for the fuel cell application has been paid much attention recently as it has been realized that mechanical and electrical properties of CNTs can be altered by adding species to the side walls. Generally, such functionalization is accomplished by immersing the CNTs in diverse chemical solutions or exposing them to vapors at high temperatures. Plasma discharge in solution, so-called solution plasma process (SPP) was a one-step method to synthesize nitrogen-functionalized CNTs (N-CNTs) using simple equipment system. The superior properties of SPP not only include no requirements of heat and/or pressure owing to the high active species generated during discharge in solution, but also enable to control the morphology of CNTs through the change of electronic properties of discharge. In this study, the CNTs and N-CNTs were synthesized by arc discharge in pure water and ammonia solution. The effect of N-functional group on the microstructure, morphology, and electrocatalytic activities of the CNTs was examined using the transmission electron microscopy (TEM), X-ray diffraction (XRD) and fourier transformed-infrared (FT-IR) in terms of nitrogen-functionalization. Electrochemical properties of the nitrogenfunctionalized CNTs supported Pt catalysts were analyzed by electrochemical impedance spectroscopy (EIS). From the results of FT-IR, the spectrum of CNTs and N-CNTs displays bands characteristic of N-H stretching (3430 cm-1), C=N stretching (1630 cm-1), N-O stretching (1380 cm-1). The results of EIS indicated that the charge transfer resistance (Rct) of CNTs and N-CNTs with Pt was separately 1.46ⅹ104 Ω and 4.47ⅹ103 Ω . Compared to CNTs and N-CNTs, the peak intensity of FT-IR was increased with increasing the nitrogen concentration due to the formation of functional groups and the N-CNTs showed much improved electrochemical performances. The detailed results will be presented. Acknowledgement : This study was supported by the National Research Foundation of Korea (NRF) funded by the Korea government (MSIP, Grant No. 2013R1A1A2060918) 12:00pm TS6-7 Atmospheric Pressure Plasma Enhanced Recycled Wastes for High Performance Si-based Lithium Ion Battery, BingHong Chen, S.I. Chuang, J.G. Duh ([email protected]), National Tsing Hua University, Taiwan, W.R. Liu, Chung Yuan Christian University, Taiwan Si/SiC composites were extracted from the wastes of solar cell industries after cutting ingots. Electrodes were fabricated with recycled waste, Super P (SP) and sodium alginate (SA) on copper foil, and the as-prepared electrodes were treated with oxygen plasma by atmospheric pressure plasma jet (APPJ). According to the electrochemical measurement, the sample with APPJ technique shows outstanding performance, which exhibits lesser resistance of solid electrode interface (RSEI) and resistance of charge transfer (Rct) through the fitting of equivalent circuit. Moreover, the broad peak of SEI formation at first cycle had vanished and the difference between oxidation and reduction peaks had reduced after APPJ treatment by cyclic voltammetry test. The mechanisms of APPJ could be interpreted via analyzing electrode by X-ray photoelectron spectroscopy (XPS) after cycling, which had shown the smootherorganic bonding. Conclusively, APPJ has the function to purify the surface of electrode to suppress the intrinsic formation of SEI to enhance the performance of silicon lithium ion battery.

11:20am TS6-5 Application of Atmospheric Pressure Plasma on PE for Increased Prosthesis Adhesion, Stijn Van Vrekhem ([email protected]), P. Cools, H. Declercq, Ghent University, Belgium, A. Van Tongel, Ghent University Hospital, Belgium, F. Barberis, Genoa University, Italy, R. Cornelissen, N. De Geyter, R. Morent, Ghent University, Belgium Biopolymers are often subjected to surface modification in order to improve their surface characteristics. The goal of this study is to show the use of atmospheric pressure plasma technology to enhance the adhesion of polyethylene (PE) shoulder prostheses. Two different plasma techniques (atmospheric pressure plasma activation and atmospheric pressure plasma polymerization) are performed on PE to increase the adhesion between the polymer and osteoblast cells or between the polymer and a PMMA bone cement. Both techniques are performed using a dielectric barrier discharge (DBD). A previous paper showed that atmospheric pressure plasma activation of PE results in the incorporation of oxygen-containing hydrophilic functional groups, which leads to an increased surface wettability. Atmospheric pressure plasma polymerization of methyl methacrylate (MMA) on PE results in a PMMA-like coating, which could be deposited with a high degree of control of chemical composition and layer thickness. The thin film also proved to be relatively stable upon incubation in a phosphate buffer solution (PBS). This paper will discuss the next stage of the study, which includes testing the adhesion of the plasma-treated and plasma-coated samples to bone cement through a pull-out test and testing the cell adhesion and proliferation on the samples. In order to perform the pull-out tests, all samples were cut to standard dimensions and fixed in bone cement in a reproducible way with a sample holder specially designed for this purpose. The cell adhesion and proliferation were tested by means of an MTS assay after culturing MC3T3 osteoblast cells on disc-shaped samples for 7 days. The results show that both atmospheric plasma activation and atmospheric plasma polymerization significantly improve the adhesion to bone cement and enhance cell adhesion and proliferation. In conclusion, it can be stated that the use of

Monday Morning, April 20, 2015

12:20pm TS6-8 Coating Preparation on Mg and Corrosion Protection for Magnesium/Steel Coupling, Fuyan Sun, X. Nie ([email protected]), University of Windsor, Canada In this study, a plasma electrolytic oxidation (PEO) process is used to form ceramic coating on AJ series magnesium. The present work is mainly to study the protective effects of coating on magnesium and galvanic coupling containing AJ series magesium and Aluminized steel. A potentiodynamic polarization corrosion test has been employed to investigate the corrosion resistance of the coating on magnesium in 3.5% NaCl solution.The galvanic corrosion rates of uncoated and coated Mg alloy respectively coupling with steel, aluminized steel, oxide-coated aluminized steels are studied by the zero resistance ammeter (ZRA) test. The scan electron microscopy (SEM) is used to investigate the coating microstructure and the coating/substrate interface. It is found that the plasma discharge behavior and treatment time significantly influence the microstructure of oxide coatings, corrosion resistances and galvanic corrosion extent.

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Monday Afternoon, April 20, 2015 there is no etching at the sapphire/AlN interface, (ii) the stress in the nucleation layer is tensile and compensated by the compressive thermal stress during the cooling down of the process. The best "quality" we have obtained with the optimized two-step process is characterized (i) by FullWidth-Half-Maximun of (0002) reflexion of XRD rocking curves (disorientation of 300 arcsec, dislocation density ~10 9 cm-2) (ii) by the frequency shift of E2(high) phonon mode of Raman spectra (643.9 cm -1 for the nucleation layer, 658.2 for the thick layer and 657.4 for unstressed). The resulting calculated stresses are 1.6 GPa (tensile) for the nucleation layer and -1 GPa for the final layer (compressive). In the third part, the applications of graphite/AlN, SiC/AlN and steel/AlN stacks are briefly presented for potential nuclear and solar applications. AlN is an excellent barrier and buffer layer to avoid diffusion or oxidation of metals and carbides. The applications of sapphire/AlN templates for deep UV light emitting diodes (UV LED) and surface acoustic wave sensors (SAW) are discussed. The "quality" of the AlN layer is not sufficient to have an emission in the UV at 210 nm. However, for surface acoustic wave devices fabricated on the AlN/sapphire stack exhibit phase noise lower than -150 dc/Hz at 4.4 GHz.

Hard Coatings and Vapor Deposition Technology Room: Golden West - Session B2-2 CVD Coatings and Technologies Moderator: Elisabeth Blanquet, University of GrenobleAlps, France, Masaharu Shiratani, Kyushu University, Japan 1:30pm B2-2-1 The Initial Stages of sp2-BN Thin Film Growth by Chemical Vapor Deposition, Mikhail Chubarov, H. Pedersen, Linköping University, IFM, Sweden, ZC. Czigány, Hungarian Academy of Sciences, Hungary, M. Garbrecht, H. Högberg, A. Henry ([email protected]), Linköping University, IFM, Sweden B and N atoms are closest neighbors to C in the periodic table which means that BN is isoelectronic to C and exhibits many properties similar to carbon. The atomic orbitals in BN can be sp2 or sp3 hybridized and in the sp2-BN BN can form hexagonal (h-BN) or rhombohedral (r-BN) forms, with structural similarities to graphite. sp2-BN attracts significant interest due the combination of properties such as wide bandgap (~ 6 eV), possibility both p- and n-type doping, chemical and thermal stability, low refractive index of around 2 and high in-plane thermal conductivity of 390 W/m*K. Hence many applications within electronics and optoelectronics are envisioned for sp2-BN. However, a great hurdle is deposition of high quality epitaxial sp 2BN thin films. There are reports on growth of sp 2-BN on different substrates but determining the crystalline structure of such films is challenging. This is due to the fact that the in-plane lattice constants are the same (2.504 Å) for both crystal structures as the spacing between basal planes which is around 3.333 Å. Thus, it is impossible to distinguish between c-axis oriented h-BN and r-BN thin films by using X-ray diffraction (XRD) in Bragg-Brentano geometry and requires atomic resolution investigation by cross-section transmission electron microscopy (TEM) or more advanced diffraction experiments. We presented deposition of high quality r-BN thin films on a-Al2O3 and different polytypes of SiC by CVD [1,2]. Here we present a study of the nucleation, film development and crystal structure development at the early stages of sp2-BN thin films growth on (0001) a-Al2O3 with AlN buffer layer (AlN/α-Al2O3) and (0001) 6H-SiC. In TEM we have observed formation of different crystal structures; AlN buffer layer promotes growth of h-BN to a thickness of around 4 nm after which a transition to r-BN growth occurs. On SiC , polytype pure r-BN is obtained. Formation of h-BN on AlN/αAl2O3 was also observed using glancing incidence XRD (GI-XRD). The growth of h-BN is characteristic for the AlN/α-Al2O3 and was found to form even at a temperature of 1200 °C. For SiC substrate, r-BN was observed at the growth temperature of 1500 °C while no traces of crystalline sp2-BN formation were found below 1500 °C. The observed growth behavior is explained by the reproduction of the substrate crystal structure by the growing film. This explanation is also suitable to describe twinning of the rBN crystal and observed suppression of twinning. [1] M. Chubarov, H. Pedersen, H. Högberg, J. Jensen, A. Henry, Cryst. Growth Des.12 (2012) 3215 [2] M. Chubarov, H. Pedersen, H. Högberg, Zs. Czigany, A. Henry, CrystEngComm., 16 (2014) 5430)

2:30pm B2-2-4 Oxidation Resistance and Mechanical Properties of Alrich Nanolamellar Ti0.05Al0.95N Coatings Prepared by CVD, Juraj Todt ([email protected]), University of Leoben, Austria, R. Pitonak, A. Köpf, R. Weißenbacher, Böhlerit GmbH & Co. KG, Austria, J. Keckes, University of Leoben, Austria Ti1-xAlxN coatings used for high-speed cutting applications are expected to withstand high temperatures, exceeding even 1000 °C, as well as high mechanical loads, making both good oxidation resistance and high hardness a requirement. In this contribution, properties of novel Ti 0.05Al0.95N coatings [1] with a self-organized lamellar nano-composite microstructure synthesized using a low-pressure CVD process will be discussed. Their unique morphology comprises alternating lamellae of soft hexagonal w-AlN and hard cubic fcc-TiN with a bi-layer period of about 13 nm, confined in grains of approximately 150 nm diameter. Coatings grown on WC-Co substrates were oxidized for 1 h in ambient air at temperatures in the range of 700 – 1200 °C and temperature-dependent changes of microstructure, phase composition, hardness and residual stresses were examined using a variety of analytical techniques, including depth-resolved nanoindentation and depth-resolved cross-sectional X-ray nanodiffraction. The residual stresses in the as-deposited and annealed coatings are compressive at about -1 GPa, which is contrary to the tensile stress state observed in most of the common CVD coatings. The presented results show excellent oxidation resistance up to 1050 °C and a comparatively high hardness of about 29 GPa that remains almost constant even after high temperature treatments. Both characteristics are explained by the unique self-organized and surprisingly stable nano-scaled microstructure of the coating. [1] J. Keckes, R. Daniel, C. Mitterer, I. Matko, B. Sartory, A. Köpf, R. Weissenbacher, R. Pitonak (2013), Self-organized periodic soft-hard nanolamellae in polycrystalline TiAlN thin films, Thin Solid Films 545, 2932. 2:50pm B2-2-5 Wear Properties of CVD Textured α - Al2O3 in Different Cutting Conditions in Stainless SteelL, Raluca Morjan Brenning ([email protected]), Sandvik Coromant, Sweden During the last years CVD textured α-Al2O3 coatings have been developed successfully as wear resistant coatings on cemented carbide cutting tools. These coatings are now found in several commercial cutting tool products. Earlier studies have shown that the controlled growth of αAl2O3 in the crystal direction increases the wear resistance of the coated cutting tools, especially in steel turning application but also in cast iron. When cutting stainless steel, the benefits of a high textured αAl2O3 is not as obvious as when cutting steel. This work show advantages and drawbacks with a high textured α-Al2O3 compared to κAl2O3/TiN multilayers coating by cutting stainless steel. It has for example been noted that both crater and flank wear is more pronounced on the textured α-Al2O3 compared to the wear of κ-Al2O3/TiN multilayer when cutting stainless steel. The tool life criterion is reached for the textured variant after 78% of tool life of the κ-Al2O3/TiN multilayered coating. The wear mechanism, studied in detail by scanning electron microscopy (SEM) and focused ion beam (FIB-SEM) will be presented.

1:50pm B2-2-2 Functionalization Of Aluminium Nitride Thin Films And Coatings, Michel Pons ([email protected]), R. Boichot, F. Mercier, E. Blanquet, S. Lay, University of Grenoble-Alps, France, D. Pique, Sil'tronix St, France INVITED The application of AlN films in optoelectronics, sensors and high temperature coatings is strongly dependent on the nano- micro-structure of the film, impurity level and defect density. AlN epitaxial thin (0.5 – 10 µm) and thick polycrystalline (> 10 µm) films were grown on different foreign substrates (steel, sapphire, silicon carbide, graphite) and single AlN crystals by Chemical Vapor Deposition (CVD), also called Hydride Vapor Phase Epitaxy (HVPE), at high temperature (800-1750 °C). In the first part, the modeling and simulation of the growth process is presented. The growth of polycrystalline or single-crystalline AlN was studied as a function of local parameters (temperature, concentrations and local supersaturation) just above the substrate, then reactor-independent. Two regions were defined by comparing experimental and numerical results. In the second part, the twostep growth process resulting from previous optimization is presented. A 170 nm AlN nucleation layer is first grown on sapphire at 1200 °C (N/Al ratio of 3) before the deposition of a thicker film at 1500 °C (N/Al ratio of 1.5). The characterization of epitaxial films, including their crystalline state, surface morphology, and inherent and thermally induced stress which inevitably lead to high defect densities and even cracking reveals that (i)

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Monday Afternoon, April 20, 2015

3:10pm B2-2-6 Deposition of Diamond Coating on Fe-Based Substrates with Al and Al/AlN Interlayers, Xiaoyu Sun, Y. Li, L. Yang, Q. Yang ([email protected]), University of Saskatchewan, Canada Because of the formation of graphite at the interface and carbon diffusion into the substrate, direct deposition of adherent diamond coatings on Febased materials is difficult. To address the issue, Al-based interlayers including Al and Al/AlN inerlayers were firstly deposited on Fe based substrates (SS316, FeCoNi). Diamond deposition was then synthesized on the pre-coated substrates by microwave plasma chemical vapor deposition (MPCVD) in a CH4-H2 mixture. The obtained samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), Raman spectroscopy, synchrotron-based X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS), and indentation testing. The results show that the Al layer can effectively suppress the formation of graphite and inward diffusion of carbon and enhance diamond nucleation and growth. The dual layers of Al/AlN multilayer can enhance the adhesion of diamond coatings comparing to the single Al interlayer.

maximum hardnesses are 3.06 GPa and 2.14 GPa, respectively, but for plasma power of 2.0kW, there is a slight reduction. To evaluate the abrasion resistance of each film, the change in the haze of its abrasion surface was investigated by using a Taber abrasion tester at standard abrasion test condition (500 g weights on both sides, CS 10-F wheels, 50 rpm, 100 cycles). The average value of the haze is 0.67% at plasma power of 1.7kW, and this value is similar to a change in haze of glass, 0.69%. The films, which are deposited at plasma power of 2kW, also have the average value of the haze less than 2%. These results satisfy the abrasion condition (haze < 2%), which must be satisfied in order to use plastic instead of glass for automobile. To evaluate the adhesion of deposited films, the adhesion test was examined by ASTM D3359-02. The films were attached well to the polycarbonate even the absence of the buffer layer. As a result, the polycarbonate coating technology was successfully developed, and this technology will contribute to replace for glass in the use of construction and automobile industries.

3:30pm B2-2-7 New Type of BN, AlBN Films Prepared by Synergetic Deposition Processes using Laser and Plasma: the Nanostructures, Properties and Growth Mechanisms, Shojiro Komatsu ([email protected]), National Institute of Materials Science, Japan INVITED In this study, we utilized the effects caused by “the interaction between plasma and nano-interface of materials”. We pursued this subject from the stand point of view of materials science. The structural analyses of obtained materials by using x-ray diffraction played an important role, and which led to discoveries of new polytypes of sp3- bonded BN. In order to understand their nature in terms of inorganic chemistry, we newly introduced Komatsu diagram, in which crystallographic indices such as hexagonality, closepacking index, metastable energy, and ionicity are found to be related systematically. As to the growth mechanism of the metastable polytypic forms, we found a consistent relationship between the B-N bond lengths and preferably grown structures. This led us to find the “Bond-Strength Initiative Rule” in the CVD growth of metastable structures. Utilizing the transparency of BN in the visible light region, we were successful to fabricate a photovoltaic cell of BN/Si hetero-junction diode, which can be versatile as a very robust and durable PV cell ever. The very peculiar morphology of the BN films with micro-cones was effective for electronfield emission. By introducing rotation of the substrate against the laser, we found the growth of the BN films with hierarchically ordered structures of three stages. It was made possible by newly employing 2D-XRD mapping method using collimated x-ray beam of 0.1 mmφ. This was one of new examples of self-organization in reaction-diffusion system, into which the pulsed excimer laser introduced far-from chemical equilibrium. Ripple pattern formation extending around isolated BN cones in sub-micrometer dimension was found and interpreted as a result of the micro-optical effect of interference due to the coherent wave nature of the laser. This also experimentally supported the photochemical growth of BN in our method. All the phenomena studied here were deeply connected with the far-from chemical equilibrium states induced by the laser irradiation. Our study here revealed that the interaction of plasma and nano-interface was enhanced and made “visible” as a result of these efforts.

Hard Coatings and Vapor Deposition Technology Room: San Diego - Session B3 Deposition Technologies and Applications for Diamondlike Coatings Moderator: Klaus Böbel, Robert Bosch GmbH, Germany, Chris Engdahl, Crystallume, USA 1:30pm B3-1 Influence of the Acetylene Precursor Dilution with Argon on the Microstructure, Mechanical and Tribological Properties of aC:H Films Deposited by Modified Pulsed-DC PECVD Method, G. Capote ([email protected]), Universidad Nacional de Colombia, Colombia, G. Mastrapa, PUC-Rio, Brazil, Vladimir Trava-Airoldi, INPE, Brazil Amorphous hydrogenated carbon (a-C:H) films have been grown using different hydrocarbon precursors in order to find the best set of mechanical and tribological proprieties. The addition of noble gases to the hydrocarbon precursor atmosphere is expected to increase the ratio of ion to neutral radicals on the surface of the growing film without changing the H/C ratio of the gas mixture. This is in fact a powerful way to investigate the effect of ion bombardment on the structural arrangement and properties of a-C:H films. In this work, acetylene (C2H2) was be studied using argon as an inert additional gas, in order to determine the mechanical and tribological properties and microstructure of a-C:H films. The films were deposited employing an asymmetrical bipolar pulsed-DC plasma enhanced chemical vapor deposition (PECVD) system and an active screen that worked as an additional cathode. The a-C:H films were analyzed according to their microstructure, mechanical, and tribological properties as a function of the amount of argon diluted in the acetylene. The film’s microstructure and the hydrogen contents were probed by means of Raman spectroscopy. The internal stress was determined through measurement of the change in the substrate curvature by means of a profilometer, while nanoindentation experiments allowed to determinate the hardness and the elastic modulus of the film. The friction coefficient and wear resistance of the films were determined using a tribometer, while the adhesion of the films was evaluated via the scratch test. In order to improve the a-C:H films’ adhesion to steel substrates, a thin amorphous silicon interlayer was used. The results showed that the atmosphere of argon diluted in acetylene induced modifications in the properties of the a-C:H films. Hard, adherent, low-stress, and high wear resistant a-C:H films were deposited on steel substrates using a combination of a modified and asymmetrical bipolar pulsed-DC PECVD system, an active screen as additional cathode, and acetylene-argon atmospheres. The use of an amorphous silicon interlayer improved the a-C:H films’ deposition onto steel substrates. These results suggest that the used methodology represented a step forward for thin film growth by using lower pressure and higher plasma density than the conventional PECVD system and may represent a new and useful alternative for mechanical and tribological applications.

4:30pm B2-2-10 Low Temperature Plasma Deposited Silicon Oxycarbide Films using Organosilicon for Polycarbonate Glazing, S.E. Lee, H.S. Jang, YoungChun Park ([email protected]), Handong Global University, Korea To improve the abrasion, scratch and chemical resistances of polycarbonate, which can be used as a replacement for glass, silicon oxycarbide films were deposited on it at low temperatures by using a SLAN ECR plasma. The SLAN ECR plasma source has a high plasma density and can thus rapidly deposit films with good mechanical properties at low temperatures. Before the film deposition, Ar and O2 plasma treatments were performed for 1 min each in order to improve the adhesion between the film and the polycarbonate substrate, and then the silicon oxycarbide films were deposited from gas mixtures of octamethylcyclotetrasiloxane(OMCTS), O2, and Ar gas onto polycarbonate and c-Si substrates at room temperature without heating the substrates. Pressure, gas flow rate (OMCTS, O 2, Ar), and deposition time have been fixed at 10 mTorr, 10 sccm, and 5 min, respectively. The properties of deposited thin films were observed by varying the plasma power from 1.2 to 2.0 kW. The transparent silicon oxycarbide films were deposited, and the average transmittance over the visible range exceeds of 90 % for all samples regardless of the deposition conditions. The deposition rates of the films are high, more than 500 nm/min. As the plasma power increases, the deposition rate is increased. When O2 and Ar are used as the plasma gas at plasma power of 2.0kW, the maximum deposition rates are 713.2 nm/min and 1058.8 nm/min, respectively. The hardness of the films also increases as the plasma power increases. When O2 and Ar are used at plasma power of 1.7kW, the

Monday Afternoon, April 20, 2015

1:50pm B3-2 Investigation of Corrosion and Adhesion Property of Diamond-like-carbon andNitrogen Doped Diamond –Like- Carbon on Ti-6Al-4V, Santu Bhattacherjee, Q. Yang ([email protected]), University of Saskatchewan, Canada Diamond -like- carbon (DLC) thin films is promising to enhance the durability and service performance of Ti-6Al-4V for engineering application due to DLC’s superior mechanical, chemical and biomedical properties. However, DLC suffers from poor adhesion to Ti alloys because

10

of the high internal stress introduced by ion-bombardment and the large expansion coefficient difference with Ti alloy. In this research, ion beam deposition using an end-hall ion source was used to prepare DLC and Ndoped DLC on Ti-6Al-4V alloys and pre-deposition of high density diamond nanoparticles by microwave plasma enhanced chemical vapour deposition was employed to address the adhesion issue. The structure and properties of the obtained samples were characterized by various advanced techniques. The results show that incorporation of diamond nanoparticles can significantly enhance the adhesion and doping of nitrogen reduce internal stress, and thus the corrosion resistance in NaCl solution is significantly improved

examined by analysis of the wear surface. From the obtained surface analytical results, it was suggested that the DLC-Si films exhibited a low friction property caused by the adsorbed water on Si-OH under the dry sliding condition. However, DLC-Si films have not been able to be used in many applications due to their weak adhesion to a steel substrate. Thus, we developed the preactivation surface process prior to the DLC-Si films, which have a strong adhesion to steel substrates. The developed coating process has a significant potential for application in various machine components. This technology can be applied to automobile parts such an engine components and drive parts, as well as machine tool parts, dies and jigs. In this session, I will review the DLC-Si coating technology for an automobile application, and share the latest data about their friction performance in tribological tests.

2:10pm B3-3 Diamond-like Amorphous Carbon Layer Deposited by Inductively Coupled Plasma System for Next Generation Dry Etching Hard Mask, SeJun Park, D. Kim, S. Lee, J. Nam, J. Won ([email protected]), Samsung Electronics, Republic of Korea As a feature size of semiconductor decreases, a new hard carbon mask film with the high etching selectivity and high transparency is demanded. An amorphous carbon film with both properties of high etching selectivity and high transparency could not have been accomplished using existing method such as Capacitively Coupled Plasma (CCP) type system. This study shows a successful synthesis of the diamond-like amorphous carbon Layer (DACL) film with high selectivity and high transparency using Inductively Coupled Plasma (ICP) type plasma system which could control the plasma density and ion impingement energy independently. DACL films were deposited from a mixture of C3H6, He and Ar, using conventional ICP system which is the device fabrication equipment with the 300mm-sized wafer. The substrate was 300mm-sized Si wafer. Raman analysis showed that DACL film contained high ratio of sp3 bonding in the film and the bias power to substrate directly controlled the ratio of sp3 bonding, density of film and k (extinction coefficient) by the change of ion impingement energy. The dry etching selectivity of DACL film was linearly changed with the film density and compared to current carbon hard mask, DACL film enhanced the dry etching selectivity more than 30%.

3:30pm B3-7 Sputtering-based Routes for High-rate Synthesis of Dense and Hard Amorphous Carbon Thin Films, Asim Aijaz ([email protected]), Uppsala University, Angstrom Laboratory, Sweden, K. Sarakinos, U. Helmersson, Linköping University, Sweden High-rate synthesis of dense and hard amorphous carbon (a-C) thin films using conventional magnetron sputtering based methods such as direct current magnetron sputtering is challenging. This is due to low sputtering yield of C as well as difficulty in generating highly ionized C fluxes which are essential for synthesizing dense and hard a-C structures such as diamond-like carbon (DLC). In this contribution, we present sputteringbased routes for high-rate synthesis of dense and hard a-C thin films using high power impulse magnetron sputtering (HiPIMS). We compile and implement a strategy for generating highly ionized carbon fluxes using Nebased HiPIMS discharge that entails energetic electrons as compared to Arbased HiPIMS discharge facilitating the generation of highly ionized C fluxes as well as a-C thin films with mass densities in the order of 2.8 g/cm 3 and film hardness exceeding 40 GPa. In order to address the issue of low deposition rate, we couple a hydrocarbon gas (acetylene) with Ar- and Ne-based high density discharges generated by HiPIMS based processes. Appropriate control of gas phase composition and energy of the ionized depositing species leads to a route capable of providing ten-fold increase in the deposition rate of a-C film growth compared to Ar-HiPIMS discharge. This is achieved without significant incorporation of H (< 10 %) into the films that exhibit relatively high hardness (> 25 GPa) and mass density (~2.32 g/cm3). Using our experimental data together with Monte-Carlo computer simulations and data from the literature we suggest that: (i) dissociative reactions triggered by the interactions of energetic discharge electrons with hydrocarbon gas molecules is an important additional (to the sputtering cathode) source of film forming species and (ii) film microstructure and film hydrogen content are primarily controlled by interactions of energetic plasma species with surface and sub-surface layers of the growing film. Key words; Diamondlike carbon, HiPIMS, HPPMS, hydrogenated amorphous carbon, ionized PVD

2:30pm B3-4 Hardness, Wettability and Electrical Conductivity of Hydrogenated Carbon Coatings Deposited by a Plasma Beam Source, Martin Fenker ([email protected]), K. Petrikowski, fem Forschungsinstitut Edelmetalle & Metallchemie, Germany Amorphous hydrogenated carbon (a-C:H) coatings have been deposited by plasma-activated chemical vapor deposition (PACVD) by using a plasma beam source (PBS). The PBS utilizes a capacitively coupled plasma excited by radio-frequency (27,12 MHz). Acetylene (C2H2) is conducted into the PBS as precursor gas. The properties of the a-C:H coatings are changed by varying the C2H2 partial pressure (p(C2H2)) and the substrate temperature (100-500 °C). Increasing the p(C2H2) leads to a decrease of the ion energy of the condensing carbon species. The a-C:H coatings have been deposited onto glass, silicon and stainless steel substrates. The hardness and density of the coatings was measured by instrumented indentation tests and X-ray reflectivity, respectively. The wettability was acquired by water contact angle measurements. The electrical conductivity was recorded by a four-point-probe. The hydrogen content was analyzed by carrier gas hot extraction method. The hardness was found to decrease with increasing p(C2H2) and at higher substrate temperature and is correlated to the density of the a-C:H coatings. The reason for the reduced hardness with increasing p(C2H2) is the decrease in ion energy. Therefore the generation of sp3 bonded carbon is reduced (less kinetic energy for subplantation) and the number of sp2 bonded carbon is increased. The change of the hydrogen content and the water contact angle is correlated and discussed with respect to the changes of the a-C:H film properties.

3:50pm B3-8 Friction and Wear Performance of Multilayered aC:H:Al Coatings, Laureline Kilman ([email protected]), Oerlikon Sorevi, France, C. Jaoul, M. Colas, P. Tristant, C. DublancheTixier, E. Laborde, SPCTS, France, F. Meunier, Oerlikon Sorevi, France, O. Jarry, Oerlikon Metaplas, Germany Hydrogenated amorphous carbon (a-C:H) thin films are among the best coating solutions for the reduction of automotive fuel consumption because of its very good tribological properties. Friction losses are indeed one of the main sources of energetic consumption in an automotive engine. 80 % of friction occurring in the valve train system is only due to the cam-follower contact, representing 20 % of the total losses in the engine. That is why the reduction of friction coefficient in dry and lubricated conditions is still in demand. Quite high values for hardness are also required to withstand the severity of this contact. Nowadays, DLC coatings are a standard and well recognized solution but research development is still necessary to improve the performance’s baseline of standard DLC regarding friction performance without impact on wear resistance. Many metallic elements have been introduced in the DLC (Diamond-Like Carbon) matrix to modify their tribological properties. In particular, elements which are not able to form carbide phases like Al enable to benefit from doping without altering the matrix properties. Al-DLC films are produced in an industrial coater by a hybrid PECVD - magnetron sputtering process using different power on the Al target to explore various Al/C ratios. X-ray photoelectron spectroscopy is performed to determine the chemical composition of the films and the structure is observed by Raman spectroscopy. Then hardness is measured by nanoindentation. Finally, tribological tests are performed with an alternative ball-on-disc tribometer to measure wear resistance and friction coefficient in dry and lubricated conditions.

2:50pm B3-5 Development of Si-Containing DLC (DLC-Si) Coatings for Automobile Application, Hiroyuki Mori ([email protected]), Toyota Central R&D Labs., Inc., Japan INVITED Diamond-like carbon has excellent tribological properties such as high wear resistance and low friction. At present, DLC films are of significant interest for automobile parts, because they possess the potential to reduce the friction coefficient under various sliding conditions. We focused on the silicon-containing DLC (DLC-Si) films produced by the DC-PACVD, and its method features a considerably higher deposition rate, higher throwing power, and lower equipment cost and treatment cost compared to conventional methods such as RF-PACVD and sputtering. Therefore, it has a significant potential for wide applications in various industries including the automobile one. Furthermore, the DLC-Si films shows tribological properties different from those of the conventional DLC film: i.e., low friction in a poorly lubricated atmosphere like dry, water, fuel, etc. The influence of the silicon content in the DLC-Si films on the friction property of the films was evaluated by a tribological test. In addition, the low friction mechanism of the films was

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For a static configuration, a-C:H coatings are doped from 0.5 to 11.5 at. % of Al and compared to a standard pure DLC. Tribological tests in dry conditions show a friction reduction from 0.21 to 0.04 by increasing the Al content to 4.7 at. %. In lubricated conditions, Al containing DLC with more than 2 at. % of Al showed a too low wear resistance to be able to evaluate the friction reduction. In order to overcome this issue and to combine wear resistance with friction decrease, multilayer coatings with non-linear Al content have been designed and evaluated.

5:10pm B3-12 Site-selective Coating of Carbon Protective Layer on Sub-micron Trenches Using Plasma CVD, Masaharu Shiratani ([email protected]), X. Dong, K. Koga, N. Itagaki, H. Seo, Kyushu University, Japan, G. Uchida, Osaka University, Japan Carbon films include plasma polymer films, amorphous carbon films (diamond-like carbon, DLC), CVD diamond films as well as graphite films [1, 2]. DLC is an amorphous network solid, containing a high fraction of carbon sp3 sites, but also sp2 sites and hydrogen. DLC films have attractive properties, such as high mechanical hardness, wear resistance, optical transparency and chemical inertness and hence have widespread applications as protective coatings in several areas such as car parts, microelectromechanical systems (MEMS) and as magnetic storage disks. Siteselective coating of the carbon protective layer on trenches is one of the concerns to realize coatings on submicron wide trench substrates. So far, we have succeeded in Site-selective coating of Cu films on trench, and have realized sub-conformal, conformal and anisotropic deposition, for which Cu is filled without being deposited on sidewall of trenches, using a H-assisted plasma CVD method [3-6]. We have applied the method to carbon protective layer on trenched substrates in order to control deposition profile [7, 8]. Here we have demonstrated three kinds of deposition profiles of carbon films on substrates with submicron wide trenches using H-assisted plasma CVD of Ar + H2 + C7H8. The three deposition profiles are subconformal, conformal and anisotropic deposition, for which carbon is deposited on top and bottom of trenches without being deposited on sidewall of trenches. Experimental deposition profiles are determined by the balance between deposition of carbon containing radicals and etching by H atoms. Irradiation of ions hardens films and hence decreases the etching rate. When the etching rate surpasses the deposition rate of carbon containing radicals, no deposition takes place there. Eventually we have realized site-selective coating, coating on top surface, on bottom surface, on sidewall surface, or combination of them on trenches. Acknowledgements: Work supported by MEXT, JSPS, and JST. [1] J. Perrin, et al., J. Vac. Sci. Technol., A16, 278 (1998). [2] M. Shiratani, et al., Jpn. J. Appl. Phys., 2, 505 (2001). [3] M. Shiratani, et al., Sci. Technol. Adv, Matr., 36, 4752 (1997). [4] K. Takenaka, et al., J. Vac. Sci. Technol., A22, 1903 (2004). [5] K. Takenaka, et al., Pure Appl. Chem., 77, 391 (2005). [6] K. Takenaka, et al., Thin Solid Films, 506-507, 197 (2006). [7] J. Umetsu, et al., Surf. Coat. Technol., 202, 5659 (2008). [8] X. Dong, et al., J. Phys. Conf. Ser. 518, 012010 (2014).

4:10pm B3-9 DLC Coatings with its Unique Properties and its use in Multiple Market Segments, Ton Hurkmans ([email protected]), IHI Ionbond Inc., USA INVITED Its industrial implementation took a while, but the wide family of Diamond Like Carbon coatings (“DLC”) has found its way in many different markets and applications. The combination of achievable coating properties through different deposition techniques and process settings have led to a wide range of engineered materials. These coatings are typically deposited at very mild processing temperatures, making it applicable to a wide range of substrate materials. Today’s industrial coating machines make the deposition of such DLC materials affordable for many industries and applications. One of the ongoing challenges is to process it cheaper and faster to even further increase the penetration in the market place. In general the family of amorphous DLC materials is well known for a high hardness, relatively low Young’s modulus, low coefficient of friction, chemical inertness, biocompatibility, semi-conductor properties, IR transparency, wettability behavior, and distinct black and grey colors. The only weak property is the in general low temperature stability. Addition of elements like Si help to increase it, but it is still less stable than mostly known for ceramic hard films. DLC coatings are rarely deposited as a single layer material. In most cases multi-layer and nano-layer configurations are formed in order to gain extra advantages out of the DLC layers. A common multi-layer approach is to start with a metallic layer in order to achieve sufficient adhesion between the desired DLC coating and the substrate material of choice. Pre- and/or post-processing steps are common in order to get maximum benefits out of the applied DLC materials. The key feature to the tool industry is the chemical inertness in combination with high hardness. In forming or machining of aluminum based alloys there is much less sticking of the aluminum to either dies or cutting edges. The high intrinsic hardness increases the abrasive wear resistance of Si fillers in the aluminum alloys. Anti-sticking behavior improvements are also seen in processing materials like rubbers and food. Besides tools to make products, many products are coated themselves with multiple variations of DLC. Depending on the tribo-system in play, specific coating properties are selected to obtain maximum benefits of applying the coatings. DLC coatings have found their way in heavy duty machinery, including aerospace and oil and gas, as well as consumer products. Among consumer goods one can think of cars, motor cycle shocks, golf gear, cutlery, medical devices and implants, and hard disk drives.

5:30pm B3-13 Effects of Normal and Shear Stresses in Rolling and Mixed Mode Contact on the Wear and Delamination of a WC/a-C:H Tribological Coating, Behzad Mahmoudi, The University of Akron, USA, C.H. Hager, The Timken Company, USA, G.L. Doll ([email protected]), The University of Akron, USA The focus of this research is to ascertain the maximum contact stress that a WC/a-C:H coating can withstand in rolling and mixed mode contact. The specific coating under study is a WC/a-C:H thin film with a microstructure specifically optimized to withstand high stress cycle rolling contact. For example, bearings that utilize this optimized coating on the rolling elements are able to achieve more than 3.5 times more stress cycles than bearings operating with commercially available WC/a-C:H coatings on the rolling elements. To determine the maximum contact stress that the optimized WC/a-C:H coating can withstand in rolling and mixed mode contact, experiments were conducted on various combinations of coated discs and rollers in a three disc on roller tribometer. Contributions of surface roughness, slide to roll ratio, and substrate hardness on coating performance were studied. Observations gleaned from the experimental results include that the coating on an isotropically finished roller can withstand contact stresses as high as 2.5 GPa with no measurable wear or delamination in a pure rolling condition. Roughness of the coated component plays a crucial role in coating wear, coating delamination, and wear on the uncoated counterpart. Nonuniform stress concentrations in coated versus uncoated contacts also affects the proclivity of the coating to delaminate from the substrate. Finally, increasing the slide to roll ratio in the experiments increases the shear stresses in the contact and reduces the maximum normal stresses that the coating can withstand.

4:50pm B3-11 Thick DLC Deposition by MF-AC PECVD Process, Hiroshi Tamagaki ([email protected]), J. Haga, A. Umeda, H. Ito, Kobe Steel, Ltd., Japan Thick diamond like carbon (DLC) coatings up to 17 microns were deposited by a MF-AC PECVD system. This new deposition system features a unique method to generate plasma for deposition, which applies a mid-frequency AC voltage between substrates divided into two groups that are connected to two outputs of an AC power supply. Because the discharge plasma is held between two groups of substrates, this new configuration results in high rate deposition of hydrogenated DLC coating with long term stabilities so that the relatively thick film can be deposited. The depositions were carried out at an industrial scale unbalanced magnetron sputtering equipment with 4 sputtering cathodes, 6-axes planetary rotary substrate table and with effective loading space of 450mm in diameter and 600mm in height. After etching and interlayer formation by sputtering, depositions of 2-17micron thick DLC coatings were carried out under 3Pa of acetylene and by applying MF-AC power of 3kW range. The deposition rate for the substrates on 2-fold rotation fixtures under full load conditions was 5-6microns/hr and 2-17microns thick DLC coatings were obtained by adjusting deposition time. The hardness of DLC coatings was almost constant around 20GPa whereas the thickness was varied from 2 to 17microns.

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The optimization of design and detailed investigation are being carried out to increase pyroelectric voltage and the measurement for thermal isolation effect of Porous-Si is underway. [1] Wei C.S., Lin Y.Y., Hu Y.C., Wu C.W., Shih C.K., Huang C.T., Chang S.H. Sens. Actuators A. 128,18–24, 2006. [2] Hsiao C.C., Huang K Y and Hu Y C. Sensors. 8, 185–92, 2008. [3] Heiland G. and Ibach H. Solid State Communications. 4,353-354, 1966. [4] Stolyarova S., Baskin E., Nemirovsky Y. Journal of Crystal Growth, 360,131–133, 2012.

Fundamentals and Technology of Multifunctional Thin Films Room: Sunrise - Session C4-2 Thin Films for Energy Related Applications Moderator: KinMan Yu, Lawrence Berkeley National Laboratory, USA, James Partridge, RMIT University, Australia

2:30pm C4-2-4 Electronic Band Structure Engineering of Highly Mismatched ZnO1-xTex Alloy Synthesized by Pulsed-Laser Deposition, Min Ting ([email protected]), University of California Berkeley, USA, R. dos Reis, Lawrence Berkeley National Laboratory, USA, M. Hettick, A. Javey, S. Mao, University of California Berkeley, USA, K.M. Yu, W. Walukiewicz, Lawrence Berkeley National Laboratory, USA It has previously been shown that alloying of Zinc Telluride (ZnTe), with ZnO modifies the band structure of ZnTe by the anticrossing interaction between extended conduction band (CB) states with localized O states at ~0.2 eV below CB edge of ZnTe [1]. On the other hand, incorporating Te into ZnO is expected to modify the valence band (VB) of the ZnO matrix through the valence-band anticrossing interaction between localized Te states at ~1 eV above the VB edge of ZnO and extended VB states of ZnO. The interaction leads to the formation of a new Te-derived VB edge above that of ZnO. The large upward shift of the VB edge could lead to stable ptype doping, and results in a strong reduction of the ZnO band-gap toward the visible range, making this material suitable for solar energy conversion devices[2]. In this study we synthesized ZnO1-xTex alloys with Te composition x < 0.23 by using pulsed laser deposition. We found that alloys with x < 0.06 are crystalline with a columnar growth structure while samples with higher Te content are polycrystalline with random grain orientation. It was found that Te atoms are randomly distributed with no observable clustering. Optical measurements show that incorporation of a small concentration of Te (x~0.01) red shifts the ZnO optical absorption edge by more than 1 eV. The minimum band gap obtained in this work is 1.8 eV for x = 0.23. The optical properties are consistent with the modification of the valence band of ZnO due to anticrossing interactions of the localized Te states with the ZnO valence band extended states. X-ray photoelectron spectroscopy (XPS) results confirm the upward shift of the valence band in ZnO 1-xTex alloys. The optical absorption results were explained using the band anticrossing model with the Te level located at 0.95 eV above the VB edge of ZnO and the anticrossing coupling constant of 1.35 eV. Combining these results with our previous work on band anticrossing in Te-rich alloys [1] allows the prediction of the compositional dependence of the band gap as well as the conduction and the valence band offsets in ZnO1-xTex alloys over the full composition range. The large Te- induced upward shift of the VBE in Orich ZnO1-xTex could alleviate the notorious p-type doping problem in ZnO [3]. Effects of doping with different group V acceptors (N, As, Sb) on electrical properties of ZnO1-xTex will be discussed. [1] K. M. Yu, et al., Phys. Rev. Lett. 91, 246403 (2003). [2] A. Janotti, et al., Rep. Prog. Phys.72, 126501 (2009). [3] E. Fortunato, et al. (2007). MRS Bulletin, 32, pp 242-247.

1:30pm C4-2-1 Surface Polarity Effects and New Hydrogen-related Complexes Observed in the High-resolution Luminescence from ZnO, Roger Reeves ([email protected]), University of Canterbury, New Zealand INVITED Zinc oxide (ZnO) is a wide-band gap semiconductor at the heart of new gallium-indium-zinc-oxide (GIZO) transparent optoelectronic materials that are now deployed as transparent TFT’s in many state-of-the-art displays. However, despite an existing pathway for zinc-oxide based devices there remain some significant stumbling blocks in forming a complete understanding of the basic ZnO optical properties. The low temperature luminescence from ZnO remains completely dominated by emission from defect-related sources. Our low-temperature photoluminescence (PL) experiments reveal more than 10 different excitonic features involving electron hole-pairs bound to different impurities and second order exciton effects. A challenge when comparing samples of ZnO is that the separation between such excitonic features is comparable to experimental accuracy. Thus careful calibration is required before definitive statements can be made about the defects contained within a particular sample. Variations in PL emission from different crystallographic faces show intriguing effects that hint at the strong influence of the ionic character of ZnO surfaces. Interestingly surface polarity dependent PL can be modified by both annealing and metal coverage indicating that PL may also play a diagnostic role in device processing. A clue to understanding such ZnO properties is to look at the role of hydrogen. Hydroxl groups on the surfaces appear to act as donors creating unusual 2-D surface electron gases that are possible sources of the polarity differences. Additionally, hydrogen implanted into the bulk material is observed to create new emission lines from hydrogen-other-defect complexes. This work will present current results from our luminescence studies of ZnO surfaces following treatment processes including annealing and ion implantation. 2:10pm C4-2-3 Porous Silicon Buffer Layer Effect on ZnO Pyroelectricity, Kenan Cicek, University of Bristol, UK, T. Karacali ([email protected]), Ataturk University, Turkey Pyroelectricity is the property of certain materials that generates voltage by temperature variations. The position of the atoms within the crystal structure of these materials slightly changes by simply heating/cooling the material. The displacement of the atoms will alter the polarization state which will result a temporary voltage across the crystal. The zinc oxide semiconductor is one of the materials that possesses great pyroelectric feature. Crystallinity and orientation of zinc oxide thin film play a crucial role in this property. In most studies, ZnO nanostructures are deposited on sapphire substrates in order to obtain a c-axis oriented thin film which is the most thermodynamically favorable and preferred orientation for pyroelectric applications [1,2,3]. Although sapphire has the same hexagonal type lattice structure with ZnO, it is expensive and hard to find in large size compared to silicon. However there is a large lattice missmatch between ZnO and silicon. Porous silicon can be the solution that reduce the degree of missmatch and a suitable substrate for c-axis oriented growth [4]. Porous silicon is not only integrated with silicon, but it also is easy to fabricate and low cost. In this study the pyroelectrical characteristic of ZnO thin film has been investigated as a sensing element for a pyroelectric sensor application. In order to observe the effect of porous-Si layer, the thin films were deposited on both Si and porous-Si/Si substrates. The results taken via XRD, AFM and SEM indicated that, the ZnO/porousSi layers exhibited a dominant peak of (002) plane which means that the film was grown with c-axis orientation. Moreover results showed that ZnO film has larger grains on porous-Si/Si substrate than the thin film on Si substrate and a rough surface. The pyroelectric analysis shows that the device with porous-Si/Si substrate has considerably high pyroelectric coefficient compared to Si substrated device. In addition the pyroelectric voltage obtained by porous-Si device is also higher than Si device.

2:50pm C4-2-5 Solar Selective Coatings for High Temperature Concentrating Solar Power: Design, Deposition and Ageing Behaviour Characterization, Borja Coto ([email protected]), J. Barriga, IK4TEKNIKER, Spain, H. Cachafeiro, Aries Ingeniería y Sistemas S.A, Spain, J. Goikoetxea, U. Ruiz-de-Gopegui, IK4-TEKNIKER, Spain Concentrating Solar Power (CSP) based on parabolic trough receivers is a well established and mature technology to obtain clean energy. Currently, there are around 3 GW of power plants installed world-wide. Nevertheless, there are issues that need to be addressed in order to improve the positioning of this technology in the energy mix. One key issue is to increase the performance of the plant to obtain higher productivity reducing the cost of energy. To this purpose it is necessary to increase the working temperature from current 400ºC to 600ºC. In this sense, it is necessary to have solar selective coatings with good spectral selectivity values which must be able to stand the new higher requirements. On the other hand, the lifetime required for the solar receivers operating in a power plant is 25 years. Currently, there is a lack of standard accelerated tests for solar collectors for high temperature operation. This is a problem to introduce in the market coatings to work at higher temperatures. Thus, it is important to understand how coatings the solar selective coatings behave in terms of degradation of their optical properties when working at high temperatures. Solar selective coatings are obtained by means of a nanostructured multilayer stack. Each layer plays a different role in order to achieve

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spectral selectivity values suitable for CSP and optical design is necessary to obtain an optimal multilayer stack with the required properties. Thus the composition and thickness of the layers must be carefully designed and controlled during the deposition process. In this work, multilayer selective nanocoatings are proposed and analyzed as candidates for 600ºC working temperature applications. Hence, alternatives such as Al and Mo as infrared reflector mirror layer to avoid thermal losses and Si3N4 and Al2O3 matrices for the absorber cermet are designed and deposited in combination with Al2O3 antidiffusion barrier layer and SiO2 antireflective top layer. The proposed coatings are deposited by means of a preindustrial magnetron sputtering equipment able to coat 4 meter long tubes. The coatings obtained have been analyzed with regard to the degradation behavior of the solar selectivity values at high temperatures.

Tribology and Mechanical Behavior of Coatings and Engineered Surfaces Room: Royal Palm 4-6 - Session E2-2 Mechanical Properties and Adhesion Moderator: Johann Michler, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland, Etienne Bousser, Ecole Polytechnique, Canada, Fan-Bean Wu, National United University, Taiwan 1:30pm E2-2-1 Electrical Resistance Response of Environmental Barrier Coated, Melt Infiltrated SiC/SiC CMCs Subjected to Tensile Loading Under High Heat-flux Thermal Gradient Conditions, Matthew P. Appleby ([email protected]), D. Zhu, NASA Glenn Research Center, USA Environmental barrier coating (EBC) coated ceramic matrix composite (CMC) systems are currently being investigated for use as turbine engine hot-section components in extreme environments. It therefore becomes critical to understand their response to environmental exposure and performance under thermo-mechanical loading conditions. Electrical resistance (ER) monitoring has recently been correlated to tensile damage accumulation in SiCf/SiC CMCs, and the focus of this study is to extend the use of ER to evaluate high-temperature, thermal gradient fracture of EBC/CMC systems. Tensile strength tests were performed at high temperature (1200° C) using a laser-based heat flux technique. Specimens included as-produced SiCf/SiC CMCs and coated SiCf/SiC substrates that had been exposed to simulated combustion environments in a high-pressure burner rig. Localized stress-dependent damage was determined using acoustic emission (AE) monitoring and compared to full-field strain mapping using a high-temperature digital image correlation (DIC) technique. The results of which are compared with in-situ ER monitoring, and post-test inspection of the samples in order to correlate ER response to damage evolution.

3:10pm C4-2-6 The Origin of In Solution-processable Bilayer Organometal Halide Hybrid Solar Cells, Y.Y. Yu ([email protected]), Rih-Sheng Chiang, Ming Chi University of Technology, Taiwan The bilayer solar cells based on Active layer and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) by a solution process were fabricated and the effect of Active layer thickness on the cell efficiency was investigated.The results show that the power conversion efficiency (PCE) of 4.7% under simulated AM 1.5G irradiation (100 mW cm2). As the thickness of Active layer increases to 80 nm, a higher PCE of 7.0% could be obtained. This study indicates that the high exciton diffusion efficiency is enabled by the long diffusion length of Active layer relative to its thickness. Furthermore, the low exciton binding energy of Active layer implies that exciton splitting at the Active layer/ PC61BM interface is very efficient. 3:30pm C4-2-7 LiFePO4-xNy Thin Film Electrodes Coated on Carbon Fiber Modified Current Collectors for Pseudocapacitors, K.-F. Chiu, S.H. Su, H.-J. Leu, Wei-Chieh Huang ([email protected]), Feng Chia University, Taiwan LiFePO4-xNy thin films have been sputter deposited on micron carbon-fibers (MCFs) under N2/Ar/H2 mixture gas as electrode materials for pseudocapacitors. The MCFs were fabricated using thermal chemical vapor deposition on stainless steel substrates as current collectors. Various amounts of nitrogen were introduced and the gas contents were controlled by the flow ratios of N2 to Ar/H2. The LiFePO4-xNy thin films coated on the surface of MCFs can be observed by field emission scanning electron microscopy. The electrochemical properties of LiFePO4-xNy thin films were characterized using cyclic voltammogram and charge-discharge processes. The LiFePO4-xNy thin film electrode deposited under the optimal N2 content exhibits a high specific capacitance of 722 F/g at 1 A/g. Even at a current as high as 20 A/g, it still delivers a capacitance of 298 F/g. The pseudocapacitors with LiFePO4-xNy thin film electrodes shows no significant capacity fading after 1000 cycles at 1 A/g. The results indicate that nitrogen-doped can improve the electrochemical performance, and LiFePO4-xNy can be a potential candidate as an active material for pseudocapacitors.

1:50pm E2-2-2 Room Temperature Viscoplasticity of Nanocrystalline Nickel Thin Films, G. Mohanty, J. Wehrs, EMPA (Swiss Federal Laboratories for Materials Science and Technology), Switzerland, Brad Boyce ([email protected]), Sandia National Laboratories, USA, M. Hasegawa, L. Philippe, J. Michler, EMPA (Swiss Federal Laboratories for Materials Science and Technology), Switzerland Room temperature creep and stress relaxation occurs in all metals, but its contribution is typically negligible, especially below the yield strength. However, nanocrystalline metals are particularly susceptible to this timedependent plasticity. While creep and stress relaxation are most commonly measured with tensile specimens, micropillar compression offers a smallscale uniaxial technique that is particularly amenable to thin films. In this study, we employ a stable, displacement-controlled in-situ SEM indenter and unusually large micropillars to precisely measure stress relaxation in electroplated nanocrystalline Ni thin films. The observed stress relaxation is significant: even well below the yield strength, under constant displacement the stresses relax by ~5% within 5 minutes; in the work hardening regime, stress relaxes by ~10% in 1 minute. A logarithmic fit of the relaxation curves is consistent with an Arrhenius thermal activation of plasticity and suggests an activation volume in the vicinity of ~10 b3. Repeated relaxation cycles permit the estimation of the rate of exhaustion of the mobile dislocation content. Finally, these measurements are compared to similar measurements performed on free-standing thin film tensile coupons. Both methods yield similar results, thereby validating the applicability of pillar compression to capture time-dependent plasticity.

3:50pm C4-2-8 Structural and Photo-electric Properties of Cuprous Oxide (Cu2O) Thin Films Prepared by Ion-beam-assisted Deposition (IBAD), Che-Kai Chang, Ming Chi University of Technology, Taiwan, C. Li, National Yang Ming University, Taiwan, J.H. Hsieh ([email protected]), Ming Chi University of Technology, Taiwan In this study, cuprous oxide (Cu2O) films were prepared by Ion-BeamAssisted Deposition (IBAD) using with varied Ar/O2 ratios and ion bombardment rate. The effects of ion bombardment rate and Ar/O2 ratios on structural and photo-electric properties were the purpose of this study. These prepared films were characterized by using UV–VIS photometer, four-point probe, and X-ray Diffractometry. The XRD results showed the films were composed of Cu2O and CuO phases depending on the process parameters. These Cu2O thin films deposited with too much or too less oxygen would transform into the CuO or Cu phase. Cu 2O had the highest transmittance and crystallinity when the oxygen flow rate was set at 13.5% and the anode current increased to 0.2A. However, too much ion bombardment may disrupt the film structure, which resulted in lower transmission. The optical spectra of the ion beam were examined using OES. It was found the O*/Ar* ratio peaked with the increase of anode current, then, decreased. This trend was consistent with the variation of optical and electrical properties.

Monday Afternoon, April 20, 2015

2:10pm E2-2-3 Orientation Dependent Mechanical Properties Of Metal-ceramic Nanolaminates, Jon Molina-Aldareguia ([email protected]), Y. Lingwei, IMDEA Materials Institute, Spain, C. Mayer, N. Chawla, Arizona State University, USA INVITED Nanoscale multilayers, made up of alternating layers of two materials with layer thickness in the nm range, have been the subject of an increasing number of studies in the past 10 years due to their exceptional high strength at room temperature. Their unique properties are mainly a result of the high density of interfaces, which change the standard mechanisms of plastic deformation and fracture, when the layer thickness is below ~100 nm. However, little is known about their anisotropic mechanical behavior due to the lack of appropriate testing techniques adequate for thin films up to date. With the development of novel nanomechanical testing techniques, like micropillar compression, it is not feasible to test the mechanical response of nanolaminated thin-films under uniaxial testing as a function of the orientation between the loading axis and the layers. In this talk, we will show the very different mechanical response displayed by Al/SiC

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multilayers, when compression is applied parallel, perpendicular and at 45º with respect to the layer direction, at temperatures between RT and 150ºC. The results reveal that the flow stress of the Al layers, which is layer thickness dependent, and the interface strength play a major role on the overall strength of the nanolaminate, when compression is applied perpendicular to the layers. However, the development of significant compressive stresses parallel to the layers triggers the formation of shear bands. The role of layer waviness on the shear band formation will be discussed.

3:30pm E2-2-7 Microstructure-scale Measurements and Simulations of Surface Deformation in Columnar Tantalum Multicrystals, Corbett Battaile ([email protected]), H. Lim, J. Carroll, Sandia National Laboratories, USA Most engineering materials have complex microstructures that can affect their properties in various ways. Metals are usually polycrystalline, and their inherently heterogeneous crystallographic nature can produce strong variations in deformation behavior at the grain (i.e. micron) scale. In small components, or when deformations are localized by defects or intentional geometry (e.g. holes or fillets), the details of grain-scale deformation can dictate the material's performance. In this work, we used micron-scale digital image correlation (μDIC), electron backscatter diffraction (EBSD), and finite element analysis to measure and predict, respectively, the evolution of surface strains and crystallographic orientations during the tensile deformation of columnar tantalum multicrystals containing only a few grains in the gauge section. These measurements are compared to crystal plasticity finite element simulations of the subgrain surface strain fields, and the predictions provide an accurate estimate of the location of failure initiation. We will outline the μDIC, EBSD, and crystal plasticity finite element methods; describe the procedure by which large-grained tantalum multicrystals were fabricated; and discuss the validation of the simulations' predictions against the experimental data.

2:50pm E2-2-5 Time and Temperature Dependence of Viscoelastic Stress Relaxation in Al and Al Alloy Thin Films, A.W. Huang, National Chung Hsing University, Taiwan, R. Vinci, W. Brown, Lehigh University, USA, C-H. Lu, C-C. Wu, Ming-Tzer Lin ([email protected]), National Chung Hsing University, Taiwan Metal thin films are using as capacitance switches in microelectromechanical systems (MEMS). Problems with long-term reliability, however, set limits on the lifetimes of MEMS capacitance switch applications. The better the thin films can resist relaxation, the longer the lifetime of the MEMS device. Al thin films have been used as capacitance switches, but they have only a weak resistance to relaxation and therefore a shorter lifetime. Solid strengthening can improve the mechanism of the material without decreasing other mechanisms. We added Mg to Al thin films in order to increase the stress relaxation resistance. The viscoelastic behavior of pure aluminum thin film in comparison with thin films of 12.63 ％ Mg and 16.30 ％ Mg are investigated by using bulge testing. Adding Mg in pure Al thin films significantly decrease the relaxation behavior and increase the mechanism of thin film. The result shows the more Mg content in Al thin films the more resistance of thin films. The results of experiments show the normalize modulus decreasing less with a greater content of Mg. This result proves that adding more different atoms can obstruct the movement of dislocation and enhance the mechanism of Al thin films. It shows that Al-Mg thin films have better relaxation resistance than Al thin films and thus serve as a better material for capacitance switches.

3:50pm E2-2-8 Measurement of Fracture Toughness in Thin Films by the Indentation Pillar Splitting Tests: Developments and Limitations, Marco Sebastiani ([email protected]), "Roma TRE" University, Italy The analysis of deformation and failure mechanisms in small-scale devices and thin films is a critical issue, not yet solved. In this presentation, we describe the recently proposed indentation pillar splitting test for the analysis of toughness in a series of thin film materials. Cohesive finite element simulations are used for analysis and development of a simple relationship between the critical load at failure, pillar radius, and fracture toughness for a given material. A series of additional simulations were performed in order to investigate the effect of the ratio between the elastic modulus and the yield strength on the critical load for pillar splitting. An explanation for the load instability during pillar’s indentation and the correlation with indentation cracking on homogeneous materials are then given. Micro-pillars are then produced by Focused Ion Beam (FIB) ring milling, being the pillar diameter approximately equal to its length; this ensures full relaxation of pre-existing residual stress in the upper portion of the specimen. Nanoindentation splitting tests are performed in-situ and the deformation mechanisms corresponding to each class of materials have been investigated. Obtained results on ceramics compare well with the independent measurements obtained by other techniques on the same samples. The limitations of the method are finally discussed. In particular, a minimum pillar’s diameter for the nucleation and growth of a crack during indentation is identified and quantified for a wide range of materials properties. The end result is that testing of a metallic or polymeric material would require loads and pillar diameters that are ~5 orders of magnitude greater than for ceramic materials. Finally, the influence of substrate’s stiffness of splitting load is described, and proper corrections are proposed.

3:10pm E2-2-6 Determination of Intrinsic Stresses in Coatings by Multi-axial Indentation, M. Fuchs ([email protected]), Saxonian Institute of Surface Mechanics, Germany, H. Grüttner, M. Nieher, Steffen Weißmantel, University of Applied Sciences Mittweida, Germany, N. Schwarzer, Saxonian Institute of Surface Mechanics, Germany It is impossible to determine the intrinsic stresses of a coated/uncoated surface by normal indentation measurements without a reference sample having known intrinsic stresses, because such experiments do not provide enough linear independent information to calculate several unknowns. Therefore, multi-axial indentation measurements, namely a lateral-force indentation which registers load and displacement in normal and tangential direction to the sample surface, in combination with a physical analysis of these experiments (lateral-force indentation analysis) [1] taking the layered structure into account [2] will be used to determine the intrinsic stresses in the coatings (regardless of their origin like thermally or mechanically induced) in terms of biaxial normal stresses. In this work, the experimental and the analysis procedure of this combined method will not only be introduced, but also demonstrated taking two samples of ta-C coatings on Si with different stress states. The superhard tetrahedral amorphous carbon (ta-C) films with low internal stress were prepared by a combination of pulsed laser deposition [3] and pulsed laser annealing [4] on silicon (100) substrates. The 500 nm thick taC films were found to have up to 85% sp3 bonds and a hardness of up to 83 GPa. By means of the laser pulse annealing (tempering), developed at the laser institute of the University of Applied Sciences Mittweida, it is feasible to set the intrinsic stress of the resulting layers to a defined value or even zero. The intrinsic stress results of the ta-C films of both samples determined by lateral-force indentation analysis have been verified by comparison with results derived from substrate bending using Stoney’s formula. Finally, a critical discussion of both methods for determination of intrinsic stress will be part of this work. [1] N. Schwarzer, J. Mater. Res., vol. 24, no. 03, pp. 1032–1036, 2009. [2] N. Schwarzer, J. Tribol., vol. 122, no. 4, pp. 672–681, 2000. [3] G. Reiße et al., patent DE10319205 A1, 11-Nov-2004. [4] G. Reiße et al., patent DE10319206 B4, 14-Aug-2013.

4:10pm E2-2-9 Interfacial Structure Effects on the Mechanical Behavior of Layered Nanocomposites, Nathan Mara ([email protected]), J. Carpenter, W. Mook, S. Zheng, Los Alamos National Laboratory, USA, T. Nizolek, University of California Santa Barbara, USA, S. Pathak, Los Alamos National Laboratory, USA, S. Kalidindi, Georgia Institute of Technology, USA, J. Wang, Los Alamos National Laboratory, USA, T. Pollock, University of California, Santa Barbara, USA, I. Beyerlein, Los Alamos National Laboratory, USA INVITED In this presentation, we report on the plastic deformation mechanisms in lamellar nanocomposites processed via Severe Plastic Deformation as a function of decreasing layer thickness. We process bulk Cu-Nb nanolamellar composites from 1 mm thick polycrystalline sheet down to layer thicknesses of 10 nm using Accumulative Roll Bonding. This technique has the advantage of producing bulk quantities of nanocomposite material, and can result in rolling textures, interfacial defect structures, and deformation mechanisms very different from those seen in nanolamellar composites grown via Physical Vapor Deposition methods. Mechanical behavior as evaluated via micropillar compression, nanoindentation, and bulk tension/compression will be discussed in terms of the effects of interfacial structure and content on deformation processes at diminishing length scales, and defect/interface interactions at the atomic scale. This class of materials has also been shown to exhibit radiation damage tolerance under ion irradiation at elevated temperatures. Radiation damage tolerance

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of nanomaterial containing different types of interfaces (twin, grain boundaries, and heterophase interfaces) will be presented, as well as a novel spherical nanoindentation test technique for quantifying the effects of ion irradiation on the stress-strain response of metallic materials.

New Horizons in Coatings and Thin Films Room: California - Session F1 Nanomaterials and Nanofabrication Moderator: Yukiko Yamada-Takamura, Japan Advanced Institute of Science and Technology, Japan, Sumit Agarwal, Colorado School of Mines, USA

4:50pm E2-2-11 Numerical and Experimental Evaluation of Critical Variables for Multilayer Coatings Failure under Indentation Loads, Newton Fukumasu ([email protected]), University of São Paulo, Brazil, E. Prados, Federal University of ABC, Brazil, A. Tschiptschin, R. Souza, University of São Paulo, Brazil In indentation tests, the material response to the loading and unloading cycle is commonly used to evaluate the mechanical properties of single and multiple layer coatings. For example, in addition to hardness and elastic modulus, the failure behavior of these materials can be analyzed based on specific signatures on the load-displacement (P-h) indentation curves. In this work, experimental and numerical methods were applied to analyze the failure behavior of single and multi-layer coatings deposited on compliant substrates. A recent publication defined a technological parameter (F1), which indicates the possibility to observe the nucleation and propagation of cohesive cracks in single-layer coatings under indentation loads. This work further explores this parameter with experimental nano-indentation tests and expands the parameter definition to include characteristics of multilayer coatings. Two sets of multilayer coatings (different number, mechanical properties and thicknesses of each layer) were produced and experimentally evaluated. The numerical model was based on a rigid indenter in contact with the coated compliant substrate. The mechanical behavior of the coating layers was based on the properties of brittle elastic materials, while the substrate was assumed as a ductile elastic-perfectly plastic material. Both cohesive and adhesive failure models were included in the analyses, allowing the evaluation of failure modes in the coating and/or at discrete interfaces (between layers and between the coating and the substrate). Results allowed not only an experimental analysis on the parameter F1 for single layer systems, but also the identification of the relevant variables to define the threshold of cohesive failure in multilayer systems.

1:30pm F1-1 Growth and Characterization of Heteroepitaxial III-N Semiconductor Films using Atomic Layer Epitaxy, Charles Eddy, Jr. ([email protected]), N. Nepal, V. Anderson, J. Hite, U.S. Naval Research Laboratory, USA Aluminum nitride (AlN), gallium nitride (GaN), and indium nitride (InN) semiconductors and their corresponding ternary films, such as InGaN, offer attractive properties, with high breakdown fields and widely tunable direct band gaps. Currently, III-nitrides are primarily deposited with molecular beam epitaxy and chemical vapor deposition. The addition of Atomic Layer Epitaxy (ALE) to the possible growth techniques is driven by the need for even thinner films integrated into complex heterostructures, somthing that is increasingly difficult to achieve by conventional techniques. Furthering the attraction of ALE is the promise of lower growth temperatures that allow the deposition of a winder range of indium containing ternary films. Here we report on ALE in a plasma-equipped Ultratech/Cambridge Nanotech atomic layer deposition system to grow AlN, GaN, and InN at temperatures significantly lower than needed for molecular beam epitaxy (MBE) and metalorganic chemical vapor deposition (MOCVD).[1] In growing epitaxial materials, the substrates and corresponding surface preparation procedures are important. The substrates include silicon(111), sapphire, and MOCVD gallium nitride on sapphire, as well as graphene.[2] For InN on a-plane sapphire, the expected wurtzitic hexagonal phase was heteroepitaxially grown for films deposited in the temperature window of 220 to 260 C, well below the typical minimum 450 C temperature used in MOCVD. At an even lower temperature, 183 C, the heteroepitaxial InN on a-plane sapphire was discovered to be cubic phase with a NaCl structure, a phase of InN that had before been unreported.[3] Heteroepitaxial AlN films were grown on GaN/sapphire at a much lower temperature (500 C) than by MOCVD, typically 1100 C or more. Finally, GaN has been included in ALE deposited ternaries in the relatively low temperature window of 250400 C even as its optimization continues. The ALE grown III-N films have carbon and oxygen contamination that hinders their immediate use in many applications, and improving film purity is a major focus. In addition, initial depositon of indium containing ternaries indicates that more stoichiometries are available by ALE than by MOCVD. The possibilities for greater use of III-nitrides are apparent even at the early stages of progress in atomic layer epitaxy. Further characterization during and after deposition of the films should lead to materials suitable for use in high electron mobility transistors, as well as optoelectronic devices. [1] N. Nepal et al., Appl. Phys. Lett. 103 082110 (2013) [2] N. Nepal et al., Cryst. Growth Des. 13 1485 (2013) [ 3 ] N. Nepal et al., Appl. Phys. Express 6 061003 (2013)

5:10pm E2-2-12 Investigation on Plastic Behavior of HPPMS CrN, AlN and CrN/AlN-Multilayer Coatings using Finite Element Simulation and Nanoindentation, K. Bobzin, RWTH Aachen University, Germany, N. Bagcivan, Schaeffler Technologies GmbH & Co. KG, Germany, T. Brögelmann, R. Brugnara, Mostafa Arghavani ([email protected]), RWTH Aachen University, Germany, T.S. Yang, Y.Y. Chang, S.Y. Chang, National Formosa University, Taiwan A comprehensive investigation of hard coatings deposited by Physical Vapor deposition (PVD) requires, in addition to the elastic properties, a precise knowledge of their plastic behavior. Nanoindentation is a commonly applied method to determine the hardness and the elastic modulus of PVD coatings. Determination of flow curve of PVD thin coatings using a combination of nanoindentation and finite element (FE) simulation is subject of actual research. In the presented work, nanoindentation tests with a Berkovich tip, in combination with its FEM simulation, were used to determine the plastic flow curves of CrN, AlN and CrN/AlN-multilayer coatings deposited by High Power Pulse Magnetron Sputtering (HPPMS) PVD on cemented carbide substrates. A high resistance of these coatings against plastic deformation is of great importance as it extends the lifetime of the coated tools in tribological applications. The applied FEM model is used to simulate the indentation process. The details of the FEM model and the applied experimental and analytical methods are discussed. The determination of the simulative flow curves is carried out by finding the coefficients of the considered plastic flow model. The coefficients are determined by comparing the experimental and simulated load– displacement curves, and additionally, by correlating the residual indents after nanoindentation in simulation and experiment. The correlation is performed by depth profiling of the residual indents using atomic force microscopy (AFM). The plastic behavior of the studied coating systems was analyzed combining the determined flow curves and the results of the residual indents. The influence of the nanostructure on the plastic behavior is explained in this work. The results show a higher resistance of the nanostructured CrN/AlN-multilayer coating against plastic deformation compared to CrN and AlN. This is due to the nm-sized alternating layers and the fine grained morphology of the CrN/AlN-multilayer compared to the pure coatings, which hinders the dislocation motion.

Monday Afternoon, April 20, 2015

1:50pm F1-2 Fast Rate and High Efficiency Cluster-assisted Epitaxy by Mesoplasma CVD, Makoto Kambara ([email protected]), S. Wu, L.W. Chen, K. Sawada, T. Ichimaru, T. Yoshida, The University of Tokyo, Japan INVITED Wafer equivalent single crystalline silicon thick film is expected as an ideal active layer of the next generation Si solar cells. Fast rate epitaxial deposition process is required for production of such films over a wide area especially to serve giant electronics. Mesoplasma CVD can be one of the potential candidates since one can envision that the plasma in the 0.1–10 Torr range will combine the advantages of both low pressure and thermal plasmas; that is, high processing rates are expected by a direct transport of radicals and/or atoms on a plasma flow while attaining relatively low damage as a result of low electron temperatures. In fact, we have demonstrated deposition of the epitaxial thick films with Hall mobility of ~240 cm2V-1s-1 at rates as fast as 700 nm/sec using trichlorosilane (TCS) as a source gas under the mesoplasma condition. Uniqueness of this process also includes that the material yield for Si epitaxy from TCS has reached ~60% while the state-of-the-art SIEMENS process for Si production reaches conventionally ~30%. In the process of the mesoplasma CVD, source gas is decomposed completely to the atomic state in the plasma flow and is directed toward the substrate. Within the thin thermal boundary layer present ahead of the film growth surface, liquid-like Si clusters are expected to form as deposition precursors during rapid condensation of high temperature Si vapor, as evidenced by the SAXS in-situ detection of formation of Si clusters of

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which constituent Si atoms are loosely bound [1,2]. Molecular dynamics simulation has also revealed that such a cluster deforms upon impingement on a film growth surface and facilitates instantaneous and spontaneous atom rearrangement to maintain the epitaxial relationship [3]. Owing to its unique cluster characteristics, epitaxial deposition over a wide area of 20 mm × 80 mm on a moving substrate was confirmed even by the injection type CVD with inductively coupled plasma, as far as the substrate temperature is maintained higher than 500 ˚C [4]. Furthermore, non-equilibrium chemical effects of the mesoplasma environment, i.e. freezing-in the high temperature chemistries during rapid condensation and generation of atomic hydrogen, are both found to quite effectively suppress the thermodynamically stable Si-Clx molecule formation at the film deposition region, leading to a significant improvement in the Si production yield [5]. References: [1] Kambara, et al., JAP, 99 (2006) 074901. [2] Diaz, et al., JAP, 104 (2008) 013536. [3] Chen, et al., J. Phys. D, 46 (2013) 425302-1. [4] Wu, et al., Sci. Technol. Adv. Mater.,15 (2014) 035001. [5] Wu, et al., Plasma Chem. Plasma Process, 33, (2013) 433.

diamond particles (nanodiamonds). I will discuss these results in detail, highlighting the potential advantages of plasma processing for carbon nanomaterial synthesis and modification. [1] W-H. Chiang and R. M. Sankaran, Nat. Mater.8, 882 (2009). [2] S. W. Lee and R. M. Sankaran, J. Phys. Chem. Lett. 3, 772 (2012). [3] A. Kumar et al., Nat. Comm.4, 2618 (2013). 3:50pm F1-8 Prospects of the Physical Vapor Deposition Synthesis of 2D Materials, Andrey Voevodin ([email protected]), Air Force Research Laboratory, USA, C. Muratore, University of Dayton, USA, N. Glavin, J. Hu, A. Waite, J. Bultman, A. Safriet, M. McConney, M. Check, R. Stevenson, R. Naguy, J. Anders, Air Force Research Laboratory, USA The practical realization of electronic, sensor, solar conversion and other devices made of two-dimensional (2D) materials with semiconductor and dielectric properties critically depends on the availability of suitable synthesis routes. These synthesis routes can allow for reproducible, substrate agnostic, scalable, and cost effective processing technologies. Results from the most recent research in developing physical vapor deposition (PVD) methods to grow few layer thick 2D materials from transition metal dichalcogenides with semiconducting behavior (such as MoS2 and others) and boron nitride with dielectric behavior are presented. Pulsed DC magnetron sputtering from MoS2 targets and pulsed laser deposition from BN targets were optimized to produce 2D materials on a variety of substrate materials, such as amorphous silicon oxide and glass, highly oriented sapphire and graphite, as well as flexible polymers at areas of over one square inch. Thermodynamically driven tendency to form islands is overcome by maximizing ad-atom atomic mobility through the control of incident flux ionization state, energies, and densities, while avoiding defect formation (i.e., vacancy creation by sputtering of S atoms). In-situ XPS was used to analyze the film stoichiometry and initial growth stages. Pin-hole and gap free, 2D MoS2 and BN films of 1-5 nm thickness were produced over 4 cm2 areas as confirmed by TEM, conductive AFM, Raman and electrical probe measurements. 2D MoS2 semiconducting and 2D BN dielectric films characteristics were verified with electrical probe and field effect transistor device studies.

2:30pm F1-4 Synthesis and Characterization of Zeolite Y Coating on Mild Steel, Keerthana Sivakumar ([email protected]), Coimbatore Institute of Technology, India, A. Santhanam, M. Natarajan, CIT, India, D. Velauthapillai, University College of Bergen, Norway, B. Rangasamy, PSG College of Technology, India Zeolite Y is synthesized in the current study by a simple Sol-Gel technique. We found that the crystal growth was controlled by varying the hydrogel synthesis time and the annealing temperature. The resulting products at various crystallization times and temperatures are studied with X-ray powder diffraction (XRD), Scanning electron microscopy (SEM), High resolution transmission electron microscopy (HRTEM), Polarization/Impedance studies. Microstructure and size in SEM images of the final Zeolite Y annealed at 300 oC revealed the formation of cubic structure. XRD analysis revealed the higher levels of crystallization at varying temperatures. Zeolites Y were dispersed in Poly ethylene glycol (PEG) in the ratio 1:20 and coated on mild steel for the formation of membrane. The membrane consisted of top layer with thickness of 1.32.0µm. Crystals in the top layer showed cubic morphology.

4:10pm F1-9 A Facile One-step Route of Synthesizing α-type MnO2/rGO Nanocomposites as Anode Materials for Lithium-ion Batteries, Shao-Chieh Weng, National Cheng Kung University, Taiwan, C.C. Chang, National University of Tainan, Taiwan, C.C. Ho, J.L. Huang ([email protected]), National Cheng Kung University, Taiwan Graphene nanosheet(GNs), consisting of a single layer of sp 2 carbon atoms arranged in honeycomb structure, with high surface area and high electron mobility values of 15,000 cm2V−1s−1 at room temperature, has attracted tremendous attentions in replacing graphite and to be used in anode active material of lithium-ion batteries(LIBs). α-type MnO2(α-MnO2) has attracted great interest as anode materials in LIBs for their high theoretical capacity, environmentally compatible, low cost, and special properties. The prospect of combining α-MnO2 and reduced graphene oxide(rGO) to obtain a synergistic effect of their respective merits is under consideration as a possible strategy for obtaining improved anode materials for high-power LIB applications. In this study, α-MnO2/rGO nanocomposites was synthesized via a facile one-step chemical route. Aqueous suspension containing MnCl2˙4H2O(α-MnO2 precursor) with graphene oxide(GO) sheets was reacted at 83 °C for 30 min. The morphology and structure of assynthesized nanocomposites were analyzed by field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy. It was found that due to the dissolution-crystallization and oriented attachment mechanisms, which enhanced the chemical interaction between GO and α-MnO2. In Li-ion batteries operating, rGO played role as an electronic conductive buffer layers to suppress the volume change of α-MnO2 and enhance the chargetransfer performance, and α-MnO2 played role as not only a spacer to suppress agglomeration and restacking of rGO but also redox site for enhancement of Li-storage capacity and ionic diffusion rate.

2:50pm F1-5 Synthesis of Nanotwins in Low and High Stacking Fault Energy Materials, Leonardo Velasco Estrada, A. Hodge ([email protected]), University of Southern California, USA Low and high stacking fault energy (SFE) materials such as Cu, Cu alloys (CuAl, CuZn, CuAg and CuNi), Al, and Al alloys (Al5052, Al5456, Al6013, and Al- 5.3 wt.% Mg) were sputtered in order to study nanotwinned (nt) structures. The SFE of the Cu and Cu alloys is relatively low (90% airborne bacteria, including antibiotic-tolerant persisters, on contact were killed within 10 min upon solar irradiation. Further experiments suggest that solar light in the near-infrared region may play dominant roles in the observed activity. This work suggests that rGO’s photothermal/photodynamic property confers rGO-based surface coating with effective antibacterial activity upon minutes of solar irradiation and sun may be alternative to a laser for potent photothermal/photodynamic cytotoxicity at ultralow irradiance.

Monday Afternoon, April 20, 2015

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2:30pm TS5-4 Direction and Sub-structures of Ionization Zones in DC Magnetron Sputtering, Yuchen Yang ([email protected]), J. Liu, Y. Qiu, A. Anders, Lawrence Berkeley National Laboratory, USA Fast imaging research of HiPIMS in the last few years has revealed the presence of dense, asymmetric, triangle shaped ionization zones that are more-or-less regularly spaced in the azimuthal direction. These zones have been observed to propagate at several 103 m/s, up to 104 m/s, yet much slower than the E x B drift velocity of electrons, which is on the order of 105 m/s [1]. In this work, we combine streak and frame imaging to study the plasma in DC magnetron sputtering. Systematic experimental studies were performed at very low currents (less than 1.2 A) for a range of pressures (from 0.1 to 2.7 Pa) in end-on and side-on views. We have discovered reverse direction, sub-structures within ionization zones, arched plasma flares, and zone structural changes greater than previously anticipated. In contrast to HiPIMS, the ionization zones in DC magnetron sputtering are much more elongated, with a wider “head” at the - E x B end of the zone. Increasing current and/or pressure splits the plasma from a single zone to multiple zones, and eventually, the zones merged and smoothed along the entire racetrack. The zones move with low velocities, on the order of 103 m/s, in the - E x B direction, which is the opposite of zone motion direction in HiPIMS. The pattern of zones along the racetrack is more-or-less azimuthally symmetric but depends on current and pressure of the process gas. In streak images we have also detected sub-zones moving in the same direction of electron E x B drift at high velocities on the order of 104 m/s. In close-up frame images, we have observed sub-structures of light intensity having patterns that match the local magnetic field lines, suggesting that they may have been caused by electrons drifting in the E x B direction while gyrating along the B field lines. The shape of the observed substructures were highly unstable. From side-on frame images, we have detected arched plasma flares jetting along the racetrack. The discovery of reversal direction, sub-structures, and plasma flares in DCMS greatly promotes the particle transport theory governed by presheath energization, with a modified potential hump structure model and zone-related instabilities and turbulence. [1] A. Anders, M. Panjan, Robert Franz, Joakim Andersson, and Pavel Ni, Appl. Phys. Lett. 103, 144103 (2013).

3:10pm TS5-6 Investigation of Gaseous By-products of Interaction of In-liquid Plasmas with Al during Plasma Electrolytic Oxidation, Aleksey Yerokhin ([email protected]), Y. Gao, The University of Sheffield, UK, Y.A. Gonzalvo, Hiden Analytical Ltd, UK, L. Snizhko, Ukrainian State University for Chemical Engineering, Ukraine, A. Matthews, The University of Sheffield, UK Plasma electrolytic oxidation (PEO) attracts significant interest for production of oxide ceramic surface layers with superior properties on lightweight metals. These layers are formed under the influence of plasma discharge triggered at the metal-electrolyte interface by high anodic potentials. Polarisation mode (direct, pulsed or alternating current) is known to affect surface morphology and phase composition but the mechanisms underlying such effects are not clear. Investigating by-products of reactions leading to the formation of the ceramic surface layers under conditions of plasma discharge can shed light on their mechanisms. In this work, we studied yield and composition of gaseous products evolved during PEO of Al carried out under DC, pulsed unipolar and bipolar polarisation. A MassStream mass flow meter (M+W Instruments) and a Hiden QGA-200 residual gas analyser were used to measure and analyse composition of the gaseous products. The results indicate that PEO can be treated as an electrochemical process with subsequent chemical reaction initiated by plasma-liquid interaction. Unexpected evolution of hydrogen on the anode is a result of thermochemical reaction between dispersed aluminium and aqueous electrolyte. Kinetics of aluminium oxidation depend on the presence of adsorbed layers and oxygen concentration at the plasmaelectrolyte interface. Pulsed unipolar and bipolar polarisation modes enhance oxide formation efficiency due to the reduced discharge duration suppressing gas evolution. 3:30pm TS5-7 Non-conventional Plasma and Sheath Diagnostics Related to Process Parameters, Holger Kersten ([email protected]), S. Bornholdt, V. Schneider, A. Spethman, T. Trottenberg, Institute of Experimental and Applied Physics, Kiel University, Germany INVITED In addition to well-established plasma diagnostic methods (Langmuir probes, optical emission spectroscopy, mass spectrometry etc.) we perform examples of “non-conventional” diagnostics [1] which are applicable in technological plasma processes for particle formation, surface structuring and thin film deposition: i) The total energy influx from plasma to substrates can be measured by special calorimetric probes (passive or active, respectively) as well as by fluorescent micro-particles. Examples for rf-discharge and magnetron sputtering will be provided [2-5]. By comparison with model assumptions on the involved plasma-surface mechanisms the different contributions to the total energy influx can be separated. ii) For a variety of thin film applications it is essential to determine the sputtering yield as well as the angular distribution of sputtered atoms. For this purpose we developed a novel and rather simple method, the so-called sputtering-propelled instrument (SPIN) [6]. It is stack nearly without friction and exposed to a vertical ion beam, rotating due to momentum transfer by the released particles, i.e. sputtered target atoms and reflected ions. Comparison of the measurements with simulation yields valuable information on the sputtering mechanisms and support validation of related sputter codes. The angular distribution of sputtered particles has also been measured by a sensitive pendulum which is commonly used for thrust measurements in ion beam sources for space propulsion systems. References [1] T. Trottenberg et.al., Plasma Phys. Control Fusion 54(2012) 124005. [2] H. Maurer, H. Kersten, J. Phys. D: Appl. Phys. 44(2011) 174029. [3] I. Levchenko, M. Keidar, S. Xu, H. Kersten, K. Ostrikov, JVSTB 31(2013) 050801. [4] K. Nishiyama et.al., J. Nucl. Mat. 438(2013), S788-S791. [5] H. Kersten, H. Deutsch, H. Steffen, et.al., Vacuum 63(2001) 385-431. [6] J. Rutscher T. Trottenberg, H. Kersten, Nucl. Instr. Meth. Phys. Res. B 301(2013) 47-52.

2:50pm TS5-5 Plasma Analysis of Inductively Coupled Impulse Sputtering by Investigation of Cu, Ti and Ni Species, Daniel Loch ([email protected]), Sheffield Hallam University, UK, Y.A. Gonzalvo, Hiden Analytical Ltd, UK, A.P. Ehiasarian, Sheffield Hallam University, UK Highly ionised pulsed plasma processes have helped to improve coating properties by enabling the control of flux of sputtered ion species. Deposition of magnetic materials, such as Nickel, is problematic with magnetron sputtering as the magnetic field necessary for the sputter process is reduced due to quenching of the magnetic field by the target material. With Inductively Coupled Impulse Sputtering (ICIS) we can remove the magnetron. To generate the plasma, pulsed RF power is applied to an internal coil. Ar ions are attracted to the target surface by utilising high power DC pulses on the cathode and initiate sputtering. The sputtered material is then ionised as it passes through the coil volume, creating a highly ionised metal flux to the substrate. For ICIS the creation rate for gas, metal and metal ion species are unknown. In the conducted experiments both DC and RF power supplies were running at a duty cycle of 7.5% and were synchronised to ensure the pulse on time was the overlapping. A power-pressure matrix was created to examine the influence on the plasma. At a constant pressure of 13 Pa the applied RF power was varied from 1000-4500 W, at constant applied RF power of 3000 W the pressure was varied from 3-26 Pa. The pulsed DC voltage to the target was kept constant at 1900 V. OES, energy resolved MS and I-V curve measurements were taken for each examined element. OES measurements for increasing power have shown a linear increase in intensity with increasing power. The slopes of gas and metal species in a log-log graph exhibit a factor 1 increase from the Ar neutral intensity for each excitation and ionisation step, suggesting electron collisions to be the main excitation mechanism. The IEDFs measured by MS show two sharp peaks, one high intensity peak at 20 eV which corresponds with the plasma potential and is ideal for increased surface mobility without inducing lattice defects. The second lower intensity peak, of high energetic ions, is visible at 170 eV. We will be discussing the voltage and current waveforms relationships of the slope factor β in an intensity-power graph, the IEDFs vs. power and pressure relations and the origin of higher energetic ions.

4:10pm TS5-9 Plasma Plume Characterization in Pulsed Laser Deposition of Ultra-thin Boron Nitride Films, Nicholas Glavin ([email protected]), Air Force Research Laboratory, USA, T. Fisher, Purdue University, USA, A.A. Voevodin, Air Force Research Laboratory, USA Few layer crystalline and amorphous boron nitride (BN) films produced by laser ablation exhibit large area, stoichiometric, pinhole free growth on a variety of substrate materials at much reduced temperatures from traditional CVD growth methods. By adjusting the incoming laser flux as well as the background pressure within the deposition chamber, a strict control of deposition rates, stoichiometry, and energies of incoming plasma species can be achieved. In this study, chemistry, energies, time of flight data, and

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specific component’s spatial distributions within the ablated plume were investigated using an ICCD camera with a spectrometer and characterized to determine optimal film growth conditions. Laser ablation occurred from a 248 nm KrF excimer laser from an amorphous boron nitride target in vacuum and in various pressures of nitrogen gas. The identification of energetic plasma species formed from background gas collisions, secondary excitation at the plume/substrate interface, as well as the increased dwell time of the excited species at the condensate surface are discussed and provide insight into understanding crystal growth at reduced substrate temperatures. Dynamics of the atomic and molecular species in the ablated plume were spectroscopically analyzed and used to optimize growth of 1-2 nm thick films over large areas, confirmed by techniques including Raman, AFM, TEM, and XPS.

plasma, the process parameters and the surface properties at different stages of the process will be presented and analyzed.

4:30pm TS5-10 Transient Analysis and Modeling for Diagnostic of Pulsed Bipolar Plasma Electrolytic Oxidation Process, Evgeniy Parfenov, A. Fatkullin ([email protected]), Ufa State Aviation Technical University, Russian Federation, A. Yerokhin, The University of Sheffield, UK, D. Lazarev, Ufa State Aviation Technical University, Russian Federation Currently plasma electrolytic technological processes attract significant attention as efficient and environmentally friendly alternatives to conventional electrochemical processes. Plasma electrolytic processes operate at high voltages from 100 to 1000 V which generate microdischarge plasma at the interface layer between the liquid electrolyte and a metal workpiece surface. The mechanism of plasma electrolytic oxidation involves complex combination of electrochemical, electrophysical, plasma and metallurgical processes, full understanding of which has not yet been reached. The aim of this paper is to propose and justify an equivalent circuit model for simulation of plasma electrolytic oxidation (PEO) electrical characteristics based on transient analysis for using it in process control. The transient analysis of the voltage and current waveforms recorded during plasma electrolytic oxidation of aluminium was performed. The decomposition of the experimental bipolar pulses uncovered three significant transients, two in the current, one in the voltage. The transients were approximated with a superposition of exponential functions which helped to propose an equivalent circuit diagram. Functions being the solutions for second order aperiodical transient process problem have been used for the analysis. The average value of R2 for all the fits is 0.94 which is consistent with the accuracy of the voltage stabilization. An inverse problem of an equivalent circuit synthesis was solved on the base of Kirchhoff’s differential equations, and its correctness was justified by a simulation using a circuit modelling software. It was shown that the components can be attributed to certain parts of the coating, and their values evolve with the coating growth. Investigation of the transients over all the experimental design shows that the time constants and steady values vary with the PEO treatment time and with the positive and negative pulse voltages. Therefore, the transient analysis of the waveforms will help to uncover the PEO electrolyzer equivalent circuit, and the evolution of its component values will help to evaluate the coating thickness and other surface properties during the treatment. Finally , the proposed method can be applied in a process control system for diagnostics of the unobservable surface properties during plasma electrolytic oxidation. 4:50pm TS5-11 Investigation of Plasma Nitriding Process by Absorption Spectroscopy, Vladimir Henrique Baggio-Scheid ([email protected]), D. Neves, Sao Jose dos Campos, Brazil In this work the glow discharge of a plasma nitriding process was investigated using absorption spectroscopy. A small hollow cathode, running inside the nitriding chamber, was used as line light source in the absorption measurements. Density profiles of sputtered atoms were measured in the cathode fall and negative glow. Furthermore, the emission signals of the gas species were also monitored. The aim of this work is to get a better understanding of the main atomic and molecular processes, which take place in plasma, in order to improve the nitriding process. Special attention was given to investigate the influence of the nitrogen content on the process. The cleaning discharge, conducted in an Ar/H 2 atmosphere prior to nitriding, was also investigated. Samples of mild steel AISI 1040 and low alloy steel AISI 4340 were used as substrates for characterization of the treatments. They were nitrided at a temperature of 723 K for 1 h in atmospheres with different nitrogen contents. The treated surfaces were analyzed with respect to composition, microstructure, crystallographic structure and Vickers microhardness. After Nitriding, a typical surface hardness of 430 HV0.05 and 820 HV0.05 was measured for the 1040 and 4340 steel, respectively. However, a decrease in hardness was observed due to decarburization in the cleaning discharge for temperatures above 700 K. The correlations between the measured densities of species in

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Tuesday Morning, April 21, 2015 thermal barrier coating on complex 3D parts has been developed. To model the coating thickness we use a first order approximation algorithm to calculate the intensity of the vapor as a function of the distance and relative source substrate deposition angle. The model allows complex substrate manipulation over two vapor sources. 3D part models are imported as .STL or other file formats by means of a simple Excel based user interface. The software then calculates the intensity of the vapor from single or multiple point emitters. To validate the basic model parameters an experimental program has been executed. The global cloud intensity can be simulated by a COS(Theta)^N power distribution where Theta is the cone angle from the center line of the emitter and N=2.5. This value yields satisfactory agreement of experiment and model. The model also accurately predicts partial shadowing on a rotating substrate such as e.g. observed with trailing edge masks. The microstructure in selected areas of the parts is modeled with an embedded atom model (EAM) molecular dynamics module. The microstructure for extreme substrate geometries is compared to the actual microstructure obtained by metallographic evaluation. The model for thickness and microstructure is in good agreement with the actual coating properties.

Hard Coatings and Vapor Deposition Technology Room: California - Session B1-1 PVD Coatings and Technologies Moderator: Alpana Ranade, GE Aviation, USA, Steffen Weißmantel, University of Applied Sciences Mittweida, Germany, Jyh-Wei Lee, Ming Chi University of Technology, Taiwan 8:00am B1-1-1 Multi-component High-entropy Materials: Suppressed Interdiffusion Kinetics and Dislocation-mediated Deformation for Applications to Diffusion Barriers and Hard Coatings, Shou-Yi Chang ([email protected]), S.Y. Lin, C.E. Li, National Chung Hsing University, Taiwan, S.J. Lin, J.W. Yeh, National Tsing Hua University, Taiwan INVITED Owing to high mixing entropies and sluggish diffusion, simple solidsolution and nanocomposite structures are typically formed in high-entropy materials (HEMs) with the equimolar incorporations of multi-principal components. The HEMs present many extraordinary properties including a good mechanical performance, a high thermal stability and an extreme interdiffusion resistance, and are promising for applications to diffusion barriers and hard coatings. Herein, high-entropy alloys (HEAs; unitary Ti to senary AlCrRuTaTiZr with different numbers of metallic elements) and their nitrides (HEANs; (AlCrTaTiZr)Nx, (AlCrTaTiZr)NxCy and (AlCrTaTiZr)NxSiz) as examples are presented. With more elements, the failure temperature of the HEAs increases from 550 to 900°C, and the activation energy of interdiffusion increases from 110 to 163 kJ/mole. The hardness (H), modulus (E), H/E and H3/E2 of the HEANs reach 35 GPa, 270 GPa, > 0.12, and > 0.4 GPa respectively; in deformed regions, the reversible activities of stacking faults are observed, suggesting suppressed dislocation activities and a high resistance to plastic deformation. Mechanistic analyses reveal that severe lattice distortions, a strengthened cohesion, a high packing density, and a nanocomposite structure increase the activation energy of atom motion by 55 kJ/mole and are believed to suppress the interdiffusion kinetics and dislocation-mediated plastic deformation of HEMs.

9:20am B1-1-5 Ion Energies in Cathodic Arcs: Charge Exchange Collisions Allow for the Revival of the Potential Hump Theory, André Anders ([email protected]), Lawrence Berkeley National Laboratory, USA Energetic deposition using cathodic (vacuum) arc plasmas is widely used to produce dense coatings for various applications. The most likely energy of ions is high, namely in the range from about 20 eV (carbon) to about 200 eV (tungsten), and somewhat less when process gas used. The origin of high ion energies has been the subject of research and debate for many decades. Early on, in the 1960s, a potential hump in front of the cathode was suggested to be responsible; however, this hypothesis was increasingly dismissed as all ions, regardless of charge state, seem to have the same velocity. Research on the ion charge state distributions indicated that charge exchange collisions have an important role for the charge of ions that arrive at a substrate or that are observed at a detector. In this contribution, the role of charge exchange collisions for ion velocities or energies is explored. It is shown that charge exchange collisions allow us to revive the potential hump hypothesis as such collisions remove the apparent conflict between electric field and gas-dynamic acceleration mechanisms.

8:40am B1-1-3 Dynamic and Structural Stability of Cubic Vanadium Nitride, Antonio Bighetti Mei ([email protected]), University of Illinois at Urbana-Champaign, USA, O. Hellman, California Institute of Technology, USA, N. Wireklint, Chalmers University of Technology, Sweden, C. Schlepütz, Argonne National Laboratory, USA, D. Sangiovanni, B. Alling, I. Abrikosov, Linköping University, Sweden, A. Rockett, University of Illinois at Urbana-Champaign, USA, L. Hultman, Linköping University, Sweden, J. Greene, I. Petrov, University of Illinois at UrbanaChampaign, USA Structural phase transitions in epitaxial stoichiometric VN/MgO(011) thin films are investigated using temperature-dependent synchrotron x-ray diffraction (XRD), selected-area electron diffraction (SAED), and resistivity measurements combined with high-resolution cross-sectional transmission electron microscopy (HR-XTEM), and ab-initio molecular dynamics (AIMD). At room temperature, VN has the B1 NaCl structure. However, below Tc = 250 K, XRD and SAED results reveal forbidden (00l) reflections of mixed parity associated with a non-centrosymmetric tetragonal structure. Upon cooling below Tc, reflections intensify following the scaling behavior I α (Τc - T)1/2. Resistivity ρ(T) measurements between 300 and 4 K consist of two linear regimes resulting from different electron/phonon coupling strengths in the cubic and tetragonal VN phases. The VN transport Eliashberg spectral function α2trF(ℏ ω), the product of the phonon density-of-states F(ℏ ω) and the transport electron/phonon coupling strength α2tr(ℏ ω), is determined and used in combination with AIMD renormalized phonon dispersion relations to show that anharmonic vibrations stabilize the NaCl structure at T > Tc. Free energy contributions due to vibrational entropy, often-neglected in theoretical modeling, are essential in understanding the room-temperature stability of NaCl-structure VN, and of strongly anharmonic systems in general.

9:40am B1-1-6 Decorative Colored Coatings on Metal Strips, Christoph Metzner ([email protected]), B. Scheffel, F. Fietzke, F.H. Rögner, Fraunhofer Inst. for Electron Beam and Plasma Tech. (FEP), Germany A great variety of coating materials can be obtained by methods of physical vapor deposition (PVD). Nearly all inorganic coating materials composed of metals, alloys and compounds can be realized. For instance high-quality oxide or nitride coatings can be produced by pulsed magnetron sputtering or by plasma-activated electron beam evaporation. The paper gives an introduction to the latest developments in relevant PVD technologies and presents some results for decorative purposes on metal strips. Interesting decorative effects were obtained by “Surface colored coatings” like nitride or carbide layers. Such compounds have a high hardness and a characteristic color. Gold-colored and well-adherent titanium nitride coatings with a micro-hardness up to 30 GPa could be deposited onto stainless steel strip by plasma-activated electron beam evaporation. Zirconium - Aluminum nitride layers were deposited by pulsed magnetron sputtering. The color of the layers can be adjusted by the composition of the compound in a wide range. “Interference colored coatings” can be made by thin transparent, mostly oxide layers like Silica, Zirconia or Titania. The color of the coatings can be adjusted by the layer thickness in a wide range. Pulsed magnetron sputtering is the most common deposition process. Nevertheless Titanium dioxide thin films were deposited on stainless steel strips by high-rate plasma-activated electron beam evaporation. The process is based on generation of titanium vapor and chemical reaction in a pure low-pressure oxygen atmosphere. Refractive index of titanium dioxide coatings was measured in the range of 2.3 to 2.5. This relatively high refractive index causes strong color effects based on thin film interference. It could be shown that scratch resistance of the coated steel surface was remarkably increased by deposition of thin fused quartz layers. These transparent coatings were prepared by plasma-activated evaporation of Silica. A further possibility to enhance the resistance against environmental impact is the final coating with organic and transparent materials. High hardness can be obtained by electron beam curing of the lacquer. This technology is useful for anti-fingerprint behavior too. On the other hand, by

9:00am B1-1-4 Modeling of Coating Thickness and Microstructure on Complex 3D Parts in an Electron Beam Physical Vapor Deposition Process, T. Wasfy, Indiana University, USA, Albert Feuerstein ([email protected]), P Apenouvon, D. McPherson, A. Fulton, M. Hoersten, Praxair Surface Technologies, Inc., USA Software for modeling the thickness distribution and microstructure of an Electron Beam Physical Vapor Deposition (EBPVD) process for ceramic

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applying the organic coating prior to PVD coating its smoothing effect for the metal strip can be used and therewith an enhancement of the decorative function can be reached.

11:00am B1-1-10 Hardness, Abrasion Wear and Optical Properties of Metal Containing a-C:H Coatings Made by rf Magnetron Sputtering, Jonathan Villalobos, J.L. Ampuero, C. Benndorf, A. Talledo ([email protected]), Universidad Nacional de Ingenieria, Peru Metal containing a-C:H, where metal = Cr, Ti and Ta, were deposited by rf magnetron sputtering on glass, as well as, metal-nitride-coated steel substrates. Coatings were analyzed by Raman Spectroscopy, Auger Electron Spectroscopy and X-ray diffraction. Vickers micro hardness and abrasion wear were measured on coatings deposited on steel. Optical Transmittance and Reflectance in the range 300-2500 nm were carried out on samples deposited on glass.

10:00am B1-1-7 New Trends , New Opportunity for Hybrid Technology – Duplex Coatings: Plasma Nitriding + PVD and PECVD, Pierre Collignon, PD2I - PerformCoat GmbH, France, Y. Sampeur, C. Kunz ([email protected]), PerformCoat GmbH, France One of the most perspective development directions of surface engineering is related to hybrid technologies, which best fulfill the expectations of the industry concerning the obtainment of adequate properties of the surface of tools or machine components. Duplex treatment is combined thermo-chemical treatment as Plasma Nitriding of the tool or components followed by: - PVD hard coatings deposition - PECVD low friction coating The nitrided layer increases the surface hardness and substrate resistance to plastic deformation and in the near-surface zone. The presentation is illustrated by few typical industrial applications. Since few years the Duplex treatment has proven successful in improving wear and fatigue resistance. This combination has been introduced successfully since few years for forming dies, aluminum dies casting, and forging dies. The Duplex treatment is made by adding devices in a PVD equipment to make the nitriding in a coating equipment. Now to introduce PLASMA NITRIDING +DLC means a Duplex /PECVD equipment we modified our plasma nitriding equipment to add special power supply to make the PECVD. The plasma nitriding process is followed by a low friction coating DLC by PeCVD technology. We get better adhesion that the best Metal / DLC , we have developed 2 different types of DLC one for wear and friction resistance and one for corrosion resistance. This technology offers many advantages: - very low running costs compare to the hybrid technology PVD/PECVD - Possibility to work on finished parts , precision parts which are carburized or full quenched require grinding after carburizing before DLC This technology offers a wide range of applications

Hard Coatings and Vapor Deposition Technology Room: Golden West - Session B4-1 Properties and Characterization of Hard Coatings and Surfaces Moderator: Uwe Beck, BAM Berlin, Germany, ChauChang Chou, National Taiwan Ocean University, Taiwan, Grzegorz Greczynski, Linköping University, IFM, Sweden 8:00am B4-1-1 Tribological Behaviour of Cathodic Arc Evaporated Ti-Al-N Based Hard Coatings, Stefan Glatz ([email protected]), J. Paulitsch, R. Hollerweger, Vienna University of Technology, Austria, R. Rachbauer, Oerlikon Balzers Coating AG, Liechtenstein, S. Kolozsvári, Plansee Composite Materials GmbH, Germany, P. Mayrhofer, Vienna University of Technology, Austria Efficiency and accuracy are highly important parameters for improving today’s industrial processes. Especially for forming and shaping of various materials, wear and friction are core issues. A possibility for adapting and hence improving of specific tribo-systems is the assessment of Ti-Al-N based hard coatings which can be further tuned to fit the particular application needs e.g. by changing deposition parameters or by alloying to form quaternary materials. This study focuses on the effect of different bias voltages, chemical composition, and thermal treatment on the tribological behaviour of physical vapour deposited Ti-Al-N based hard protective coatings. Therefore, we have performed pin-on-disc tests and estimated the evolution of the wear tracks and counterparts by non-contact optical profilometry, X-ray diffraction, and energy dispersive x-ray spectroscopy in order to characterize the structural and chemical development of various tribo-systems. Differences in wear behaviour are obtained if either the disc or the ball is coated or if both counterparts are coated. We show that the wear performance of Ti-Al-N coatings can significantly be improved by the development of quaternary Ti-Al-N based hard coatings.

10:20am B1-1-8 Effects of Annealing on NIR Shielding Properties of Cs-doped Tungsten Oxide Thin Films Deposited by Electron Beam Evaporation, Chak Seng Long, National Cheng Kung University, Taiwan, H.W. Lu ([email protected]), National Chin-Yi University of Technology, Taiwan, D.F. Lii, Cheng Shiu University, Taiwan, J.L. Huang, National Cheng Kung University, Taiwan There are great interests in near-infrared shielding properties for solar films and filter of solar cells over past decades. In this study, Cs xWO3 films were prepared by electron beam evaporation. The CsxWO3 films were characterized by X-ray diffraction, X-ray photoelectron spectroscopy and spectrophotometer. The microstructure and the effects of annealing on the near-infrared shielding properties were also investigated. The results showed that the near-infrared shielding properties of CsxWO3 films could be improved by annealing at 300-450 ˚C under pure H2 atmosphere, the amorphous of thin films could be transform into the crystalline. Especially, the 450 ˚C annealed CsxWO3 films in the pure H2 atmosphere showed high transmittance of visible light attaining to 70% and NIR shielding ratio attaining to 99%, respectively.

8:20am B4-1-2 Tuning Hardness and Fracture Resistance of ZrNbased Nanostructured Thin Films, S.P.Kumar Yalamanchili ([email protected]), Linköping University, Sweden, E. Jiménez-Piqué, Universitat Politècnica de Catalunya, Spain, N. Ghafoor, M. Odén, Linköping University, Sweden High film hardness is a necessary but not sufficient criterion to achieve good wear resistance, Instead a favorable hardness to toughness ratio is desirable, which is a long-standing materials development challenge. Here we present two different approaches to address the issue: (1) alloying to introduce microstructural variation such that plastic deformation and crack growth behavior is affected, and (2) multilayer architecture, where the epitaxially stabilized metastable phases are exploited to enhance both hardness and fracture resistance by stress-induced transformation toughening. The mechanical behavior of the films was evaluated by nanoindentation and extractions of transmission electron microscopy samples under the indent such that plastic deformation and crack patterns could be recorded. Reactive arc evaporation and reactive dual magnetron sputtering were used to grow the films. In the first approach the microstructure of the films was varied from columnar to nanocomposite by Si additions to ZrN. The deformation and crack growth behavior is altered by these microstructural modifications, i.e. homogeneous dislocation glide dominates in the columnar structure resulting in a higher resistance to plastic deformation compared to the relatively softer nanocomposite in which grain boundary mediated heterogeneous plastic flow dominates. The columnar structure also offers higher fracture resistance due to additional energy dissipation mechanisms such as crack deflections, which is not seen in the nanocomposite structure. In the second approach multilayer architecturing was used to tune both the hardness and fracture resistance of the films using ZrN/Zr0.63Al0.37N as a model system. Zr0.63Al0.37N is an immiscible material system that chemical segregates into nm-sized ZrN- and AlN-rich domainsduring high

10:40am B1-1-9 Hardness, Abrasion Wear and Corrosion Resistance of Multilayer Coatings Based on Titanium Nitride, Junior Asencios, K. Paucar, C. Benndorf, A. Talledo ([email protected]), Universidad Nacional de Ingenieria, Peru Multilayers TiN/AlN, TiN/TaN and TiN/NbN were deposited on silicon and steel substrates by dc magnetron sputtering. Structure and stoichiometry were obtained by X-ray diffraction and Auger Electron Spectroscopy, respectively. Vickers indentations with 5, 10 and 50 gf were observed by Scanning Electron Microscopy. In all cases Vickers Hardness was higher than 50 GPa. Abrasion wear was determined by the crater test. Corrosion resistance was determined by polarization curves in an electrolitycal cell with Ag/AgCl as reference electrode in a 0.01 solution of NaCl and 0.1 M of Na2SO4.

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the brittle tetragonal β-Ta, resulting in increased contact damage upon local loading and also in coating failure during simulator testing. [1] R. Hauert, et al. Surf. Coat. Technol. 233 (2013) 119. [2] K. Thorwarth, et al. Int. J. Mol. Sci. 15 (2014) 10527. [3] D. Bernoulli et al. Thin Solid Films 548 (2013) 157–161

temperature growth. The crystal structure of the AlN-rich domains varies from cubic (c) to wurtzite (w) structure as a function of Zr0.63Al0.37N layer thickness. Maximum fracture resistance is achieved through a stressinduced transformation toughening mechanism, where the epitaxially stabilized metastable c-AlN-rich domains transform in to a more volume consuming w-AlN phase when subjected to the external stress fields caused by indentation. Hardness maximum is achieved when the w-AlN-rich domains are semi-coherent with the c-ZrN-rich domains. This crystallographic relationship with incompatible slip systems causes coherency strains that collectively generate a formidable resistance to dislocation glide.

9:40am B4-1-6 Role of Droplets in the Phase Formation of Arc Evaporated (Al0.70Cr0.25Fe0.05)2O3 Coatings, Christian Koller ([email protected]), Vienna University of Technology, Austria, J. Ramm, Oerlikon Balzers, Oerlikon Surface Solutions AG, Liechtenstein, S. Kolozsvári, Plansee Composite Materials GmbH, Germany, J. Paulitsch, Oerlikon Balzers Coating Austria GmbH, Austria, P. Mayrhofer, Vienna University of Technology, Austria By alloying small amounts of Fe to (Al0.7Cr0.3)2O3 cathodic arc evaporated thin films a significant increase in hexagonal phase fractions can be attained. However, the reasons for the enhanced occurrence of hexagonal crystallitesis not yet satisfactorily determined. Therefore, the focus of the present work is set on incorporated macroparticles in (Al0.7Cr0.3Fe0.05)2O3 coatings and a potential correlation with the growth of distinct V-shaped hexagonal crystallites. Detailed transmission electron microscopy studies give strong indication for film growth of an α-phased solid solution (Al,Cr,Fe)2O3—at least partially—triggered by smaller spherical droplets. Local analyses of the chemical composition of these particles reveal an enrichment of Cr and—in particular—Fe. Contrarily, flat-shaped Al-rich particles indicate renucleation of cubic film growth, independent on the phase constitution on which the droplet is incorporated. Additional studies on other— predominant cubic phased—coatings demonstrate that respective effect is also present, albeit less frequent. According to present results we suggest, that the addition of Fe to powder metallurgically produced Al0.7Cr0.3 targets for arc evaporation processes in oxygen atmosphere significantly contributes to enhanced hexagonal crystal growth due to partial epitaxy on small Fe-rich particles.

8:40am B4-1-3 Phase Transformations During Annealing in Air and Vacuum Atmosphere in Arc Evaporated (Ti,Cr,Al)N Coatings Studied by In-situ High-energy X-ray Diffraction, Daniel Michael Ostach ([email protected]), Helmholtz-Zentrum Geesthacht, Germany Hard and wear resistant cubic (c)-(Ti,Al)N based coatings have many applications, such as protection of the underlying material and improved wear resistance. In the cutting tool industry, the improved wear resistance increases the lifetime of the coated tools. The mechanical properties of TiAlN deteriorates at high temperatures due to formation of the hexagonal (h) AlN phase, while by alloying of Cr in (Ti,Al)N coatings the detrimental effect of h-AlN on the mechanical properties can be reduced [1]. Further, the oxidation resistance of CrAlN coatings is improved compared to that of TiAlN [2], thus, a TiCrAlN coating could be expected to have improved high temperature properties under both oxidizing and non-oxidizing conditions. In this study, in-situ high-energy synchrotron x-ray diffraction studies during annealing in a vacuum or air atmosphere have been performed to study the phase evolution in (Ti,Al,Cr)N coatings. The results show that both the phase separation of the c-TiCrAlN phase as well as the growth of h-AlN depends on Al-content where a higher Al-content results in a faster growth of h-AlN in a vacuum atmosphere. Further, the effect of Al-content on the oxidation resistance of c-TiCrAlN during annealing in an air atmosphere was studied. The results reveal that in (TixCryAlz)N coatings with 38 < z < 60 at. % the oxidation behavior changes with Al-content. For coatings with z=0.48, the oxidation of the coating continues throughout the 3 h long annealing at a temperature of 1100 °C. In coatings containing higher Al-content and lower Ti-content, the amount of nitride phases does not decrease significantly after ~50 min of annealing suggesting that the oxide layer formed acts as a barrier for further oxygen diffusion into the remaining nitride coating. [1] R. Forsen, et al., J. Vac. Sci. Technol. A 30 (6), 061506-061508 (2012). [2] A.E. Reiter, et al., Surf. Coat.Technol. 200 2114 (2005).

10:00am B4-1-7 Erosion Resistance of CrN, TiN, CrAlN and TiAlN Coatings Deposited by Cathodic Arc Evaporation, Zuhair Gasem ([email protected]), N. Ankah, King Fahd University of Petroleum and Minerals, Saudi Arabia CrN, TiN, CrAlN, and TiAlN coatings were deposited on AISI 304 stainless steel by cathodic arc evaporation technique. Microstructural and mechanical properties of the resulting coatings were examined. Solid particle erosion tests were carried out at various impingement angles. The erosion scars caused by alumina particle impingement were examined using scanning electron microscopy. The erosion rates of the coatings were estimated using the mass loss. The results indicated that ternary nitride coatings containing Al (CrAlN and TiAlN) exhibited higher erosion resistance as compared to the binary counterparts without Al (CrN and TiN). TiN, CrAlN and TiAlN coatings exhibited lower erosion rates while CrN coating showed higher erosion rate under the same test conditions. The erosion mechanism at 90˚ for all coatings was characterized by brittle fracture with the formation of craters in random positions. The erosion scars observed at 30˚ and 45˚ were typical of ductile fracture.

9:00am B4-1-4 Properties and Characterization of Interfaces and Interlayers and the Correlation to Long-term Adhesion, Roland Hauert ([email protected]), K. Thorwarth, U. Müller, B. Weisse, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland, D. Bernoulli, R. Spolenak, ETH Zurich, Laboratory for Nanometallurgy, Switzerland INVITED We demonstrate that in case of a stable adhesion promoting interlayer, DLC coated articulating spinal-disk implants show no detectable wear up to 101 million articulations on a spine simulator - corresponding to about 100 years of articulation in vivo[1,2]. From the tribological point of view, this would allow to have a new generation of livelong articulating implants which do not generate wear particles and therefore will not trigger the known adverse effects to particles such as allergic reactions, pseudotumors and bone resorption. However, long term adhesion of the coating in-vivo is the main issue to be addressed. At each interface good mechanical adhesion is obtained by covalent chemical bonds resulting in a few atomic rows of a reactively formed interface material. The structure and composition of these interface materials, as well as an adhesion promoting interlayer, critically depend on the deposition conditions. It will be shown that even small amounts of oxygen contamination during deposition can change the composition and therefore also the corrosion properties of interfaces and interlayers. Delayed in-vivo delamination of the coating can then occur by slow crack growth due to stress-corrosion-cracking with delayed crack initiation, fatigue or by crevice corrosion. The adhesion tests such as scratch and Rockwell tests will only determine the fracture strength of an interface and are not addressing any corrosion related phenomena and may therefore generate false lifetime expectations in vivo. Especially critical is delamination by crevice corrosion since this process will not be accelerated by increased loads or by accelerated simulator testing [1]. Using biocompatible Ta as an adhesion promoting interlayer, its mechanical properties critically depend on the substrate surface and the feed gas used on deposition. On the one hand, by promoting a ductile body-centered cubic α-Ta phase with a TaN seed layer [3] the contact damage can be significantly reduced due to the plastic deformation of the interlayer material. On the other hand, residual oxygen or surface oxides will promote

10:20am B4-1-8 Effect of Phase Content on Fracture Toughness of ZrNxOy Coatings, Haw-Wen Hsiao, J.H. Huang ([email protected]), G.P. Yu, National Tsing Hua University, Taiwan Fracture toughness is a significant mechanical property in material applications. Recently, we proposed an energy-based method, internal energy induced cracking (IEIC), for measuring fracture toughness on hard coatings. This method was successfully applied on TiN, ZrN and TiZrN hard coatings. The results showed that the fracture toughness of randomtextured TiN hard coating was 16.7 J/m2 , within the extension of reported values. For ZrN hard coating, the results revealed that the fracture toughness varies with different texture. In addition, the results of TiZrN hard coating indicated that composition could influence the fracture toughness. However, there is little information available on the variation of fracture toughness of multiphase coatings with different phase contents. The major objective of this study was to investigate the effect of phase content on the fracture toughness. ZrNxOy hard coating, an adjustable thin film material, was chosen as a model system. Based on Griffith criterion, the release of elastic energy due to crack propagation is equal to the energy that creates two new surfaces, suggesting that fracture toughness is strongly related to the binding energy. ZrNxOy coating is composed of soft phase ZrO2 and hard phase ZrN. Since the binding energy of ZrN, ZrO 2 and that of interface between two phases are different, fracture toughness may vary with changing phase ratio. ZrNxOy coatings on Si substrate with different phase contents of ZrN and ZrO2 were deposited by adjusting the N2/O2 ratio

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of the reactive gases. The fracture toughness was measured following IEIC method. The residual stress, was assessed by laser curvature and XRD cos2αsin2φ methods, and the film thickness was measured by cross-sectional SEM image, from which the stored energy (Gs) could be calculated. The difference in stored energy before and after cracking was defined as the fracture toughness. Moreover, the critical thickness of coating could be predicted from the fracture toughness.

Fundamentals and Technology of Multifunctional Thin Films Room: Sunset - Session C3 Transparent Conducting Oxides and Related Inorganic and Organic Materials Moderator: Junichi Nomoto, Kochi University of Technology, Japan, Marco Cremona, Pontifícia Universidade Católica do Rio de Janeiro, Brazil

10:40am B4-1-9 Deformation of CrAlN/Si3N4 Nanocomposite Coating at Elevated Temperatures, Shiyu Liu ([email protected]), Singapore Institute of Manufacturing Technology, Singapore, J. Wheeler, J. Michler, EMPA (Swiss Federal Laboratories for Materials Science and Technology), Switzerland, X.T. Zeng, Singapore Institute of Manufacturing Technology, Singapore, W. Clegg, University of Cambridge, UK CrAlN/Si3N4 nanocomposite coatings with grains approximately 10 nm in size and surrounded by a grain boundary silicon nitride phase show a greatly improved wear resistance compared with conventional CrAlN coatings. This is generally attributed to the improvements in hardness, though there has been no clear understanding of how these coatings deform. In this work, micropillar compression was used to make direct measurements of the coating yield stress at both room and elevated temperatures. It is demonstrated, for the first time, that plastic flow at the theoretical yield stress can be obtained when the grain-size is sufficiently small, with shear yield stresses of ~ G/25 at room temperature, which extrapolates to ~ G/20 at 0 K. This suggests that the deformation occur by dislocation nucleation in the individual grains rather than by the formation of slip bands as is more often seen. The strain rate sensitivity of the coating flow stress was measured using nanoindentation at different strain rates, and it is shown that the deformation is determined by the CrAlN, rather than the grain boundary phase, suggesting that boundary effects should not influence the flow behaviour. A simple model explaining the deformation mechanism and its implications are also discussed.

8:00am C3-1 Cu2O-based Heterojunction Solar Cells Using Metal Oxide Thin Films as the n-type Semiconductor Layer, Tadatsugu Minami ([email protected]), Y. Nishi, T. Miyata, Kanazawa Institute of Technology, Japan INVITED In this paper, we describe the present status and prospects for further development of high-efficiency Al-doped ZnO (AZO)/n-type oxide semiconductor/p-type Cu2O heterojunction solar cells that feature a structure that is fabricated by inserting an n-metal oxide thin film between an AZO transparent electrode and a Cu2O sheet. The Cu2O sheets and the AZO and n-oxide thin films were prepared by oxidizing Cu sheets using a heat treatment process and by using a pulsed laser deposition (PLD) method, respectively. To achieve a higher efficiency in AZO/n-oxide semiconductor/p-Cu2O solar cells, we have reported that it was necessary to improve the interface at the n-oxide/p-Cu2O heterojunction as well as reduce the series resistance and increase the parallel resistance of the solar cells. In addition, we have investigated the effect of the inserted n-metal oxide semiconductor thin film on the obtainable photovoltaic properties in the Cu2O-based solar cells by inserting various kinds of n-oxide thin films such as binary compounds and multi-component oxides, prepared under various deposition conditions. As a result, we have recently reported that Cu2O-based p-n heterojunction solar cells with an energy conversion efficiency over 5% could be fabricated by using the PLD method to deposit AZO and n-Ga2O3 thin films at a low temperature on Cu 2O sheets [1]. We have more recently found that an improvement of obtainable photovoltaic properties in n-oxide semiconductor/p-Cu2O heterojunction solar cells could also be achieved by both decreasing the resistivity of Cu2O sheets without changing the Hall mobility of 100-110cm2/Vs as well as optimizing the chemical composition of multi-component oxides such as Ga2O3-Al2O3 and Ga2O3-ZnO systems, used as the n-semiconductor layer. The for mer was achieved by incorporating Na into the Cu2O sheets by heat treating, in an Ar gas atmosphere, Cu2O sheets covered with an appropriate Na compound, resulting in an increase of hole concentration from 10 13 to 1018 cm-3, as recently reported by us. As a result, we have achieved a conversion efficiency over 6% in a MgF2/AZO/(Ga2O3)0.975-( Al2O3)0.025/Cu2O heterojunction solar cell fabricated by depositing a (Ga 0.975Al0.025)2O3 thin film on a Cu2O sheet with a resistivity on the order of 10Ωcm. [1] T. Minami, Y. Nishi, and T. Miyata, Appl. Phys. Express 6 (2013) 044101.

11:00am B4-1-10 Tribological and Adhesion Properties of the CrZrN Coatings with Various Interlayers with Different H/E Ratios, HoeKun Kim, J.H. La, S.Y. Lee ([email protected]), Korea Aerospace University, Republic of Korea Various metal nitride coatings for protecting the cutting tools have been widely developed and applied in the many applications of the tool and die. Despite of its excellent properties of the CrZrN coatings such as high hardness, very low surface roughness and friction coefficients under dry conditions, the utilization of the CrZrN deposited on WC substrate was much limited due to the poor adhesion strength between the coating and the substrate. Recent work reported that the H/E ratio of the interlayer between coating and substrate influences strongly tribological property of the coating. In this work, the CrZrN coatings with various interlayers with different H/E ratios were synthesized using unbalanced magnetron sputtering system on WC-6 wt.% Co substrate. The Cr-N interlayers were deposited with various N2 partial pressures in the range from 0.6×10-1 to 2.8×10-1 Pa. With increasing N2 partial pressure, the crystalline phase of CrN interlayer varied from Cr2N to Cr2N+CrN, and then CrN, and the hardness and elastic modulus of the Cr-N interlayers varied, showing the maximum hardness and elastic modulus of 28 GPa and 357 GPa (CrN interlayer at 2.8×10-1 Pa of N2 particle pressure). Wear and scratch test showed that the CrZrN coating with CrN interlayer exhibited the lowest friction coefficient of 0.28 and the highest adhesion strength of Lc3=46.1N. These improved tribological properties and adhesion strength could be attributed to the ratio of hardness to elastic modulus (H/E) of CrN interlayer between the CrZrN coating and WC. In view of the coating structure, there exists a gradual decrease in the H/E ratio from the CrZrN coating, to the CrN interlayer, and the substrate (0.090, 0.068, 0.045 respectively) and this would induce a smooth transition of the stress under loading conditions. Tribological and adhesion properties could be improved significantly by structuring the coating with an optimal gradient of the H/E ratio. Acknowledgement This research was supported by a grant from the Fundamental R&D Program for Core Technology of Materials funded by the Ministry of Commerce, Industry and Energy, Republic of Korea.

Tuesday Morning, April 21, 2015

8:40am C3-3 Effects of Oxygen Gas Flow Rate and Ga Contents on Structural Properties of Ga-doped ZnO Films Prepared by Ion-plating with a DC Arc Discharge, Tomoaki Terasako ([email protected]), Ehime University, Japan, J. Nomoto, H. Makino, N. Yamamoto, Kochi University of Technology, Japan, S. Shirakata, Ehime University, Japan, T. Yamamoto, Kochi University of Technology, Japan Gallium (Ga)-doped zinc oxide (GZO) is one of the most conceivable candidates for the alternative material for tin-doped indium oxide (ITO). Many different types of growth methods have been reported for obtaining polycrystalline GZO films. We have paid attention to ion-plating using a DC arc discharge because the method enables the deposition of GZO films on large area substrates at high deposition rates with low plasma damage. In our previous papers, we reported carrier concentration dependences of carrier-scattering mechanism [1] and of photoluminescence (PL) properties [2]. In this paper, to clarify the relationship between the structural and electrical properiies, we study the structural properties of the GZO films systematically in terms of the oxygen (O2) gas flow rate during the deposition process and the Ga contents. 200-nm-thick GZO polycrystalline films were deposited on alkali-free glass substrates at 200 ºC by the ion-plating. The source GZO pellets were prepared by sintering of the ZnO powder containing the several amounts of Ga2O3 powder (0.003-4 wt%). The O2 gas was introduced into the deposition chamber. The O2 gas flow rate was varied in the range from 0 to 30 SCCM. The out-of-plane θ-2θ scan X-ray diffraction (XRD) patterns of all the GZO films were dominant by the (002) diffraction peak, indicating highly c-axis

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orientation perpendicular to the glass substrates. With increasing O 2-gas flow rates and/or the Ga contents, the (002) diffraction peak shifted higher angles. This showed a decrease in the lattice constant of the c-axis. On the other hand, the in-plane 2θχ-ϕ scan XRD measurements revealed an increase in the lattice constant of the a-axis with increasing O2-gas flow rates and/or the Ga contents. The results showed the biaxial stress of GZO films: the compressive stress acting along the c-axis direction together with the tensile stress acting along the a-axis direction. We found strengthened stress with an increase in O2-gas flow rate and/or Ga contents. Considering that all of the as-deposited samples were deposited on the same type of substrates with a fixed substrate temperature, the behavior of the residual stress should be discussed in terms of the changes of intrinsic stress. We found that the electrical properties strongly depend on both O2-gas flow rates and Ga contents. We will demonstrate the relationship between the structural and electrical properties. Reference: [1] T. Terasako, H. Song, H. Makino, S. Shirakata, T. Yamamoto, Thin Solid Films 528 (2013) 19. [2] T. Terasako, Y. Ogura, S. Fujimoto, H. Song, H. Makino, M. Yagi, S. Shirakata, T. Yamamoto, Thin Solid Films 549 (2013) 12.

have large magnetization. (Ga, Co)-ZnO films for use as DMSs have been fabricated using various techniques, including molecular beam epitaxy (MBE) [1], pulsed laser deposition (PLD) [2] and inductively coupled plasma enhanced physical vapor deposition (ICP-PVD) [3], etc. However, there are very few reports about (Ga, Co)-ZnO thin films deposited using radio frequency (rf) magnetron sputtering . In this study, (Ga, Co)-ZnO [CoxGayZn(1-x-y)O] films with different Ga contents are co-sputtered on glass substrates by rf magnetron sputtering. The x content [Co/(Ga+Co+Zn)] in the films is ~ 0.05. The content of y [Ga/(Ga+Co+Zn)] varies from 0 to 0.032. Using Hall effect analysis, the resistivity (ρ) of the film is 42.9 Ω-cm when y content is 0. When the content of y increases to 0.032, the ρ value drops greatly to 4.93 × 10 -3 Ωcm. In photoluminescence analysis, all the oxygen-rich (Ga, Co)-ZnO films contain acceptor-like defects. In magnetic properties analysis, when low Ga contents are doped and with low carrier concentration range (< 2.48 × 10 17/ cm3), saturation magnetization (Ms) is established by Bound Magnetic Polaron (BMP) due to defects and magnetic atoms in the films. However, Ms is created by the free electrons and Co atoms that produce the exchange coupling effect when high Ga concentration is present in the films and in high carrier concentration range (> 7.34 × 1018/ cm3). In the transition zone, since the two mechanisms mentioned above are overlapped and exchanged, Ms value drops when the carrier concentration in the films increases from 2.48 × 1017/ cm3 to 7.34 × 1018/ cm3. Keywords：rf magnetron co-sputtering, diluted magnetic semiconductor s, (Ga, Co)-ZnO films, optical properties, electrical properties, magnetic properties. Reference [1] Zhonglin Lu, Hua-Shu Hsu, Yonhua Tzeng, Fengming Zhang, Youwei Du and Jung-Chun-Andrew Huang , Appl. Phys. Lett. 95 (2009) 062509. [2] Liping Zhu, Zhigao Ye, Xuetao Wang, Zhizhen Ye and Binghui Zhao, Thin solid films 518 (2010) 1879-1882. [3] Xue-Chao Liu, Zhi-Zhan Chen, Bo-Yuan Chen, Er-Wei Shi and DaQian Liao, J. Cryst. Growth 312 (2010) 2871-2875

9:00am C3-4 Bandgap tuned Zn1-xMgxO Thin Films Co-deposited Using High Impulse Power and Direct Current Magnetron Sputtering, Edwin Mayes ([email protected]), B. Murdoch, RMIT University, Australia, M. Bilek, D. McKenzie, University of Sydney, Australia, D. McCulloch, J. Partridge, RMIT University, Australia The high exciton binding energy, radiation hardness and range of achievable bandgaps of wurtzite Zn1-xMgxO make it suitable for a range of applications including UV filters and detectors. In this work, h igh impulse power- and direct current- magnetron sputtering have been used to reactively co-deposit Zn1-xMgxO films onto sapphire at 200 °C. The unintentionally doped n-type Zn1-xMgxO films exhibit low surface roughness, high transparency and a Mg fraction (x) depending on substrate location. The optical bandgap of the films varied monotonically with x up to the miscibility limit of x ~ 0.32, beyond which a mixed cubic/wurtzite structure formed. As-deposited, the films exhibited very high sheet resistance, making them unsuitable for devices. However, annealing the wurtzite Zn1-xMgxO at 550 °C in forming gas (95% N2, 5%H2), caused reduced compressive stress, increased optical band-gap and dramatically reduced electrical resistivity without detectable phase transformation. These results will be discussed in more detail and characteristics from UV detectors fabricated on these films will be presented.

10:00am C3-7 Photocatalytic Study on Indium Tantalum Oxide Thin Film Deposited by Sputtering, C. Li ([email protected]), National Yang Ming University, Taiwan, J.H. Hsieh, Ming Chi University of Technology, Taiwan, P.H. Hsueh, National Central University, Taiwan InTaO4 thin films are transparent with photocatalytic function if appropriate compositions are obtained. The photocatalytic function is due to the formation of intermediate bands between conduction and valance bands in the original In2O3 and Ta2O5 structures. Such intermediate bands provide the opportunity for electron-hole separation under which free electrons can move to free surfaces or grain boundaries to combine with radials there. This is the basic mechanism for photocatalytic function. Although single oxide is possible to be photocatalytic, the combination of two transition metal oxides in principle should be much easier to achieve such function with higher efficiency. Current understanding about the mixture of transition metal oxides is that the structure should be homologous, i.e. a mix of crystallites of In2O3 and Ta2O5 to give the apparent compositions InTaO4. Such structure can guarantee the formation of intermediate bands and be easily achieved by sputtering. To realize this idea and characterize the properties of combined films, we prepared the InTaO4 thin films by sputtering through a specifically designed process. A multilayer In 2O3 and Ta2O5 thin films were alternately deposited on heated glass substrates. Each layer is about 5-7 nm and 8 – 10 layers of each oxide were deposited to have total thickness around 100 nm. After deposition, the whole multilayer film was rapidly annealed at 700°C to have a compound mixture. To examine this annealed compound films, we shall use surface profiler and FESEM to inspect the thickness and surface morphology; XRD and TEM to study the microstructures; EDX or XPS to examine the chemical compositions; UV-visible-NIR spectrometer to assess the optical properties. The photocatalysis will be conducted by the electrochemical test to evaluate the decomposition of methylene blue/methylene orange under visible light radiation. It is expected this newly fabricated compound films shall have applications in many biomedical devices.

9:20am C3-5 Fabrication and Analyses on the Flexible Electrochromic Device of Tungsten Oxide, C. Li ([email protected]), National Yang Ming University, Taiwan, J.H. Hsieh, Ming Chi University of Technology, Taiwan, T.Y. Su, National Central University, Taiwan WO3 is known for its electrochromic function by which the material can switch between color (dark blue) and bleach states depending on the imposed electrical voltage. Such switch of multiple states can be achieved by electrochemical insertion of cations and electrons into the tungsten oxide. In this study, a stack of flexible electrochromic device made of NiO –Ta2O5 - WO3 is deposited by sputtering with various supplies of argon and/or oxygen. The stack is sandwiched by two electrodes made of In 2O3 and on top of polyethylene terephthalate (PET) substrate. Each film was individually fabricated at first to determine the optimal parameters of deposition. Structures, compositions and properties of deposited films were examined and analyzed by the following tools: Surface profiler and FESEM to inspect the thickness and surface morphology; XRD and Raman spectrometers for the study of microstructures; EDX and XPS to examine the chemical compositions; four-point probe and Hall effect sensor to measure the electrical resistivity; UV-visible-NIR spectrometer for the assessment of optical properties. After the optimal parameters were determined, a stack of films was fabricated and used the electrochemical insertion of Li cations and electrons into the WO3 film to make it electrochromisic. Our goal is to utilize the current physical deposition process to fabricate a flexible device with optimal performance. The fabricated electrochromic WO3 stack shall be flexible enough, which can fit the requirement of incoming generation of mobile devices. 9:40am C3-6 Optical, Electrical and Magnetic Properties of (Ga, Co)ZnO Films by Radio Frequency Magnetron Co-sputtering, S.C. Chen, Chung-Hsien Wang ([email protected]), Ming Chi University of Technology, Taiwan, C.L. Tsai, Industrial Technology Research Institute, Taiwan, T.Y. Kuo, National Taiwan University, Taiwan, Y.K. Fu, Y.H. Fang, Industrial Technology Research Institute, Taiwan Diluted magnetic semiconductors (DMSs) based on ZnO have attracted a great deal of attention due to their potential application in magnetic semiconductor devices. In particular, they are predicted to display ferromagnetic properties at Curie temperature above room temperature and

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Chemical Vapor Deposition (IBACVD) of the octamethylcyclotetrasiloxane (OMCTS) precursor. The flexibility of the IBACVD technique allows one to synthesize films with different hybridicity levels. Particular attention has been paid to the effect of the hybridicity on the tribo-mechanical properties of such films assessed by newly developed characterization techniques such as in situ scratching and in situ real-time nano-wear testing. We particularly address the effect of the chemical composition on the elastic rebound, mechanical stress and the environmental degradation mechanisms of the hybrid films.

Tribology and Mechanical Behavior of Coatings and Engineered Surfaces Room: Royal Palm 4-6 - Session E2-3 Mechanical Properties and Adhesion Moderator: Johann Michler, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland, Etienne Bousser, Ecole Polytechnique, Canada, Fan-Bean Wu, National United University, Taiwan

9:00am E2-3-4 In-Situ Optical Oblique Observation of Scratch Testing, Jeffrey Wheeler ([email protected]), J. Wehrs, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland, G. Favaro, TriTec SA, Switzerland, J. Michler, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland Scratch resistance, while not a fundamental property of materials, is often a significant and common property of importance in many applications such as glass screens on mobile phones. In the broadest sense, scratch deformation occurs during any loading condition in which both normal and shear force components are applied. This combination occurs very frequently in both everyday life and during industrial machining. Modern scratch testing systems incorporate a variety of sensors to quantify the deformation which occurs during the application of a controlled normal load and translation rate. The parameters measured by these sensors typically include initial, loaded, and residual penetration depths; normal and tangential loads; and acoustic emission intensity. Less commonly, due to the scarcity of the instrumentation, the scratch deformation is also observed in situ using optical microscopy to observe the contact underneath the translating indenter or electron microscopy to obliquely observe the surface near the indenter. In this work, the advantages of oblique observation used in electron microscopy are combined with those of long working distance optical microscopy to achieve unique observational capabilities for opaque materials. A variety of materials were selected to demonstrate the advantages of the imaging capabilities. A ductile metal were chosen to highlight the ability to visualize the plastic pile-up around the scratch. Both a transparent, glass, and opaque, silicon, brittle solid were chosen to demonstrate the ability of the system to observe crack formation. Lastly, a brittle coating was selected to demonstrate the ability of the system to characterize the cracking and delamination of the coatings.

8:00am E2-3-1 In-situ Characterizations for Interfacial Performances of Materials, Yeau-Ren Jeng ([email protected]), National Chung Cheng University, Taiwan INVITED The recent drive to reduce the characteristic size of devices prompted by the evolution of nanotechnology renders the understanding of mechanical properties a pivotal issue. Recently, nanoindentation using depth-sensing technique has been utilized to characterize the hardness and surface properties of material at small scale. In this proposal, we have applied this technique to characterize physical phenomena and mechanical properties for a wide array of materials. T his study employs a series of experimental insitu techniques and theoretical methods including the nanomechanics and continuum mechanics to investigate tribological behaviors and mechanical properties of nanomaterials. Real-time buckling deformation of an individual carbon nanotube (CNT) was studied through in-situ TEM nanoindentation. These in-situ observationsreveal a significant shell-to-Euler phase transformation in the buckling response of CNTs. Objective evidences that the CNT possesses time-dependent characteristic were first suggested by combining in-situ TEM nanoindentation performed strain rate influences on the CNTs with molecular dynamics simulations. Moreover, CNTs reinforced metal matrix nanocomposites have been fabricated by a molecular level process, which involves aligned CNTs in by surface construction, depositing Cu ions upon CNT alignment and reduction, etc, to investigate the nano-mechanism for enhancement of martial strength. Lateral junction growth (LJG) at nano-scale is fundamental for the atomic origins of macroscopic friction and wear. Our in-situ characterization reveals that the lateral junction growth during incipient sliding coincides with the occurrence of dislocation in the junction. This observation echoes our atomic simulations and suggests that plastic deformation is the central mechanism for LJG. Additionally, our results also reveal that the presence of an adsorbed layer on the asperity surface significantly delays the onset of LJG until the adsorbed layer is splayed out from the interface. Comparisons among molecular simulations, continuum approach and experimental findings are conducted to elucidate the underpinning of the tribological mechanisms and shed light on how to build durable systems to fulfill the compelling energy saving trend. Our studies uncover the underpinning of using soft pad for fine surface polishing and provides a theoretical foundation for the selection and fabrication of a polishing pad and the selection of operation parameters during polishing that cannot be achieved with empirical findings and phenomenological approaches.

9:20am E2-3-5 Influence of Shot Peening and Grit Blasting on the Adhesion and the Tribological Behavior of Diamond-like Carbon Coating (a-C:H), Matthias Kachel ([email protected]), Fraunhofer IWM and Karlsruhe Institute of Technology KIT, Germany While shot peening is a widely used method to improve the mechanical properties of materials for highly stressed components, grit blasting is commonly used for cleaning surfaces. A combination of both methods as surface preparation before coating steel substrates leads to a distinct change in the adhesion and the tribological behavior of DLC coating (a-C:H). In the case of shot peening, globular grains of WC/Co were applied which leads to high induced residual stress, a change in texture, roughness, micro hardness and surface energy. Additionally, the surface is contaminated heavily with residuals from the grains. In the case of grit blasting, a slurry with a fixed ratio of water and sharpedged grains of Al2O3 was used which results in surface smoothening and cleaning from WC/Co residuals. The characteristics of the above described effects is strongly dependent on the shot peening/grit blasting parameters like distance, angle, velocity (air pressure), grain size and form, grain hardness and peening time. For different sets of these parameters, the gained surface characteristics of 100Cr6 samples were investigated using the profile method, SEM, EDX, XRD, LSM and contact angle measurements. All samples were coated with the same a-C:H film via PECVD and subject to the characterization methods named above as well as Raman spectroscopy and nanoindentation. The adhesion was evaluated using Rockwell indentations and calculating the delamination area. The tribological behavior was tested using a ball on disc method. Depending on the surface topography and the degree of WC/Co residuals, the film adhesion could be improved distinctly. A better mechanical and chemical bonding as well as different failure mechanisms compared to polished surfaces could be identified. Additionally, the tribological tests showed that the friction coefficient can be decreased by choosing specific substrate preparation methods.

8:40am E2-3-3 Tribo-mechanical Properties of Highly Elastic Hybrid SiOCH Optical Coatings, Thomas Schmitt, J. Schmitt, T. Poirie, O. Zabeida, J.E. Klemberg-Sapieha ([email protected]), L. Martinu, Ecole Polytechnique de Montreal, Canada The use of plastic substrates in different areas of application (optical lenses, consumer electronics, displays etc.) frequently leads to problems related to their compatibility with inorganic coatings. The deposition of durable inorganic layers on compliant substrates becomes difficult due to the large mismatch in the elastic and thermal properties of the substrate and the coating. In addition, daily use of such coated devices implies that they must withstand various external mechanical solicitations such as cleaning, interaction with hard particles, humidity and thermal cycling, radiation effects and others. By keeping in mind that modern optical coating systems involve complex multilayer stacks with individual layers as thin as several tens of nanometers, it is clearly necessary to develop films possessing controlled optical characteristics coupled with superior mechanical and tribological properties. The application of hybrid organosilicone materials is a promising avenue to enhance the tribo-mechanical properties of low index optical materials. Indeed, by combining both inorganic (SiOx) and organic (CHx) molecular groups, we found that it is possible to achieve improved film characteristics such as higher elasticity than for standard SiO2 evaporated films and increased resistance to crack formation and propagation. In the present work, we systematically studied hybrid SiOCH coatings deposited onto transparent plastic substrates using Ion Beam Assisted

Tuesday Morning, April 21, 2015

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9:40am E2-3-6 Investigation of Adhesion of Diamond-like Carbon on Ti6Al4V, Chunzi Zhang ([email protected]), Q. Yang, L. Yang, H. Niakan, Y. Li, S. khatir, University of Saskatchewan, Canada, Y.F. Hu, Canadian Light Source Inc., Canada Adhesion of diamond-like carbon (DLC) thin films on Ti6Al4V substrates was investigated using direct ion beam deposition with ion energy varying from 65 eV to 100 eV. The samples prepared were characterized by Raman spectroscopy, synchrotron near-edge X-ray absorption fine structure spectroscopy, scanning electron microscopy, X-ray diffraction, and nanoindentation testing. Indentation testing by Vickers hardness tester was used for adhesion evaluation. Results show that the adhesion of DLC thin films on Ti6Al4V substrates mainly depends on ion energy used in the deposition process. Higher ion energy resulted in higher sp 3 concentration of DLC thin films but lower adhesion of DLC on Ti6Al4V substrates, in which ion energy of 70 eV shows the best adhesion. Interlayers of diamond nanoparticles (DNP), tungsten (W), and Titanium nitride (TiN) were applied for adhesion enhancement of DLC thin films on Ti6Al4V. Results show that better adhesion was achieved by incorporated DNP compared with W and TiN interlayers due to greatly enhanced interfacial bonding.

New Horizons in Coatings and Thin Films Room: Sunrise - Session F3 New Boron, Boride and Boron Nitride Based Coatings Moderator: Aharon Inspektor, Kennametal Incorporated, USA, Mikhail Chubarov, Linköping University, IFM 8:00am F3-1 Mechanical and Tribological Properties of Arc Evaporated Ti1-xAlxN/Mo1-x-ySixBy Multilayer Coatings, Helmut Riedl ([email protected]), Vienna University of Technology, Austria, J. Kalas, Oerlikon Balzers Coating AG, Liechtenstein, P. Polcik, Plansee Composite Materials GmbH, Germany, P. Mayrhofer, Vienna University of Technology, Austria Previous studies in the field of PVD processed low friction coatings pointed out the possibilities of architectural designs, such as multilayer or nanocomposite coatings (e.g. TiAlN/VN, TiC-C), to combine particular properties and hence gain superior tribological performance. To follow this concept we investigated the mechanical and tribological properties of arc evaporated Ti1-xAlxN and Mo1-x-ySixBy multilayer coatings. The combination of Ti1-xAlxN - as a well-established thin film showing high hardness and thermal stability - and Mo1-x-ySixBy - as a Mo based coating system with excellent thermal stability and the ability to form lubricious Magnéli phase oxides such as MonO3n-1 - aims for excellent wear behavior at elevated temperatures. A chemical variation of the Mo1-x-ySixBy layers allows designing a high thermal stability and high oxidation resistance by forming stable borosilica scales and the necessary oxidation to form MonO3n-1 Magnéli phase oxides. Further modifications of the coating architecture are obtained by varying the bilayer period between 20 and 120 nm. The individual coating characteristics, such as hardness, wear rate, coefficient of friction, and thermal stability are correlated with detailed transmission electron microscopy studies.

10:00am E2-3-7 On the Use of the In-situ Observation of the Contact and the FE Modelling to Analyse the Damage of Coated Polymeric Surfaces, Christian Gauthier ([email protected]), University of Strasbourg / Institut Charles Sadron, France INVITED The objective of the talk is to present the benefit of the in-situ observation in case of transparent material. We have developed to analyse the scratching and the surface behaviour of polymeric surfaces a home made device which allows to record trough the sample the contact area, over a large range of velocity and temperature. Using spherical tips of different radiuses to avoid the effects of singularity of the tip, the mean contact stress versus the mean contact strain analysis will be presented. In case of coated surfaces, some cracking and delimitation mechanisms will be explained. Regarding the FEM simulations, anti-scratch coated system is studied in order to define interfacial damage criteria in relation with the observed damage mode. To achieve this goal we plot shear stress according to normal stress for the nodes at the coating/substrate interface. We obtain many loops which represent how the nodes undergo stresses. Thus we can locate those which are under tensile stress and are likely to be the cause of the film damages.

8:20am F3-2 Mo2BC Coatings for Metal Forming: Interactions Between Tool Surface and Aluminium by Theory and Experiment, H. Bolvardi, D. Music, Jochen Schneider ([email protected]), RWTH Aachen University, Germany Low temperature growth strategies for Mo2BC coatings are reviewed and initial theoretical and experimental data pertaining to the applicability of these coatings during forming of Al based alloys are discussed. A Mo2BC(040) surface was exposed to O2. The gas interaction was investigated using ab initio molecular dynamics and x-ray photoelectron spectroscopy (XPS) of air exposed surfaces. The calculations suggest that the most dominating physical mechanism is dissociative O2 adsorption whereby Mo – O, O – Mo – O and Mo2 – C – O bond formation is observed. To validate these results, Mo2BC thin films were synthesised utilizing high power pulsed magnetron sputtering and air exposed surfaces were probed by XPS. MoO2 and MoO3 bond formation is observed and is consistent with here obtained ab initio data. Additionally, the interfacial interactions of O2 exposed Mo2BC(040) surface with an Al nonamer is studied with ab initio molecular dynamics to describe on the atomic scale the interaction between this surface and Al to mimic the interface present during cold forming processes of Al based alloys. The Al nonamer was disrupted and Al forms chemical bonds with oxygen contained in the O 2 exposed Mo2BC(040) surface. Based on the comparison of here calculated adsorption energy with literature data, Al – Al bonds are shown to be significantly weaker than the Al – O bonds formed across the interface. Hence, Al-Al bond rupture is expected for a mechanically loaded interface. Therefore the adhesion of a residual Al on the native oxide layer is predicted. This is consistent with experimental observations. The data presented here may also be relevant for other oxygen containing surfaces in a contact with Al or Al based alloys for example during forming operations.

10:40am E2-3-9 Improved Adhesion of CVD-Diamond on Cemented Carbide Tools by Microwave Plasma-enhanced Surface Engineering, Manuel Mee ([email protected]), Fraunhofer IWM and Karlsruhe Institute of Technology KIT, Germany Diamond coatings for cemented carbide tools have been used for years, but for many applications layer adhesion still appears to be inadequate. Key issue of this study is the development of a microwave plasma assisted process in order to archive surface recrystallization of fine-grained cemented carbides with the objective to improve layer adhesion of CVD diamond. The effect of plasma parameters on the surface microstructure and this, in turn on the coating adhesion is evaluated. By controlling gas composition, the surface properties and its characteristics concerning hardness, roughness and surface energy could be influenced. Since Cobalt back diffusion has proved to be problematic, its quantification and impact on diamond quality and adhesion was analyzed. For the purpose of comparing interface and layer adhesion the common chemical etching pretreatment using Murakami solution and Caro’s acid was used and optimized. Microstructure investigations were done by SEM, EDS, XPS and Raman spectroscopy. Layer adhesion was tested by Rockwell indentation. The results show that by recrystallizing the WC grains at the surface, contiguity and surface roughness increases. An enhanced nucleation density is archived by deposition of a thin layer of graphene or graphite on top of the surface. Addition of Oxygen during diamond deposition allows reducing the interaction between Cobalt and the growing Diamond coating. Taking all these improvements into account, the new approach improves layer adhesion compared to the wet chemical pretreatment and enhances tool life.

8:40am F3-3 Experimental and Computational Study of B xAl1-xN, Holger Euchner ([email protected]), P. Wiehoff, P. Mayrhofer, Vienna University of Technology, Austria Computational materials science has proven to be a reliable tool for developing high performance materials, tailor made for specific applications. Recent studies show, that first principle calculations allow reliably predicting crystal structure, phase stability or elastic properties of ceramic-like hard coatings. In a computational feasibility study, we have investigated three different structural modification of BxAl1-xN for their respective stability, showing that solid solutions are likely to be accessible by physical vapour deposition. Based on the computational studies, BxAl1-xN thin films were deposited using pulsed DC magnetron sputtering of a boron and an aluminium target

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under nitrogen and argon atmosphere at different substrate temperatures . The coatings, typically 1 - 2 µm thin, were studied in detail by X-ray diffraction, secondary ion mass spectroscopy, nanoindentation, and cross sectional transmission electron microscopy. Selected samples, especially the B-rich samples, were additionally investigated after vacuum annealing treatments up to 1000 °C.

[9] T. C. Doan, S. Majety, S. Grendadier, J. Li, J. Y. Lin, and H. X. Jiang, Nuclear Inst. and Methods in Physics Research Section A 748, 84 (2014). 10:00am F3-7 Growth Kinetics of Boride Coatings Formed at the Surface AISI M2 During Dehydrated Paste Pack Boriding, MarcoAntonio Doñu Ruiz ([email protected]), Universidad Politécnica del Valle de Mexico, Mexico, N. Lopez-Perrusquia, Universidad Politecnica del Valle de Mexico, Mexico, C.R. Torres San Miguel, G.M. Urriolagoitia Calderón, Insituto Politécnico Nacional, Mexico, E.A. Cerillo Moreno, Universidad Politecnica del Valle de Mexico, Mexico, J.V. Cortes Suarez, Universidad Autónoma Metropolitana Azcapotzalco, México The growth kinetics of the boride coatings (FeB and Fe2B) at the surface of AISI M2 high speed steels were studied in this work. Boriding thermochemical treatment was carried out by dehydrated paste pack at three different temperatures 1172, 1227 and 1273 K and four exposure times 1, 3, 5 and 7 h, respectively. The presence of FeB and Fe2B phases were identified by scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and X-ray diffraction method. In order to obtain the boron diffusion coefficients at the FeB/Fe2B boride coatings, a mathematical model based on the mass balance at the growing interfaces was proposed under certain assumptions. Likewise the boride coatings thickness (FeB and Fe2B) were established as a function of the parameters η(T) and ε(T), which are related to the temperature and the effect of the incubation times for the boride formation. The activation energy values estimated for the FeB and Fe2B layers were 233.42 and 211.89 kJ mol−1 respectively. A good agreement was obtained between the simulated values of boride layers thicknesses and the experimental conditions used in this work. Finally, empirical relationships of boride coatings thickness as a function of boriding temperature and time are presented.

9:00am F3-4 Growth and Nanostructure of Zirconium Diboride Thin Films for High Temperature Electronics, David Stewart, R. Meulenberg, R. Lad ([email protected]), University of Maine, USA In thin film form, zirconium diboride (ZrB2) may be an invaluable material for use in high temperature sensors and other electronic components, thanks to its high electrical and thermal conductivity, and remarkably strong bonding. In this work, a series of thin films with controlled composition ranging from pure Zr to pure B have been grown on sapphire substrates by electron beam co-evaporation from individual elemental sources. Films grown at temperatures below 400°C are predominantly amorphous, whereas for higher growth temperatures, films with an excess of Zr show nano-sized ZrB2 crystallites and those with excess B remain amorphous. No morphological changes are observed by scanning electron microscopy (SEM) upon annealing the films in ultra-high vacuum up to 1000°C, however x-ray diffraction (XRD) reveals ZrB2 grain growth in films with excess Zr. The as-deposited nanocrystalline films exhibit a ZrB2 texture, and the degree of texture increases, particularly for Zr-rich film compositions. Regardless of composition, XRD shows no Zr-B phases other than ZrB2 crystallites in an amorphous matrix. However, x-ray absorption spectroscopy measurements near the Zr K edge indicate distinct changes in the local bonding environment around the Zr atoms with changes in composition, independent of crystallinity. Analysis of x-ray absorption fine structure (XAFS) spectra confirms that the nearest–neighbor distances are dependent on both composition and annealing temperature. The electrical conductivity of the Zr-B thin film series ranges from 0.01 to 0.6 MS/m, with increased ordering and grain growth leading to increased conductivity.

New Horizons in Coatings and Thin Films Room: Royal Palm 1-3 - Session F6-1

9:20am F3-5 Hexagonal Boron Nitride – Wafer-scale Epitaxial Growth and Exploration of Active Devices, Jingyu Lin ([email protected]), H.X. Jiang, Texas Tech University, USA INVITED As a member of the III-nitride wide bandgap semiconductor family, boron nitride (BN) has received much less attention in comparison with other nitride semiconductors. The stable phase of BN synthesized at any temperature and under normal pressure is hexagonal. Hexagonal BN (hBN) possesses extraordinary physical properties including wide bandgap (Eg ~ 6 eV), high temperature stability and corrosion resistance, and large optical absorption and neutron capture cross section. Due to its similar lattice constants to graphene, hBN is also an ideal template and dielectric layer for graphene devices. Furthermore, hBN represents an ideal platform for probing fundamental 2D properties in semiconductors. The synthesis of wafer-scale hBN epilayers by MOCVD has been demonstrated [1-6]. It was shown that the unique 2D structure of hBN induces high density of states and large exciton binding energy, which result in high optical absorption and emission intensity [3,4,7]. P-type conduction and diode behaviors in the p-n structures consisting of p-hBN/n-AlxGa1-xN (x~0.62) have been demonstrated [2,5]. Carrier mobility-lifetime products and diffusion lengths of hBN thin film detectors have been characterized. As deep UV photodetectors, hBN detectors exhibit a peak responsivity at 217 nm and a cut-off wavelength at around 230 nm with virtually no responses for below bandgap excitation. As thermal neutron detectors, hBN detectors exhibit an effective conversion efficiency approaching ~80% for the absorbed thermal neutrons and the measured pulse height spectra exhibit unprecedented narrow peaks registered by the product energies of 10B and thermal neutron reaction [8,9]. [1] S. Majety, X. K. Cao, J. Li, R. Dahal, J. Y. Lin & H. X. Jiang, “Appl. Phys. Lett. 101, 051110 (2012). [2] R. Dahal, J. Li, S. Majety, B.N. Pantha, X. K. Cao, J. Y. Lin, and H.X. Jiang, APL 98, 211110 (2011). [3] J . Li, S. Majety, R. Dahal, W. P. Zhao, J. Y. Lin, & H. X. Jiang, Appl. Phys. Lett. 101, 171112 (2012). [4] B. Huang, X. K. Cao, H. X. Jiang, J. Y. Lin, and S. H. Wei, Physical Review B 86, 155202 (2012). [5] S. Majety, J. Li, X. K. Cao, R. Dahal, B. N. Pantha, J. Y. Lin, and H. X. Jiang, APL 100, 061121 (2012). [6] S. Majety, J. Li, W. P. Zhao, B. Huang, S. H. Wei, J. Y. Lin, and H. X. Jiang, APL 102, 213505(2013) [7] X. K. Cao, B. Clubine, J. H. Edgar, J. Y. Lin, and H. X. Jiang, Appl. Phys. Lett. 103, 191106 (2013). [8] J. Li, R. Dahal, S. Majety, J.Y. Lin, and H.X. Jiang, Nuclear Inst. and Methods in Physics Research Section A 654, 417 (2011).

Tuesday Morning, April 21, 2015

Thin Films and Coatings for Fuel Cells & Batteries Moderator: Chintalapalle Ramana, University of Texas at El Paso, USA, Sanjay Khare, University of Toledo, USA 8:00am F6-1-1 Electrochemical Performance of Multilayered Si thin Film Anodes for Li-ion Batteries, Gayatri Dadheech ([email protected]), General Motors R&D Center, USA, C.U. Uthaisar, Fraunhofer USA, USA, V. Miller, University of California Berkeley, USA, T. Schuelke, M. Becker, Fraunhofer USA, USA We present an alternative approach to integrate ultrathin Al2O3 into stacked C/SiOx layers for the stabilization of anode materials in Li-ion batteries. The heterogeneous C/SiOx/Al2O3 thin films were constructed by utilizing plasma magnetron PVD techniques. The deposition of the anodes followed either C/SiOx/C or C/SiOx/C/SiOx/C assemblies, 200nm on C substrates and 100 nm on SiOx substrates with an additional 20 nm Al2O3 coating to immobilize the two established films. Raman spectra show the C/SiOx stacks consist of amorphous structures for both C and SiOx layers. The multilayer thin films with Al2O3 coating exhibit a maximum initial discharge capacity of about 1000 mAh/g and maintained a reversible capacity of about 500 mAh/g over 100 cycles at a current density of 300 mA/g (~C/2) with a half-cell anode. The Al2O3 layers slightly improved the electrochemical performance of the stacked C/SiOx anodes, and the capacity retention rate increased about 25% with good rate-capability in comparison to those not coated with Al2O3. The improved electrochemical performance of depositing C/SiOx layers with Al2O3 coating can be attributed to the formation of an artificial solid electrolyte interphase layer stabilizing the interaction of C/SiOx and the electrolyte. Furthermore, we examined a fullcell battery using a C/SiOx/Al2O3 layered anode and a LiNiOx cathode, and their electrochemical performance will be presented. 8:20am F6-1-2 On the Surface Evolution in Stressed Films: from Metal Films at High Temperature to Electrode Films in Li-ion Batteries, Rahul Panat ([email protected]), Washington State University, USA INVITED Several physical processes show surface roughening under moderate to high stress under diffusive processes either at high or at low temperatures. Although the length scales and the time scales observed in these phenomenon are vastly different; they are governed by the same set of equations. Starting from internal energy and entropy terms, governing equation is derived that gives the amplitude change of such surfaces as a function of time. A parametric study is then carried out using a diverse range of practically important cases such as thin films electrodes of Li-ion batteries and metal films in thermal barrier systems. It is shown that the

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characteristic surface roughening observed depends upon the stress as well as diffusivity. These results have an important bearing on the crack initiation at thin film surfaces and interfaces. 9:00am F6-1-4 Study on Enhancing Performance of Thin Film Amorphous SnOx on C60 as an Anode Material for all Solid State Battery, KangSoo Lee, Yonsei University, Republic of Korea, Y.S. Yoon ([email protected]), Gachon University, Republic of Korea Tin oxide, a potential anode material for all-solid-state batteries has high capacity (~ 1490 mAh g-1). Although it has high capacity, tin oxide shows volume expansion during electrochemical reaction and poor electrical conductivity. The volume expansion induces delamination of the active material from current collectors and then isolation from the electrical networks. Thus, modification of the active material structure is necessary to enhance the resistance of the volume expansion. In order to reduce the volume expansion and low conductivity, we have introduced a buffer and conducting layer of C60 thin film below SnOx layer which microstructure can be confirmed by scanning electron microscope (SEM) image and electric conductivity was measured by 4 point prove. After 50 th cycle of charge-discharge, it shows significant reduction of volume expansion. The SnOx thin film layer was deposited on C60 thin layer using radio-frequency (RF) sputtering system under Ar gas atmosphere at different input power. Their electrochemical properties were evaluated with charge/discharge test and differential capacity plot. In these results, capacity, cycle life, and electrical conductivity of the SnOx/C60 structure show higher stability than bare SnOx thin film material. 9:20am F6-1-5 CeO2-Doped (Co,Mn)3O4 Coatings for Protecting Solid Oxide Fuel Cell Interconnect Alloys, Jiahong Zhu ([email protected]), J. Simpson, M. Lewis, Tennessee Technological University, USA In the planar design of a solid oxide fuel cell (SOFC) stack, the interconnect acts not only as electrical connection between the various cells but also as the mechanical support for the thin electroactive ceramic parts and as gasproof separation of air and fuel gas. With the reduction of the SOFC operating temperatures to 600-800°C, chromia-forming ferritic steels are widely used as interconnect materials in the planar-type SOFC stacks currently under development. Two of the most serious problems for these ferritic steels such as Crofer 22 APU is (1) the Cr volatility and associated “poisoning” of the cathode under the operating environments of SOFC; and (2) the continuous oxidation of the alloy and subsequent thickening of the chromia scale and increase in scale electrical resistance. Reactive elementdoped (Co,Mn)3O4 spinel is considered as the most promising coating system to protect the interconnect alloy. In this presentation, different approaches to adding reactive element into the spinel coating are reviewed. Two methods that have been developed in our research lab, i.e. electrolytic codeposition and environment-assisted reactive sintering, are compared and their advantages are outlined. The effect of the CeO2-doped (Co,Mn)3O4 coating on the oxidation resistance and scale area-specific resistance of Crofer 22 APU are discussed .

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Tuesday Morning, April 21, 2015

Tuesday Morning, April 21, 2015 Exhibitors Keynote Lecture Room: Town & Country - Session Ex Exhibition Keynote Lecture 11:00am Ex1 Synthesis of Oxides by Reactive Cathodic Arc Evaporation: Cathode Surface and Coating Properties, Jürgen Ramm ([email protected]), Oerlikon Balzers Coating AG, Liechtenstein INVITED Reactive cathodic arc evaporation is an attractive method to produce thin oxide coatings at moderate substrate temperatures. Characteristic for this deposition method are two distinctive features which influence the crystalline phases of the synthesized coatings: the freedom to select the chemical composition of the compound cathodes and the control of the metal-to-oxygen ratio during the deposition. An attempt is made to predict the phase formation generated by the arc at the cathode (target) surface and correlate it with the phases of the synthesized coating. The development of the phases at the target surface depends on the oxygen partial pressure and on the particle size utilized to fabricate the powder metallurgical targets. A comparison of the processes at the target surface with the coating synthesis unveils correlations. This knowledge is helpful in the designing of oxide coatings for dedicated applications. The influence of the chemical composition of the targets and the oxygen partial pressure on the formation of the binary and ternary oxide phases was investigated for the Al-Cr, Al-Hf and Al-Ni material systems. The application of oxide coatings in high-temperature environments as oxidation and diffusion barriers is of particular interest. The oxidation process was studied for intermetallic coatings during annealing in ambient atmosphere with temperatures up to 1300°C. The spontaneous selective oxide growth in these materials was investigated by in-situ hightemperature XRD and explains the mechanical malfunctions of the coatings. In search of oxidation barrier coatings for these intermetallic layers, oxide coatings were synthesized for which the metallic components correspond to the metallic components in the underlying intermetallic layer. These coatings showed improved thermal stability which is a result of the preformation of high-temperature oxide phases during oxide synthesis already at a substrate temperature of 550°C. Outstanding barrier quality was found for the solid solution of (Al,Cr)2O3 in corundum structures for several applications.

Tuesday Morning, April 21, 2015

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Tuesday Afternoon, April 21, 2015 between the measured and computed phase fractions and phase distributions after specific time intervals. The computational approach assists in estimating the lifetime of the coating and provides a tool to predict microstructural changes in coating systems as a function of alloy/coating composition, time and temperature.

Coatings for Use at High Temperature Room: Royal Palm 4-6 - Session A1-1 Coatings to Resist High Temperature Oxidation, Corrosion and Fouling Moderator: Mark Weaver, The University of Alabama, USA, Vladislav Kolarik, Fraunhofer Institute for Chemical Technology ICT, Germany, Elizabeth Opila, University of Virginia, USA

2:50pm A1-1-5 Structure and Degradation Mechanisms of Pd-Ptaluminide Bond Coatings for EB-PVD TBCs, Radoslaw Swadzba ([email protected]), Institute for Ferrous Metallurgy, Poland, L. Swadzba, Silesian University of Technology, Poland, J. Wiedermann, Institute for Ferrous Metallurgy, Poland, M. Hetmanczyk, B. Mendala, B. Witala, Silesian University of Technology, Poland INVITED Diffusion aluminide and Thermal Barrier Coatings (TBC) are widely applied on jet engine turbine blades and vanes operating under the most severe conditions. The ceramic layers are often applied using EB-PVD method on Pt-modified aluminide coatings (bond coats) providing excellent oxidation and high temperature protection. The beneficial effect attributed to Pt is improvement of oxide scale adherence during cyclic and isothermal oxidation as well as mitigation of the detrimental effects of sulfur impurities on scale adherence and inhibition of void formation at the scale-metal interface. While the Pt-modified aluminide coatings have been widely studied in the literature other solutions are being sought for due to high costs of Pt. The paper presents the results of research conducted on partial replacement of Pt with Pd indicating that the modification of aluminide coatings with Pd or both these elements provides very good oxidation resistance along with significant cost reduction, due to the fact that Pd is two times cheaper than Pt. The Pd/Pt modified aluminide coatings demonstrate cyclic oxidation resistance comparable to this of Pt modified aluminide coatings. However, under service conditions these bond coatings undergo a number of commonly reported degradation mechanisms that limit their durability and eventually lead to spallation of the YSZ top coat. These include i.a. surface roughening, also referred to as rumpling, β→γ’ and martensitic transformations due to Al depletion, void formation and formation of secondary oxides. The macroscopic degradation analysis of TBC systems is aided by a non-destructive 3D optical scanning method which allows prediction of YSZ spallation both on samples and real turbine components. Special effort has been done in order to investigate the microstructure of the Thermally Grown Oxide (TGO) formed during oxidation heat treatment prior to YSZ deposition and the phenomena occurring at the interface between the YSZ, TGO, and the bond coat. Microstructure evolution of the TGO is described and related to the conditions of the pre-oxidation treatment and the chemistry of the bond-coating. During thermal exposure the TGO grows by inward oxygen diffusion forming distinctive columnar grains. Several segregation phenomena can be found in the TGO that include i.a. the Reactive Element Effect involving the presence of Hf, Zr and Y on α-alumina grain boundaries that reduce the growth rate of Al2O3 and simultaneously the extent of vacancy injection to the interface with the bond coating.

2:10pm A1-1-3 Solvothermally Densified Ceramic Coatings as Corrosion Protection for Boiler Tubes in Waste-to-energy (WTE) Plants, Dirk Müller ([email protected]), D. Aßbichler, S. Heuss-Aßbichler, Ludwig-Maximilians-Universität München, Germany Steam tubes in WTE plants have short life-time, due to intense corrosion processes. In general, pure metal-based alloy weld overlays are in use. The goal of this study is to develop cost-effective anti-corrosion coatings. Recently, coating structures consisting of a metal-based alloy (Inconel 625) as bond-coat, followed by a ceramic top-coat, both deposited by air-plasmaspray method (APS), are in discussion. One drawback of the ceramic coating is the high porosity, which gives way for corrosive gas species, attacking the underlaying steel tube. To diminish this destructive process an innovative chemical densification process is applied to the ceramic coating. Based on a solvothermal mobilization and recrystallization of the ceramic material, herein yttria-stabilized zirconia (YSZ), the porosity can be reduced by half. This leads to a better adhesion of the ceramic top-coat onto the bond-coat and enables the ceramic coating to act as a protective gas-barrier. This solvothermal effect was found for the first time on coated test-probes, mounted in a WTE plant [1]. A successful reproduction was done in lab scale experiments under simulated WTE plant conditions [2]: temperature 600-800°C, atmosphere of 98 vol.% N2 and 2 vol.% HCl together with an equimolar mixture of potassium and zinc chlorides and sulfates, added into the gas flow. In recent experiments, O2 is added to the atmosphere, giving a solvothermal medium of O2, HCl, Cl2, H2O and SO2. These conditions enable a mobilization of the Zirconium. The recrystallization is triggered by changing partial pressures of the involved species within the ceramic topcoat. [1] D. Bendix et al., Mater. Corros., 2008, 59, 389. [2] P.J. Masset et al., ECS Trans., 2013, 50, 109. 2:30pm A1-1-4 Thermodynamic and Kinetic Modelling for Predicting the Microstructural Evolution in Oxidation Resistant Coatings during High Temperature Exposure, Rishi Pillai ([email protected]), A. Chyrkin, Forschungszentrum Jülich, Germany, W. Sloof, Delft University of Technology, Netherlands, W. Quadakkers, Forschungszentrum Jülich, Germany Protective metallic coatings enhance the oxidation and corrosion resistance of the underlying high temperature materials. Some of the widely used types of coatings are MCrAlY (M = Ni, Co) overlay coatings and nickel aluminide (NiAl) diffusion coatings which ensure the growth of a slowly growing adherent alumina scale and thus protect the underlying substrate from rapid oxidation attack. Aluminium from the bondcoat is lost to the external oxide layer on the coating surface and to the substrate by interdiffusion resulting in dissolution of the ß-NiAl phase in the coating. Coating life generally corresponds to the operating life of the components and is usually measured in terms of the depletion of the ß-NiAl phase as it serves as an Al-reservoir for the growth of the protective alumina scale. The performance of a coated material depends on the compatibility of a given type of a coating with its base material. Evaluation of the material’s high temperature behaviour requires extensive experimental testing. A reduction in the time and effort can be complemented by computational methods. A new computational approach to model the microstructural evolution in coating systems and thereby evaluate their lifetime was undertaken in the present study for typical coatings on Ni-based alloys and superalloys. Microstructural development in the alloys was modelled by considering simultaneously occurring oxidation and interdiffusion processes. Using available thermodynamic and kinetic data for all occurring phases from Thermo-Calc the current work differs from contemporary modelling methodologies. Element concentrations and phase distribution were obtained by scanning electron microscopy (SEM). Phases were identified by energy/wavelength dispersive X-ray spectroscopy (EDX/WDX) and electron backscatter diffraction (EBSD). Good agreement was found

3:30pm A1-1-7 Study of Oxide Scale Formed in Thermal Barrier Coating System on CMSX-4, CM 247 LC and PW1483 Alloys, K. Unocic ([email protected]), Bruce Pint, ORNL, USA A MCrAlY (M = Ni,Co) modified with Si and Hf was deposited on three commercial Ni-base alloys: CMSX-4, CM 247 LC and PW1483. Duplicate specimens were also prepared on which additionally yttria-stabilized zirconia (YSZ) was deposited. All samples were tested in a cyclic rig at 1100°C in laboratory air in order to evaluate the oxide scale adhesion formed on the bond coating. The effect of substrate was investigated by studying in detail the microstructures and morphology of the oxide scales formed in specimens containing three different substrates using transmission electron microscopy (TEM). The effect of the YSZ presence on scale formation and morphology was also investigated. Additionally, after oxidation exposure in-situ TEM compression testing on the alumina scale formed on MCrAlY bond coating will be performed for quantitative in-situ deformation experiments. These tests will be used to evaluate the differences in mechanical behavior of the oxide scales between the three different substrates.

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3:50pm A1-1-8 Modelling the Influence of Alloying Elements on the Microstructrural Evolution in MCrAlY Coatings at High Temperatures, Anton Chyrkin ([email protected]), R. Pillai, Forschungszentrum Jülich, Germany, W. Sloof, Delft University of Technology, Netherlands, R. Vaßen, Forschungszentrum Jülich, Germany, U. Glatzel, University of Bayreuth, Germany, W. Quadakkers, Forschungszentrum Jülich, Germany, T. Galiullin, Forschungszentrum Jülich GmbH, Germany Ni-base superalloys are widely used in the gas turbine technology as construction materials for single-crystal blades and vanes. The excellent creep resistance of these materials is achieved by a specific γ/γ´microstructure as well as solid solution strengthening by refractory metals such as W, Ta, Re. The single-crystal blades are usually coated with (Ni,Co)CrAlY overlay coatings to provide a better oxidation/corrosion resistance. The MCrAlY coatings are known to interact both with the corrosive environment (oxidation-induced Al-depletion) and the alloy substrate (interdiffusion), which are the two main chemical degradation modes of such coating systems. The chemical lifetime prediction is one of the fundamental issues in the gas turbine technology. In general practice, the lifetime estimates are based on extensive experimental testing. A reasonable alternative to this tedious and time consuming practice is the CALPHAD-based thermodynamic-kinetic modelling. In the present study the interaction between a commercial (Ni,Co)CrAlY coating with model single-crystal Ni-Cr-Al-X (X = Co, Ta, W) alloys was investigated. In all tested coating systems the formation of secondary βNiAl was observed in the alloy substrate. Scanning electron microscopy (SEM) and electron microprobe analysis (EPMA) provided local element concentrations in a multiphase microstructure. The extent and the character of the microstructural changes are dependent on the substrate chemistry. The effect of the alloying elements in the substrate on the interdiffusion processes and β-NiAl depletion was evaluated by employing a thermodynamic-kinetic model. The model was able to explain the observed microstructural changes in the investigated coating systems. A good agreement was observed between the measured and calculated phase fractions and positions of the interfaces between the different multiphase zones.

in power boilers (reducing the amount of NOx) leads to the introduction of ammonia, which is very chemically aggressive, to the fuel mixture in the combustion chamber. In this paper, laser clad and thermal sprayed (HVOF) layers of fine grain powders (15 µm) were examined. Long-term tests of corrosion resistance of boiler steel P265GH covered with the coatings were conducted. The tests were performed at 450oC for 1000 hours in a complex corrosive atmosphere containing: N2 + 10% CO + 0,2 % HCl + 0,08% SO2 + ammonia (contents in the mixture within 2÷5 ppm). This type of environment is considered as a model for tests of high temperature corrosion of materials for service in power boilers with low-emission combustion. The structure of the coatings examined was characterized before and after the corrosion tests (LM, SEM, XRD). The tests revealed that in the corrosive environment analyzed, the laser clad coating provides better protective properties for steel. 4:50pm A1-1-11 Synthesis of MCrAlYCcoatings via an Electrolytic Codeposition Process, J. Witman, B. Bates, Ying Zhang ([email protected]), Tennessee Technological University, USA MCrAlY coatings were synthesized by electrolytic codeposition of CrAlYbased particles and a metallic matrix of Ni or Ni-Co to form a composite coating, followed by a diffusion treatment at elevated temperatures. The electro-codeposition experiments were carried out in both beakers and a rotating barrel system. The effects of several important deposition parameters on the amount of particles incorporated in the composite coating were investigated, including current density, agitation rate, particle shape/density, and concentration of particles in the solution. As compared to the beaker setup, the barrel system demonstrated the capability of coating the entire specimen with a more uniform coating thickness and particle incorporation. The influence of post-deposition heat treatment parameters, such as temperature and environment (Ar vs. vacuum), on the surface composition of the MCrAlY coatings was also studied.

Hard Coatings and Vapor Deposition Technology Room: California - Session B1-2

4:10pm A1-1-9 Interdiffusion between MCrAlY Bond Coats and Nibase Single-Crystal Superalloys, Philipp Terberger ([email protected]), R. Vaßen, Forschungszentrum Jülich, Germany Ni-base single-crystal superalloys with plasma sprayed thermal barrier coatings are commonly used for high-temperature, high-load applications in gas turbine blades. The thermal barrier coating often consists of a MCrAlY (M=Ni,Co) bond coat for oxidation protection and a ceramic top coat for thermal insulation. During operation interdiffusion between the superalloy substrate and the metallic bond coat takes place. On the one hand, interdiffusion is needed for good adhesion of the bond coat. On the other hand, interdiffusion induced loss of critical elements in the bond coat and the resulting deterioration of the superalloy microstructure are undesirable. In this work, the interdiffusion is investigated and quantified for three distinct crystal orientations of the Ni-base single-crystal superalloy CMSX4, namely [001], [100], and [110]. The substrate surfaces are subjected to different pretreatment processes and then coated with a bond coat using vacuum plasma spraying. Three different MCrAlY bond coats are used to study the influence of the chemical composition on the interdiffusion behavior: a Ni-base, Al-rich bond coat, a Ni-base, Al-rich bond coat with Re additions, and a Co-base bond coat with reduced Al content. After an initial diffusion bonding process at 1140 °C for 4 h and 870 °C for 16 h, heat treatment is conducted isothermally at 1050 °C in air for up to 1000 h. SEM investigations show that the microstructures of the interdiffusion zones at the beginning of thermal treatment are similar to the bond coat microstructures. This can be observed best for the Re-containing bond coat which shows precipitation of Cr-rich phases in the bulk coating and the interdiffusion zone that are consistent with thermodynamic simulations. During thermal treatment the interdiffusion zones evolve in different ways, depending on the chemical composition of the bond coat. The Co-base bond coat forms a slightly thicker interdiffusion zone than the Ni-base bond coats. However, the choice of surface pretreatment is found to be the main reason for different sizes of interdiffusion zone and secondary reaction zone. The impact of the crystal orientation zone is negligible for both zones.

PVD Coatings and Technologies Moderator: Alpana Ranade, GE Aviation, USA, Steffen Weißmantel, University of Applied Sciences Mittweida, Germany, Jyh-Wei Lee, Ming Chi University of Technology, Taiwan 1:50pm B1-2-2 Effect of Oxygen Incorporation on the Structure and Elasticity of Ti-Al-O-N Coatings Synthesized by Cathodic Arc and High Power Pulsed Magnetron Sputtering, Marcus Hans ([email protected]), M. to Baben, D. Music, J. Ebenhöch, RWTH Aachen University, Germany, D. Primetzhofer, Uppsala University, Sweden, D. Kurapov, M. Arndt, Oerlikon Balzers, Oerlikon Surface Solutions AG, Liechtenstein, H. Rudigier, Oerlikon Balzers Coating AG, Liechtenstein, J.M. Schneider, RWTH Aachen University, Germany Ti-Al-O-N coatings were synthesized by cathodic arc and high power pulsed magnetron sputtering. The chemical composition of the coatings was determined by means of elastic recoil detection analysis and energy dispersive X-ray spectroscopy. The effect of oxygen incorporation on the stress-free lattice parameters and Young’s moduli of Ti-Al-O-N coatings was investigated by X-ray diffraction and nanoindentation, respectively. As nitrogen is substituted by oxygen, implications for the charge balance may be expected. A reduction in equilibrium volume with increasing O concentration is identified by X-ray diffraction and density functional theory calculations of Ti-Al-O-N supercells reveal the concomitant formation of metal vacancies. Hence, the oxygen incorporation-induced formation of metal vacancies enables charge balancing. Furthermore, nanoindentation experiments reveal a decrease in elastic modulus with increasing O concentration. Based on ab initio data, two causes can be identified for this: First, the metal vacancy-induced reduction in elasticity; and second, the formation of, compared to the corresponding metal nitride bonds, relatively weak Ti-O and Al-O bonds.

4:30pm A1-1-10 Long-term Tests of Resistance of Laser Clad and Thermal Sprayed Inconel 625 Coatings to Hot Gas Corrosion in a Complex Atmosphere Containing HCl, SO2, and Ammonia, Barbara Iwaniak ([email protected]), Hi-Technology, Poland, D. Paluch, A. Iwaniak, Silesian University of Technology, Poland Inconel 625 coatings are used in the chemical and energy industries, among others, for the protection of construction elements working in difficult corrosive conditions. The necessity of reducing emissions from combustion

Tuesday Afternoon, April 21, 2015

2:10pm B1-2-3 Improvement of the Fatigue and Wear Resistance of the Nitride-based Coatings used in Forming Tool Applications, Ali Khatibi ([email protected]), M. Arndt, Oerlikon Balzers, Oerlikon Surface Solutions AG, Liechtenstein Forming tools are subjected to a high level of cyclic loads. This results in an increased rate of abrasive and adhesive wear as well as fatigue of the tool material. Therefore, application of wear and fatigue resistant coatings may decrease the deterioration rate of the tool resulting in a longer tool life. This

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along with the less frequent maintenance of the tool/die gives rise to the productivity of the whole system. Commercially available nitride-based coatings have shown great potential for such purposes. However, in many cases these coatings were originally aimed for improvement of cutting tools functionalities where the failure mechanisms may differ significantly compared to those in forming tool applications. Development of more fatigue and wear-resistant coatings devoted to forming tool applications is further motivated by the increasing utilization of AHSS metal sheets used in e.g. automotive industry. In this respect, the role of alloying elements in improvement of wear and fatigue resistance of the binary, ternary and quaternary nitride-based coatings are of great potential for more intensive investigations.

Additonaly, a simple and direct testing method was developed that enables quantitative measurements of the soldering behavior between the die casting alloys and the coated dies. 3:30pm B1-2-7 Fabrication and Characterization of Nanolayered Single Element Nitride Coating: Case for TaN and HfN, Ya-Huei Yang, K.Y. Liu, Y.X. Qiu, J.H. Wu, F.B. Wu ([email protected]), National United University, Taiwan Through Ar/N2 inlet gas ratio control during magnetron sputtering, Tantalum nitrides (TaN) and Hafnium nitrides (HfN) layers were manipulated with amorphous and crystalline structure .The columnar crystalline structures of TaN and HfN were fabricated under Ar/N2 ratios of 18/2 and 19/1 sccm/sccm respectively, while the amorphous structure appeared at 12/8 and 17/3. The thickness, deposition rate, as well as crystallinity of TaN and HfN decreased with increasing N2 flow. The X-ray diffraction patterns of TaN under the ratio of 18/2 showed strong peaks of TaN phase with a preferred orientation (200). The TaN crystalline feature diminished at a higher N2 flow. For HfN, the X-ray diffraction patterns showed the phase transition from 18/2 to 17/3 of Ar/N2 ratio. The surface condition of HfN was smooth relatively and the surface roughness (Ra) slightly increased with N2 flow. To enhance the mechanical properties of TaN and HfN films, crystalline and amorphous layers with various bilayer thickness and ratios were alternately stacked into nano-multilayers, i.e. cTaN/a-TaN and c-HfN/a-HfN. The multilayer coating has slightly lower hardness and Young’s modulus, but shows a better adhesion and lower friction coefficient than single layer coating. Characterization of multilayer amorphous/crystalline coatings was investigated and discussed.

2:30pm B1-2-4 Influence of Composition on the Wear Properties of Boron Carbonitride (BCN) Coatings Deposited by High Power Impulse Magnetron Sputtering, Tina Hirte ([email protected]), R. Feuerfeil, V. Peréz-Solórzano, T. Wagner, Robert Bosch GmbH, Germany, M. Scherge, Fraunhofer Institute for Mechanics of Materials, IWM, Germany Boron carbonitride (BCN) is a promising candidate for wear protection applications, because of its mechanical and tribological properties, such as hardness, coefficient of friction, wear resistance and temperature stability. In this work, we investigate the influence of the composition of such BCN coatings on the mechanical and tribological properties of wear resistant films. In a previous study we focused on BCN coatings with a B:C ratio of 4:1 and variable nitrogen contents grown by sputtering from a B 4C target in pulsed DC or High Power Impulse Magnetron Sputtering (HiPIMS) mode. The film’s structure in this area of the ternary phase diagram was amorphous and showed high hardness, but coefficients of friction in dry testing conditions were comparably high. In this study, we aim to improve the film’s tribological behavior by modifying the film’s carbon content by reactive sputtering with acetylene or pulsed DC co-sputtering from a graphite target. Sputtering with acetylene is advantageous for industrial applications due to a high deposition rate, however, reactive sputtering with acetylene leads to an incorporation of hydrogen into the coating structure which is detrimental to the temperature stability of the films. Therefore, we compare the tribological properties and temperature stability of films deposited by reactive sputtering with acetylene and hydrogen-free BCN films. Furthermore, we discuss the influence of the high ionization of plasma species found in HiPIMS observed by optical emission spectroscopy on the film composition and resulting mechanical properties and temperature stability. Finally, we correlate the coating composition determined by X-ray photoelectron spectroscopy with topography and morphology examined by scanning electron microscopy and hardness as well as adhesive properties determined by nano- and Rockwell indentation.

3:50pm B1-2-8 High Transparency AZO film Synthesis by Magnetron Sputtering with Dual Confined High Density Magnetic Field, Long Wen, Sungkyunkwan University, Korea, S.B. Jin ([email protected]), Sungkyunkwan Univerisity, Korea, M. Kuma, B. Sahu, J. Han, Sungkyunkwan University, Korea Al doped ZnO(AZO) thin film has been attracting as one of promising candidate film replacing ITO film for transparent conductive oxide film of next generation flexible digital electronics devices. The relatively low resistivity and transparency of AZO film deposited at low temperature are still hurdles to overcome for replacing ITO film even though its unique advantages in low cost and high toughness over those of ITO film. It is well known that resistivity is closely associated with carrier concentration and mobility which are controlled by stoichiometry, binding energy of atoms and lattice defects of film including oxygen vacancy as well as Al replacement in Zn atom sites. The control of those atomistic structures and lattice defects are affected by surface energy accumulated with atoms and molecules deposited at top surface layer during film nucleation and growth depending on process parameters during deposition process. The surface energy is mostly comprised of kinetic energy of neutrals, electronic energy of activated neutral molecule and atoms and ions as well as flux density. We have investigated effects of those atomic and molecular level energy analysis on structure formation and related electrical property changes by in-situ diagnostics during sputtering process under dual confined high density magnetic field. The kinetic energy and flux of sputtered atoms are controlled by independent variation of power density for direct sputtering and in-direct sputtering targets on polymer substrate at low temperature. Optical emission spectroscopy and radical diagnostics as well as Langmuir probe analysis have been performed to measure plasma parameters. Carrier concentration and mobility have been analyzed depending on microstructure changes including binding energy of atoms and Al replacement of Zn site etc.. The resistivity is significantly reduced with atomic level nano process control and can be reached less than 6E-4 at low temperature. This paper discusses on fundamental mechanism of film nucleation and growth with top surface energy accumulation with atomic and molecular energy diagnostics for AZO film synthesis by dual confined high density magnetic field, and illustrates control of resistivity associated with control of carrier concentration and mobility. Also, the transmittance of the films is controlled with optimization of high plasma density.

2:50pm B1-2-5 Low Temperature In-situ Crystallization TiNi Shape Memory Thin Film Deposited by Magnetron Sputtering, Hikmet Cicek ([email protected]), I. Efeoglu, Y. Totik, K.V. Ezirmik, E. Arslan, Atatürk University, Turkey TiNi films deposited by magnetron sputtering are usually have amorphous structure and must annealed at high temperature to crystallization. We were synthesized in-situ fully crystalline TiNi shape memory thin film at low temperature by closed-field unbalanced magnetron sputtering. Applying pulse- dc to the substrate has effective to obtain crystalline TiNi film. Nine different deposition conditions were used to obtain crystalline structure. Silicon and thin copper plates were used as substrates. Structural and transformation temperature properties of the TiNi films were investigated. To examine the structural properties of the fabricated films, XRD, SEM and EDS were used. Austenitic and martensitic transformation temperatures and hysteresis were observed via DSC (differential scanning calorimeter). TiNi (110) B19 martensite peaks were obtained from as deposited films. Crystalline TiNi films showed single-stage phase transformation (B19 to B2 on heating and B2 to B19 on cooling).

4:10pm B1-2-9 Bio-inspired Organic/Inorganic Multilayer Coatings Synthesized by RF Sputtering and Pulse Laser Deposition, Po-Yu Chen ([email protected]), H.-M. Yang, T.-H. Hsu, H.-K. Chang, Y.-C. Chan, National Tsing Hua University, Taiwan, J.W. Lee, Ming Chi University of Technology, Taiwan, J.G. Duh, National Tsing Hua University, Taiwan INVITED Biological materials are often functionally optimized through million years of evolution. Abalone nacre possesses exceptional mechanical properties to prevent predatory. Consisting of 95 wt.% CaCO3 with only 5 wt.% organics contents, nacre has formed a unique “brick-and-mortar” microstructure which significantly enhanced its toughness. Arthropod exoskeleton has multilayer twisted plywood structure with graded mechanical properties,

3:10pm B1-2-6 Study on AlCrN Coatings Deposited by Modulated Pulsed Power Magnetron Sputtering for Lube Free Die Casting, Bo Wang, G. Bourne, S. Midson, A. Korenyi-Both, M. Kaufman ([email protected]), Colorado School of Mines, USA During Al die casting, it is important to prevent the soldering that frequently occurs between the Al alloy and the steel dies and core pins. The overall objective of this study is to develop coatings that are non-wetting with liquid Al with the long-term objective of circumventing the need to use liquid-based organic lubricants prior to each shot. In this research, AlCrN coatings have been deposited on H13 tool steel by modulated pulsed power magnetron sputtering (MPPMS). The structural, mechanical, tribological and adhesion properties of the AlCrN coatings will be described.

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consisting of hard external exocuticle and tough endocuticle, which give better impact resistance. Sponge spicules are composed mainly of SiO2 and small amount of proteins organized into a concentric structure. The organic/inorganic interfaces prevent crack propagation and significantly enhance fracture toughness. Inspired from the organic/inorganic multilayer composites in nature, a novel PVD system combining reactive RF sputtering and pulsed laser deposition is designed and utilized. The ceramic constituents are coated by RF sputtering and polymer phases are synthesized by ultraviolet pulsed laser deposition. Three examples will be illustrated in this talk. Firstly, ceramic (ZrN, ZrO2) and polymer (PMMA, polyimide) multilayer films were successfully fabricated to mimic the abalone nacre structure. By changing the thickness ratio and interfacial roughness of organic and inorganic layers, better fracture toughness of thin films was obtained. Secondly, a multifunctional composite composed of hard ZrO2 outer layers and tough TiO2/polyimide inner multilayers was designed to mimic the arthropod exoskeletons, resulting in a hybrid coating with both good abrasion resistance and high impact resistance. Finally, SiO2/PDMS multilayer thin films inspired from sponge spicules, which has high transparency and crack resistance, were synthesized and can be applied as flexible optical device. The energy-based micro-indentation fracture toughness test was performed to evaluate the fracture toughness of thin films, while the impact resistance of protective coatings was measured by cyclic dynamic loading on specimens. Through these studies, toughening mechanisms were elucidated and optimal bio-inspired designs for novel multifunctional coatings were established.

Hard Coatings and Vapor Deposition Technology Room: Golden West - Session B4-2 Properties and Characterization of Hard Coatings and Surfaces Moderator: Uwe Beck, BAM Berlin, Germany, ChauChang Chou, National Taiwan Ocean University, Taiwan, Grzegorz Greczynski, Linköping University, IFM, Sweden 1:50pm B4-2-2 Thermal Effects Influencing Stability and Performance of Coatings in Automotive Applications, J. Becker ([email protected]), Oerlikon Balzers Coating Germany GmbH, Germany, Astrid Gies, Oerlikon Balzers, Oerlikon Surface Solutions AG, Liechtenstein, S. Hessel, Oerlikon Balzers Coating Germany GmbH, Germany, J. Karner, Oerlikon Balzers Coating AG, Liechtenstein INVITED Coatings are well established to solve tribological problems in automotive applications. In systems under high load and / or high pressure carbonbased coatings, usually called DLC for diamond-like carbon, reduce friction and wear. Other coatings, e. g. chromium nitride coatings, are useful to prevent scuffing. A real challenge in evaluating coatings for their suitability in automotive applications is the broad range of conditions which defines the load collective of the tribological system. Current investigations are focused on the temperature. The temperature range of a tribological system in a car engine may be much broader than the -20°C to 120°C as given by the average oil temperature. In the frictional contact with and without temporary dry running the temperatures may be higher by up to several hundred degrees Celsius. These local temperatures affect the properties of the elements of the tribological system; but the temperature itself may be influenced by the properties of these elements. The relatively low thermal conductivity of coatings results in high local and transient temperature peaks. This may lead to a degradation of a carbon-based coating or to a lower viscosity of an intermediate medium like oil. A simple calculation following Blok’s approach gives an approximation for the peak temperature in the frictional contact. An uncoated surface gets a localized additional temperature share of about 125°C at 400 MPa Hertzian pressure. Due to the low thermal conductivity of some actual coatings which were measured to be in the range of 0.8 WK-1m-1 to 7.0 WK-1m-1 the respective temperature rise can be as high as 300°C. Assuming a base temperature of 100°C this additional temperature would be well above the graphitization temperature of a DLC coating of about 350°C. While graphitization limits the application of DLC, it also allows the great running-in properties of carbon-based coatings. Measurements with a pin-on-disc test set-up and a SRV test set-up (reciprocating wear test) give a deeper insight. It is widely accepted that coatings show a significant effect when the tribological system runs in mixed lubrication or even in boundary lubrication: body and counter-body are at least partially in contact and the friction itself is dominated by the properties of the coating. An impressive friction reduction can also be obtained under full lubrication, when body and counter-body are well separated. In this case, the relatively low thermal conductivity of coatings results in a locally reduced viscosity of the intermediate medium by the local “heat confinement”. A simple tribometer shows a friction reduction under full lubrication of up to 50%.

4:50pm B1-2-11 The Effect of Substrate Pulsed Bias Voltage on Microstructure, Mechanical Properties and Coating-Substrate Adhesion of PVD Cr-Cu-N Nanocomposite Films, Xingguang Liu, L. Liu, A. Leyland ([email protected]), A. Matthews, The University of Sheffield, UK Cr-Cu-N nanocomposite coatings of varying copper content were produced using an unbalanced magnetron sputtering system. Pulsed DC (PDC) and fixed DC (FDC) bias voltages were applied to the substrates, in order to investigate the effects of a direct pulsed bias on the coating-substrate adhesion, hardness, elastic modulus and microstructure. Coating adhesion strength was measured by scratch testing. Coating surface and crosssectional morphology were observed by high-resolution field-emission gun scanning electron microscopy (FEG-SEM). The hardness and elastic modulus were measured using nanoindentation. The chemical and phase composition were investigated using energy dispersive X-ray spectroscopy (EDX) and X-ray diffraction (XRD). Results showed that PDC coatings exhibit better coating-substrate adhesion compared to FDC coatings. The thicknesses of both PDC and FDC coatings ranged from 2.1 μm to 6.3 μm, depending mainly on the relative sampletarget distance during deposition. PDC coatings showed more compact and almost equiaxed fracture cross sections compared to FDC coatings, which appeared columnar and porous. It was also shown that coatings with higher Cu content tend to exhibit a more obviously columnar structure, regardless of substrate bias condition. 5:10pm B1-2-12 Reversing the Inverse Hardness-Toughness Trend using W/VC Multilayer Coatings, Kaicheng Shi ([email protected]), Shanghai Jiao Tong University, China, C. Wang, Northwestern Polytechnical University, China, C. Gross, Y.W. Chung, Northwestern University, USA It is desirable to increase the hardness of protective coatings for reduced abrasive wear and to increase the toughness for improved wear performance due to fatigue and formation of flaws or cracks. Unfortunately, there is an inverse relationship between hardness and toughness: the harder the coating, the lower the toughness. Using W/VC multilayer coatings, we demonstrated that it is possible to reverse this hardness-toughness trend. These coatings were synthesized by DC magnetron sputtering with bilayer periods of about 10 nm and different thickness fractions of W. They are crystalline, with hardness and toughness exceeding that of pure VC (25 GPa and 1.0 MPa-m1/2). In particular, the W/VC multilayer coating with thickness fraction of 90% W achieves hardness of 28.5 GPa, comparable to many ceramics-based hard coatings, and toughness of 7.5 MPa-m1/2, similar to many nanocrystalline metals. This investigation shows that one can synthesize coatings as hard as ceramics and as tough as metals. These results also indicate that H/E and H3/E2 (H = hardness and E = elastic modulus) are not good proxies for coating toughness.

Tuesday Afternoon, April 21, 2015

2:30pm B4-2-4 Hydrogen Permeation Behavior of Nitride Coatings and Surface-nitride Stainless Steel, Motonori Tamura ([email protected]), The University of Electro-Communications, Japan Thin ceramic nitride coatings such as TiN and BN deposited by PVD on steel substrates have been shown to reduce hydrogen permeability and such coating materials can be applied to the structural metals in fusion plants or the components in fuel cells. However, there was limited information on hydrogen permeation of surface-nitride stainless steel. The hydrogen permeation behavior of surface-nitride SUS316L stainless steel was investigated in comparison with nitride coatings. Various nitride methods were applied and the relation between the characterization of the nitride surface of stainless steel and the hydrogen permeation behavior was evaluated. Some surface gas-nitride methods (nitride thickness was 1-3 μm) were effective to reduce the rate of hydrogen permeation of stainless steel by a factor of more than 10.

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2:50pm B4-2-5 Influence of Target Composition and Bias Voltage on the Microstructure, Mechanical, Tribological and Thermal Properties of Arc Evaporated Ti1-xAlxN Hard Coatings, Birgit Grossmann ([email protected]), N. Schalk, Montanuniversität Leoben, Austria, C. Czettl, M. Pohler, CERATIZIT Austria GmbH, Austria, C. Mitterer, Montanuniversität Leoben, Austria For various machining applications tailored coating properties are necessary. Within this work, the properties of arc evaporated Ti 1-xAlxN hard coatings were systematically investigated by varying the Al content and the deposition parameters. A series of Ti1-xAlxN coatings was deposited from four different targets with Al/Ti atomic ratios of 40/60, 50/50, 60/40 and 67/33, using two different sets of deposition parameters; one with a low bias voltage of -40 V and one with a high bias voltage of -100 V. The Al/(Al+Ti) fraction was in all coatings slightly lower than in the respective targets. All coatings deposited from targets with an Al fraction of x=0.60 or higher showed dual-phase structures consisting of cubic and wurtzite phases, where formation of wurtzite was promoted by a lower bias voltage. Due to an increasing amount of the wurtzite with increasing Al content, hardness and Young’s modulus significantly decreased, resulting also in a deterioration of the tribological properties at room temperature. However, at elevated temperatures high Al contents proved to be beneficial, since formation of an Al-rich oxide scale leads to reduction of friction and wear coefficient. The higher bias voltage resulted in a significantly higher droplet density on the coating surface and thus, in a slightly worse tribological behaviour, especially at room temperature. Additional annealing tests in vacuum and differential scanning calorimetry with subsequent X-ray diffraction were done, to illuminate the effect of the Al content and the growth conditions on the thermal stability of the coatings.

3:30pm B4-2-7 Measuring Elastic Constants of TiZrN Thin Films by Combining cos2α sin2ψ XRD and Laser Curvature Methods : Effect of Film Compositions, Hung-Lun Liu, G.P. Yu ([email protected]), J.H. Huang, National Tsing Hua University, Taiwan Measurement of elastic constant € with good precision and accuracy is crucial for thin film applications. Accurate Young’s modulus of thin films can be used in calculating storage energy (Gs) and various industrial uses. TiZrN thin film was chosen to be the model material, because it remained single phase structure in the entire compositional range when deposited at temperatures below 500oC and possessed superior mechanical properties compared with binary TiN and ZrN. In this study, we proposed a standard procedure to determine the elastic constants of polycrystalline TiZrN thin films, by which the effects of composition on elastic constants were studied. The residual strain of the thin films was measured by cos2αsin2ψ X-ray diffraction method at multiple rotational angles (φ). From the slope of strain vs. cos 2αsin2ψ plot, we can obtain average X-ray strain (AXS), which can effectively lower the statistical fluctuations. The residual stress of the thin films was determined using laser curvature method. Combing AXS from cos 2αsin2ψ method, and stress from laser curvature method, we could obtain average effective X-ray elastic constant (AEXEC = E/1+υ). In this study, TiZrN films with three different compositions were deposited on Si (100) substrate using unbalanced magnetron sputtering . The AEXECs were measured by the proposed method, and the effect of different Ti/Zr compositions was investigated. Since Young’s modulus is derived from atomic interaction in a solid, the variation in composition will lead to the change of interatomic force in TiZrN films, and thereby affecting the elastic constants. The variation of the resultant AEXEC with Ti/Zr ratio was discussed and correlated with the elastic constants of TiN and ZrN.

3:10pm B4-2-6 Plasma-sprayed Coatings: Identification of ElastoPlastic Properties using Macro-indentation and an Inverse LevenbergMarquardt Method, Nora Kind ([email protected]), B. Berthel, S. Fouvry, LTDS - Ecole Centrale de Lyon, France, C. Poupon, O. Jaubert, Airbus Group, France Plasma-sprayed coatings are widely used for thermal protection and wear stability of components and their importance with respect to structural durability is significant. These coatings feature an anisotropic porous structure as a direct result of the thermal spraying process. Although current literature provides methods for the identification of elastic properties of these materials, to our knowledge little research is dedicated to describing their plastic behavior, let alone to identifying the coatings’ plastic properties when subjected to macro-scale contacts encountered in industrial applications. In this work we present a novel inverse method for the identification of elasto-plastic properties of thick plasma-sprayed coatings by means of macro-indentation, providing a macroscopic contact, and the LevenbergMarquardt algorithm. In contrast to conventional instrumented indentation techniques that rely on a precisely measured load-displacement curve of indentation, the proposed method only requires knowledge of the residual indentation profile. In this study we investigate various coatings featuring a thickness of around 150μm and degrees of porosity of 1.0-5.5%. For macro-indentation an experimental device based on a servo-hydraulic testing machine with a maximum capacity of 25kN was employed. Here, both spherical and flatended conical indenters were used. Interferometric profilometry was employed for 3D profiling of the residual indents, followed by deduction of a representative 2D-trace by azimuthal averaging of that profile around its central axis. For the determination of the coatings’ E-modulus and degree of porosity a conventional CSM micro-indentation instrument with different indenters and optical microscopy were used, respectively. For a description of the coatings’ plastic behavior we made use of the Gurson-Tvergaard plasticity criterion coupled to a linear isotropic work hardening of the matrix. This criterion is appropriate for ductile porous solids as it takes into account the hydrostatic pressure, and it is readily implementable in Abaqus. The constitutive parameters to be identified include the yield strength σy0 and the work hardening coefficient K of the solid matrix as well as two dimensionless fitting parameters q1 and q2. These unknowns were successfully identified using the gradient-based Levenberg-Marquardt method that recursively updates input variables of the Abaqus-implemented FEM model to obtain a numerical indentation profile that sufficiently approximates the experimentally obtained one. We could show that the proposed method is reliable to identify the plastic properties of all investigated coatings.

3:50pm B4-2-8 Cutting Performance and Wear Behavior of AIP Deposited AlCrN Based Coating, Hiroaki Nii ([email protected]), K. Yamamoto, M. Abe, Kobe Steel Ltd., Japan AlCrN based coatings becomes popular as a protective coating for various cutting tools in addition to TiAlN based coatings. It has been reported that AlCrN based coating shows better oxidation resistance and can retain mechanical property at elevated temperatures. In this study, a series of AlCrN based coating was investigated their cutting performance and wear behavior. A series of AlCrN based coatings were deposited at 500CΟ in nitrogen atmosphere by arc ion plating (AIP-SS002) under different compositions and deposition conditions. After the deposition, samples were subjected to standard compositional and structural analysis such as EDX, XRD and nano-indentation measurement for mechanical property. Cutting performance was determined by drilling tests, using WC-Co drills (MDS085SG, Sumitomo Electric Hardmetal). Regarding the cutting conditions, cutting speed is 75m/min., feed is 0.24mm/rev., depth of cut is 23mm, and work material is chrome molybdenum steel (AISI4140). These all coating showed hardness more than 30GPa by nano-indentation, and monolithic cubic phase by XRD regardless of applied substrate bias. Residual compressive stress shows its maximum around substrate bias of 100V. Hardness slightly decreased as the substrate temperature was increased. Cutting tests were conducted up to a few thousand holes and from the observation of the flank wear, flank wear width decreased with increasing substrate bias voltage. After cutting 1000 holes, the cross-section of cutting edge was observed by TEM. The worn surface was covered by oxide, and the oxide was consisted of coating and workpiece material like Al, Mn and Si. The wear mechanism of AlCrN based coating in drilling operation will be considered. 4:10pm B4-2-9 Mechanical and Tribological Properties of PVD Titanium-based Multilayer Coatings with Modulated Nitrogen-totitanium Ratio, Chanon Iamvasant, J. Kavanagh, A. Matthews, A. Leyland ([email protected]), University of Sheffield, UK There is a sustained interest in protective coatings and treatments for a variety of erosion resistance applications, including particulate erosion, liquid cavitation and water droplet impact. Among many other potential candidates, PVD ceramic-ceramic and ceramic-metal multilayer coatings have been extensively investigated in this regard (and some are now used commercially – eg. TiN/Ti) whilst, for example, duplex nitriding + PVD ceramic coating has recently been explored for cavitation erosion resistance. Several coating models have also been proposed for water droplet erosion protection (including PVD multilayer architectures) – but with little or no test validation of their durability. Furthermore, the way in which the impact energy is delivered to the (coated) substrate can be very different for each of the three main erosion regimes listed above; thus there may be no single ‘optimal’ coating architecture which can satisfy all requirements. One of the most widely reported PVD multilayer architectures for particulate abrasion and erosion protection is the TiN/Ti ceramic-metal system, where

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alternating layers of hard/soft (or, in this particular case also, stiff/compliant) material can impart satisfactory performance. In this study, we examine the mechanical and tribological behaviour of the PVD Ti-N binary system, but also include ‘nitrogen-doped’ Ti (and/or substoichiometric TiN), to explore the influence of different hardness/ductility (and H/E ratio) coating layer characteristics on film performance. We also discuss the specific effects of phase constitution in the metallic layer (eg. Titanium is polymorphic – and the ‘high-temperature’ bcc beta phase has very different physical properties to the ‘ambient-temperature’ hcp alpha phase), considering how the use of different Ti-alloy layers might beneficially modify overall coating performance.

chronoamperometry were used to reduce MB to leucomethylene blue (LMB) and thereby change the optical properties of the SAM without changing its integrity. The response of the functionalized SCTF is detected using both electrochemistry and in-situ generalized spectroscopic ellipsometry in the visible spectral range. In addition, information about the integrity of the SAM as well as the double layer capacitance was monitored by quartz crystal microbalance with dissipation (QCM-D). For the first time electrochemically induced changes of the optical adsorption of analytes attached to the surface an SCTF are detected ellipsometrically. We find that effective medium based optical model approaches allow accurate analysis of measured optical response. The combination of simultaneous in-situ electrochemical, QCM–D, and ellipsometric characterization opens new avenues to characterize highly ordered nanostructured surfaces and will advance the fundamental understanding of analytical electrochromic processes in the vicinity of these surfaces.

Fundamentals and Technology of Multifunctional Thin Films Room: Sunset - Session C2

2:30pm C2-4 Copper Oxide Thin Films: Comparative Study of Spectroscopy Ellipsometry and Morphology for Gas Sensing Applications, A. Bejaoui, City University of Hong Kong, China, A. Labidi, Université de Carthage, Tunisia, J. Guerin, K. Aguir, Université AixMarseille, France, C.H. To, JuanAntonio Zapien ([email protected]), City University of Hong Kong, China We study cuprous oxide, Cu2O, thin films prepared by RF reactive magnetron sputtering with film thickness between 50 and 400 nm. The structural and morphological properties of the as-prepared and thermally annealed films, 400 °C for 30 min under ambient conditions, are investigated by X-ray diffraction, scanning electron- and atomic forcemicroscopies. These measurements are correlated with optical characterization by spectroscopic ellipsometry (SE) in the wavelength range from 200 to 1700 nm. The SE data was analysed to obtain a unique solution for multi-sample, multi- angle of incidence to obtain the optical constants, thickness and porosity of the prepared films. The as-deposited films can be readily modelled by a homogeneous bulk film with a small surface roughness. In contrast, annealing is found to result in cupric oxide (CuO) films as determined by x-ray diffraction and corresponding changes in morphology (increased surface roughness and porosity) as well as refractive index ‘n’, extinction coefficient ‘k’, and band gap. In particular, the annealed films present additional structure in the form of an inhomogeneous bulk film composition characterized by a void volume fraction gradient attributed to density changes resulting from the large CuO grains after annealing. Significantly, SE reveals the non-homogeneous nature of oxygen incorporation with thickness upon annealing. The nature of such nonhomogeneity and implications for the use of annealed copper oxide films for resistivity sensing of ozone gas at 573 K are discussed. Acknowledgements: work supported by RGC-HKSAR (Project No. CityU 122812).

Novel Aspects in Thin Film Characterization and Data Modeling Moderator: Tino Hofmann, University of NebraskaLincoln, USA, Nikolas Podraza, University of Toledo, USA 1:30pm C2-1 Passive PT Symmetry in Organic Thin Films and Waveguides via Complex Index Modulation, Chris Giebink ([email protected]), Penn State University, USA INVITED Photonic crystals have led to numerous technological advances in areas ranging from optical communications to solid-state lighting by manipulating the flow of light through nanoscale variation in refractive index. Recently, exploration has begun to focus on a more generalized form of photonic crystal with independent variation of the real and imaginary refractive index components. Such ‘complex index modulation’ (CIM) has recently become the focus of intense theoretical interest because it forms the basis for parity-time (PT) symmetric optical potentials that enable one-way waveguides as well as more exotic effects such as unidirectional invisibility. It has nevertheless been challenging to realize CIM materials to date because of the added difficulty in controlling both refractive index components at subwavelength scale. Here, we demonstrate PT symmetric organic thin films by co-evaporating small molecules with different complex refractive indices (n=n+ik) and continuously varying the relative proportion of each during growth. Teflon and tris-(8-hydroxyquinoline)aluminum [Alq3] are used to vary the real index component (Δn) while 4-(dicyanomethylene)-2-methyl-6-(4dimethyleaminostyryl)-4H-pyran [DCM] is used to vary the imaginary index component (Δk). The index variation profile is made symmetric with respect to its complex conjugate as a function of position, x, along the film growth direction, resulting in the PT symmetry condition, n(x)=n*(-x). The resulting films are characterized by variable angle ellipsometry and reflectivity measurements, where we observe PT symmetry breaking through a maximum left/right asymmetry in normal incidence reflectivity at the exceptional point Δn = Δk, consistent with numerical simulation. We also demonstrate passive PT symmetry in the modal effective index of large area composite organic thin film waveguides achieved through shadowed oblique angle deposition of copper phthalocyanine on embedded photoresist sinusoidal gratings. PT symmetry breaking in the leaky waveguide is evident through asymmetry and the appearance of an exceptional point in the Littrow diffraction of light incident from opposite left/right directions. These results open up a new opportunity for organic materials to serve as a platform in studying PT symmetry in optics as well as an avenue for realizing integrated photonic devices such as unidirectional waveguides, coherent perfect absorbers, and all-optical switches.

2:50pm C2-5 Spectroscopic Ellipsometry Studies of n-i-p Hydrogenated Amorphous Silicon based Photovoltaic Devices, Laxmi Karki Gautam ([email protected]), M. Junda, H.F. Haneef, R.W. Collins, N.J. Podraza, University of Toledo, USA Thin film photovoltaics (PV) are reliant on the capability for characterizing the opto-electronic and structural properties of each layer over large areas and correlating these properties with electrical performance of the device. Growing and characterizing each layer in complete devices facilitate comparison of the substrate dependent growth process with individually grown layers. Spectroscopic ellipsometry (SE) provides not only the information about thickness and optical response in the form of complex dielectric function (ε = ε1 + iε2) of solar cell component layers but also band gap, grain size, defect density, disorder, and stress as well. We have applied SE to extract layer thicknesses, interface composition, and optical response in the form of ε for all doped and undoped hydrogenated silicon (Si:H) layers grown by plasma enhanced chemical vapor deposition (PECVD) onto a common sputtered back reflector (BR). In-situ real time SE (RTSE) is used during PECVD of Si:H to monitor the growth evolution and nucleation of crystallites from the amorphous phase of each layer as a function of hydrogen to reactive gas flow ratio R=[H2]/[SiH4]. A parameterized model has been developed for the BR structure consisting of sputtered intrinsic zinc oxide on top of silver coated glass substrates. Additionally, models generated from RTSE have been applied to study the room temperature exsitu visible range SE simultaneously with infrared extended SE (IR-SE) measurements ranging from 0.04 to 5 eV. In conjunction with higher photon energy range measurements, the use of reflection mode IR-SE has been successfully applied as an optical metrology technique for characterization of the hydrogen bonding configuration of amorphous Si:H thin films in the solar cell device configuration. This study has yielded identification of higher energy absorption features in each material, the relative absorption strength of various hydrogen-related modes in Si:H to give some insight

2:10pm C2-3 Electrochemical Reduction of Methylene Blue Immobilized on Highly Ordered 3-dimensional Nanostructured Surfaces Studied by in-situ EC, QCM-D and Generalized Spectroscopic Ellipsometry, A. Zaitouna, D. Sekora ([email protected]), Tino Hofmann, E. Schubert, M. Schubert, R.Y. Lai, University of NebraskaLincoln, USA The anisotropic optical properties of highly ordered, 3-dimensional nanostructured thin films change dramatically upon adsorption of analytes to the nanostructured surface. However, the dependence of these changes on the optical properties of the analyte has not been systematically studied. Here, use of a self-assembled monolayer (SAM) composed of both HS(CH2)6-OH and HS-(CH2)6-K-MB (methylene blue) as a model analyte. The SAM was deposited onto a 45 nm thick gold slanted columnar thin film (SCTF) grown by glancing angle deposition on a quartz crystal microbalance substrate. Alternating current voltammetry and

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into the hydrogen content, relative disorder within layers, and free carrier absorption in zinc oxide and silver components of the BR.

address the challenges of this approach by comparing different strategies in the selection of angle of incidence (AoI) and wavelength for both SE measurement and FDTD method modeling. This FDTD–SE approach inherits the distinctive advantages of the FDTD method: (i) calculation of spectral broadband results from a single simulation; (ii) sources of error are well understood, leading to the ability to simulate a large variety of electromagnetic problems; (iii) potential to simulate arbitrary general subwavelength to nano-sized structures and in particular single nanostructures; (iv) natural capacity as a time-domain technique to study complex optical phenomena such as plasmonic and nonlinear effects; and (v) ability to visualize field dynamics. Acknowledgements: work supported by RGC-HKSAR (Project No. CityU 122812). Y. Foo acknowledges support from the by RGC-HKSAR for HK PhD Fellowship Scheme 2014/15. References [1] K. T. Cheung, Y. Foo, C. H. To, J. A. Zapien, Towards FDTD modeling of spectroscopic ellipsometry data at large angles of incidence, Appl. Surf. Sci.281(2013) 2-7. [2] Y. Foo, K. T. Cheung, C. H. To, J. A. Zapien, On the development of Finite-Difference Time-Domain for modeling the spectroscopic ellipsometry response of 1D periodic structures, Thin Solid Films, in-press (Feb. 2014) DOI: 10.1016/j.tsf.2014.02.017.

3:10pm C2-6 Insights into the Physical Properties of Organic Based Thin Film Electronic Devices by Using Light-Bias, Modulation, and Transient Measurement Techniques, David Gundlach ([email protected]), National Institute of Standards and Technology, USA INVITED Organic thin film electronics offer the potential to significantly impact how humans interface with their surroundings and society in general. The ability to chemically-tailor the electrical and optical properties of organic semiconductors to achieve specific electronic functionality combined with the numerous low-cost additive processing methods by which organic semiconductors can be deposited offers the potential to realize electronics on arbitrary substrates or physical structures for current, emerging, and entirely new applications. Despite tremendous improvement over the past two decades in discrete device performance and several impressive advanced technology demonstrations, the fundamental understanding and quantification of the physical properties and processes that govern device operation remains limited compared to conventional semiconductors, such as silicon. In this presentation I will discuss the development and application of combined and correlated optical-electrical measurement methods to obtain a more nuanced understanding and quantification of the critical semiconductor and device properties and fundamental processes. In particular, I will discuss the use of steady state and pulsed light bias techniques combined with modulated, DC, and magneto electrical measurements tailored to the specific operating regimes of organic solar cells, light emitting diodes, and transistors to provide greater understanding of transport, lifetime, charge density, recombination kinetics, and electronic structure.

4:30pm C2-10 Structural, Optical and Electrical Characteristics of SrTiO3 Thin Films Deposited by RF Magnetron Sputtering, Turkan Bayrak, C. Ozgit-Akgun, M. Kumar, A. Haider, S.A. Leghari, A.K. Okyay, N. Biyikli, E. Goldenberg ([email protected]), Bilkent University, Turkey Strontium titanate, SrTiO3 (STO), is one of the promising oxides for application in modern nano electronics and optics, such as integrated devices, ultrathin gate oxide insulators, capacitors, dynamic random access memories. In this work, we present a comprehensive and systematic study on RF sputtered STO films by correlating their material properties with deposition parameters. STO films were deposited on Si (100) and UV fused silica substrates by radio-frequency (RF) magnetron sputtering using RF power of 75W at 0.4 Pascal total deposition pressure at room temperature (RT). The effect of oxygen flow rate on film characteristics was investigated. The oxygen content in the films was varied by changing the flow ratio of O2/Ar+O2 while the total flow was kept at 30 sccm. Film microstructure, optical and electrical properties were evaluated for both asdeposited and annealed films (700°C, 1 hour). The thickness of the films ranged from 71.6 to 251.5 nm, while the oxygen flow was varied between 0 to 20%. Film structure and optical properties were evaluated by grazingincidence X-ray diffraction, spectrophotometer, ellipsometry, and photoluminescence measurements. As-deposited and annealed films were found to be amorphous. The average optical transmission of as-deposited films was ~ 60% to 70% with the increased O2 content in the visible and near infrared spectrum, whereas optical transmission of annealed films was ~80% in the same spectrum. The optical band gap was found to be around 4.2 eV. The refractive index ranged from 2.04 to 2.12 and absorption coefficient was approximately zero at 550 nm. After the post-deposition annealing, the film refractive indices slightly increased (2.12 to 2.15 for 10% O2), while the band gap remained unchanged. Emission bands were investigated by photoluminescence measurements at RT, the band maxima was found in the visible region for all films. The results were corroborated by optical band gaps obtained via spectral transmission measurements. Metal-insulator-semiconductor (Ag/STO/p-Si) diodes were fabricated and characterized by capacitance-voltage, current-voltage measurements. The dielectric constants were found to be in the range of 20 to 260 within 50 to 900 kHz at RT.

3:50pm C2-8 X-RAY Scattering Methods for the Characterization of Layered Structures, Lars Grieger ([email protected]), J. Woitok, N. Norberg, PANalytical B.V., Netherlands Today’s technologies for electronic, optical, mechanical and energy devices are driven by the engineered development of advanced materials. One of the key aspects is the progress in growth technologies for the deposition of thinlayered structures with thicknesses down to the nanometer range. Typical materials that are involved are semiconductors, metal alloys, dielectrics and also polymers. The characterization and monitoring of the properties of a material are significant for its application and essential for further development and improvement. X-ray diffraction has been appreciated in research and analytical labs for a long time due to its nondestructiveness and versatility to study structural properties of materials of any kind. In recent years other relevant X-ray techniques evolved to meet the upcoming requirements: high-resolution diffraction, grazing-incidence diffraction, reflectometry, diffuse scattering and small angle scattering. From the scattering data, information can be extracted to identify and quantify phases, to determine composition and strain profiles, thickness, roughness, density, grain size, residual stress and preferred orientation. While in the past for each analysis method dedicated instruments were applied modern lab equipment with exchangeable optics offers all techniques on one single instrument. In this presentation a brief overview will be given about the experimental aspects including recent hardware developments and evaluation methods of X-ray characterization techniques. Their applicability to extract depth resolved structural information of advanced layered structures is illustrated on some examples of technologically relevant materials like TiN and CrN coatings. 4:10pm C2-9 Application of Spectroscopic Ellipsometry Data Analysis with Finite-Difference Time-Domain Method on 1D Periodic Structures, Yishu Foo, J.A. Zapien ([email protected]), City University of Hong Kong, Hong Kong Special Administrative Region of China Variable Angle Spectroscopic Ellipsometry (VASE) data analysis using the finite-difference time-domain method (FDTD method) could provide a general method for quantitative broadband optical characterization of nonlayered, structurally complex samples, including metallic nanostructures. Specifically, our results demonstrate an alternative approach to in-situ critical dimension (CD) monitoring using rigorous coupled wave analysis (RCWA) and Spectroscopic Ellipsometry (SE). In this contribution, we show the accuracy limit of this approach by calculating the SE response of both metallic and dielectric ideal thin films. We then demonstrate a practical multi-parameter broadband optimization of the SE response from 1D periodic structure. This method requires a variable angle variable wavelength approach in acquiring SE measurements as to overcome frequency response limits in the FDTD method model. We

4:50pm C2-11 Determination of Low Absorption Levels in Dielectric Films using the R&T Direct Absorption Method, R. Vernhes, Ludvik Martinu ([email protected]), Polytechnique Montreal, Canada Assessing absorption in optical thin films can be challenging, especially when extinction coefficient values are in the range of 10 -4 or below. Although sophisticated techniques have been developed for such purpose over the years (laser calorimetry, photoacoustic measurements), there is still a need for a simple, quick and low-cost method that would determine both the film thickness and optical properties [n(l ), k(l )] from a single measurement with a high level of accuracy. Thanks to recent advances in UV-VIS-NIR spectrophotometers, in particular the possibility to perform multi-angle Reflection/Transmission measurements with a single accessory, combined to an optimized measurement methodology, we show that it is possible to evaluate the film thickness and refractive index from R/T measurements performed at low angle of incidence, while determining the extinction coefficient down to 10-5 from R/T measurements carried out near the Brewster angle of the coating in p polarized light. We also demonstrate how modelling errors can be significantly reduced by fitting absorption

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spectra (A=1-R-T) rather than R and T separately. This new methodology is exemplified for several practical cases displaying various degrees of complexity.

study the hydride formation. The palladium hydride films were investigated by grazing incidence x-ray diffractometry (GIXD), in-situ high temperature diffractometry (HT-GIXD), and x-ray reflectometry (XR) . The effect of hydrogen plasma depends on the applied negative bias voltage. Up to -50 V we observe an increase of the fcc Pd unit cell volume. Hydrogen atoms occupy octahedral interstices to form PdH0.55. However, bias voltages of -100 V and -150 V cause a shrinking of the fcc Pd unit cell to fcc Pdvac . Subsequent reactions under long time plasma exposure form pure cubic PdH1.33 [4]. HT-GIXD experiments confirm the existence of different palladium hydrides. PdH0.55 lost its hydrogen at temperatures > 300 °C. In situ high temperature diffractometry measurements also confirm the existence of Pdvac as a palladium hydride phase. Up to 700 °C hydrogen removal does not occur. We observe phase transformations from cubic PdH1.33 to fcc Pdvac in the temperature range 400 to 600 °C and the transformation back again of Pdvac into PdH1.33 at 700 °C. The formation mechanisms of palladium hydrides will be discussed.

New Horizons in Coatings and Thin Films Room: Royal Palm 1-3 - Session F6-2 Thin Films and Coatings for Fuel Cells & Batteries Moderator: Chintalapalle Ramana, University of Texas at El Paso, USA, Sanjay Khare, University of Toledo, USA 2:10pm F6-2-3 Designing Electrode Coatings to Enhance Life of Lithium-Ion Cells, Daniel Abraham ([email protected]), Argonne National Laboratory, USA INVITED Layered Li-rich transition metal oxides have theoretical charge and energy densities exceeding 250 Ah-kg-1 and 900 Wh-kg-1 when these materials are charged beyond 4.5V vs. Li+/Li. However, significant capacity loss and impedance rise is observed when these materials are repeatedly cycled or held at high voltages against graphitic negative electrodes in electrochemical full-cells. In this presentation, we investigate one particular system, containing Li1.2Ni0.15Mn0.55Co0.1O2-based positive electrodes, and show how capacity loss and impedance rise can be reduced by modification of the positive electrode. This modification is done in several ways that include the following: i) coating alumina onto composite electrodes via atomic layer deposition (ALD); ii) by blending commercially available Al2O3 powder with the other electrode constituents; (iii) by preparing electrodes from oxide particles coated with alumina by a sonochemical process. Full-cells containing the alumina-coated particles and positive electrodes, cycled between 2.2-4.6V, show better capacity retention and lower impedance rise than the baseline electrodes. Electrochemical and physicochemical data will be presented to discuss mechanisms that lead to the observed improvement in electrode performance and cell life.

3:30pm F6-2-7 Electrolytic Coating of Sn on Nickel Foam Support for Highly Reversible Anode for Li Ion Batteries, Mahmud Tokur ([email protected]), H. Algul, M. Uysal, T. Cetinkaya, H. Akbulut, Sakarya University, Turkey In the past decade, tin based anodes have been extremely focused as an alternative to graphite anode, because of its high theoretical capacity of 990 mAh/g [1]. However, pulverization of electrode during lithiation and delithiation process, which caused from high volume expansion and consequent rapid capacity fading is one of the main disadvantages [2]. To improve electrochemical performance of pure Sn anodes, Sn–M intermetallic compounds have been designed to provide an inactive phase that acts as buffer matrix against volumetric changes and contribute conductivity reported as one effective solution. These matrix systems are Sn–Ni [3], Sn–Co [4], Sn–Cu [5] etc. Nickel substrates with foam structure have been used as current collectors to enhance the electrochemical performance of Sn electrode, since the porous structure of nickel foam will accommodate stresses and electrode pulverization because of the volume expansion and also maximize the utilization of active materials by ensuring that the electrolyte is easily diffused into the anode materials [6]. In this study, Sn was electrodeposited onto the porous nickel foam substrate under pulse electrodeposition conditions. Pulse electrodeposition was carried out at three different peak current densities of 10, 20 and 40 mA/cm2 for 5 minutes in a pyrophosphate bath containing 40 g/L SnCl2.2H2O, 164 g/L K4P2O7 and 19 g/L Glycin. Surface morphology of Sn-Ni foam electrode was characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) was conducted to understand the elemental surface composition of composites. X-ray diffraction (XRD) analysis was carried out to investigate the structure of Sn-Ni foam electrode. The electrochemical performance of electrodes have been investigated by charge/discharge tests, cyclic voltammetric experiments and the ac impedance technique. The results yielded encouraging discharge capacities since Ni foam behaves as a stress bearing support and electronic conductivity component. References [1] R. Zhang, J.Y. Lee, Z.L. Liu, J. Power Sources 112 (2002) 596-605. [2] J.W. Park, J.Y. Eom, H.S. Kwon, Electrochem. Commun. 11 (2009) 596–598. [3] N.-R. Shin, Y.M. Kang, M.S. Song, D.Y. Kima, H.S. Kwon, J. Power Sources 186 (2009) 201–205. [4] H.Gul, M. Uysal, T. Cetinkaya, M. O. Guler, A. Alp, H. Akbulut, International Journal of Hydrogen Energy, In Press, Accepted Manuscript [5] M. Uysal, T. Cetinkaya, M. Kartal, A. Alp, H. Akbulut, Thin Solid Films In Press, Accepted Manuscript [6] Y. Xu, L. Fei, E. Fu, B. Yuan, J. Hill, Y. Chen, S. Deng, P. Andersen, Y. Wang, H. Luo, of Power Sources 242 (2013) 604-609

2:50pm F6-2-5 The Shielding Effect of Fe2O3 Coated LiCoO2 Particles in Radiation Environment, Youna Lee, Y.S. Yoon ([email protected]), Gachon University, Republic of Korea With the development of space science and technology, it is necessary to develop lithium ion batteries that can be applied to high radiation environment. However, lithium-ion batteries based on organic materials have issues with material degradation by gamma irradiation. To overcome these problems, the electrode is desired to exhibit high stability and energy density in high radiation environment. In this study, we have investigated the cycle stability of Fe2O3 coated LiCoO2 (LCO) as cathode material in radiation environment. The Fe2O3 thin film layer can act as radiation shield in order to prevent structured degradation of LCO. The LCO powder was coated with Fe2O3 thin film using the radio frequency magnetron sputtering and mechanical stirring at the same time. The Fe2O3-coated LCO was irradiated by gamma-ray from 10 to 50 kGy. The electrochemical properties of various gamma-ray irradiated Fe2O3-coated LCO were studied using a battery cycler system and electrochemical impedance spectroscopy analyzer to confirm ionconductivity. Also, their crystal structures were investigated using X-ray diffraction and transmission electron microscopy. It is observed that crystal structure in irradiated Fe2O3-coated LCO was slightly modified. Moreover, micro crack of LCO particles was not observed by scanning electron microscope after 100th cycles. Although electrical conductivity of the coated LCO active material was decreased, capacity retention of the Fe2O3-coated LCO was improved by Fe2O3 shielding layer. 3:10pm F6-2-6 Formation of Palladium Hydrides in Low Temperature Ar/H2-Plasma, H. Wulff ([email protected]), Greifswald University, Institute of Physics, Germany, M. Quaas, LITEC-LP, Germany, H. Ahrens, University of Greifswald, Institute of Physics, Germany, Maik Froehlich, INP Greifswald, Germany, C.A. Helm, Greifswald University, Institute of Physics, Germany A specific challenge in low temperature plasma science is the investigation of chemical reactions in solid surface layers as a response to external plasma parameters. The formation of stable Pd hydrides under vacuum conditions at temperatures of 250 °C is not yet described to the best of our knowledge. In 1993, Fukai and Ökuma [1] discovered that gradual lattice contraction took place when Pd specimens were placed under high H2 pressures and temperatures (5 Gpa, 800°C). The formation of defect structures with vacancy-hydrogen (vac-H) clusters is now recognized as one of the fundamental properties of M-H alloys. [2,3]. In our experiments 20 nm thick palladium films were exposed to argonhydrogen microwave plasma using different negative substrate voltages to

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3:50pm F6-2-8 Development of Composite Electrode using Oxide Solid Electrolyte for all Solid State Lithium Ion Battery by Spark Plasma Sintering, SungPil Woo, Yonsei University, Republic of Korea, Y.S. Yoon ([email protected]), Gachon University, Republic of Korea All solid state lithium ion battery based on composite-electrode is one of the most attractive power sources for electronics devices. Recently, several researchers have focused on the development of composite electrode combined cathode material and solid electrolyte forming the conduction pathways for the diffusion and migration of lithium ion. However, it still shows a high interface resistance that creates need of new synthesis and coating method for coated cathode material using melted solid electrolyte. In this study, LiMnO2/Li3BO3 composite electrode is prepared by using spark plasma sintering. Spark plasma sintering method has many advantages such as simple protocol, low sintering temperatures, and short

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processing time. The synthesized composite electrode has been analyzed by SEM and confirmed that LiMnO2 surface was coated with Li3BO3. The all solid state lithium ion battery full cell shows a surface capacity of 0.2 mAh cm-2 at 80 oC with a good cycling performance of 80% capacity retention after 10 cycles. The battery shows a good stability with the interface contact between the composite electrode and thin film solid electrolyte and shows no diffusion of solid electrolyte materials from composite electrode to thin film electrolyte after cycles.

Topical Symposia Room: Sunrise - Session TS3 Energetic Materials and Micro-Structures for Nanomanufacturing Moderator: Carole Rossi, LAAS-CNRS, France, Ibrahim Gunduz, Purdue University, USA

4:10pm F6-2-9 Functionally Graded CuSi Thin Film Anode by Magnetron Sputtering for Lithium Ion Battery, D. Polat ([email protected]), Istanbul Technical University, Turkey, O.L. Eryilmaz, Argonne National Laboratory, Ozgul Keles, Istanbul Technical University, Turkey, A. Erdemir, K. Amine, Argonne National Laboratory, USA A functionally graded CuSi thin film was deposited by a magnetron sputtering technique on Cu discs. Cu and Si distribution in the thin film was confirmed by glow discharge optical emission spectrometry. The electrochemical performance of this material was compared to a thin film that was produced by the co-deposition of Cu and Si. The results showed that a composite CuSi thin film having 30%at. Cu exhibited 1100 mAh g-1 discharge capacity with 80% Coulombic efficiency; but the cycle life of this film degraded very quickly, only 300 mAh g -1 capacity remaining after 50th cycles. On the other hand, functionally graded thin film electrode delivered 1400 mAh g-1 with 78% coulombic efficiency in the first cycle and then 600 mAh g-1 with 99% coulombic efficiency even after 50th cycles. The results showed that Cu content and its distribution along the film thickness were the main contributors to the superior performance of the functionally graded CuSi film. We believe that Cu enhanced the electrochemical performance of Si anodes mainly because it is electrically more conductive and mechanically more ductile than Si. However, an optimization of Cu content in the film was needed to minimize the impact on capacity due to the inactive behavior of Cu. Therefore, it is believed that a gradual decrease in Cu content of the film from the bottom (30% at. Cu) to the top (0% at. Si) of the coating would result in electrode formation with higher electrochemical performance. Because the film rich in Cu at the bottom and rich in Si on the top increases adhesion of the deposit to the substrate and also relaxes the stresses along the thin film electrode during cycling without sacrifying the capacity delivered by the cell.

1:50pm TS3-2 Reactive Gasless Nanocomposites: Structure – Reactivity Relationship, Alexander Mukasyan ([email protected]), K. Manukyan, C. Shuck, University of Notre Dame, USA, A. Rogachev, Institute of Structural Macrokinetics and Materials Science, Russia INVITED It is well recognized that initiation of self-sustained exothermic reaction in micrometer-scale gasless reactive mixtures (e.g. Ni+Al, Ti+C) is correlated to the formation of a liquid phase at the melting point of the less refractory reactant or at the lowest eutectic temperature of the system. In some cases (e.g. Ta+C; Mo-B) the impurity gases adsorbed on the surface of the precursors may also significantly accelerate mass transport. In recent studies [1-5] we have shown that short-term (minutes) high energy ball milling (HEBM) of such powder mixtures leads to a significant (on hundreds or even thousands of degrees) decrease of the self-ignition temperatures (Tig). The relatively low values of ignition temperature, which are well below the melting points of all reagents, indicate that solely solid-sate mass transport is responsible for the reaction self-initiation in the mechanically activated medium. In this work we discuss the phenomenon, which takes place during energetic milling of different binary reactive gasless systems, such as Ni-Al (ductile-ductile), Ti-C (ductile-brittle), Si-C (brittle-brittle). To understand the influence of HEBM on enhancement of the system’s reactivity, a comprehensive analysis of the mechanically-induced composite structures for such systems has been performed. The relationship between the microstructures and reactivity of such materials are discussed. Our results indicate that, during early stages of HEBM, the initially micrometer-scale heterogeneous mixtures transform into nanostructured composite particles. For example, it was shown in the Ni+Al (ductileductile) system that Ni/Al composite particles are formed by cold welding within the first 2 min of milling. Further mechanical treatment leads to a significant refinement of inner structure of such composite particles, which results in the formation of intermixed Ni/Al layered nanostructure with average layer size less than 50nm. It was experimentally proven that such nano-laminated structures are responsible for the self-ignition of HEBMNi/Al composite particles at temperature as low as 500K [1-3]. During HEBM of Ti + graphite and Ta + graphite mixtures (ductile-brittle) the crystalline graphite flakes rapidly (1 min) transforms to amorphous carbon followed by the Me/C composite particles formation. Microstructural refinement of the inner structure of such composite particles leads to nanomixing of amorphous carbon and the metal, which simultaneous results in the formation of tiny (1-2 nm) nuclei of carbide phases (e.g. TiCx) [4]. Such mechanically-induced particles react through a solely solid-state mechanism. During HEBM of the Si + graphite (brittle-brittle) mixture, nano-scaled (80-300 nm) composite particles form, which consist of amorphous carbon and crystalline silicon. Such structure allows for direct synthesis of SiC nanopowders in the combustion wave [5]. In general it was concluded that the following main factors are responsible for the reactivity enhancement in the mechanically-fabricated gasless high energy density systems: - formation of oxygen-free high surface area contacts between the reagents; - mixing of the reactants on the nano-scale level; - formation of a sold solution or nucleation of the product phases; - amorphization of the reagents References: 1. A.S. Mukasyan, B. B. Khina, R.V. Reeves, S.F. Son, Chem. Eng. J., 174, 77 (2011). 2. K.V. Manukyan, B.A. Mason, L.J. Groven, Y.-C. Lin, et al., J. Phys. Chem. C, 116, 21027 (2012). 3. A.S. Rogachev, N.F Shkodich, S.G Vadchenko, F. Baras, et al., J. Alloys & Compounds, 577, 600 (2013). 4. K.V. Manukyan, Y.-C. Lin, S. Rouvimov, P.J. McGinn, A.S. Mukasyan, J. Appl. Phys, 113, 024302 (2013). 5. A.S. Mukasyan, Y.-C. Lin, A.S. Rogachev, D.O. Moskovskikh, J. Amer. Ceram. Soc., 96, 111 (2013).

4:30pm F6-2-10 Resistivity Analysis of BiTiO Thin Films Produced by Unbalanced Magnetron Sputtering, Giovany Orozco Hernandez ([email protected]), J.J. Olaya-Florez, E. Restrepo Parra, Universidad Nacional de Colombia, Colombia Thin films of Bismuth Titanium Oxides (BTO) were growth onto oriented silicon and stainless steel AISI 316L substrates in an unbalanced magnetron sputtering system with a target of Bi 99,999% pure. On the surface of the target used for sputtering processes assisted by a magnetron system is the high erosion zone called “race-track”. Through this zone squares of titanium of 7*7 mm and 3 mm of thickness were located in four different configurations 1, 5, 9 and 17 squares. It conduces to the variation of the elementary composition in the thin films. In addition to that the temperature of the substrates during the growth were changed with the aim of evaluate the influence of this on the structural properties of the thin films. Bismuth oxide has four main structural phases but in terms of conductivity the delta phase has values two times higher than for instance YSZ, a preferred material in the solid oxide fuel cells research field. In that way the study of the electrical properties on the thin films produced is of high interest. Four points probe method was used to measure the electrical resistance; thus four electrodes are situated on the surface of the thin film; through both of them a current is applied and by the others the voltage produced by the material is measured. It is supposed that the higher the current the higher the voltage and their relation must be lineal, the slope of a curve current versus voltage (I-V) tell us about the resistivity of the film. Resistivity on thin films produced by the system were measured and the results show well slopes and linearity. Actually studies on X-Ray diffraction and Auger electron spectroscopy are been made in order to know the morphological and structural properties and to correlate this properties with those of resistivity. Regarding to the morphological properties we will perform scanning electron microscopy (SEM), atomic force microscopy (AFM) and profiler analysis. The value of roughness over the surface of the film is quite important as well as the topography for the behavior of the resistivity.

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2:30pm TS3-4 On the Micro/Nano-intermetallic Structures Formation During Steel to Aluminum Weld-brazing Process, Guillaume Filliard ([email protected]), Renault & ENSAM, France, S. Mezghani, M. El Mansori, ENSAM, France, J-C. Saint-Martin, Renault, France The steel to aluminum weld-brazing process is recently investigated by automotive manufacturers in joining functional hybrid metallic structures for car weight reduction. To achieve good mechanical strength of these join structures and to be able to industrialize this process, manufacturers are currently facing different issues. One of them is the formation of active micro/nano-intermetallic phases between the seam and the steel part leading to generally to brittle fracture. This phenomenon depends mostly on the weld-brazing process parameters optimization and particularly on the composition of the wire. In this study several wires with different composition are used and their influences on the mechanical strength response of the welded join are analyzed. Moreover, the influence of the wire composition on the micro-nano intermetallic structures formation is discussed. The results are hence cross-checked and classified according to the process parameters optimization to establish an efficient weld-brazing method at full scale.

reactant exposure times of 1 s for each precursor and purge times of 5 s between each precursor pulse. Using in situ IR spectroscopy in an ultra-high vacuum environment, we find that DEZ is reactive with the surface OH groups, providing the initial grafting for ZnO growth on the nanopatterned surfaces. The interaction of TMA on such ultra-thin ZnO surfaces is then examined using a combination of in-situ studies including FTIR, LEIS and XPS, and compared to that on CuO surfaces [1]. Experimental findings will be confronted to Density Functional calculations to shed light on molecule/surface basic chemical mechanisms. Finally, the grow ZnO films using Pulsed Laser Deposition is attempted, and found to give rough films due to columnar growth, just as in the case of sputter-deposited films. 1 ACS Appl Mater Interfaces. 3, 605-13 (2013) 2 Appl. Phys. Lett ., 56, 656-658 (1990) 3 Nature Mater. 9, 266–271 (2010) 4 Chem. Mater.15, 1020-1028 (2003) 3:30pm TS3-7 The Utilization of Metal/Metal Oxide Core-Shell Powders Optimizes the Dilution of Thermite Mixtures, Karsten Woll ([email protected]), Karlsruhe Institute of Technology (KIT), Germany, J.D. Gibbins, K. Slusarski, A. Kinsey, T. Weihs, Johns Hopkins University, USA When thermite mixtures react and self-propagate considerable amounts of gas can be released. This impedes their application in the various fields, such as joining. Diluting the thermite with excess metal can lower the reaction temperature and thereby minimize gas release. However, increasing the degree of dilution reduces reaction efficiency. We choose Al:NiO as a model system to demonstrate a boost in reaction efficiency if the excess metal (Ni) is added using an fuel-core-shell geometry. Al fuel particles are mixed with Ni/NiO core-shell particles. The use of Ni/NiO core-shell particles reduces the average distance for Al and O intermixing by placing the fuel (Al) in direct contact with the oxide (NiO), separate from the diluent (Ni). We fabricated and characterized powders compacts using Al and Ni/NiO core-shell powders, and we compared them to compacts fabricated using conventional Al, NiO, and Ni powders for dilutions as high as 40 wt% Ni. The fuel-core-shell particle geometry increased reaction velocities for all Ni dilutions, while reaction temperatures and mass ejection decreased uniformly for both particle geometries as the degree of dilution increased.

2:50pm TS3-5 Investigating the Compositional Limits of SelfSustained Propagating Reactions in Sputter-Deposited Alx/Pty Multilayers, David Adams ([email protected]), R.V. Reeves, C.E. Sobczak, Sandia National Laboratories, USA Reactive multilayers grown by sputter deposition have recently attracted interest for emerging applications including material joining (soldering, brazing) and energy sources. For these applications, a metal-metal multilayer is typically designed to have a composition that corresponds to the peak enthalpy for a given material system as this approach maximizes heat output or design targets a particular intermetallic compound with optimal mechanical properties. With the focus on a single composition, little is known about the range of composition that gives rise to selfsustained, high temperature synthesis (SHS) reactions for a given reactive metal pair. With this presentation, we describe the compositional limits of reactive Al/Pt multilayers. For multilayers having a total thickness of 1.6 microns, self-sustained, high temperature reactions occur when the net multilayer composition is in the range of Al0.25Pt0.75 to Al0.75Pt0.25. Multilayers having a net composition of Al0.2Pt0.8 and Al0.8 Pt 0.2 do not react when stimulated at a point. Results are correlated with measurements of heat of reaction as determined by differential scanning calorimetry (DSC). Equiatomic Al/Pt multilayers have the maximum heat of reaction of all films investigated in this study, consistent with the maximum reaction velocity. Attempts are made to extract heats of formation for the various compositions studied. Reaction speeds are also reported for the various multilayers as a function of composition and multilayer periodicity (bilayer thickness).

3:50pm TS3-8 Development of Free Standing, Flexible Tape Cast Energetic Material Films, Billy Clark, M. Pantoya ([email protected]), Texas Tech University, USA, R. Heaps, M. Daniels, Idaho National Laboratory, USA A new method for synthesizing flexible free standing energetic material coatings and the characterization of their reactivity in terms of energy propagation is presented. Aluminum (Al) and molybdenum trioxide (MoO 3) were mixed with potassium perchlorate (KClO4) additive and combined with a silicone/xylene binder/solvent system. The formulation was tape cast to form a free standing flexible energetic film and could also be used as a coating. The concentration of KClO4 was varied to understand the role of this additive on energy propagation of the tape case film. All films were cast to a thickness of 2.5 mm with a constant volume percent solids to ensure rheology of the samples remained constant, which has been previously shown to affect homogeneity of reactants as well as combustion. The films were ignited and analyzed using a high speed camera aligned perpendicular to the direction of energy propagation. The results show that films synthesized with this new method are capable of supporting their own weight as well as retaining a high degree of flexibility. The sample containing a higher mass concentration of KClO4 exhibited increased flame speeds when compared to the lower KClO4 concentration sample. Also shown is that the release agent used to aid sample delamination from the substrate does not influence energy propagation. Thermochemical simulations and thermal gravimetric analysis reveal negligible gas generation resulting from the KClO4 additive such that the additive facilitates the diffusion of energy during propagation. These newly synthesized flexible free standing energetic materials are gaining increased attention due to the desire for a stable, easy to store, and safe method of producing energetic composites.

Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-AC04-94AL85000.

3:10pm TS3-6 Growth of Atomically Smooth ZnO for Energetic ZnO/Al Nanolaminates, Yuzhi Gao, C. Nanayakkara, J.F. Veyan, University of Texas at Dallas, USA, J.M. Ducéré, A. Esteve, C. Rossi, Université de Toulouse, France, Y. Chabal ([email protected]), University of Texas at Dallas, USA The interface between an oxidizer and a reducing agent such as in Al-based reactive thin film nanolaminates (e.g. CuO/Al, ZnO/Al) has been shown to impact drastically their thermalproperties. Despite promising studies of the formation mechanism of interfaces and the role of surface engineering to improve their performance 1, the main difficulty in deriving fundamental chemical mechanisms is the intrinsic roughness of metal oxide films. For instance, sputter deposited CuO or ZnO films exhibit a columnar growth with surface roughness exceeding 10 nm. The synthesis of thin model oxides on atomically controlled substrates would greatly facilitate the interpretation of surface characterization techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray Photoelectron Spectroscopy (XPS) and low energy ion scattering (LEIS) 1. We present here an attempt to grow ZnO thin film on atomically flat surfaces using atomic layer deposition (ALD). ZnO is chosen to build the model system because deposited layer is crystalline at low deposition temperature and the roughness can be well controlled with ALD. Two atomically flat model-surfaces are used. The first is a monohydrideterminated Si(111) surface, obtained by aqueous NH4F etching 2, and the second is a nano-patterned OH-terminated Si(111) surface (~30% Si-OH and ~70% Si-H), obtained by methanol treatment of previous H/Si(111) surface 3. The ALD process is based on diethylzinc (DEZ) and water precursors alternated exposures 4. The growth conditions are set to be

Tuesday Afternoon, April 21, 2015

4:10pm TS3-9 Role of Trimethylaluminum and Cu at the Interfaces of Al/CuO Nanolaminates, Charith Nanayakkara ([email protected]), Y. Lu, Y. Gao, J.F. Veyan, University of Texas at Dallas, USA, J.M. Ducéré, A. Esteve, C. Rossi, Université de Toulouse, France, Y. Chabal, University of Texas at Dallas, USA Interface layers in Al-based reactive thin films play a crucial role in the energetic properties and reactivity of such materials 1. The composition and related microstructure of the interface of Al-based reactive films can greatly

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influence the ignition temperature, reaction kinetics and even the stability at low temperature. This work aims at developing an understanding of the interface formation processes between Al and metal based oxidizer and investigating the role of interface treatment in the reaction kinetics. Al/CuO nanolaminates represent a good model system for studying the reactive interfaces because they have a high energy density and are particularly sensitive to the nature of the AlxOy interface created during deposition. In this work, we combine three techniques to obtain bonding information (IR spectroscopy), oxidation state (XPS) and atomic position (Low Energy Ion Scattering) during interface formation, all located within the same ultra-high vacuum cluster system. These results are completed with Density Functional calculations for allowing spectra assignation or unraveling chemical kinetic information. Similarly to a previous study1, the bonding configuration and evolution of Al atoms is examined upon exposure of trimethylaluminum (TMA) of the CuO surface, prior to Al deposition. As expected for vapor phase exposure typically used in ALD, the surface reaction and coverage is conformal and complete (i.e. saturated as evidenced by the lack of more adsorption with multiple exposures). TMA is found to be adsorbed by shedding one of its methyl ligand onto a surface Cu atom and forming (CuO)–Al(CH3)2 eventually leading to (CuO)–Al(CH3)–O–CH3 by reducing CuO1. Once saturated with TMA, the surface is exposed to atomic Al by physical evaporation and the interface composition monitored. In particular, the role of TMA to stabilize the interface (i.e. slow the Al penetration into the CuO substrate) is examined by comparing the Al position as a function of Al coverage with and without TMA treatment. A similar study with Cu physical evaporation on sputter deposited CuO will be carried out prior to Al deposition. Preliminary data indicates that a thin Cu layer dramatically increases the ignition rate. Similarly, a thin Cu layer will be deposited on Al film prior to CuO deposition. The focus here also will be on examining Cu atom diffusion and the surface composition at the interface of both CuO and Al. This work will shed light on the interface formation mechanisms and composition of Al and Cu based nanolaminates which will be particularly important in engineering Al/CuO based new energetic materials. 1 Appl. Mater. Interfaces 2013, 5, 605−613

an atomic scale precision, in relation with the deposition process parameters (temperature, partial pressures …). To push forward their nanoscale–controlled fabrication, predictive atomic scale modeling of the deposition process can help, by providing a fundamental description on how they are achieved. Simulations appear here as a powerful tool for the characterization of phenomena occurring at the nanoscale as a deep dive into the matter, to guide the technologists toward the development of advanced nanostructured materials. In our approach, we propose a model based on a kinetic Monte Carlo (KMC) method to simulate multilayered Al/CuO materials deposition, as PVD process, in order to get clues, depict and predict a realistic interfacial formation. Here, Density Functional Theory-based (DFT) calculations are used to identify and characterize, kinetically and thermodynamically, atomic scale events. Then these DFT data are used as input parameters to parametrize a KMC model. Presented results will include CuO chemistry on the Al surface, and the early stages of PVD deposition will be examined up to the complete passivation of the Al surface. This methodology offers the possibility to access to the exact structure of the material as a function of the manufacturing process and thus to access to the detailed composition, that depends on the conditions in which it was synthesized. We except to propose microscopic elements that could guide the technologist to improve processing and improve the properties of the operating material. 5:10pm TS3-12 Ignition and Combustion Characteristics of Metastable Intermolecular Composites for Material Joining Purpose, H. Sui, J. Rawlins, J. Kang, John Wen ([email protected]), University of Waterloo, Canada, N. Chaumeix, CNRS, France One of these promising applications of Metastable Intermolecular Composites (MIC) is reactive bonding [1], which utilizes heat produce from the thermite reaction for joining, welding, soldering and brazing. Thanks to the dominant solid-state chemical reactions and localized heat and mass transport phenomena, successful MIC-based joining processes are developed for components with different material and thermal properties such as electrical conductivities and thermal expansion coefficients. This work aims at developing effective electrophoretic deposition (EPD) to fabricate MIC foils and wires with tunable ignition and combustion properties. As demonstrated early [2] EPD is a very flexible deposition technique that can be arranged with simple apparatus, and its rate of deposition and foil microstructures can be effectively controlled by adjusting the applied voltage, colloid concentrations, pH value and operating temperature, etc. [3]. In this study the thermite components, fuel (aluminum nanoparticles of 130 nm and 60-80 nm) and a variety of oxidizers (CuO, NiO and Fe2O3 nanoparticles), are deposited separately or in a mixed way onto interested substrates. The EPD suspensions are prepared with HPLC grade ethanol (≥99.8%). The colloidal particle concentrations range from 0.25% to 1.5% (by weight) and the operating temperature and pH values are monitored and controlled. The MICs and as-produced thermite foils/wires are characterized by Thermal Gravimetric Analysis (TGA)/ Differential Scanning Calorimetry (DSC), SEM and Flame propagation experiments. In flame propagation experiments different ignition methods and these substrates with various thermal properties are used. Gas/vapor generation, flame propagation rate and product compositions are investigated. References: [1] X. Zhou, M. Torabi, J. Lu, R. Shen and K. Zhang (2014) “Nanostructured energetic composites: synthesis, ignition/combustion modeling and applications”, ACS Applied Materials and Interfaces 6: 30583074. [2] K.T. Sullivan, M.A. Worsley, J.D.d Kuntz and A.E. Gash (2012) "Electrophoretic deposition of binary energetic composites," Combustion and Flame 159: 2210-2218. [3] J.J. Moore, J.H. Kang, S.H. Jayaram and J.Z. Wen (2012) “Performance of nanotube-based electrodes from temperature-controlled electrophoretic deposition”, Journal of Applied Electrochemistry 42: 501-508.

4:30pm TS3-10 Flash and Laser Ignition of Composite Al Particles with Dielectric Inclusions, Ibrahim Gunduz ([email protected]), S. Son, Purdue University, USA Recent discoveries on xenon flash ignition of nanoscale aluminum (nAl), carbon nanotubes and mechanically activated Al-PMF composite particles sparked interest on electromagnetically assisted ignition of reactive materials. We performed flash and laser ignition experiments on microscale ball-milled particles of Al-Sucrose and Ti-Sucrose. Bare and soot covered thin thermocouples were used to measure maximum temperatures for comparison. The results show that regular heating alone is not sufficient and an amplifying effect is necessary to explain composite particle ignitions, for example through localized surface plasmon resonance (LSPR) in nanoparticles of aluminum (nAl). It is possible that the incorporation of dialectric material through milling enhances LSPR among nanoscale Al lamella that normally occurs due to air gaps in nAl. The wavelength-particle size dependence due to LSPR can possibly be explored with different milling conditions for tuning the wavelength response of nanostructured microscale particles. 4:50pm TS3-11 An Atomic Scale Insight into Interface Layers Formation in Al/CuO Nanolaminated Thin Films: a Kinetic Monte Carlo Simulation of Deposition Process, M. Guiltat, A. Esteve, C. Rossi, M. Djafari Rouhani, LAAS-CNRS, France, Y. Chabal, University of Texas at Dallas, USA, Anne Hemeryck ([email protected]), LAAS-CNRS, France Nanolaminated materials made of nanometer-thick layers are nowadays facing the technological challenge of mastering interfacial layers, inevitably formed during technological fabrication processes. At these dimensions, interfacial layers become preponderant and play a determining role on the macroscopic properties of designed materials. In nanolaminated energetic materials, more precisely multilayered Al/CuO nanothermites, in which intimacy of Al and CuO components must be maximized, it has been proven that interfacial layers, still unknown in composition and not well controlled during processing, impact final performances of achieved materials, such as stability, reactivity and energy release. In this field, master of interfaces during their fabrication is a major issue since it offers the new opportunity to increase and tune their performances as for example in the perspective of their integration into MEMS technologies. Actually, multilayered nanothermites suffer from a lack of knowledge of the structure and composition of both the deposited layers and interfaces, with

5:30pm TS3-13 Effect of Nano-engineered Interfaces in Alumina-free Magnetron Sputtered AL-CUO Nanolaminates, S. Pinon, LAAS-CNRS, France, N. Charith, Y. Gao, J.F. Veyan, University of Texas at Dallas, USA, J.M. Ducéré, A. Esteve, A. Hemeryck, LAAS-CNRS, France, Y. Chabal, University of Texas at Dallas, USA, Carole Rossi ([email protected]), LAASCNRS, France Reactive multilayered foils, wherein two or more layers of different materials are stacked on top of each other, represent an interesting class of nanostructured energetic materials. These multilayered structures can sustain a self-propagating exothermic reaction once it is thermally by a local perturbation (e.g. a spark). Most studies of multilayered reactive materials have been focused on Al/Ni systems, motivated by both fundamental science and varioius potential applications such as bonding, brazing and

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Tuesday Afternoon, April 21, 2015

sealing. Thermite-based multilayered foils have received comparatively less attention despite their higher energy densities and reactivity compared to intermetallic systems. We present here a new growth sequence of Al/CuO nanothermites, in which intermediate pure metallic or pure organometallic exposures transforms the response of the system previously limited by poorly controlled interfacial alumina-based barrier layers formed during standard fabrication. All layers, except the organometallic treatment, were deposited by DC magnetron sputtering. A comparison study was performed with conventionally processed multilayered material, i.e. with formation of alumina-based barrier layers composed of 8 layers of 100 nm of Al and 7 layers of 200 nm of CuO. The heat of reaction and onset temperature were measured using differential scanning calorimetry (DSC). As expected from previous results, the heat of reaction is around 1.6 KJ/g, and the burning rate is around 60 m/s. For alternative barrier layers, with an intermetallic layer between Al and CuO, an increase of the heat of reaction of more than 50% attributed to the absence of interfacial Al2O3 layer. This relatively modest improvement increases the burning rate by a decade. First Principles calculations and advanced characterization including in situ IR, XPS and LEIS are beginning to shed light onto the basic mechanisms of interface formation, and adsorptions and penetration bulk diffusion of atoms deposited at the surface. . The ability to tune the interfaces of nanothermites, along with other attributes such as high volumetric energy density and the capability to produce environmentally benign products, make reactive multilayered foils a very attractive nanoenergetic material for wide applications, including environmentally clean primers, detonator, explosives, and in situ welding.

Tuesday Afternoon, April 21, 2015

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Wednesday Morning, April 22, 2015 Coatings for Use at High Temperature Room: Royal Palm 4-6 - Session A1-2

9:00am A1-2-4 APS TBC Performance on Directionally-Solidified Superalloy Substrates with HVOF NiCoCrAlYHfSi Bond Coatings, Michael Lance ([email protected]), J. Haynes, B. Pint, Oak Ridge National Laboratory, USA For large land-based turbines, directionally-solidified (DS) superalloy components with advanced thermal barrier coatings (TBC) to lower the metal operating temperature can replace more expensive single crystal superalloys. In order to assess relative TBC performance, furnace cyclic testing was used with superalloys 1483, X4 and Hf-rich DS 247 substrates and high velocity oxygen fuel (HVOF)-NiCoCrAlYHfSi bond coatings at 1100 °C with 1-h cycles in 10% H2O. There was no statistically significant effect of substrate alloy on the average lifetime of the air plasma sprayed (APS) yttria-stabilized zirconia (YSZ) top coatings for these conditions. The residual compressive stress in the α-Al2O3 scale underneath the YSZ top coating and on a bare bond coating was measured using photostimulated luminescence spectroscopy (PSLS) and was similar for all three substrates. Two-dimensional maps collected from the same region at regular cycling intervals revealed delaminations occurring at the YSZ/bond coating interface across all three coating systems at roughly the same rate and frequency. X-ray fluorescence (XRF) measurements collected from the bare bond coating surface revealed higher levels of Ti interdiffusion occurring between the 1483 substrate and the bond coating, which was expected because it contained the highest Ti content. Research sponsored by the U. S. Department of Energy, Office of Fossil Energy, Coal and Power R&D.

Coatings to Resist High Temperature Oxidation, Corrosion and Fouling Moderator: Mark Weaver, The University of Alabama, USA, Vladislav Kolarik, Fraunhofer Institute for Chemical Technology ICT, Germany, Elizabeth Opila, University of Virginia, USA 8:00am A1-2-1 Influence of Substrate Composition on the High Temperature Oxidation Behavior of Various Coating Systems, James Haynes ([email protected]), K. Unocic, B. Armstrong, B. Pint, Oak Ridge National Laboratory, USA INVITED Alloys intended for use at high temperatures in oxidizing environments would ideally be capable of forming and maintaining a protective oxide scale for time periods appropriate to the design life of a component. However, in many demanding applications the preferred alloy does not have an adequate combination of high temperature mechanical properties and oxidation resistance. This may be due to extreme temperatures or environments, or may be a result of design limits requiring the use of a less expensive class of alloy. In such cases, a variety of high temperature coating materials and processes can be employed to improve the performance and durability of the component. The addition of a high temperature coating adds increased expense and risk to the design process, and selection of the most effective coating for each application can be challenging. It is essential to recognize that there are no one-size-fits-all solutions for high temperature coatings, and that each specific combination of coating, alloy and operating environment results in a unique system. The performance of some alloy-coating systems is sensitive to variations in the composition of the alloy, trace elements within the system, coating processing, diffusion rates, or environmental factors such as water vapor. This presentation will contrast the oxidation behavior of a variety of alloycoating systems over a range of temperatures (800 – 1150C), in order to demonstrate the importance of understanding system dynamics to enable appropriate coating selection. Classes of alloys to be discussed include lowCr steels, stainless steels, and various Ni-base superalloys, whereas coatings and processes will include slurry aluminides, chemical vapor deposition aluminides, diffusion aluminides, and thermal spray MCrAlX coatings. Effects of various alloy elements and impurities, including Al, Pt, Cr, Hf, Y, Ti and S, on coating oxidation behavior will be described.

9:20am A1-2-5 Effect of Substrate Surface Condition on the Performance of Cr Oxide Coatings on 316L Steel in Carburizing Atmospheres, L. Melo, Instituto Politécnico Nacional, México, C. Hinohosa, O. Salas ([email protected]), D. Melo-Máximo, A. Murillo, Itesm-Cem, México, R. Torres, Pucpr, Brazil, VM. López, Instituto Politécnico Nacional, México, Joaquín Oseguera, Itesm-Cem, México In the present work, the effect of substrate surface finish and ion cleaning prior to deposition on the performance of Cr oxide/Cr coated 316L stainless steel substrates in carburizing atmospheres was investigated. Thermogravimetry experiments (TGA) on the coated substrates indicated that the surface condition of the substrate had little effect on the weight gain after exposure, however more detailed structural analysis revealed some differences in adhesion behavior and surface morphology. 9:40am A1-2-6 Chemical and Mechanical Evolution of Ceramic Abradable Turbine Coatings Subjected to Simulated High Hydrogen Content Combustion Environments, Madhura Basu Majumder, R. Clayton, D. Mumm ([email protected]), University of California, Irvine, USA Turbine efficiency can be improved by increasing the operating temperature, but also by reducing the gas path flow clearance to minimize the leakage and back flow of combustion gases. In general, air plasma sprayed (APS) abradable coating materials are used in the turbine hot section to reduce the stator-rotor gap. The layered structure of these seal coating materials assists with the desired removal of material in thin layers when the turbine blades sweep through the coating; the compliant sacrificial coating structure protects the mechanical integrity of turbine blade. To lower CO2 emissions, the use of Integrated Gasification Combined Cycle (IGCC) technology is being explored, where the turbines are powered on high H2 content (lower carbon) fuel that may affect the composition, microstructure, abradability and durability of the coatings at turbine operational temperatures. The presence of high water vapor in the combustion chamber of the turbine may lead to accelerated degradation of the abradable coating materials, and an associated reduction in the life expectancy of turbine hot-section components. These coating materials are comprised of a metal or ceramic matrix, generally incorporate second phase designed to enhance machinability, and are sprayed with polymer pore formers to enhance the open porosity of the coatings (in part to enhance abradability). In this work Zirconia based composite materials with varying machinability phases and varied porosity have been used to study the thermal conductivity, chemical stability, mechanical stability and abradable characteristics of baseline abradable coating systems as a function of emerging IGCC combustion environments. Investigation of the mechanisms that control the removal of materials and performance of the abradables through the use of laboratory thermo-mechanical test methods will be discussed. Particular attention is placed on the application of a test intended to simulate the effect of the motion of turbine blades cutting into the abradable seals.

8:40am A1-2-3 Factors Affecting Performance of Thermal Barrier Coatings During Hot Corrosion Tests, Krishna Praveen Jonnalagadda ([email protected]), IEI, Linköping University, Sweden, R. Eriksson, Siemens AG, Large Gas Turbines, Germany, R.L. Peng, IEI, Linköping University, Sweden, X. Hai, Siemens Industrial Trubomachinery AB, Sweden, S. Johansson, IEI, Linköping University, Sweden Detrimental effect of molten corrosive salts on life of thermal barrier coating (TBC) systems are widely known. Corrosive species such as vanadium oxide and sodium sulphate leach yttria from YSZ and form t – YVO4. Leaching of yttria causes conversion of metastable t’ – ZrO2 to m – ZrO2 , resulting in volume change which will damage the top coat thereby the whole TBC system. Formation of t- YVO4 induces growth stresses in the coating which also comprimises the mechanical integrity of the top coat. Yttria leaching and YVO4 formation, which happen simultaneously, depend on the concentration of the corrosive salt, exposure time and temperature. The extent of the top coat damage by these corrsive salts also depend on the thickness and the density of the coating. Understanding the influence of these factors is important for development of more durable coatings. In the present work, a thick TBC coating, 750µm, and a standard TBC coating, 300µm, were subjected to hot corrosion tests involving vanadium pentoxide and sodium sulphate as the corrosive salt. The tests were conducted at 750oC, 900oC and 1000oC where at each temperature the salt concentration was varied from 4 mg/cm2, 10 mg/cm2 to 20 mg/cm2. Results show that the concentration of the salt has stronger influence on coating life than the time and temperature. Thick denser coatings seemed to show lower resistance to corrosion than thinner, denser coatings at a given temperature and concentration.

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Wednesday Morning, April 22, 2015

10:00am A1-2-7 Novel Coatings Against Metal Dusting by a Combination of a Catalytic and a Barrier Approach, Mathias Galetz ([email protected]), S. Madloch, M. Schütze, Dechema Forschungsinstitut, Germany INVITED Metal dusting is a severe form of corrosion, which occurs in high carbon activity atmospheres at temperatures of 400-900°C (e.g. in reformer or coal gasification plants). Steels and nickel base alloys are strongly affected because of the catalytic effect of nickel and iron on the dissociation of carbon containing gas species, followed by carbon uptake and subsequent graphite nucleation inside the material. Conventional protection is given either by dense oxide scales on coatings or on alloys with high amounts of oxide scale forming elements. Sulphur in the gas is known to suppress Metal Dusting by a catalytical surface modification. A similar catalytic surface effect was shown to be also effective on a new functional Ni-Sn coating, which was developed at the DECHEMA-Forschungsinstitut, DFI. A combination of an electrochemical nickel plating step with a subsequent tin powder pack cementation led to the formation of an intermetallic Ni-Sn layer. In this work this approach was further improved by modification with oxide forming aluminium. While the Ni-Sn coating is prone to oxidizing environments, the enrichment of the coating with oxide scale forming elements extends the application range for such coatings significantly. These novel coatings can provide sufficient protection e.g. even in steam containing Metal Dusting atmospheres by a dual protection: the classical oxide barrier (conventional approach) and the catalytic inhibition.

Hard Coatings and Vapor Deposition Technology Room: California - Session B1-3 PVD Coatings and Technologies Moderator: Alpana Ranade, GE Aviation, USA, Steffen Weißmantel, University of Applied Sciences Mittweida, Germany, Jyh-Wei Lee, Ming Chi University of Technology, Taiwan 8:00am B1-3-1 Construction and Characterisation of a Device to Coat Large Quantities of Granular Materials by Magnetron Sputtering, Andreas Eder ([email protected]), G. Schmid, H. Mahr, C. Eisenmenger-Sittner, Vienna University of Technology, Austria Granular Materials have many applications in the field of material science and catalysis, especially if coated with functional surface layers. With Physical Vapor Deposition (PVD) processes in general and DC magnetron sputtering in special, as used within this work, various layers ranging from metals via oxides and nitrides to complex composite materials such as nanocomposites and multilayered heterostructures can be deposited. Due to the line-of-sight nature of magnetron sputtering each particle surface has to be exposed equally to the vapour beam to achieve homogeneous layers. Therefore continuous intermixing is necessary with special attention to not damage fragile granulate and avoid agglomeration. A device has been designed to coat up to one liter of granular material with particle diameters ranging from 20 µm to 500 µm. Basically this device is an upscaled version of special coating geometries developed and tested in former projects at the Vienna University of Technology [1,2] and has similarities to a concrete mixer regarding rotation of the mixing bowl and gear mechanism. The most efficient way to suppress agglomeration during sputter process is to execute strokes against the bowl containing the granular materials. The optimisation of the deposition rate and coating uniformity is made possible by using two sputtering sources which can be tilted in different angles to obtain a vapour beam ideally directed exactly towards the exposed surface of the particle ensemble. In addition the sputter rate varies with the distance between sources and substrate, which leads to higher deposition rates at higher amounts of granulate. Within this work hollow glass micro spheres are the most used substrate. To characterize the deposition device and the behaviour of the micro spheres under vacuum conditions, the films deposited are mostly Copper and Aluminium due to the high sputter yield. The filmthickness and filmthickness distribution of mono metallic layers can be determined by using a light microscope and a software developed at the Vienna University of Technology [3]. The uniformity of the films was also verified with the scanning electron microscope (SEM). The financial support of the Austrian Science Fund (FWF) under Grant Nr. TRP-281-N20 is gratefully acknowledged. References [1] G. H. S. Schmid, C. Eisenmenger-Sittner, J. Hell, M. Horkel, M. Keding, H. Mahr, Surface & Coatings Technology 205(7) (2010) 1929. [2] G. H. S. Schmid, C. Eisenmenger-Sittner, Surface & Coatings Technology 236 (2013) 353. [3] M. Horkel, H. Mahr, J. Hell, C. Eisenmenger- Sittner, E. Neubauer, Vacuum 84(1) (2009) 57.

10:40am A1-2-9 Extended Exposure of Protective Al Oxide Thin Films in Carburizing Atmospheres, E. Uribe, Olimpia Salas ([email protected]), D. Melo-Máximo, Itesm-Cem, México, R. Torres, Pucpr, Brazil, J. Oseguera, Itesm-Cem, México Al oxide/Cr thin films produced by reactive magnetron sputtering have proven to be promising coatings for protection of ferrous materials in carburizing atmospheres at high temperature up to 20h of exposure1. The present work includes the results of a 304L coated and uncoated substrates after an extended exposure of 50h to a CH4+H2+residual O2 atmosphere at 800°C. The results were compared with those of 20h to study the evolution of both the substrate and the film in such conditions. Even after 50h, the coated 304L steel remains largely unaffected by the carburizing atmosphere, however both its structure and that of the protective coating undergo some changes due to diffusion of the various components. The results from the uncoated exposed sample indicate that the small amount of oxygen in the carburizing atmosphere still plays an important after 50h of exposure. 1. E, Uribe et al., Surf. Eng. 2014, DOI: http://dx.doi.org/10.1179/1743294414Y.0000000322 11:00am A1-2-10 High Temperature Tribological Behaviour of Fluorinated Tetrahedral Amorphous Carbon (ta-C-F) Coatings against Aluminum Alloys, S. Bhowmick, MuhammadZafarUllah Khan, A. Banerji, University of Windsor, Canada, M.J. Lukitsch, General Motors R&D Center, Canada, A. Alpas ([email protected]), University of Windsor, Canada Friction and wear behaviour of tetrahedral amorphous carbon containing 12 at% F, designated as ta-C-F) coating were studied at temperature range between 25 ˚C and 500 ˚C. The sliding-induced surface and subsurface damage features at these temperatures were investigated. Pin-on-disk type tests conducted on ta-C-F against Al-6.5% Si (319 Al) showed that the steady-state COF (μS) of 0.23 at 25 ˚C decreased to 0.15 at 200 ˚C and 0.11 at 400 ˚C. At 500 ˚C the ta-C-F showed a high COF of 0.53. It was observed that F atoms transferred to the 319 Al contact surface in higher amounts with an increase in the test temperature. It was suggested that the presence of F would lead to the formation of a stable AlF3 compound on the 319 Al contact surface based on the evidence provided by X-ray photoelectron spectroscopy and micro-Raman analyses of the transfer layer. It is conceivable that the formation of stable AlF3 facilitated development of a carbonaceous transfer layer passivated by F atoms which prevented Al adhesion to the ta-C-F surface and accounted for the low μS observed for taC-F at elevated temperatures between 200 ˚C and 400 ˚C.

Wednesday Morning, April 22, 2015

8:20am B1-3-2 Characterization and Piezoelectric Properties of Reactively Sputtered ScAlN on Y-128o LiNbO3, Pin-Hung Chen, J.L. Huang, National Cheng Kung University, Taiwan, D.F. Lii, Cheng Shiu University, Taiwan, S. Wu ([email protected]), Tung-Fang Design University, Taiwan Y-128o Lithium niobate (LiNbO3) is a very well known and commercialized piezoelectric material for surface acoustic wave (SAW) devices. There are many researches to deposit some films including AlN, ZnO, SiO2 on Y-128o LiNbO3 to be new composite SAW substrates. AlN layer doped with scandium (Sc) is a novel and attractive piezoelectric material because of its large piezoelectricity. In this research, it was the first time to deposit wurtzite ScAlN thin films on Y-128o LiNbO3 substrate successfully by a cosputtering method using Al and Sc targets. The substitution of Sc atoms at Al positions causes a lattice distortion and induces a large piezoelectric response. The different sputtering power of Sc on the crystalline structure was investigated. X-ray diffraction patterns indicated all the films showed (002) peak and the best crystallinity appeared at the Sc 50 W. Then the piezoelectric coefficient (d33) would be enhanced obviously after doping Sc element into thin films and the highest value, 58.8 pC/N, was achieved at Sc 100 W. The cross-section of TEM results showed that amorphous and

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randomly structures were formed in the initial sputtering period, but the higher c-axis orientation structure formed as the film thickness increased. These great results have potential applications in surface acoustic wave (SAW) devices.

9:20am B1-3-5 Mixing Thermodynamics, Age-hardening Potential, and Electronic Structure of Ternary M11 − xM 2xB2 Alloys, Theory and Experiments, A.B. Björn, I. Zhirkov ([email protected]), A. Mockute, R.A. Armiento, H. Högberg, L. Hultman, Johanna Rosen, Linköping University, IFM, Sweden Transition metal diborides are ceramics with potential applications as hard protective thin films and electrical contact materials. We investigate the possibility to obtain age hardening through isostructural clustering, including spinodal decomposition, or ordering induced precipitation in ternary diboride alloys. By means of first-principles mixing thermodynamics calculations, 45 ternary M11-xM2xB2 alloys with AlB2 type structure are studied. Several alloys, among them Al1−xTixB2, are found to be of interest for coherent isostructural decomposition with a strong driving force for phase separation, while having a weak concentration-dependence of a and c lattice parameters. The mixing thermodynamics results are explained by revealing the nature of the electronic structure in these alloys. In particular the pseudogap at EF in TiB2, ZrB2, and HfB2 was found to originate from d-d interaction between metal sites in the hexagonal structure, further enhanced by metal-boron interactions. The theoretical work is compared to results from PVD synthesis of ternary diboride thin films made by magnetron sputtering and cathodic arc synthesis methods.

8:40am B1-3-3 Effect of Mo-Cu Cathode Composition on Plasma Generation, Macroparticle Formation, and Thin Film Deposition in DC Vacuum Arc Synthesis, Igor Zhirkov ([email protected]), Linköping University, IFM, Sweden, P. Polcik, K. Szilard, Plansee Composite Materials GmbH, Germany, J. Rosen, Linköping University, IFM, Sweden Mo-Cu composite materials display properties such as high electrical and thermal conductivity, low coefficient of thermal expansion, and good hightemperature performance. The material properties are dependent on how well Mo and Cu can be mixed, however, classical methods such as powder metallurgy and/or infiltration are limited concerning the residual porosity as well as the grain size of Mo-Cu bulk material. An alternative synthesis method, at least for thin films, is vacuum arc, which allows generation of metallic flux even from refractory materials, and which could produce increased Mo-Cu intermixing. In this work, we present the correlation between cathode composition and resulting macroparticle generation, ion energy and plasma- and/or film composition for Mo, Cu, Mo0.78Cu0.22 and Mo0.60Cu0.40 (at%) cathodes used in a DC vacuum arc deposition system. Both kinetic energies and ion charge states are significantly reduced when going from elemental to compound cathodes. At base pressure, the metal ions from the pure Mo and Cu cathodes have peak kinetic energies around 136 eV and 62 eV, respectively, while for a Mo0.78Cu0.22 cathode, the corresponding energies are 45 and 28 eV. The average charge states are accordingly reduced from 2.1 to 1.6 for Mo ions and from 2 to 1.2 for Cu ions. Furthermore, observed intense macroparticle generation from the MoCu cathodes shows no correlation to the resulting particle free films, with a composition displaying a slight excess of Cu. The obtained results are discussed in the light of the Mo-Cu phase diagram which shows no solubility between Mo and Cu.

9:40am B1-3-6 A Study of the Properties of CrN-Ag Coatings for Orthopaedic Applications, Sarah Banfield ([email protected]), Wallwork Tecvac R&D, UK, J. Housden, Tecvac Ltd, UK, A. Leyland, A. Matthews, The University of Sheffield, UK, J. Shelton, D. De Villiers, Queen Mary, University of London, UK, A. Traynor, Corin, UK Young active patients who require joint replacement surgery are driving research into developing new implants that can potentially last a lifetime. The cost of revision operations is also an important driving factor. In order to extend the lifetime of joint implants, a suite of novel CrN-Ag coatings have been developed. Through extensive wear testing on an orbital hip simulator system, CrN-Ag-coated hip implants have been shown to possess excellent wear resistance properties leading to a significant reduction in metal ion release and a reduction in the volume of wear debris generated. The mechanical and structural properties of CrN-Ag were also investigated and the results revealed that although the coating hardness decreases with increasing silver content, a uniform structure is observed in all cases. Furthermore, the presence of Ag is shown to improve the antimicrobial properties of the CrN-Ag coatings which will be beneficial for reducing the risk of post-operative infections.

9:00am B1-3-4 Effects on Photosensitivity and Photocatalysis of TIO2 Thin Film by Doping Fe and N, Chih-Chiang Wang, National Chung Hsing University, Taiwan, H.C. Shih ([email protected]), Chinese Culture University, Taiwan This study focuses on the preparation and characterization of Fe- and Ndoped TiO2 thin films by metal plasma ion implantation (MPII) and N2 annealing treatment. The band gap of anatase TiO2 (3.2eV) only absorbs UV light, which is less than 10% of the solar energy and results in the limitation of practical applications. The band gap of TiO2 can be controlled by tuning the position of the impurity level, which can then significantly increase the practical application and result in many industrial applications. As the Fe concentration ranges from 5× 10 15 to 1× 1017 ions/cm2, the films revealed the characteristic anatase TiO2. The Fe content of the Fe-implanted TiO2 films was found to be 0.5-1.5at%. The band gap of Fe-doped TiO2 was ranged from 2.87 to 3.14eV. The photocatalytic activity of Fe-implanted TiO2 is higher than that of as-deposited TiO2 (5.6%), and the removal ratio was increased to 14.1-17.8%. The N-doped TiO2 films were prepared by using N2 thermal annealing. As the annealing temperature increased from 400°C to 600°C, the films revealed the characteristic anatase TiO 2. The N content was found to be 0.1-0.3at%. The band gap decreased with increasing N concentration. The band gap of N-doped TiO2 decreased to 2.16-2.30eV. The N-doped TiO2 films exhibited excellent visible photocatalytic activity, and the removal ratio was increased to 9-14.1%. For (Fe, N) co-doped TiO2 films, the Fe content was 0.5at% and the N content was found to be 0.3-0.5at%. The band gap decreased with increasing N concentration. The band gap of (Fe, N) co-doped TiO2 was ranged from 1.97 to 2.22eV. The (Fe, N) co-doped TiO2 design conforms to the requirements for highly effective photocatalytic activity, and the removal ratio was 16.4-30.1%. The narrowing of the band gap in the substitutional N dopant was more effective than that in the substitutional Fe dopant. The substitution of Fe and N for Ti and O atoms can form the impurity levels near conduction band (CB) and valence band (VB), respectively. The distance from CB or VB to impurity can be controlled by changing the dopant concentration, and the tunable region was approximately 0.45eV and 0.48eV, respectively. The band gap decreased along with the concentration of Fe and N dopants. However, when the dopant concentration exceeds the optimal value, the photocatalytic activity of the film significantly decreases due to the formation of deep impurity. The tuning band gap of the TiO2 system can yield not only a singleelement-doped TiO2, but also a multi-element TiO2 films, which have great industrial applications.

10:00am B1-3-7 Intrinsic Structural, Mechanical and Corrosion Properties of Sputtered Al-Zr Thin Films, M. Reffass, LRC CEA/UTBM LIS-HP, Site de Montbéliard, France, A. Billard, Lrc Cea-Irtes-LermpsUtbm, France, E. Conforto, Université de La Rochelle, France, Frédéric Sanchette ([email protected]), LRC CEA- UMR CNRS 6279-ICD LASMIS, France, J. Creus, Université de La Rochelle, France Al-Zr thin films were deposited on glass slides by dc magnetron sputtering with Zr content ranging between 0 and 25 at %. Microstructure, morphology, hardness and intrinsic corrosion resistance in NaCl solution were investigated. Microstructural characterisation reveal the formation of a supersaturated solid solution for Zr content up to 12 at % and a single amorphous phase for higher Zr contents. Microhardness is found to increase with the increase of Zr content up to 18 at %. The electrochemical measurements, in 5 wt % NaCl solution, show an increase of corrosion resistance with addition of Zr and are correlated with microstructures of as-deposited films. The improved pitting corrosion resistance is ascribed to compact structure of alloys and also to enrichment of Zr in the passive film. 10:20am B1-3-8 A Novel Industrial PLD-System for the Production of Superhard Stressfree ta-C Films, Steffen Heicke ([email protected]), Creavac GmbH, Germany INVITED The lecture starts with a brief review of the state of the art in pulsed laser deposition equipment. A novel deposition system for the production on industrial scale of super hard tetrahedral amorphous carbon (ta-C) coatings will be presented. The resulting layers characterized by low internal stress using a combination of pulsed laser deposition (PLD) and pulsed laser stress relaxation (LR) as deposition method. The system has been designed on the basis of scientific findings showing the possibility to remove the high mechanical stresses in as- deposited ta-C films with optimum sp³-content and hardness by irradiating them after deposition with nanosecond laser pulses of 248 nm wavelength, where the maximum thickness of ta-C must not exceed 100 nm, however. Thick ta-C films can be prepared by applying this stress relaxation method alternating to the PLD method, for which nanosecond pulses of 248 nm wavelength and high pulse energy are used, too.

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Wednesday Morning, April 22, 2015

The general method as it has been used in research and the parameters allowing the preparation of ta-C films with hardness up to 60 GPa will be outlined. The main part of the talk will be directed to the integration of the method in an industrial deposition system with the focus on general aspects and modifications required for up-scaling and industrialization of the process. This includes: - Target and substrate handling, - In-situ cleaning of the windows through which the laser beams are guided into the chamber, - In-situ monitoring of coating quality - The controlling of the system and the system and the production process. Some examples of ta-C coated parts prepared in the system and the properties of the coatings will also be presented. Finally, a summary of coating rates and productivity attainable with the system and the costs of ta-C coatings produced with it, will be given. Keywords: PLD, ta-C, industrial Systems,

the highest H2 concentration (67 vol.%) in the gas feed. Alternatively, the coating with the maximum H (36 Gpa), H/E, and H3/E2 was obtained with lower H2 (~20 vol.%) and low C2H2 concentrations (~1 vol.%). The role of hydrogen and acetylene in the gas feed as dominant parameters affecting the structure and properties of the produced coatings is presented and discussed. 9:00am B4-3-4 Numerical Evaluation of Scratch Tests on Borided Layers, A. Meneses-Amador ([email protected]), LuisFernando Jiménez Tinoco, C.D. Reséndiz-Calderón, Instituto Politecnico Nacional, Mexico, A. Mouftiez, ICAM, France, G.A. Rodríguez-Castro, I.E. Campos-Silva, Instituto Politecnico Nacional, Mexico The scratch test on boriding layers was analyzed. Experiments tests and numerical simulations by finite element method of the scratch test were development on a FeB/Fe2B coating. The boride layers were formed at the surface of AISI 304 steels by developing the powder-pack boriding process at temperature of 1223 K with 2, 6 and 10 h of exposure times. From the set of experimental conditions of boriding process, scratch test were performed with linearly-increasing load mode of 1 to 90 N on 7 mm in length to determinate the most effective and informative testing conditions and to determine the critical load (Lc) for coating failure. The damage in the coating was examined by high resolution SEM. Experiments tests indicated that at a critical load the coating fails through brittle fracture. Numerical calculations considering the residual stress field generated by the scratch load showed that at this load the tensile stresses inside the coating become large enough to cause brittle failure. The residual stress field generated by the scratch load was analyzed and related with the failure mechanics observed by the experimental test.

Hard Coatings and Vapor Deposition Technology Room: Golden West - Session B4-3 Properties and Characterization of Hard Coatings and Surfaces Moderator: Uwe Beck, BAM Berlin, Germany, ChauChang Chou, National Taiwan Ocean University, Taiwan, Grzegorz Greczynski, Linköping University, IFM, Sweden

9:20am B4-3-5 On the Mechanisms and Mitigation of Volcanic Ash Attack on YSZ Thermal Barrier Coatings, Rudder Wu ([email protected]), National Institute for Materials Science, Japan INVITED Yttria stabilized zirconia (YSZ) made thermal barrier coatings (TBCs) have been widely utilized in commercial aero engines for decades. Unlike the injection of airborne particles forming calcium-magnesium-alumino-silicate (CMAS) on TBCs, which has been widely investigated, the implications of volcanic ash deposition on TBCs are not well understood. Previously, it has been demonstrated that volcanic ash readily reacts with alumina around 1310 °C, forming anorthite (CaAl2Si2O8), magnetite (Fe3O4), and spinel (Al1.75Mg0.889Mn0.351O4) as reactive products, having melting temperatures above that of the volcanic ash. The present study continues to explore the possibility of using aluminum based oxides and alumina doped YSZ in the reaction with volcanic ash to form compounds with melting temperatures higher than the typical service temperatures of TBCs. I call this the ‘melting-temperature engineering’ approach to mitigate melting induced penetration of volcanic ash in TBCs.

8:20am B4-3-2 Flow Curves of Hard Coatings: Determination from Nanoindentation Experiments and Fiinite Element Methods as well as Validation with Micropillar Compression Tests, Ivan Krajinović ([email protected]), M. Tkadletz, Materials Center Leoben Forschung GmbH, Austria, N. Schalk, C. Mitterer, Montanuniversität Leoben, Austria, R. Tichy, W. Ecker, Materials Center Leoben Forschung GmbH, Austria, C. Czettl, CERATIZIT Austria GmbH, Austria The performance of hard coatings in high-temperature applications, e.g. cutting, is significantly affected by their flow behavior. Within this work, an approach which combines nanoindentation experiments, finite element modeling and micropillar compression tests is presented. Nanoindentations were done using a spherical indenter on five different coating materials, namely chemically vapor deposited α-Al2O3 and TiCN as well as sputter deposited TiN, AlN and TiAlN. An approach which combines optimizing numerical algorithm and finite element (FE) model was developed to calculate flow curves on the basis of load-displacement curves obtained by nanoindentation experiments. The Ramberg-Osgood law was used to create a model of material plasticity for which initial parameters need to be defined. FE simulations were then performed and the calculated forcepenetration curve is compared to the experimental load-displacement curve. Sufficient adequacy of both curves was obtained by FE iterations with slightly modified Ramberg-Osgood parameters. The resulting flow curves are validated with stress-strain curves recalculated from force-displacement curves obtained in micropillar compression tests.

10:00am B4-3-7 Evaluation of Carbon Steel Surface Treated by AIHFPP using a Ti and Al Particles, Shuya Saito, K.S. Suzuki, J.K. Komotori ([email protected]), Keio University, Japan We have proposed an atmospheric controlled induction-heating fine particle peening (AIH -FPP) system which creates thick and stable modified layers with element of shot particles at the surface of steel. The aim of this study is to create a Ti-Al intermetallic compound at the carbon steel surface by AIHFPP treatment. AIH-FPP treatments were performed on the carbon steel surface with Ti and Al mixed particles at 900 ℃ for 10 seconds. The particles were prepared by means of a planetary mill using isopropanol as a process control agent. The treated surfaces were analyzed using a scanning electron microscope, an energy dispersive X-ray spectrometer, and an X-ray diffractometer (XRD). The result of XRD analysis showed the generation of Ti-Al intermetallic compound at the treated surface. The Vickers hardness test results also showed the hardened modified layer comparable to Ti-Al intermetallic compound. Consequently, the AIH-FPP treatment can create the Ti-Al intermetallic compound at the treated surface within a short amount of time.

8:40am B4-3-3 The Role of Hydrogen and Acetylene in the Synthesis of Nano-Crystalline Titanium Carbide Coatings, J.E. Klemberg-Sapieha ([email protected]), Etienne Bousser, Ecole Polytechnique, Canada The unique properties of titanium carbide (TiC), such as high hardness and elastic recovery, high corrosion resistance at elevated temperatures and high electrical conductivity make TiC very attractive as a protective coating for nuclear, aerospace and tool steel applications. In this study, coatings were prepared by Radio-Frequency Plasma Enhanced Chemical Vapor Deposition (RF-PECVD) onto silicon and Ti-6Al-4V alloy substrates using titanium tetrachloride (TiCl4) and acetylene (C2H2) in argon-hydrogen mixtures. The deposition was performed at a substrate temperature of 400° C and an RF self-bias voltage of -400 V while studying the effect of the H2 concentration and the C2H2:TiCl4 ratio on the coating structure and mechanical properties. The controlled parameters were found to affect the phase formation, grain size and orientation, as well as hardness H, Young's modulus E, internal stress σ, wear and adhesion. In order to improve the adhesion to the Ti-6Al-4V substrates, nitriding or carburizing was performed prior to the deposition. XRD revealed that the grain size varied between 6 and 12 nm for different H2 and C2H2 concentrations. The high hardness of 32-35 Gpa as well as the highest H/E, and H3/E2 ratios were correlated either with the smallest grain size and (111/200) peak ratio, or to

Wednesday Morning, April 22, 2015

10:20am B4-3-8 Microstructural Design: A Successful Strategy for Fracture Toughness Enhancement of Hard Coatings Studied by MicroCantilever Testing, Rostislav Daniel ([email protected]), J. Zalesak, M. Meindlhumer, Montanuniversität Leoben, Austria, B. Sartory, Materials Center Leoben Forschung GmbH, Austria, C. Mitterer, J. Keckes, Montanuniversität Leoben, Austria The limited fracture toughness of most hard materials limits their usage in applications where both hardness and toughness are required. Besides strategies to enhance fracture toughness by transformation toughening, coherency strain, increase of intrinsic compressive stress or formation of a nanocomposite structure, we focus on microstructural design to control crack formation and propagation. A successful strategy is to induce crack deflection or bridging at interfaces between two or more different phases or

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to control the crack propagation by a combination of materials with different elastic properties. In both cases, the increased energy which a crack needs to propagate through the interface results in enhanced fracture toughness. We will demonstrate these strategies for CrN/Cr and TiN/SiOx multilayers, combining two crystalline and crystalline and amorphous components with different properties, by microscale cantilever testing. Furthermore, we will present a new strategy for fracture toughness enhancement by grain-boundary engineering. In this way, even common nanocrystalline brittle materials may exhibit markedly enhanced plasticity, if their columnar grains are repeatedly tilted during growth. These microstructural design strategies open new possibilities how to optimize the mechanical response of coated tools and increase their lifetime and efficiency.

For different refractory metals obtained results on measured densities is in agreement with their elemental masses, but differs for film and bulk Young moduli of Ta and Mo. There is an additional XRD peak for the thickest Ta film at lower angle, which is not associated with any of the Ta related peaks in JSPDS database, and might have originated from an unstable transition phase of Ta. Optimum thickness of refractory sputtered films can be reached based on the highest values of Young’s modulus. 11:40am B4-3-12 Study on Thermal Stability and Mechanical Properties of Nanocomposite Zr-W-B-N Thin Films, Paritosh Dubey, R. Chandra ([email protected]), Indian Institute of Technology Roorkee, India, V. Arya, BHEL R&D, India, M. Kumar, Indian Institute of Technology Roorkee, India The thermal stability and mechanical properties of co-sputtered deposited Zr-W-B-N films on Si (100) substrates have been studied in detail. The power density for boron target has been varied from 0.1 to 7.5 watt/cm 2 to obtained films with varying compositions. Electron microscopy, x-ray diffraction analysis, atomic force microscopy, raman spectroscopy, nano and micro indentations were used to investigate the interrelations between the fine structure and the variations in strength properties of nanocomposite Zr-W-B-N thin films. It has been observed that for boron concentration 104 Ω-cm) and large optical transmittance change (> 60 %) in the nearinfrared region across the transition. We have fabricated various active metamaterials at terahertz frequencies using the phase transition in VO2 thin films. We will present details on the electrical and optical properties of VO 2 films and discuss examples of active metamaterials based on VO2 thin films. This work was funded by the Office of Naval Research (ONR) through the Naval Research Laboratory Basic Research Program.

8:40am C5-3 Nitride- and Oxide-nanorods for High-gain Photoconductors and Solar Fuels, Li-Chyong Chen ([email protected]), National Taiwan University, Taiwan INVITED Among the alternative energy sources, photo-electrochemical (PEC) cells are advantageous due to the possibility to convert light to hydrogen without carbon emission. Here, I will present the PEC mode of solar hydrogen generation using GaN, in both forms of epitaxial films and nanowires, as well as their related hetero-structures. In addition, PEC studies performed in a closely related system, ZnO, will also be introduced. The III-nitride semiconductors, such as GaN and InGaN, are promising for PEC for the following reasons. First, GaN demonstrates considerable resistance to corrosion in many aqueous solutions and its band edge potentials are situated in positions that allow for zero-bias hydrogen generation. Although the band gap of GaN is high at 3.4 eV, it may be tuned through the incorporation of indium to enhance optical absorption in the visible range. Moreover, several merits of their nanostructured forms have been demonstrated. For instance, the GaN nanorods (GaN NRs) exhibit very high photocurrent gain, efficient charge transfer in electrochemical environment. Photoconduction and PEC properties can be affected by various factors, such as axial crystal orientation of the NRs and polarity in epi-film, carrier concentration, as well as surface area. Just like solar cells, light harvesting is an important step for the high-efficiency PEC cells. Substantially enhanced hydrogen generation can be obtained in the arrayed GaN NRs, mimicking the so-called moth-eye structures, thus enhanced light trapping over their thin-film counterparts. Several other approaches, including surface plasmon resonance enhancement (e.g., Ag nanoparticles decoration on ZnO NRs), and semiconductor coupling (e.g., reduced graphene oxides on ZnO NRs) for enhancing light harvesting and/or carrier separation and transfer will also be presented.

10:00am C5-7 1 ML InN/GaN Matrix Coherent-structure QW System and its Evolution to Short-period Superlattice (SPS)-based InGaN Ternary Alloys, Akihiko Yoshikawa ([email protected]), K. Kusakabe, Chiba University, Japan INVITED We have proposed and successfully developed unique ALE-like InN deposition processes to fabricate novel coherent structure 1 ML-thick InN/GaN matrix-based QWs by using a custom-made MBE equipped with a spectroscopic ellipsometry (SE) system. The attached SE system is quite useful and effective as an in-situ monitoring, deep understanding, and precise controlling tool for the growth processes. The novel InN QWs were fabricated under self-ordering and self-limiting processes achieved at remarkably higher growth temperatures (600-700 C) than the higher side critical temperature (~500 C) for continuous InN film growth under +cpolarity growth regime by MBE. The fundamental structure of the novel QWs consisted of 1 ML-thick InN well coherently embedded in GaN matrix, and the QW could be controlled in fractional ML-thick and also 2 ML-thick InN wells in the GaN matrix depending on the growth conditions. Then, these InN QWs are generically expressed here as “1 ML” InN QWs. On the basis of above mentioned development on coherent structure “1 ML” InN/GaN matrix QWs, we have also been investigating to extend them to (InN)m/(GaN)n short-period superlattices (SPSs), where we simply call them as SMART structure and/or SMART process. Here SMART stands for “Superstructure Magic Alloys fabricated at Raised Temperature”. We expect that the InN/GaN SPS-based SMART structures can play a role as high quality artificial or digital InGaN ternary alloys. Of course, the GaN barrier layer thickness must be also ultimately reduced in this case down to a few monolayers or several monolayers level so that localized wave functions at the InN wells can be overlapped with each other. Furthermore, it should be noted that the SMART process has been successfully developed first in MBE but it has been extended to MOVPE now. It was found that the structural quality of the SMART structure devices is getting worse in the case of MOVPE than that of MBE, but MOVPE-grown devices often show better device performances than those for MBE due to higher growth temperatures. In this paper, we first summarize what is the novel “1 ML”-InN/GaN matrix QW system and then also discuss how and where those “1 ML”-InN QWs are fabricated on or inside the GaN matrix by MBE. Next, the basic idea for their potential application to InN/GaN SPS-based artificial or digital InGaN ternary alloys, i.e. SMART structure, will be reported. Furthermore, our idea and recent efforts for applying the “1 ML” InN QW/GaN matrix QW system and the SMART structure to develop blue-green light emitters and high efficiency III-N tandem solar cells, respectively, are also discussed, and their initial stage results will be reported.

9:20am C5-5 Highly Textured AlN Thin Films on Si by Reactive High Power Impulse Magnetron Sputtering, Tomas Kubart ([email protected]), T. Torndahl, M. Moreira, I. Katardjiev, Uppsala University, Angstrom Laboratory, Sweden Piezoelectric AlN films for electroacoustic devices are typically deposited by magnetron sputtering. Sputtering is compatible with standard microelectronic fabrication processes and requires lower deposition temperatures than other techniques. In order to enhance the texture of AlN, metal seed layers, such as molybdenum, are usually used. Low temperature growth of AlN films for devices where the seed layer cannot be used is challenging. Here we report on the growth of thin textured (002) AlN layers directly on Si substrates without any metal seed layer. The films were deposited by reactive High Power Impulse Magnetron sputtering (HiPIMS) from an aluminium target in argon/nitrogen atmosphere. Because in HiPIMS very high degree of ionization of the sputtered material is achieved, this technique provides highly ionized flux to the substrate and thus promotes surface diffusion. Moreover, nitrogen dissociation which occurs in the high density HiPIMS plasma increases reactivity of the nitrogen. For comparison, pulsed DC sputtering was also performed under identical conditions. We show that for 200 nm thick AlN films grown on (100) Si, the HiPIMS process produces well textured (002) films already at room temperature while the pulsed DC films are very poor. At 400°C, which is the optimal temperature for pulsed DC deposition, the HiPIMS films are superior with the FWHM value of 5.1 and 14.2° for the HiPIMS and pulsed DC, respectively. No appreciable stresses were observed in the films. The HiPIMS deposition process is more robust than standard DC sputtering and provides sufficient energy input even for configurations with relatively large target-to-substrate distance. It is therefore suitable also for cosputtering of ternary nitrides based on AlN. 9:40am C5-6 Active Plasmonic Metamaterials Based on the Phase Transition of VO2 Thin Films, Heungsoo Kim ([email protected]), N. Charipar, E. Breckenfeld, M. Osofsky, A. Pique, Naval Research Laboratory, USA Vanadium dioxide (VO2) has been extensively studied due to its ability to reversibly transform from a semiconducting monoclinic phase (low-

Wednesday Morning, April 22, 2015

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order to assess the possibility of these coatings to be used for orthopedic devices. Samples were prepared by DC unbalanced reactive dual magnetron sputtering using two targets, Zr and Ag, in Ar, C 2H2, N2 atmosphere. The materials were characterized in terms of composition and structure using electron probe microanalysis, X-ray photoelectron spectroscopy, X-ray diffraction and Raman spectroscopy. The results revealed that the coatings are composed by a variety of phases among which ZrCN, Ag and a:C phases have the predominant content. The electrochemical assessment evidenced a large dependence of the corrosion resistance on the silver content in the films, deteriorating the electrochemical stability of the material as the silver content increases. The amorphous carbon phase also negatively influenced the polarization resistant, behaviour ascribed to the induced morphological changes. The immersion test revealed a progressive increment of the polarization resistance as the time evolves, attributed to the passivation of both the surface and the pores, due to either ZrO2 formation on the top or a protective layer of albumin on the surface, result corroborated by X-ray photoelectron spectroscopy.

Coatings for Biomedical and Healthcare Applications Room: Sunrise - Session D3 Coatings for Bio-corrosion, Tribo-corrosion and Biotribology Moderator: Jean Geringer, Mines Saint-Etienne, France, Tolou Shokuhfar, Michigan Technological University, USA, Yu Yan, University of Science and Technology, China 8:00am D3-1 Mechanistic Study of Wear of Ceramic Heads by Metallic Stems in Modular Implants, N. Moharrami, D. Langton, Steve Bull ([email protected]), Newcastle University, UK Titanium-based and cobalt-chrome alloys as well as some ceramics have been widely used in orthopaedic applications as these materials can significantly enhance the quality of human life as implant materials. The longevity of these materials is highly influenced by their mechanical properties. In some devices alumina-based ceramic components articulate with titanium alloy counter faces (e.g. in the taper connections of titanium alloy stems and zirconia toughened alumina femoral heads in modern modular designs) and damage has been reported of the harder ceramic surface by the softer titanium alloy component. In such contacts the chemically inert ceramic component is not expected to corrode so the electrochemical damage mechanisms often suggested for metal-metal contacts are not appropriate. This study attempts to understand why this wear might occur by investigating bulk and surface mechanical properties (such as hardness and Young’s modulus) of a number of hip implants and test samples using a Hysitron Triboindenter. AFM images were also obtained to determine the contact area and hence, pile-up correction factors for the metallic material. It was found that the alumina ceramic heads were generally subject to chemomechanical softening after exposure to water for an extended period whilst titanium oxidised preferentially generating a hard oxide surface which was not softened by water. Furthermore, the oxidised titanium showed significantly higher hardness values therefore damaging the chemomechanically softened alumina material. The implications for device design and manufacture will be discussed.

9:00am D3-4 Femtolaser Micro-Texturing on CoCr Alloy for Heads of Hip Joints: Effect of Dimples' Parameters on Friction and Wear in MoM and MoP Contacts, N. Crisan, Vincent Fridrici ([email protected]), P. Kapsa, LTDS - Ecole Centrale de Lyon, France In order to improve the wear resistance and the friction properties of materials for the head / cup contact of hip prostheses, we studied the effect of the presence of dimples on one of the contacting bodies. Our research focused on CoCr – UHMWPE and CoCr – CoCr bearing couples, in a contact between a textured flat specimen made of CoCr and a polished ring (in metal or polymer), on a laboratory tribometer, at 37°C in calf serum. The dimples (of circular shape in a hexagonal network) were produced with a femtosecond laser and the effects of dimples’ parameters (diameter - from 15 µm to 40 µm -, height - from 10 µm to 25 µm -, and pitch - from 60 µm to 100 µm -) on friction and wear were studied. Steady state friction coefficients are analyzed vs. dimples’ parameters, area ratio (% of dimples’ surface on the whole contacting surface) and aspect ratio (diameter / height). Worn surfaces of both counterbodies are observed by optical microscope, digital microscope and SEM. Interferometry measurements are performed to measure the wear volume. Dimples’ filling by wear debris is analyzed. In MoP contact, micro-texturing cannot decrease friction, compared to smooth polished surface. In MoM contact, friction coefficient of textured surface can be lower than the one of polished reference surface for high value of area ratio (≥10%) and low value of aspect ratio (≤2). Moreover, concerning wear of MoM contact, for all values of area ratio (from 4% to 23%), if the aspect ratio is large enough (≥2), wear volume of textured surface is lower than the one of the reference polished surface. It is possible to divide the wear amount by more than 2 by putting dimples with a diameter of 30 µm, a height of 10 µm and a spacing of 60 µm, in MoM contact.

8:20am D3-2 Chemistry, Structure, and Wear Properties of Nb1-xTixN Thin Films, A. Martins, R. Sanjines, Ayat Karimi ([email protected]), Swiss Federal Institute of Technology Lausanne (EPFL), Switzerland, A. Santana, N. Goebbels, IHI Ionbond AG, Switzerland, R. Heuberger, L. Eschbach, RMS Foundation, Switzerland The NbTiN coatings are considered promosing candidate materials for biomedical applications because of their potential to improve the wear life and corrosion resistance of bearing components. In this paper, we present a systematic study of Nb1-xTixN system with x = 0 – 1. The films are deposited onto CoCr substrates by magnetron sputtering and cathodic arc, where the nitrogen partial pressure is varied and the substrate bias is adjusted to modify the crystal structure, stoichiometry, and growth morphology of the films. Chemical composition and microstructures are characterised using RBS, XPS, XRD, SEM, TEM, and mechanical properties by nanoindentation. Wear properties and friction coefficients are studied using a ball-on flat tribometer with polyethylene ball as the counterface material. Although the presence of (Ti) favours the formation of cubic phase over a vide range of N2/Ar ratio, the very low and the very high nitrogen partial pressure lead to the occurrence of hexagonal phases either alpha or delta prime, respectively. Grazing incidence XRD under different angles shows that the initial stage of growth is accompanied by the formation of hexagonal phase, which changes to the cubic phase at higher thickness. On the basis of XPS, most of the films are N over stoichiometry. Hardness and modulus are very sensitive to Nb/Ti ratio, and both parameters increase with the Nb content in the cubic coatings. In this presentation, structural and mechanical properties will be discussed in terms of deposition parameters and growth kinetics.

9:20am D3-5 Effects of Duty Cycle and Electrolyte Concentration on the Microstructure and Biocompatibility of Plasma Electrolytic Oxidation Treatment on Zirconium Metal, Shao-Fu Lu, Y.C. Yang, National Taipei University of Technology,Taiwan, J.W. Lee ([email protected]), Ming Chi University of Technology, Taiwan, B.S. Lou, Chang Gung University, Taiwan Recently, plasma electrolytic oxidation (PEO) process has been widely studied and applied in industries due to its ability to create functional oxide layers on Al, Ti and Zr alloys. In this work, a pulsed DC power supply was adopted to grow the zirconia coating on the pure Zr metal by PEO treatment. Three duty cycle values, 25%, 50%, 75% at a fixed frequency of 1000 Hz and direct current (DC) of power supply control were used, respectively, to fabricate the zirconia coatings in the aqueous solution containing K3PO4 and KOH in three different concentration ratios. The processing time was kept at 10 min. The structures of PEO coating was determined by the X-ray diffractometer (XRD). The surface and the crosssection morphologies of the PEO coating were examined by scanning electron microscopy (SEM). The HRC-DB method was used to evaluate the adhesion quality of the coating. The surface roughness was examined by a profilometer. The biocompatibility of the zirconia coating was examined by the 3T3 cell cultivation and the MTS assay . The corrosion resistance of the PEO coating was evaluated by the potentiodynamic polarization test in Hank’s solution. Effects of duty cycles and electrolyte concentration on the microstructure, adhesion property and biocompatibility of the zirconia coatings by PEO treatment were discussed in this work.

8:40am D3-3 Electrochemical Response of ZrCN-Ag-a(C,N) Coatings in Simulated Joint Electrolyte, Sebastian Calderon ([email protected]), University of Minho - University of Coimbra, Portugal, A. Cavaleiro, University of Coimbra, Portugal, S. Carvalho, University of Minho - University of Coimbra, Portugal Magnetron sputtering has been recognized as a suitable surface modification technique to improve the performance of a material by using a wide spectrum of coatings, which also can provide additional capabilities. In this study, Zr-C-N-Ag coatings were deposited onto stainless steel 316L aiming to evaluate the corrosion resistance and chemical changes of the coatings after immersion in simulated body fluids containing proteins, in

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Wednesday Morning, April 22, 2015

9:40am D3-6 Experimental Techniques for Bio-tribocorrosion Studies and Available Models for Interpretation, Anna Igual Muñoz ([email protected]), Universitat Poltècnica de València, Spain INVITED Metallic materials for the design and construction of biomedical implants (i.e. hip and knee joint prostheses) are still one of the considered materials because of their excellent mechanical properties, corrosion resistance and biocompatibility. However, they are also subjected to the interaction between wear and corrosion during the operating conditions, thus degrading through a tribocorrosion mechanism. Fundamental understanding of the involved phenomena will serve as the basis for specific material design under bio-tribocorrosion situations. Mechanistic approach of tribocorrosion has leaded the development of new models for describing this interaction. Consideration of corrosion principles together with tribological laws has allowed establishing the basis for new tools in tribocorrosion modeling. This work introduces the fundamental concepts of tribocorrosion for biomedical applications and describes the experimental techniques available for those tribocorrosion studies (in-vitro and in-vivo) together with the analysis of the existing models for interpretation

[1]H. Kato, Severe-mild wear transition by supply of oxide particles on sliding surface, Wear 255 (2003), 426-429 8:20am E3-1-2 Friction Influenced by Surface Roughness and Sliding Speeds at Oil Lubricating Conditions, Guang Wang, X. Nie ([email protected]), University of Windsor, Canada A linerless aluminum (Al) engine block has potential to reduce the weight of an automotive engine and improve the fuel economy. However, the Al cylinder surface of an aluminum engine block is not usually strong enough to withstand the sliding wear against piston rings. A few surface processing technologies are used to protect the surface of cylinders directly. Among them, plasma transferred wire arc (PTWA) thermal spraying coating is already popular. Plasma electrolytic oxidation (PEO) coating is also proposed for increasing the wear resistance of aluminum-silicon alloy (A356) and reducing the friction between the cylinder and piston. In this work, two different PEO coatings with a thickness of around 23 µm were prepared, and a high speed pin-on-disc tribometer was used to study the tribological behavior of the coating at oil lubricant conditions. A cast iron sample was also used to do the same tribological tests for comparison. The coefficient of friction (COF) vs surface roughness (R a: 0.2 - 0.8 µm) and sliding speeds (up to 6.0 m/s) were particularly studied. The results show that the COF significantly decreased with the increase of sliding speeds, and a smoother coating surface generally exhibited a lower COF and a steeper descent rate of the COF. While such observations were true for both PEO coatings and the cast iron sample, the polished PEO coatings may have a lower COF than cast iron. The study indicates that the Al-Si alloy with PEO coatings could be a feasible solution to reduce the weight and improve the fuel efficiency of an Al engine.

Tribology and Mechanical Behavior of Coatings and Engineered Surfaces Room: San Diego - Session E3-1 Tribology of Coatings for Automotive and Aerospace Applications Moderator: Astrid Gies, Oerlikon Balzers, Oerlikon Surface Solutions AG, Gary L. Doll, The University of Akron, USA, Pantcho Stoyanov, Kennametal Incorporated, USA

8:40am E3-1-3 Exploring the Mechanical and Thermal Stability of Nanocrystalline Metal Composite and Alloy Thin Films, Nicolas Argibay ([email protected]), M. Dugger, S. Prasad, B. Clark, J.E. Mogonye, B. Boyce, M. Chandross, Sandia National Laboratories, USA INVITED The extraordinary mechanical properties of nanocrystalline metals are well documented, though in many ways these materials remain impractical for engineering design. The transition from grain boundary to defect dominated plasticity associated with grain coarsening can be brought about by the addition of even modest amounts of thermal or mechanical energy, dramatically altering their mechanical properties. As recently as 2012 a new class of binary metal alloys was discovered that exhibits intrinsically thermodynamically stable nanocrystallinity. The unusual stability of these alloys was described as a local energetic minimum, where the entropy of segregation exceeds the entropy of mixing for the grain boundary segregated phase, pinning boundaries and mitigating thermally activated grain growth. Modern advances in PVD have similarly enabled the deposition of metal-ceramic nanocomposites with significant thermal and mechanical stability. We present the motivations for, potential impact and results of ongoing investigations of the stability of both nanocrystalline metal matrix composites and binary metal alloys, and explore their practicality as wear resistant tribological coatings. Sandia National Laboratories is a multi-program laboratory managed and operated by Sandia Corporation, a wholly owned subsidiary of Lockheed Martin Corporation, for the U.S. Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000

8:00am E3-1-1 Wear Laws and Glaze Layer Formation on New Coatings for Aeronautics in a Ceramic Versus Metallic Alloy Contact under Fretting Wear at High Temperatures, Ariane Viat ([email protected]), S. Fouvry, LTDS - Ecole Centrale de Lyon, France, L. Pin, Herakles groupe Safran, France, M.-I. De Barros Bouchet, LTDS - Ecole Centrale de Lyon, France, A. Mouret, Herakles groupe Safran, France Thanks to their thermostructural properties, CMCs (Ceramic Matrix Composites) draw interest from aeronautics to partly substitute metals. However, CMC-metal contact induces chemical interactions that call for an environmental barrier to prevent severe degradation. The present study aims at selecting protective ceramic coatings for the CMC and understanding the major mechanical and chemical processes involved at the plane-to-plane ceramic-metal contact under fretting wear. As a representative contact, a 4-mm-diameter punch made of HS25 (Co-CrNi-W alloy) put on a coated CMC plane is investigated. Different ceramic coatings are submitted to fretting wear tests that model the basic in-flight conditions at 700°C, to both measure wear kinetics and analyse damaging scenarios. Fretting laws are established to quantify wear kinetics as functions of frequency, sliding amplitude and contact pressure that change within an in-flight cycle. As shown for metal-metal interfaces [1], a glaze layer for some ceramic-metal contacts is formed. Depending on the coating, two damaging scenarios are identified: abrasive wear for coatings containing alumina and glaze layer-style wear for ceramics containing metals. SEM and EDS analyses on polished cross sections of worn surfaces show that for abrasive wear, thin (about 5 µm) and non-continuous sediments are trapped in ceramics’ hollows. By contrast, when formed, the glaze layer is thick (up to 40 µm) and covers the whole contact path [Fig.1]. Glaze layers are formed by mechanical and diffusional (sintering) processes. Even if the sediment layers contain mainly metallic oxides from the punch, the ceramics’ microstructure is crucial as a substrate. Surface energy is dissipated either in the fracture of ceramics and newly formed debris or in a sticky glaze layer. In the first case, fragments are abraded by alumina contained in the ceramic and ejected. In the second case, ceramics are protected and barely worn. However, the glaze layer is only formed above an inherent threshold temperature. Worn volumes are up to 10 times bigger when no glaze layer is formed. When applied on the ceramic coating, a solid lubricant limits friction during the first 5% of the test before being completely worn. However, worn volumes are much smaller for lubricated ceramics compared to raw coatings. EDS analyses show that after the complete wear of the lubricant layer, particles from the lubricant are blended in sediments, which indicates the double function of the lubricant that firstly reduces friction and secondly keeps wear down.

Wednesday Morning, April 22, 2015

9:20am E3-1-5 An Endeavour to Examine Erosion Failure Mechanisms in TiCrN Coatings, Krishna Valleti ([email protected]), R. Krishna, S. Joshi, International Advanced Research Centre for Powder Metallurgy and New Materials (ARCI), India Industrial systems such as gas turbines, air craft compressors will generally experience the problem of blade erosion by solid particles such as dust, soot or scale leading to changes in the blade's shape and surface finish. Therefore, under the dynamic operating conditions, the solid particle erosion gradually reduces turbine efficiency and increases the average fuel consumption rate. The long lasting blades not only reduce the maintenance cost, but also reduce the emission of greenhouse gases. Hence, any measures which can reduce the erosion rate of the blades can be a high value addition for the above sectors. The thin coatings with exceptionally high hardness, toughness and ease of deposition, can be potentially used on numerous components suffering from diverse forms of wear. Therefore, any turbine engine or rotary compressor that suffers from erosion due to airborne particle impact will benefit from such coatings. In the present study, TiCrN coatings with varying Cr content are deposited on SS 304 and Ti-6Al-4V substrates using cylindrical Cathodic Arc Physical Vapor Deposition (CAPVD) system available in the author’s laboratory (Model: π 300, PLATIT). The coatings were extensively studied for their physical (thickness, adhesion, residual stress and phase composition and micro structure), mechanical (hardness, modulus and

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toughness) and tribological (sliding and erosion wear) properties. The results obtained were systematically analysed and compared to arrive at the best suitable coating composition for erosion resistance applications. Towards understanding thickness and residual stress effects on erosion properties, coatings with optimized composition were deposited with varying thicknesses (5-20 µm) under continuous and discontinuous modes (with intermediate heat treatment step: T Heat treatment > T Deposition). Towards benchmarking comparison, the erosion resistance as offered by well known TiN coatings has been comparatively investigated. The mechanism of erosion failures has been studied thoroughly using Focussed Ion Beam and Scanning Electron Microscope. The results demonstrate that the 20 μm thick TiCrN coating can be a better choice for erosion resistance applications than the TiN coating. The critical coating thickness required to withstand the erosion damage is an important outcome of the present study. For multi-layer and intermittently heat treated films, the predominant material removal mechanism is through chipping of the coating at interfaces and the low density spots like droplets. The results pertaining to the above study will be presented and discussed.

microanalysis of chemical composition, phase constituent by X-ray diffraction and laser profilometer were used. The evident influence of TiC addition on corrosion resistant of coatings has been shown. Financial support of Structural Funds in the Operational Program Innovative Economy (IE OP) financed from the European Regional Development Found - Project No POIG.0101.02-00-015/09 is gratefully acknowledge. 10:40am E3-1-9 Development of DLC Coating Architectures for Demanding Functional Surface Applications Through Nano- and Micro-mechanical Testing, Ben Beake ([email protected]), M. Davies, Micro Materials Ltd, UK, T. Liskiewicz, University of Leeds, UK, V. Vishnyakov, Huddersfield University, UK DLC coatings can combine high hardness with low friction. However, they are often deposited with high levels of intrinsic stress and display low adhesion strength resulting in poor performance in demanding applications. A highly topical challenge is to develop advanced DLC coatings capable of withstanding more demanding applications in the automotive, cutting tools, MEMS and oil and gas sectors. The results from several nanomechanical and tribological test techniques nanoindentation, nano-scratch and nano-fretting (nano-wear) – can be used together to aid the design of DLC coating architectures for enhanced durability in specific applications [1-3]. The behaviour of multilayered DLC coatings (Cr/W-C:H/a-C:H, Cr/WC:H/Si-a-C:H) deposited using industrial scale PECVD Flexicoat 850 system (Hauzer Techno Coating) was compared to that of commercial CrN/a-C:H:W (WC/C, Balinit C Star from Oerliken Balzers). We have previously reported that in nano-wear tests the coatings with higher H/E display greater wear resistance [2]. The stress fields during nano- and micro-scale scratch tests however are different and consequently the behaviour is completely different. Under these conditions the coatings with lower H/E display improved performance. High resolution SEM imaging has been used to investigate this further. A simple contact model [1] strongly suggests that the position of the maximum in the von Mises stress in relation to the coating-substrate interface is a critical factor in determining the type of wear behaviour observed. 1. Review of recent progress in nanoscratch testing, BD Beake, AJ Harris and TW Liskiewicz, Tribology 7 (2013) 87. 2. Short note on improved integration of mechanical testing in predictive wear models, TW Liskiewicz, BD Beake, N Schwarzer and MI Davies, Surf Coat Technol 237 (2013) 212. 3. Nano-scratch, nanoindentation and fretting tests of 5–80 nm ta-C films on Si(100), BD Beake, MI Davies, TW Liskiewicz, VM Vishnyakov and SR Goodes, Wear, 301 (2013) 575.

9:40am E3-1-6 PVD- Thin Films for Static Friction Applications, Otmar Zimmer ([email protected]), V. Weihnacht, Fraunhofer IWS Dresden, Germany Frictionally engaged joints are widely used in mechanical engineering and require a high static friction. Typical applications are flange joints or shafthub joints for example. Dimensions and weight of those joints can be reduced by increasing the static friction coefficient of the relevant friction surfaces. PVD thin films have a high potential to fulfil this requirement. However, almost all research activities are traditionally focused on the decrease of the dynamic coefficient of friction. In this paper the static coefficient of friction of Nimonic – AlTiN hard coatings and rough ta-C coatings against 42CrMo4 counterparts in torsion experiments was studied. The slipping curves have been determined and a maximum static coefficient of friction μmax up to 0.8 was measured. Because of the low film thickness in the range of 5 microns the coatings can be used in a great variety of applications and environments. It is a significant addition to existing solutions with thermally sprayed coatings or foils. 10:00am E3-1-7 Tribological Properties of WC-CoCr Coatings Sprayed at Supersonic Velocities (HVOF) using Ultra Fine Grain Powders, Aleksander Iwaniak ([email protected]), M. Hetmanczyk, Silesian University of Technology, Poland, R. Swadzba, Institute for Ferrous Metallurgy, Poland, G. Wieclaw, K. Rosner, Certech, Poland In the work, the microstructure and tribological properties of HVOF sprayed WC-CoCr carbide coatings of ultrafine (< 10µm), spherodiz ed and nano structured powders were examined. The spraying was performed with a power gun and powder feeder from Thermico. The tests were conducted with the "ball on disc" method. The counter specimens "ball" were made of various materials: tungsten carbide, silicon carbide, and a carbon-graphite material impregnated with antimony. For the purposes of comparison, a coating sprayed from a powder having a conventional grain size distribution (45µm) and solid ceramics (SiC "disc") were examined. The condition of the top layer of the specimens and counter specimens was determined before and after the friction tests (SEM, EDS, XRD, 3D laser profilometry). The examination revealed that the fine powder coating exhibited less wear. The lowest coefficients of friction were noted for the following friction test pair: tungsten carbide "disc" and counter specimens ("ball") of silicon carbide doped with antimony and resin. Financial support by The National Centre for Research and Development (NCBiR) in Warsaw, Poland - Project No INNOTECHK2/IN2/2/181798/NCBR/13 is gratefully acknowledge.

11:00am E3-1-10 Effect of Humidity on Tribological Behaviour of Cd and Zn-Ni Coatings, Richard Chromik ([email protected]), L. Lee, P. Behera, S. Rajagopalan, McGill University, Canada Low Hydrogen Embrittling (LHE) Cd and Zn-14wt% Ni coatings are used in close contact conditions for aerospace components such as landing gears and fasteners. Recent regulations have limited the use of Cd due to its carcinogenicity and use of cyanide in the plating process. Intermetallic Zn14wt% Ni coating has shown promising properties as a suitable replacement for LHE Cd with improved wear and tribological properties. Although LHE Cd coatings are used for last five decades and Zn-14wt% Ni has been studied in the past two decades, open literature available for tribological properties of both coatings is limited or mostly within the industries. This study focuses on evaluating and comparing the tribological properties of LHE Cd and Zn-14wt% Ni coatings under varying relative humidity (RH). A linearly reciprocating pin on disk tribometer was used to study the evolution of coefficient of friction combined with post tribological study of third bodies formed. Piezoelectric sensors were used to measure the lateral force at a sampling rate of 800 Hz and generate friction maps (i.e. triboscopy). For LHE Cd, increasing RH resulted in accelerated wear of the coating. Whereas for the Zn-Ni coating, increase in RH resulted in the formation of Zn oxide and a change of the wear mechanism from mechanical to chemical.

10:20am E3-1-8 Electrochemical Behavior of WC-Co Thermal Spray Coatings, Modified by Sub-microcrystalline Carbides, Hanna Myalska ([email protected]), J. Michalska, K. Szymański, G. Moskal, Silesian University of Technology, Poland Electrochemical behavior of high velocity air fuel (HVAF) WC-Co modified coatings was presented in this article. The commercial powder of WC-Co 83/17 type was used as a basic material. The modification process was relying on mechanical mixing of WC-Co powder with submicrocrystalline TiC addition in weight ratio from 3 to 10 % wt. In first step of investigations the internal morphology of coatings was characterized. In this area the thickness, porosity, phase composition and overall quality of deposited coatings were analyzed. The second step of investigations consists ofelectrochemical behavior characterization of coated samples at ambient temperature in NaCl, NaOH and H2SO4 solutions. To characterize coatings top-surface morphology the scanning electron microscopy with

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different O2 flows. Prior to the film growth, the average power of the HiPIMS plasma was measured for various O2 flows and pulse repetition frequencies, and the transition of the vanadium target from metal mode to oxide mode was mapped. The growth rate and plasma stability was also determined for each state of the target. As the O2 flow increases from 1 to 6 sccm, X-ray diffraction patterns reveal the transition of the epitaxial films from V2O3 through VO2 to V2O5 for both HiPIMS and dcMS processes. The increased O2 flow results in an additional incorporation of oxygen atoms and ions into the films which induced vacancies and epitaxial degradation for the dcMS grown films while the increased O2 flow has less impact on the quality of the epi-layers in the HiPIMS process. X-ray reflectivity measurements show that the HiPIMS grown films are denser and smoother compared to the dcMS grown films. Atomic force microscopy measurements reveal that at higher O2 flows, the surface roughness increases drastically in the dcMS grown films while the HiPIMS grown films demonstrate lower surface roughness for elevated O 2 flows compared to dcMS grown films. Therefore, an O2 flow interval can be found to obtain stoichiometric VO2 films for each process. The resistivity of VO2 films grown by HiPIMS and dcMS processes was also measured as a function of temperature and their insulator-to-metal transitions are compared. [1] M. Nakano et al., Nature. 487 (2012) 459 - 462. [2] L. Wang et al., Opt. Lett. 37 (2012) 4335. [3] A. L. Pergament, ISRN Condens. Matter Phys. (2011) 605913. [4] E. Kusano et al., J. Vac. Sci. Technol. A, 6 (1988) 3. [5] A. Zimmers et al., Phys. Rev. Lett. 110 (2013) 056601. [6] S. Kittiwatanakul et al., J. Appl. Phys. 114 (2013) 053703.

New Horizons in Coatings and Thin Films Room: Sunset - Session F2-1 High Power Impulse Magnetron Sputtering (HiPIMS) Moderator: Stephanos Konstantinidis, University of Mons, Belgium, Tomas Kubart, Uppsala University, Angstrom Laboratory, Sweden 8:00am F2-1-1 Controlled Growth of Transition-metal Nitride Alloy Films via Hybrid HIPIMS/Magnetron Co-sputtering using Synchronized Metal-ion Irradiation, Grzegorz Greczynski ([email protected]), J. Lu, J. Jensen, Linköping University, IFM, Sweden, I. Petrov, J. Greene, University of Illinois at Urbana-Champaign, USA, W. Kölker, S. Bolz, C. Schiffers, O. Lemmer, CemeCon AG, Germany, L. Hultman, Linköping University, IFM, Sweden INVITED Two features of high-power pulsed magnetron sputtering (HIPIMS) render this technique particularly attractive for growth of transition metal (TM) nitride alloys: (i) the high ionization degree of the sputtered metal flux, and (ii) the time separation of metal- and gas-ion fluxes incident at the substrate.[1] The former implies that ion fluxes originating from elemental targets operated in HIPIMS are distinctly different from those that are obtained during dc magnetron sputtering (DCMS), which helps to separate the effects of HIPIMS and DCMS metal-ion fluxes on film properties. The latter feature allows one to minimize compressive stress due to gas-ion irradiation, by synchronizing the pulsed substrate bias with the metal-richplasma portion of the HIPIMS pulse. We use pseudobinary TM nitride model systems TiAlN, TiSiN, and TiTaN to carry out experiments in a hybrid configuration with one target powered by HIPIMS, the other operated in DCMS mode. [2],[3] This allows us to probe the roles of intense M1n+ and M2n+ metal-ion fluxes (n = 1, 2) from HIPIMS-powered targets on film growth kinetics, microstructure, and physical properties over a wide range of M1M2N alloy compositions. TiAlN and TiSiN mechanical properties are shown to be determined by the average metal-ion momentum transfer per deposited atom .[4] Irradiation with lighter metal-ions (M1 = Al+ or Si+ during M1-HIPIMS/TiDCMS) yields fully-dense single-phase cubic Ti1-x(M1)xN films. In contrast, with higher-mass film constituent ions such as Ti+, easily exceeds the threshold for precipitation of second phase w-AlN or Si3N4. Based on the above results, a new PVD approach is proposed which relies on the hybrid concept to grow dense, hard, and stress-free thin films with no external heating. Film densification is achieved by pulsed synchronized bombardment with metal-ions that are film constituents; this, in turn, minimizes film stress.[5]

9:00am F2-1-4 Hydrogenated SiyNx Coatings Deposited by HiPIMS using NH3, Susann Schmidt ([email protected]), T. Hänninen, C. Goyenola, L. Hultman, J. Jensen, G. Gueorguiev, H. Högberg, Linköping University, Sweden Hydrogenated SiyNx (0.06 < x < 0.42) coatings were deposited by reactive high power impulse magnetron sputtering (rHiPIMS) using a pure Si target, NH3/Ar or NH3/N2/Armixtures onto Si and steel substrates. The depositions were carried out in an industrial coating system. During coating deposition the pressure and temperature were kept constant at 400 mPa and 150 °C, respectively. For this study, the NH3-to-Ar flow ratio, the pulse frequency, and the average target power were varied. The processes as well as the coating properties were also addressed theoretically. Synthetic Growth Concept calculations based on Density Functional Theory were conducted in order to assess the availability and role of precursor species during the rHiPIMS processes in NH3/Ar and N2/Armixtures. The SiyNx properties were studied by elastic recoil detection analysis, X-ray photoelectron spectroscopy, X-ray diffraction, X-ray reflectivity, and nanoindentation as well as Rockwell C tests in order to investigate the H and N contents of the films, their chemical bonding structure, residual stress, density, and mechanical properties, respectively. Our theoretical results suggest that 16 different film forming species are prevalent in the Si/NH3/Ar discharge. Most important species for the film formation were predicted to be dimers such as NH, Si2, SiH, and SiN, trimers like N2H and SiNH as well SiNH2 and N2H2 molecules. While the former category of plasma species is highly reactive, trimers and XNH2 molecules contribute to SiyNx film formation not only by their comparatively high amount of dangling bonds, but also by their high cohesive energies, providing cohesive and adhesive strength of the coating. The experimental results show that the reactive Si yNx deposition process and film properties are strongly influenced by the NH3-to-Ar flow ratio, the pulse frequency as well as the average target power. The pulse frequency was found to be a powerful tool to tailor the composition of the Si yNx films and thus, their mechanical properties. Consequently, the chemically enhanced rHiPIMS discharge of Si in NH3/Ar atmosphere suggests an improved control of the thin film properties.

[1] G. Greczynski, J. Lu, J. Jensen, I. Petrov, J.E. Greene, S. Bolz, W. Kölker, Ch. Schiffers, O. Lemmer and L. Hultman, JVSTA 30 (2012) 061504-1 [2] G. Greczynski, J. Lu, M. Johansson, J. Jensen, I. Petrov, J.E. Greene, and L. Hultman, Surf. Coat. Technol. 206 (2012) 4202 [3] G. Greczynski, J. Lu, M. Johansson, J. Jensen, I. Petrov, J.E. Greene, and L. Hultman, Vacuum 86 (2012) 1036 [4] G. Greczynski, J. Lu, J. Jensen, I. Petrov, J.E. Greene, S. Bolz, W. Kölker, Ch. Schiffers, O. Lemmer and L. Hultman, Thin Solid Films, 556 (2014) 87 [5] G. Greczynski, J. Lu, I. Petrov, J.E. Greene, S. Bolz, W. Kölker, Ch. Schiffers, O. Lemmer and L. Hultman, JVSTA 32 (2014) 041515 8:40am F2-1-3 Characterization of Epitaxial V2Ox Thin Films on Cplane Sapphire Grown Under Various O2 Flows by High Power Impulse Magnetron Sputtering, Seyedmohammad Shayestehaminzadeh ([email protected]), E.B. Thorsteinsson, U.B. Arnalds, H.P. Gislason, E.O. Sveinbjornsson, S. Olafsson, University of Iceland, Iceland VO2 films have recently attracted much attention in microelectronics and optics due to their ultrafast insulator-to-metal phase transition near room temperature [1, 2]. Other vanadium oxides (V2O3 and V2O5) also exhibit similar properties either below or above room temperature [3] but VO 2 is believed to be the most promising candidate among these oxides to be utilized for various applications. VO2 thin films have been previously grown on various substrates by pulsed laser deposition [1], dc (dcMS) and rf magnetron sputtering [4, 5] and reactive bias target ion beam deposition [2] under various O2 partial pressures [6] and their electrical properties have been extensively studied [1, 2, 4, 5]. To benefit the impact of the highly ionized plasma on the film properties, we have grown vanadium oxide thin films on c-plane sapphire by high power impulse magnetron sputtering (HiPIMS) and dcMS under

Wednesday Morning, April 22, 2015

9:20am F2-1-5 A Comparative Study of TiSiCN Nanocomposite Coatings Deposited using DCMS, PDCMS, PEMS, and DOMS Techniques, Jianliang Lin ([email protected]), R. Wei, R. Castillo, K. Coulter, Southwest Research Institute, USA Plasma enhanced magnetron sputtering (PEMS) is an improved version of the DC magnetron sputtering (DCMS) technique by introducing an extra global plasma generated by an electron source, e.g. hot filaments, to enhance the Ar ionization. Deep oscillation magnetron sputtering (DOMS) is a new high power impulse magnetron sputtering (HiPIMS) technique that uses large voltage oscillation packets to achieve high power pulses for sputtering. As compared to conventional DC and pulsed DC magnetron sputtering (PDCMS), the PEMS and DOMS techniques aim at increasing the plasma ionization degree and hence the ion flux, thereby improving the structure and properties of the coating. It is important to understand the

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characteristics of these processes and their capabilities/limits for coating depositions. In this study, thick TiSiCN nanocomposite coatings were reactively deposited in a closed field unbalanced magnetron sputtering system by sputtering metal Ti targets using DCMS, PDCMS, PEMS, DOMS, or the hybrid of PEMS+DOMS technique in a reactive gas mixture containing argon, nitrogen and trimethylsilane. The PEMS process showed the highest mean substrate current density mainly contributed from low energy Ar ions. The DOMS process showed high peak substrate current density in the pulses mainly contributed from ionized metal target ions with a distribution of ion energies. The deposition rate, ion current density on the substrate, process temperature, and the process stability will be compared. More importantly, the microstructure, residual stress, mechanical and tribological properties of the TiSiCN nanocomposite coatings deposited by these techniques will also be reported.

The protection against poisoning or the reduction of arcing during the reactive sputtering mode with the combination of HiPIMS and mid frequency is one of a possibility to solve such problems.

9:40am F2-1-6 Microstructure and Mechanical Properties Evaluation of CrVN Coatings Fabricated by a Hybrid HIPIMS and RF Sputtering System, Po-Wei Chang, J.W. Lee ([email protected]), Ming Chi University of Technology, Taiwan High power impulse magnetron sputtering (HIPIMS) is a newly developed coating technology, characterized by its ultra-high peak current and peak power density to achieve unique thin film properties, such as high hardness, good adhesion and tribological performance. In this study, a hybrid coating system consisting with high power impulse magnetron sputtering (HIPIMS) and radio frequency (RF) sputtering was used to deposit CrVN coatings with various V contents. The phase of the coatings was analysis by X-ray diffractometer (XRD). The microstructures of thin films were examined by the field-emission scanning electron microscopy (FE-SEM). Atomic force microscopy (AFM) was used to characterize the surface morphology. The nanoindentation was used to evaluate the hardness properties of thin films. The scratch tests, Daimler- Benz Rockwell-C (HRC-DB) adhesion tests and pin-on-disk wear tests were used to evaluate the adhesion and tribological properties of thin films, respectively. Effects of vanadium concentration, duty cycle and pulse frequency of HIPIMS system on the microstructure and mechanical properties of CrVN thin films were discussed in this work. 10:00am F2-1-7 High Power Impulse Magnetron Sputter Deposited pType Titanium Monoxide on Flexible Substrate and Its Thin-film Transistor Performance, WuChang Peng ([email protected]), National Chung Hsing University, Taiwan, M.Y. Chen, Y.H. Chen, J.L. He, Feng Chia University, Taiwan, D.S. Wuu, National Chung Hsing University, Taiwan Despite the tremendous potential of oxide semiconductors, further advancements have been hampered by a lack of hole-transporting (p-type) oxides with similar or comparable transport characteristics to their n-type counter parts. In responding to the diversifying and active field of oxide semiconductor materials recently, the titanium monoxide (TiO) having great potential for thin-film transistor (TFT) is elucidated its optical and electrical properties. In particular, rock-salt type γ-TiO is deposited on an unheated flexible substrate . High power impulse magnetron sputtering (HIPIMS), known to provide high density plasma, was used as the sputter power generator. Substrate bias voltage and thermal annealing effect were evaluated. Experimental results reveal that the as-prepared TiO film obtained very high density. The saturation mobility, the electrical conductivity and the optical transmittance are dependent on the output waveform of the HIPIMS generator. The properties of the TFT device using TiO layer as the channel layer are also explored. 10:20am F2-1-8 Circuits and Applications of Increasing of the HiPIMS Deposition Rate for an Industrial Scale, Guenter Mark ([email protected]), M. Mark, MELEC GmbH, Germany, S. Ulrich, J. Ye, S. Schweiger, M. Stüber, H. Leiste, Karlsruhe Institute of Technology (KIT), Germany The Super Imposed Pulse Power Technology ( SIPP Technology) offers significant advantages in HiPIMS technology. The Combination of unipolar pulse HiPIMS plasma with a synchronized DC-plasma using a single magnetron allows a higher deposition rate compared to a conventional HiPIMS pulse sequence only. The influence and the different rise pulse current time (di/dt) of the high pulse power using the classic single HiPIMS pulse, or the high pulse package mode, will be presented by the measured OES system of the related thin film structures. This study will present circuit applications and resulting of micro structure and properties of the deposited coatings using an industrial PVD equipment. The coatings are deposited from a metallic Ti target in a reactive mode with Ar-N2 and Ar-N2-CH4 as gas mixtures, respectively under different target power and gas pressure.

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Wednesday Afternoon, April 22, 2015 failure of the component. Therefore, the development of protective coatings may be necessary. This presentation will describe the mechanisms of the oxidation-induced microstructural changes.

Coatings for Use at High Temperature Room: Royal Palm 4-6 - Session A1-3 Coatings to Resist High Temperature Oxidation, Corrosion and Fouling Moderator: Mark Weaver, The University of Alabama, USA, Vladislav Kolarik, Fraunhofer Institute for Chemical Technology ICT, Germany, Elizabeth Opila, University of Virginia, USA

2:30pm A1-3-4 Design, Properties and Degradation Mechanisms of PtAL2O3 Multilayer Coating for High Temperature Solar Thermal Applications, Carine Gremion ([email protected]), C. Ducros, N. Scheer, University of Grenoble Alpes, France, C. Seassal, E. Drouard, Université de Lyon, Institut des Nanotechnologies de Lyon (INL), France Thin solar selective film design is a key issue to address in developing carbon free ways to harvest energy in the future. The working temperature of such coatings must be increased from 350°C, the current working temperature of commercial solution, to 650°C to make them cost effective and they must be able to operate in air, not only in vaccum. To allow that, new solar absorber materials must be developed to withstand such temperature for years, without losing their optical properties. Thin films composite materials can be good candidates, especially alumina-platinum (Al2O3-Pt) multilayer coatings, because of the good resistance of these materials to heat and oxidation. In this paper, we will present our work on the design and realization of such coatings. Our absorbers are composed of a substrate, a metallic infrared (IR) reflector and an alternation of thin Al2O3 and Pt layers. The number of layers and the thickness of each layer were optimized by optical simulations. Then we used magnetron sputtering to deposit these coating on different substrates: Si substrate to study the intrinsic properties of the coating and metallic alloys substrates (stainless steel and nickel-based alloy) to study the effect of the substrate on the aging of the absorber. Then we made optical characterization, TEM and chemical characterization to study these coating as deposited and after thermal aging at 650°C in air. By using different kind of IR reflector (molybdenum (Mo) reflector, Pt reflector or no reflector) we demonstrate that the choice of this layer is of great importance for the stability of the whole absorber. We show that Mo reflector is not suitable for applications at high temperature. Best results were obtained with a 7 layer stack, comprising Pt reflector: a solar absorption of α=0.93 and a thermal emissivity of ε=0.43 (calculated for a temperature of 650°C) were measured after ageing at a constant temperature of 650°C in air during 100h.

1:50pm A1-3-2 New Interpretation of the Type II Hot Corrosion of Co- and Ni-base Alloys, Juan Alvarado-Orozco ([email protected]), University of Pittsburgh, USA, J. Garcia-Herrera, CINVESTAV, Mexico, G. Meier, F. Pettit, University of Pittsburgh, USA The components of gas-turbine engines operating in marine environments are highly susceptible to hot-corrosion which has been classified as Type II hot-corrosion attack (650-750°C) and Type I hot-corrosion attack (900950°C). Even though hot-corrosion has been widely investigated in the last 50 years, several critical questions remain unanswered and new ones have emerged based on new observations as well as the increasing complexity of the alloy systems and sulfate-deposit chemistries. The present work is focused on the well-accepted Type II hot-corrosion mechanism proposed by Luthra [1] for Co-base alloys. A new interpretation of this mechanism of degradation, based on the synergistic fluxing mechanism proposed by Rapp [2], is presented to explain recent results for CoCrAlY and NiCoCrAl alloys ( isothermally exposed at 700 and 800 °C under different atmospheres, including: air and O2 with 100 and 1000 ppm SO2). Our observations suggest the rapid dissolution of Co is not the controlling factor in the degradation mechanism, as was proposed by Luthra, since the g-phase which is richer in Co, has not been attacked significantly and therefore Al (present in γ-Al2O3) is probably the element responsible of the rapid attack observed which is in good agreement with previous results reported by Chiang et al. [3] References 1. K.L. Luthra, Low Temperature Hot Corrosion of Cobalt-Base Alloys" Part II. Reaction Mechanism, Metallurgical Transactions A, 13A, 1982 (1853) 2. Y. S. Hwang and R. A. Rapp, Synergistic Dissolution of Oxides in Molten Sodium Sulfate, J. Electrochem. Soc., 137/4, 1990. 3. K.T. Chiang, F.S. Pettit and G.H. Meier, Low-Temperature HotCorrosion, High Temperature Corrosion (R. A. Rapp ed.), NACE, Houston, TX. 4. Y. S. Hwang and R. A. Rapp, Synergistic Dissolution of Oxides in Molten Sodium Sulfate, J. Electrochem. Soc., 137/4, 1990.

2:50pm A1-3-5 Behavior of La-Sr-Mn Coatings for SOEC Interconnector Materials in Water Vapor and Pure Oxygen under High Pressure, MariadelMar Juez Lorenzo ([email protected]), V. Kolarik, V. Kuchenreuther-Hummel, Fraunhofer Institute for Chemical Technology ICT, Germany, D. Schimanke, C. Geipel, sunfire GmbH, Germany Steam Electrolysis (SOEC) operated under pressures up to 30 bar at temperatures around 850°C has recently attracted interest as technology for an efficient conversion of renewable energy into liquid fuel (power-toliquid). The impact of such severe conditions on the oxidation behavior of the interconnector coatings and thus on a reliable operation, is a crucial issue and needs detailed understanding. Two commercially available interconnector materials were selected, one of them pre-coated by a Co containing thin layer. They were coated by a LaSr-Mn based coating deposited by roll coating and thermal spray. Pure water vapor and pure oxygen, both at opposite extremes of the possible process atmosphere compositions, were selected for the study. Laboratory test autoclaves from Alloy 602 were prepared to conduct the experiments. The autoclaves were closed by welding, inserted into a muffle furnace and connected to the pressured gas supply system. The samples were oxidised for up to 1000 h at 850°C under a pressure of 30 bar. Post-oxidation analysis was performed by field emission scanning electron microscopy (FE-SEM) with EDX element analysis and XRD. After exposure in pure oxygen the coating exhibits a homogeneous morphology with higher porosity in the case of roll coating deposition. Cr is found in the whole coating when deposited by rolling and concentrated on the coating surface when thermal spray was applied for deposition. In water vapor a fine grained structure is still observed after 300 h, whereas after 1000 h coarse grains are found. Those with higher La content are concentrated towards the surface and those with Mn towards the interface. Cr is detected very weakly and only in areas with high La content. The coatings are undergrown by a duplex Cr2O3 and MnCr2O4 scale with a total thickness about 2 microns. The primary coating on pre-coated interconnector is reduced to metallic Co in water vapor.

2:10pm A1-3-3 Oxidation-Induced Microstructural Changes in NIand CO-based Alloys and Ferritic Steels at High Temperature, Laura Garcia-Fresnillo ([email protected]), G. Meier, University of Pittsburgh, USA, W. Quadakkers, Forschungszentrum Jülich, Germany Commercial chromia forming Ni- and Co-base alloys, as well as some ferritic steels are currently being considered as candidate materials for applications, such as high-efficiency steam turbines and low temperature Solid Oxide Fuel Cells. The service environments for these applications include water containing atmospheres and operating temperatures in the range of 700-800ºC. Experimental results showed that under these conditions, the alloys exhibited very good oxidation behavior, since a thin, protective chromia layer formed on the surface. Nonetheless, it was observed that long-term oxidation led to substantial microstructural changes in the subsurface layer, mostly enrichment/depletion of intermetallic phases. Due to the surface scale growth process, chromium is depleted beneath the oxide layer. This decrease in chromium concentration affects the activity of other alloying elements. In the case of, e.g. Nb or W, the activity gradient established provides a driving force for uphill diffusion of these elements towards the scale-alloy interface, and thus for the formation/enrichment of intermetallic phases beneath the oxide scale. This subsurface enrichment of intermetallic phases can negatively affect the mechanical behavior of the material. Additionally if the oxide layer becomes damaged, e.g. by spallation or particle erosion, a material which is chromium depleted and enriched in elements which form rapid growing oxides will be exposed to the oxidizing atmosphere leading to accelerated

Wednesday Afternoon, April 22, 2015

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3:10pm A1-3-6 Laser Deposition of NiCrAlY/ZrO2–8wt%Y2O3 for TBC Applications, Viviane Teleginski, D.C. Chagas, Aeronautical Institute of Technology, Brazil, A.C. Oliveira, University Center of FEI, Brazil, S.A. Pianaro, State University of Ponta Grossa - UEPG, Brazil, G. Vasconcelos ([email protected]), Aeronautical Institute of Technology, Brazil Ceramic materials are widely employed as top-coating for Thermal Barrier Coatings (TBC), due to its excellent wear and corrosion resistance at high temperatures. The zirconium-based ceramics are developed in such a way that the microstructural control is possible through the control of chemical composition, fabrication route, thermal treatment, final machining, and in the case of laser processing, as a function of the power density and interaction time, as it will be demonstrated in this work. The application of ceramic coatings include aeronautical and industrial turbine blades, where the working conditions involve oxidizing environments and temperatures above 1000°C . To increase the coating’s lifetime and performance, this work proposes a laser technique deposition to increase adherence and coating homogeneity. The aim was to study the influence of the CO 2 laser beam (Synrad Evolution 125) parameters on the deposition process of yttria-stabilized zirconia (YSZ) powders on NiCrAlY/Inconel 718 substrates. The resulting coating surface and interface were characterized by scanning electron microscopy, energy dispersive spectroscopy, filed emission gun and X-ray diffraction. The laser process completely transforms the multiple phases YSZ powder to a homogenous tetragonal phase. The evaluation of the ceramic deposition mechanism of melting or diffusion on the substrate was performed as a function of the laser parameters.

4:10pm A1-3-9 Synthesis of Hydroxide Thin Film on the Magnesium Alloys using Hydrothermal Method, Hyunju Jeong ([email protected]), Y. Yoo, Pohang Iron and Steel Company, Korea Magnesium alloys have been considered an attractive material in various applications due to their specific properties such as low density, high thermal conductivity and electromagnetic interference resistance. However, their applications are still limited because of the low corrosion resistance due to a high surface reactivity and low standard potential. Although many studies have been carried out to improve the corrosion characteristics and surface properties, it is still important research area. Dense and uniform hydroxide thin film has been synthesized on magnesium alloys using a hydrothermal method. The alkaline aqueous solution has been used to fabricate protective coating layers. The results turn out that the layers are compact and uniform as non-porous structures and improve the corrosion resistance. The structures are composed of hexagonal nanosheets with a low contact angle on the surface. We also examine the characteristics of the film through the treatment time, temperature and concentration of solutions. The morphology and structure of the films are examined by field emission scanning electron microscopy (FE-SEM) and transmission electronic microscope (TEM). The structure and orientation of Mg(OH)2 film are investigated by X-ray diffraction (XRD) analysis. The compositions of the film are studied by Scanning Auger Microscopy (SAM). Potentiodynamic polarization measurements and salt spray tests (SST) are used to determine the corrosion behavior of the layer. 4:30pm A1-3-10 Mechanical Property and Oxidation Behavior of an aCNx Deposited Tungsten Carbide with Various Silica-Alumina Hybrid Composite Interlayers Prepared by Sol-Gel Technique, C.-C. Chou ([email protected]), J.-S. Lin, National Taiwan Ocean University, Taiwan, R. Wu, National Institute for Materials Science, Japan, J.W. Lee, Ming Chi University of Technology, Taiwan, Meng-Ku Hsu, National Taiwan Ocean University, Taiwan Alumina-silica composite interlayers were coated on 6 wt.% cobalt contained cemented tungsten carbide (WC) substrate by sol-gel dip coating technique and sintered in an argon atmosphere at 700 ˚C for 1 h. The Al/Si ratios of the composite films were adjusted by the combination of the solgel precursors. A carbon nitride (CNx) outmost layer was deposited on alumina-silica composite films by rf-PECVD technique. The oxidation behavior of the coatings were studied after an annealing process in a nitrogen atmosphere with 15 ppm oxygen at 600 ˚C. The surface morphology and cross-section structure of the films were observed by scanning electron microscopy and atomic force microscopy. The microstructure and composition were investigated by X-ray diffraction, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and Raman scattering spectroscopy. The mechanical properties of the films were evaluated by nano-indentation and nano-scratch. The results showed that the microstructure of alumina-silica composite films were amorphous and constructed by nano-particles of 5-10 nm diameter. The hardness and critical load of the composite films increased with their Al/Si ratio. However, these mechanical properties were significantly promoted by the deposition of the outmost CNx layer. After the annealing process, the roughness of the CNx-deposited samples maintained the same as the original ones and the diffusion of the cobalt from WC substrate was also obstructed by the alumina-silica composite film, which suggested that this hybrid film can be a promising interlayer of DLCs and cemented WC as the material of a glass mold.

3:30pm A1-3-7 Corrosion Resistance of BIXTIYOZ Coatings Deposited on TI6AL4V Alloys and its Dependence on the Sputtering Parameters Magnitude, Jose Edgar Alfonso ([email protected]), M. Pinzon, Z. Rojas, J.J. Olaya-Florez, Universidad Nacional de Colombia, Colombia, C. Pineda-Vargas, Cape Peninsula University of Technology, South Africa Bismuth titanate (BixTiyOz) has received widespread attention due to the fact that during recent times it has found important applications in strategic research fields such as optics and optoelectronic, and more recently studies have shown how their physico-chemical properties may be cast-off in order to be able to use BixTiyOz, as an anticorrosive coating. In this work Bismuth titanate (BixTiyOz) coatings were grown on titanium alloy (Ti6Al4V) substrates, using RF magnetron sputtering. The main objectives of the research project were to observe and quantify the evolution of phase formation, the crystallinity and chemical composition and to characterize the behavior of the resistant corrosive layer. The coatings were deposited by changing deposition parameters, such as: electrical power applied at the target, flux of the argon gas and the substrate temperature. The crystalline structure was characterized by X-ray diffraction (XRD) and the chemical composition was analyzed by Rutherford backscattering Spectroscopy (RBS). The corrosion resistance of the coatings was studied by Potentiodynamic polarization test (Tafel extrapolation). Preliminary results revealed a change in its microstructure as a function of the electrical power applied at the target, since they evolved from a completely amorphous phase to a polycrystalline phase. As determined by RBS analysis and by the electrochemical test the activation energy associated with bismuth on the surface and activation energies associated with the titanium in the coating and the substrate showed that corrosion resistance of the coating is far better in the amorphous phases of bismuth titanate than in the polycrystalline phases. 3:50pm A1-3-8 Thermal Properties Of Europium Zirconate, Cerate And Hafnate, Michal Stopyra ([email protected]), G. Moskal, M. Mikuśkiewicz, H. Myalska, D. Niemiec, A. Jasik, Silesian University of Technology, Poland The binary rare earth metal oxides with pyrochlore or fluorite type of structure exhibit remarkable insulating properties which makes them potential candidates for top-coat materials in thermal barrier coatings. In this paper structural and thermal characterization of europium zirconate Eu2Zr2O7, hafnate Eu2Hf2O7 and cerate Eu2Ce2O7 is presented. The feedstock powders were nano-crystalline Eu2O3, ZrO2, HfO2 and CeO2. They were mixed in proper molar ratio and homogenized. The calorimetric studies of mixtures were performed. The final product was obtained via high temperature vacuum sintering at 1350°C under 15MPa. Phase composition of obtained materials was analyzed by X-ray diffraction. The internal morphology, especially porosity, presence of impurities and chemical inhomogeneity was also investigated. Thermal properties of obtained materials, including thermal diffusivity, specific heat and coefficient of thermal expansion were measured in the temperature range 25-1400°C. For comparison purposes, same test were carried out for sintered feedstock powders and conventional top-coat material – 8YSZ.

4:50pm A1-3-11 The Creation of Thermal Stable Hydrogenimpermeable TiN-based Coatings on Zirconium Alloys, E. Kashkarov ([email protected]), N. Nikitenkov, Yu. Tyurin, Viktor Kudiiarov, National Research Tomsk Polytechnic University, Russian Federation The hypothetic nuclear accidents can create a real danger to the Zr alloys and stability of parts made of these alloys, and especially such as loss of coolant accident (LOCA) and reactivity initiated accidents (RIA). The hydrogen degradation can manifest itself in an appearance of hydride phases resulting in a substantial loss of plasticity, an increase in ductile–brittle transition, sometimes in a decrease in mechanical strength. This paper describes the coating technology of titanium nitride while performing reactive magnetron sputtering, which leads to reduction of hydrogen permeation through TiN-coated zirconium alloys (Zr1%Nb) of more than two orders of magnitude. Hydrogen permeation was calculated from the kinetic curves of hydrogen sorption at elevated temperature of the specimen (T = 623 K) and pressure (P = 2 atm). Dense titanium (Ti) layers were prepared between TiN protection films and a Zr substrate to improve thermal stability and adhesion between the TiN and the substrate at high temperatures. The applying of a Ti underlayer by vacuum arc deposition and 1,54μm TiN by reactive magnetron sputtering leads to the formation of thermal stable coating under cycling up to 1073 K.

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0.06. Best erosion resistance was obtained at the highest Al ratio of 0.6 where H/E ratio is also highest. [1] Y, Iwai, et al., Wear, 251/1-12 (2001) 861-867

Hard Coatings and Vapor Deposition Technology Room: Golden West - Session B4-4 Properties and Characterization of Hard Coatings and Surfaces Moderator: Uwe Beck, BAM Berlin, Germany, ChauChang Chou, National Taiwan Ocean University, Taiwan, Grzegorz Greczynski, Linköping University, IFM, Sweden

2:10pm B4-4-3 New Tantalum Nitride Interlayer for Diamond Deposition on Cutting Tools, Maureen Cheviot ([email protected]), M. Goune, A. Poulon, CNRS, Univ. Bordeaux, ICMCB, France Weight reduction of aeronautic devices raises composite machining issues. The challenge lies in designing cutting tools able to resist to the specific machining conditions of these materials. One of the possible solutions is to use diamond as a wear resistant coating. However, bare cutting tools, made of cobalt-bound tungsten carbide, can not be coated because cobalt promotes graphite formation instead of diamond. We propose to interpose an interlayer between the diamond coating and the substrate. Its function is not only to limit cobalt diffusion toward the surface, but also to control carbon diffusion phenomenon during the process in order to enhance diamond nucleation. Tantalum nitride (TaN), which can be carburized during CVD diamond deposition, appears as a good candidate for this purpose. TaN exhibits two crystallographic structures. An accurate control of cathodic deposition conditions allows us to isolate both phases. The efficiency of the stable hexagonal phase of TaN as a cobalt diffusion barrier has already been shown but its influence on diamond nucleation is limited. In this study, we gauge the potentiality of the metastable face-centeredcubic phase of TaN. Its original response to carbon diffusion during the CVD process opens up new horizons for diamond nucleation and adhesion.

1:30pm B4-4-1 Compositional Driven Phase Evolution and Mechanical Properties of Mo-Cr-N Hard Coatings, Fedor Klimashin ([email protected]), H. Riedl, J. Paulitsch, H. Euchner, P. Mayrhofer, Vienna University of Technology, Austria High-performance, multifunctional protective coatings for machining applications have to combine for example high hardness, high thermal stability and excellent tribological properties. Especially ceramic-like coatings are well known for their outstanding properties combinations. Whereas many research activities are conducted on TiN, ZrN and CrN based coatings, only little is known for Mo–N based materials. Especially the cubic phase of molybdenum nitride (Mo2N) exhibits excellent mechanical properties but is extremely sensitive to the nitrogen content and the N2-partial pressure used during deposition. We therefore studied in detail the structural evolution of Mo–N coatings as a function of the nitrogen partial pressure used during deposition. Based on ab initio calculations and experimental studies within the binary Cr–N and Mo–N systems, ternary Mo–Cr–N thin films along the quasi-binary Mo2N–CrN tie-line were developed. Whereas all available literature reports deal with the Cr-rich side Mo/(Mo+Cr)0.5. These coatings are studied in detail by scanning and transmission electron microscopy, X-ray diffraction and nanoindentation. The coating with an Mo/(Mo+Cr) ratio of ~0.85 exhibits the highest hardness of about 34 GPa as well as the highest resistance against plastic deformation with (H3/E*2) of ~0.2 GPa. The lattice parameters experimentally obtained for the individual high Mo-containing Mo–Cr–N coatings excellently fit ab initio calculations along the Mo2N–CrN tie line and thus verify their structural description.

2:30pm B4-4-4 Effect of Composition on the Fracture Toughness of Ti1-xZrxN Hard Coatings, Jia-Hong Huang ([email protected]), Y.F. Chen, G.P. Yu, National Tsing Hua University, Taiwan The objective of this study was to evaluate the fracture toughness of Ti 1xZrxN hard coatings with different compositions using the internal energy induced cracking (IEIC) method [1], from which the optimum composition for fracture toughness could be attained. Ti1-xZrxN remained single phase structure in the entire compositional range when deposited at temperatures below 500 °C. Three compositions of Ti1-xZrxN, x=0.25, 0.55 and 0.85, were deposited using unbalance magnetron sputtering. The IEIC method involved the residual stress measured by the laser curvature method, Young’s modulus obtained from nanoindentation and the film thickness from SEM cross-sectional image. The elastic stored energy (Gs) was calculated from the residual stress and film thickness before specimen fracture, from which the fracture toughness could be derived. The resultant fracture toughness of Ti1-xZrxN varied with Zr fraction, ranging from 26.5 to 48.7 J/m2, and reaching a maximum for Ti0.15Zr0.85N. Adding Zr atoms into TiN could effectively increase the fracture toughness, which was possibly due to the atomic size difference of Zr and Ti. The increase of fracture toughness for Ti0.15Zr0.85N was higher than that for Ti0.75Zr0.25N. This asymmetrical behavior could be attributed to the difference in lattice constants between Ti-rich and Zr-rich compounds, where the capability of increasing elastic stored energy may be higher for a smaller Ti atom incorporate into a larger ZrN lattice. If the cracks penetrate into the substrate, the contribution of substrate cracking should be considered. [1] An-Ni Wang, Ge-Ping Yu, Jia-Hong Huang, Surf. Coat. Technol. 239(2014)20.

1:50pm B4-4-2 Erosion Behavior of AIP Deposited Thick (Ti 1-xAlx)N Coatings by High-velocity Particle Impact, Kenji Yamamoto ([email protected]), Kobe Steel Ltd., Japan, Y. Iwai, University of Fukui, Japan Erosion damage by high-velocity impinging particles is commonly observed such machine elements as blades of jet engine or power generation turbine. Conventionally, these materials are made of ferrous materials and recently it becomes popular to use Ti alloys due to specific strength at elevated temperature. Aerodynamic integrity is compromised once blade shape is changed by erosion and to prevent such deterioration in engine efficiency, so application of hard coating to those machine elements is common practice. Commonly used coating is the combination of ductile and brittle material such as Ti/TiN. Detailed mechanism, however, not clarified yet particularly between property of the coating and erosion behavior for nitride coatings and in this study, erosion behavior of (Ti 1-xAlx)N coating, depending on x, is investigated (Ti1-xAlx)N coatings with different Al contents (x) were deposited by newly developed arc cathode. This new cathode is characterized by optimized magnetic field design and makes it possible to deposit thick (up to 20um) coating with low level of residual stress. Ti or TiAl alloy target was discharged in nitrogen atmosphere of 4 Pa at 400°C. Coatings deposited on SUS630 substrates were subjected to the MSE test [1] for erosion resistance evaluation. 1 mass% suspension containing alumina particle with average grain size of 50 um was used for MSE test. Coatings deposited on WC-Co were subjected to compositional, structural and mechanical property analysis using EDX, X-ray diffraction and nano-indentation technique. Preliminary study on effect of crystallographic orientation on erosion behavior was conducted using TiN with nearly random orientation. EBSP image of the surface before and after the erosion test indicate that coating grains rather than (111) texture are preferentially removed by the impact of incident particles. Regarding effect of Al content on erosion resistance, TiN showed a largest erosion rate and it decreased with Al content is increased. To investigate this behavior hardness and Young’s modulus of the coating was measured. Hardness increased as the Al content increased almost linearly while Young’s modulus stayed fairly constant over the range of Al ratio. Correlation between erosion rate and these mechanical properties is investigated. The erosion rate sharply drops as the H/E ratio range up to

Wednesday Afternoon, April 22, 2015

2:50pm B4-4-5 Stress Distribution by Residual Stress Depth Profiling in Wear Resistant Oxide and Nitride Coatings; the Effect on Process Conditions, Microstructure and Mechanical Properties, M. JohanssonJõesaar ([email protected]), Jon Andersson, N. Norrby, T. Larsson, Seco Tools AB, Fagersta, Sweden INVITED Oxide and nitride coatings grown by CVD or PVD techniques have found successful applications as tool coatings in the field of metal machining. An important parameter for this success is the ability to control and adjust its stress distribution during growth, which not only affects the coating hardness but also the overall toughness of the cutting tool. The present study focuses on residual stress depth profiling of coatings with respect to their process condition, microstructure and mechanical properties. Several PVD and CVD coated cutting tool case studies including the effect of preand post-deposition surface treatments, i.e., grinding, polishing, brushing, blasting, etc. will be emphasized. The coatings were synthesized by both industrial CVD and PVD techniques with a controlled through-thickness stress profiles ranging from a tensile to a compressive stress state, even gradients. The stress depth profiles were evaluated by grazing incidence XRD at different information depths using Cu-Ka and Cr- Ka radiation. Results show strong stress profiles both in the PVD coatings as a result of deposition process parameters, and the CVD coatings as a result of ex-situ post treatment, e.g., wet blasting. In both cases the evaluated stress levels in

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the surface region is about -4 GPa, i.e., highly compressive, gradually changing to lower compressive stress levels with increased depth into the coatings. Here, the compressive stress in PVD coatings mainly correlates with the bias level whereas the blasting pressure is the strongest contributor to the different compressive stress levels in the CVD coatings. The validity of the results are discussed and related to complementary studies on coating structure and properties by, e.g., electron microscopy in scanning and transmission mode and nanoindentations.

to a-C:H and a-C coatings. The mechanical properties of these coatings, e.g. their hardness to elastic modulus ratio (H/E), and substrate interfacial adhesion were investigated by Nano-indentation and scratch testing. The microstructure, stress state and chemical composition were also examined by SEM, TEM and Raman Spectroscopy. Pin-on-disc sliding wear tests were performed in an environmentally controlled chamber to evaluate coating friction and wear performance under atmospheric conditions with different levels of humidity.

3:30pm B4-4-7 Effective Method to Control Elemental Composition in Ternary and Quaternary Hard Coatings by Mosaic Steered Cathodic Arc deposition, Yasuo Yamazaki, G. Kamath ([email protected]), G. Gal, H. Richter, Richter Precision Inc., USA, D.E. Wolfe, The Pennsylvania State University, USA Elemental composition control in ternary and quaternary hard coatings synthesized via cathodic arc deposition (CA) is extremely challenging. To address these challenges, the current work tailored the individual elemental compositions of nanostructured ternary Ti1-xAlxN coatings using a novel mosaic target configuration consisting of multiple tiles of Ti and Al via steered CA. The quantity, size and arrangement of each individual tile was found to be a critical factor in controlling the concentration of constituent elements within the deposited Ti1-xAlxN coating. Ti1-xAlxN coatings deposited by mosaic steered CA and conventional steered CA using a compound TiAl alloy target with 50:50 ratio deposited under similar conditions were compared. The results for Ti1-xAlxN coatings 2.5 µm thick and deposited under two different N2 partial pressures will be presented. The coating roughness, microstructure, composition, mechanical and tribological properties were investigated using optical profilometry, SEM, XRD, EDS, nanoindentation and pin-on-disc tribology, respectively. Ti 1xAlxN coatings deposited by each method as a function of N 2 partial pressure showed comparable coating composition, structure and properties for the respected conditions. However, the results reveal that surface roughness of the mosaic Ti-Al steered CA deposited coating (Ra - 0.07 µm) was twice that of the traditional Ti1-xAlxN coating deposited from solid TiAl alloy o (Ra - 0.035 µm). All coatings showed dense columnar microstructures with cubic NaCl structure with (111) preferred orientation. Coating hardness (H) was found to be approximately 29 GPa for all coatings, whereas the Elastic modulus (E) for mosaic Ti-Al steered CA deposited coating was slightly higher ~390 GPa when compared to solid TiAl CA deposited coating (350 GPa). A systematic comparative study has been carried out for Ti1-xAlxN coatings deposited by steered CA deposition technique using two different target configurations (i) traditional compound TiAl alloy and (ii) mosaic Ti-Al target, to tailor coating composition and properties.

Hard Coatings and Vapor Deposition Technology Room: California - Session B7 Computational Design and Experimental Development of Functional Thin Films Moderator: Ferenc Tasnadi, Linköping University, Sweden, Holger Euchner, Vienna University of Technology, Austria 1:30pm B7-1 Surface Adsorption Phenomena From First Principles: an Application to Protective Coatings, David Holec ([email protected]), Montanuniversität Leoben, Austria, H. Riedl, Vienna University of Technology, Austria, D. Music, RWTH Aachen University, Germany, O. Jantschner, Montanuniversität Leoben, Austria, J. Paulitsch, Oerlikon Balzers Coating Austria GmbH, Austria, P. Mayrhofer, Vienna University of Technology, Austria INVITED First-principles calculations have proved to be a useful tool to assist knowledge-based coating design. Their major role is to provide an insight and explanation to complement experimental observations, as well as to yield material-related trends to explore new horizons for evermore demanding applications. In this presentation we will discuss adsorption phenomena of single atoms as well as simple molecules on various surfaces of a wide variety of materials, and thereby address topics of adhesion transfer, surface diffusion, and friction. When implanting Al and Fe atoms into the TiN (001) surface, Al atoms need to overcome approximately 40% higher energy implantation barrier than Fe atoms. However, the implantation force for both species is approximately the same, though the repulsive forces act closer to the surface on Al and further from the surface on Fe atoms. Calculations of potential energy landscapes reveal that O experiences the same diffusion barrier on both, CrN and TiN (001) surfaces. On the other hand, the same procedure suggests that H ad atoms are significantly more mobile on TiN than on CrN surfaces. A comparison of adsorption energies and potential energy landscapes for H, O,-OH, and H2O groups on Si-doped graphene clearly show preferential attraction to Si-sites as compared to C-sites. These results combined with ab initio molecular dynamics simulations of gas interactions with the a-C surface rationalise the low-friction effect in Si containing a-C thin films experimentally observed at increased temperatures beyond 240 ∘C.

3:50pm B4-4-8 Applying Reflectance Spectroscopy for the Characterization of the Surfaces of Gray Iron Cast, Catalina Melo Piraquive ([email protected]), O.E. Piamba Tulcan, National University of Colombia, Colombia The gray iron cast surfaces are submitted to a high index of corrosion in the exposition with different environmental substances due mainly to the formation of iron oxides such as goethite, hematite, maghemite, and lepidocrocite, causing a deterioration in the mechanical properties of these materials. This work describes the optical reflectance technique that has been developed to the study of this corrosion products. Specially, this technique will allow the identification of the presence of iron oxides in situ, is a fast and cheap tool and environmentally friendly procedure that could be an alternative to the conventional surfaces analysis method. The diffuse reflectance spectrum in the visible and infrared regions were recorded and studied to assess the spectral dependence of these oxides, predict their relationship and thereby identify it. The agreement with the experimental results show that the diffuse reflectance spectroscopy could be a helpful method of quantifying of iron oxides on surfaces.

2:10pm B7-3 Surface Softening in Metal - Ceramic Sliding Contacts: An Experimental and Numerical Investigation, Pantcho Stoyanov ([email protected]), Kennametal Incorporated, USA, P. Romero, Fraunhofer-Institute for Mechanics of Materials IWM, Germany, M. Dienwiebel, Fraunhofer Institute for Mechanics of Materials IWM and Karlsruhe Institute of Technology KIT, Germany, O. Abad, R. Gralla, INM – Leibniz-Institute for New Materials and Saarland University, Germany, M. Moseler, Fraunhofer-Institute for Mechanics of Materials IWM, Germany, R. Bennewitz, INM – Leibniz-Institute for New Materials and Saarland University, Germany The sliding of components is known to result in third body formation, which characteristically consists of mechanical mixing and grain refinement in the near surface region as well as transfer film formation on the counterface. Understanding the behavior of these so called third bodies can help to optimize the tribological response of sliding components by selecting the right combination of materials, environmental and contact conditions (e.g. pressure, contact area). This study investigates the tribolayer properties at the interface of metal and ceramic (i.e. WC/W) sliding contact using various experimental approaches and classical atomistic simulations. Experimentally, nanoindentation and micropillar compression tests as well as adhesion mapping by means of atomic force microscopy are used to evaluate the strength of tungsten-carbon tribolayers. In order to capture the influence of environmental conditions, a detailed chemical and structural analysis is performed on the worn surfaces by means of XPS mapping and depth profiling along with transmission electron microscopy of the debris particles. Experimentally, the results indicate a decrease in hardness and modulus of the worn compared to the unworn one. Atomistic simulations of nanoindentation on deformed and

4:10pm B4-4-9 The Effect of Humidity on the Friction and Wear Behaviour of Hydrogenated DLC, Non-hydrogenated DLC and Modified a-C:H:Si Coatings, Chang Liu, The University of Sheffield, UK, H. Zhao, A. Neville, University of Leeds, UK, A. Matthews, A. Leyland ([email protected]), The University of Sheffield, UK Hydrogen containing diamond-like carbon (a-C:H) coatings tend to exhibit an ultra-low Coefficient of Friction (CoF) in dry sliding; however, the CoF of such coatings can rise dramatically with increasing humidity. In contrast, the CoF of hydrogen-free diamond-like (a-C) coatings typically shows an opposite trend. Furthermore, silicon-doped a-C:H (a-C:H:Si) coatings may exhibit better humidity adaptability compared with either a-C:H or a-C coatings. In this study, a-C:H:Si coatings with different silicon doping contents were deposited by PECVD with different experimental parameters and compared

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undeformed specimens are used to probe the strength of the WC tribolayer and despite the fact that the simulations do not include oxygen, the simulations correlate well with the experiments on deformed and undeformed surfaces, where the difference in behavior is attributed to the bonding and structural differences of amorphous and crystalline W-C. Adhesion mapping suggests a decrease in surface adhesion, which based on chemical analysis is attributed to surface passivation.

multi-scale computational approaches to mimic real deposition conditions and gain insights on the microstructural and morphological evolutions during growth. The accurate description of growth kinetics and energetics remains a challenging task, especially for magnetron sputtering for which particle bombardment may alter the resulting microstructures. To explain experimental findings of TiN thin film growth regimes during sputter- deposition, different approaches can be used. We chose to perform kinetic Monte Carlo (kMC) simulations using a 3D rigid lattice model. At this time only one 3D lattice orientation is considered. The lattice is obtained by a superposition of two FCC sub-lattices, each of them corresponding to a kind of atom (metal sub-lattice and N sub-lattice). For both kinds of particles, two main events are taken into account, 3D diffusion and deposition event. A 3D diffusion event can take place, obeying certain conditions that fulfil the symmetry of the system, between sites belonging to the same sublattice. To compute the diffusion barrier to a vacant site, different diffusion models have been used, all of them taking into account the interaction of the diffusing atom with its nearest and next nearest neighbours. Energy barriers were taken from existing DFT data of the literature. Together with a given diffusion model a deposition model has been used as well. Starting with normal incidence deposition for both kinds of particles, the deposition model has been extended to take into account the different aspects of a real sputter deposition experiment (e.g., angle distribution from SIMTRA) or GLAD geometry. Different combinations of diffusion-deposition models will be firstly discussed. Then, for a given model, the influence of the most important experimental parameters (substrate temperature, deposition rate, angular distribution of particles arriving at the substrate, stoichiometry) on the resulting morphology of the growing 3D structure will be presented. Together with 3D diffusion some microscopic mechanisms (interaction of the incident particle with an already existing 3D object in the neighbourhood of its trajectory, reflection or diffusion into the volume) have been also included. This work belongs to the “MC2” project funded by ANR in the framework of M.ERA-NET program.

2:30pm B7-4 Impact of Al on Structure and Mechanical Properties of NbN and TaN, Paul Mayrhofer ([email protected]), Vienna University of Technology, Austria, D. Holec, Montanuniversität Leoben, Austria Transition metal nitrides (TMN) are widely used as wear-resistant hard coatings for e.g., machining, casting or hot-forming applications. However, TMN’s rapidly oxidise and often form porous oxides allowing for rapid scale growth. Therefore, ternary TM1-xAlxN coatings are the focus of many research activities as Al-incorporation promotes the formation of dense oxides. But the superior thermal and mechanical properties of TM 1-xAlxN’s are mainly obtained for face-centred-cubic (fcc) structures, requiring the need for detailed information on phase stability ranges. Especially NbNy and TaNy coatings are highly complex due to the variety of crystallographic phases present. Stoichiometric NbN as well as TaN can crystallize in either hexagonal or cubic structure. Through the incorporation of Al, soon the fcc structure is stabilised for x=0.1-0.44 (Nb1-xAlxN) and 0.1-0.36 (Ta1-xAlxN). Highest hardnesses are obtained for Nb0.56Al0.44N with ~32 GPa and Ta0.64Al0.36N with ~34 GPa. Single phase hexagonal Nb1-xAlxN and Ta1-xAlx coatings are accessible for Al contents above x=0.61 and 0.65, exhibiting hardnesses of ~23 GPa, respectively. The results obtained are in excellent agreement to computational predictions. 2:50pm B7-5 Influence of Passivation Layer on the Performance of Gold Films under Thermal Treatment, Shujun Zhou, T.M. Shao ([email protected]), Tsinghua University, China Gold films attract great interests because of their desirable properties and are widely used in various electric and electronic devices. The stability of gold films is of great importance to the long-term performance and reliability of these devices. Passivation layer is widely used to package metallic films to obtain stable performance. In this paper, response of gold film with and without passivation layer during thermal treatment and natural storage was studied. Substrate curvature method was employed to study the residual stress based on the calculation with Stoney equation. Surface topography and morphology of the samples were observed by atomic force microscope (AFM) and scanning electron microscope (SEM). Results show that the presence of passivation layer altered the response of gold film to thermal treatment. Influence of passivation material and layer thickness on the performance of gold films was also analyzed and discussed.

4:10pm B7-9 Molecular Dynamics Simulations of TiN/TiN(001) Growth, D. Edstrom, Linköping University, IFM,Sweden, D. Sangiovanni, Valeriu Chirita ([email protected]), L. Hultman, Linköping University, IFM, Sweden, I. Petrov, J. Greene, University of Illinois at Urbana-Champaign, USA The Modified Embedded Atom Method (MEAM) interatomic potential within the classical Molecular Dynamics (MD) framework enables realistic, large-scale simulations of important model materials such as TiN. As a step toward understanding atomistic processes controlling the growth of TiN on a fundamental level, we perform large-scale simulations of TiN/TiN(001) deposition using a TiN MEAM parameterization which reproduces experimentally-observed surface diffusion trends, correctly accounts for Ehrlich barriers at island step edges [1], [2], and has been shown to give results in excellent qualitative and good quantitative agreement with Ab Initio MD based on Density Functional Theory (DFT) [3], [4]. Half a monolayer of TiN is deposited on 100x100 atom TiN(001) substrates at a rate of 1 Ti atom per 50 ps, resulting in simulation times of 125 ns. The TiN substrate is maintained at a typical epitaxial growth temperature, 1200 K during deposition using Ti:N flux ratios of 1:1 and 1:4 with incident atom energies of 2 and 10 eV to probe the effects of N2 partial pressure and substrate bias on TiN(001) growth modes. We observe nucleation of Ti xNy molecules; N2 desorption; the formation, growth and coalescence of mixed , , and faceted islands; as well as intra- and interlayer mass transport mechanisms. For equal flux ratios at 2 eV incidence energy, islands begin to form atop existing islands at coverages ≳ 0.25 ML, leading to 2D multilayer growth. At 10 eV, the film growth mode shifts toward layer-by-layer growth. We discuss the implications of these results on thin film growth and process tailoring. Our classical MD predictions are supported and complemented by DFT-MD simulations. [1] D. G. Sangiovanni, D. Edström, L. Hultman, V. Chirita, I. Petrov, and J. E. Greene, “Dynamics of Ti, N, and TiNx (x=1–3) admolecule transport on TiN(001) surfaces,” Phys. Rev. B, 86, 155443 (2012). [2] D. Edström, D. G. Sangiovanni, L. Hultman, V. Chirita, I. Petrov, and J. E. Greene, “Ti and N adatom descent pathways to the terrace from atop two-dimensional TiN/TiN(001) islands,” Thin Solid Films, 558, 37 (2014). [3] D. G. Sangiovanni, D. Edström, L. Hultman, I. Petrov, J. E. Greene, and V. Chirita, “Ab initio and classical molecular dynamics simulations of N2 desorption from TiN(001) surfaces,” Surf. Sci., 624, 25 (2014). [4] D. G. Sangiovanni, D. Edström, L. Hultman, I. Petrov, J. E. Greene, and V. Chirita, “Ti adatom diffusion on TiN(001): Ab initio and classical molecular dynamics simulations,” Surf. Sci., 627, 34 (2014).

3:10pm B7-6 Overcoming Growth Limitations by ab initio Guided Surface Engineering, Jörg Neugebauer ([email protected]), L. Lymperakis, Max-Planck-Institut für Eisenforschung, Germany INVITED To systematically explore and optimize the design of functional thin films the availability of computational tools that allow to understand and predict the relation between atomistic growth mechanisms and the technologically desired properties of the thin film is crucial. A challenge in this respect is the complexity of realistic conditions in thin film growth: The growth occurs under conditions that are often far away from thermodynamic equilibrium and intended as well as unintended forign chemical elements are commonly present in high concentrations. As a consequence the surfaces present under actual growth conditions have little in common with the chemically clean and ideal structures that are accessible to experimental surface science studies. Atomistic ab initio calculations that are free of any materials-specific input parameters have evolved over the last two decades into a powerful tool to study the structure, the chemistry as well as the kinetics of surfaces under realistic growth conditions. The key ideas behind this new approach and the opportunities which it opens will be discussed for a few selected examples: (i) The identification of suitable selective surfactants to control the roughness/smoothness of thin films, (ii) the design of atomistically controlled growth strategies to achieve doping levels well above/below thermodynamic equilibrium, and (iii) the application of surface phase diagrams to control adatom kinetics and spinodal decompositions. 3:50pm B7-8 A 3D Kinetic Monte Carlo Model of TiN Growth Morphology, Grégory Abadias ([email protected]), F. Nita, C. Mastail, Université de Poitiers, Institut Pprime, France Transition metal nitride thin films are largely used nowadays in a wide range of applications from microelectronics to mechanical machining operations. Predictive design of these materials can be achieved by using

Wednesday Afternoon, April 22, 2015

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4:30pm B7-10 Computational Fluid Dynamics (CFD) Simulation of CVD Process for MT-Ti(C,N) Coating, Shaoqing Wang, Y. Du ([email protected]), Central South University, China, X.M. Chen, Zhuzhou Cemented Carbide Cutting Tools Co., Ltd., China, L. Chen, Central South University and Zhuzhou Cemented Carbide Cutting Tools Co., Ltd., China, S.Q. Wang, Zhuzhou Cemented Carbide Cutting Tools Co., Ltd., China In the present work, the CVD process for MT-Ti(C,N) coating in the vertical hot-wall reactor was studied through the Computational Fluid Dynamics (CFD) based on the Finite Volume Method (FVM). By means of commercial FLUENT software, the flow characteristics and temperature gradients in the preheater was simulated and validated with the benchmark solutions from the experimental measurement. The computational model was then applied to investigate the deposition procedure of MT- Ti(C,N) coating from TiCl4-CH3CN-N2-H2 gas mixture. The thermal and hydrodynamic characteristics of the flow within the reactor was simulated. The influence of concentration of gas species on the growth rate of Ti(C,N) coating deposited on specimens, which are located at different position of the reactor, is predicted. The computational predictions of the growth rate are in agreement with the experimental measurements. The CFD approach is of general validity and applicable to optimize the process parameters and to provide theoretical guidance for improving coating uniformity in thermal CVD process. The financial supports from the Doctoral Scientific Fund Project of the State Education Committee of China (Grant No. 20120162110051) and the National Natural Science Foundation of China (Grant nos. 51371201 and 51371199) are greatly acknowledged.

films were deposited by closed-field unbalanced magnetron sputtering system onto aluminum, Ti6Al4V and magnesium materials in Ar/N2/C2H2 atmosphere. The friction and wear properties of Ti:Ta-based DLC coating were investigated for tribological applications. The coated specimens were characterized by SEM, XPS and X-ray diffraction techniques. Reciprocation multipass and pin-on-disc wear tests were carried out to compare their friction and wear properties. Hardness measurements was performed by micro indentation. A multi-mode operation was used as sliding fatigue, like multi-pass scratching in the same track at different loads. Failure mechanisms were discussed according to SEM examinations of the scratch tracks. Our results suggest that Ti-Ta-doped DLC film shows very dense microstructure, high hardness with low CoF and high wear resistance. 1:50pm C1-2 Thin Films Composed of Gold Nanoclusters Dispersed in a Dielectric Matrix, Joel Borges ([email protected]), Czech Technical University in Prague, Czech Republic, T. Kubart, Uppsala University, Angstrom Laboratory, Sweden, M. Vasilevskiy, University of Minho, Portugal, A. Cavaleiro, SEG-CEMUC, University of Coimbra, Portugal, F. Vaz, University of Minho, Portugal, T. Polcar, Czech Technical University in Prague, Czech Republic Noble metal nanoparticles (NPs) have been used for many centuries, providing different colours in Roman glasses or in the windows of medieval cathedrals. Nowadays, the interest in nanocomposite materials containing those metal NPs embedded in dielectric matrices, such as TiO2 or Al2O3, is related with their potential use for a wide range of advanced technological applications, including colour filters, bio- and optical sensors, absorption elements of solar cells, enhancement of electrical/thermal conductivity of coatings, photocatalytic antibacterial and pollutant-degradation materials, gas sensors and Surface Enhanced Raman Spectroscopy (SERS). Most of these applications, particularly, those in the decorative field, rely on the socalled localized surface plasmon resonance (LSPR) absorption, which is governed by the type of the noble metal NPs, their distribution, size and shape and as well as of the dielectric properties of the matrix. The main focus of the presentation will be placed in the demonstration on how the morphological and structural changes are a function of the annealing temperature, as well as on the particular amounts, shape, size and distribution of the noble metal particles dispersed in the dielectric matrix. Since changes in size, shape and distribution of Au clusters are fundamental parameters for tailoring of the LSPR effect, a set of films with a wide range of Au concentration was prepared. The films were deposited by DC magnetron sputtering, and in order to promote the clustering of the Au nanoparticles, the as-deposited samples were subjected to an in-air annealing protocol.

4:50pm B7-11 Electronic and Bonding Analysis of Hardness in Pyritetype Transition-metal Pernitrides, Sanjay Khare ([email protected]), Z. Liu, University of Toledo, USA, D. Gall, Rensselaer Polytechnic Institute, USA Most commonly known hard transition-metal nitrides crystallize in rocksalt structure (B1). The discovery of ultraincompressible pyrite-type PtN2 10 years ago has raised a question about the cause of its exceptional mechanical properties. We answer this question by a systematic computational analysis of the pyrite-type PtN2 and other transition-metal pernitrides (MN2) with density functional theory. Apart from PtN2, the three hardest phases are found among them in the 3d transition-metal period. They are MnN2, CoN2, and NiN2, with computed Vickers hardness (HV) values of 19.9 GPa, 16.5 GPa, and 15.7 GPa, respectively. Harder than all of these is PtN2, with a HV of 23.5 GPa. We found the following trends and correlations that explain the origin of hardness in these pernitrides. (a) Charge transfer from M to N controls the length of the N-N bond, resulting in a correlation with bulk modulus, dominantly by providing Coulomb repulsion between the pairing N atoms. (b) Elastic constant C44, an indicator of mechanical stability and hardness is correlated with total density of states at EF, an indicator of metallicity. (c) Often cited monotonic variation of HV and Pugh’s ratio with valence electron concentration found in rocksalt-type early transition-metal nitrides is not evident in this structure. (d) The change in M-M bond strength under a shearing strain indicated by crystal orbital Hamilton population is predictive of hardness. This is a direct connection between a specific bond and shear related mechanical properties. This panoptic view involving ionicity, metallicity, and covalency is essential to obtain a clear microscopic understanding of hardness. This work was funded by NSF CMMI 1234777, and has been accepted in Phys. Rev. B (2014).

2:10pm C1-3 Optical Filters and Coatings for Earth Observation from Space, Angela Piegari ([email protected]), ENEA, Italy INVITED Many optical instruments are present in the artificial satellites orbiting around the Earth. Such instruments, as spectrometers, imagers, interferometers, contain typically a number of thin-film optical filters and coated optics. Special thin-film filters are often required and represent the critical elements for the construction of the instrument itself. Two examples will be described: a spatially variable filter for an image spectrometer dedicated to the observation of Earth and a near-infrared narrow-band filter dedicated to the detection of the oxygen emission lines during the lightning phenomena in the atmosphere. In the first case the main difficulty consists in the accurate control of a graded film thickness over a dimension of few millimeters. On the contrary, in the second case the diameter of the filter is larger than 100 mm and the main problem is to maintain high thickness uniformity over the whole surface. Besides the optical performance, there are additional requirements that should be taken into account when the coatings are manufactured. An important issue in space is the dimension and weight of all components, thus the optical filters should contribute to the realization of miniaturized instruments. Another critical issue is the survival of optical coatings in the space environment that is necessary for the correct operation of space instrumentation. In fact, either the failure or the variation of the performance of a coating could compromise the success of the mission. Therefore is advisable to investigate in advance the behavior of optical coatings when exposed to space radiation and extreme temperatures. Representative thin-film materials and optical filters have been selected for testing and all coatings have been deposited by energetic techniques to ensure high-density materials with a better resistance to the space environment. The effect of particle irradiation, especially protons and ultraviolet solar photons, on the coating performance will be shown. The influence of other space environmental conditions, as contamination and low-temperature excursions, on the behavior of coatings will be discussed as well.

Fundamentals and Technology of Multifunctional Thin Films Room: Royal Palm 1-3 - Session C1 Recent Advances in Optical Thin Films and Nanomaterials Moderator: Ludvik Martinu, Polytechnique Montreal, Canada 1:30pm C1-1 Friction and Wear Properties of Ti:Ta-doped DLC Coatings, Ihsan Efeoglu ([email protected]), Y. Totik, K.V. Ezirmik, E. Arslan, Atatürk University, Turkey, A. Keles, Ataturk University, Turkey, E.E. Sukuroglu, Atatürk University, Turkey Carbide and nitride of transition elements are natural candidate materials for wear resistance applications as protective coatings. Extreme hardness, high wear resistance, low friction coefficient, chemically stability of transition metal(s) doped-diamond-like carbon (DLC) films make them popular. From this point of view, transition metals, Ti and Ta doped hydrogeneted DLC

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Wednesday Afternoon, April 22, 2015

The synergy among all effects of space conditions remains still an open problem to which the experiments on the International Space Station may give an important contribution.

3:30pm C1-7 Glass Ceramic Phosphor Thin Layer for LED Lighting Package, Jin-Hong Liao, Y.R. Chung, F.B. Wu ([email protected]), National United University, Taiwan LED lighting has attracted attention for a long time since its potential in high efficiency, effective energy saving and elongated life time. The lighting device and its package are requested for high performance, strengthened thermal and mechanical stability, and improved reliability nowadays. Designing phosphor containing glass thin layer for light conversion is one of the important techniques in the pursuit for high performance lighting. In present study, the borosilicate and aluminophosphate glasses with low characteristic temperatures to replace conventionally adopted epoxy matrix in the phosphor containing system is applied. The developed of B-Si-Bi-Zn glass has low characteristic temperatures 447 and 626°C for Tg and Tc, namely glass transition and crystallization points, respectively. Glass ceramic phosphor (GCP) thin layer is formed by the YAG phosphors driven into the designed B-Si-Bi-Zn glass substrate under heat treatments with various temperature and time parameters. Through SEM observation, the phosphors powders are well distributed in glass substructure surface layer and the deepest GCP layer thickness reaches 15 µm. The light emission could be manipulated from blue to white then to yellow with heat treatment time and temperature control. The microstructure, phase distribution about glass/ceramic interaction, and the optical performance of CIE coordinates of the GCP layer are investigated. In addition, the developed P2O5-Al2O3-R2O-Bi2O3 (R=Li and Na)quaternary system with even lower characteristic temperature is analyzed with the glass transition point around 320°C.

2:50pm C1-5 Energetic Deposition of Hafnium-based Oxides and Oxynitrides: Comparison of Cathodic Arc and HiPIMS, Billy Murdoch ([email protected]), RMIT University, Australia, R. Ganesan, D. McKenzie, M. Bilek, The University of Sydney, Australia, D. McCulloch, J. Partridge, RMIT University, Australia Hafnium-based oxides and oxynitrides exhibit wide bandgaps, high refractive indices, high laser damage thresholds and acid resistance. Many potential integrated optical device applications exist for thin hafnia-based films, especially in the UV spectral region. Possessing a dielectric constant between 16 and 30, band-offsets with Si above 1.4 eV and higher thermodynamic stability (when in contact with Si) compared with other high- kmaterials, HfO2 is also known as a viable replacement for SiO2 gate insulators in complementary metal-oxide-semiconductor (CMOS) transistors. Energetic deposition of HfO2 has been performed using a filtered cathodic vacuum arc (FCVA) system and by high-power impulse magnetron sputtering (HiPIMS). Both approaches result in dense coatings with low fixed oxide charge densities, high refractive indices, wide optical band gaps and dielectric constants comparable to those achieved by other physical vapour deposition methods. In HiPIMS deposition of hafnium oxynitride, the nitrogen partial pressure has been identified as critical in determining the energy of the depositing flux. HfOxNy films produced by HiPIMS exhibit higher refractive indices than those produced by other physical vapour deposition methods. The material characteristics and potential applications of these films will be presented and discussed in more detail.

3:50pm C1-8 Functionalization of SiC Substrates by a SOL-GEL Route in order to Optimize their Spectral Selectivity, Jessica Mollicone ([email protected]), P. Lenormand, F. Ansart, CIRIMAT, France, B. Rousseau, LTN, France Between all the optical systems used to collect the incoming solar radiation, the solar receiver that must deliver hot air is one of the key component. To design it, porous ceramic foams appear very interesting in the range of 3001200°C because of their large specific surface which directly heats the air flowing through them. Generally, porous SiC-based materials are chosen as solar receivers because of their high temperature mechanical resistance [1]. Note that materials used as solar receivers have to efficiently absorb the visible-near infrared waves and they have to simultaneously reflect the mid and far-infrared rays. This rule defines here the spectral selectivity. However, selected SiC compounds absorb all rays in the whole visibleinfrared spectral domain making them inappropriate for our purpose [2]. To solve this challenging issue, a first step is to enhance the spectral selectivity of SiC receivers by depositing a suitable coating with appropriate optical properties on the whole solid network. YBa2Cu3O6+x coatings, when their thicknesses are higher than 400 nm and for x~0.8-0.9, are likely to show low reflectivity in the far and mid infrared spectral range and a high absorptivity in the visible spectral range at T = 20°C [3]. However, the spectral selectivity of YBaCuO depends on the oxygen stoichiometry, which is governed by the thermal treatment used to synthesize it. The sol-gel route is used to easily control both the stoichiometry and the nanostructure of the synthesized oxide and to coat SiC substrates. SiC pellets with YBa2Cu3O6+x-typecoatings are studied, in particular their optical properties. The influence of the oxygen stoichiometry and the microstructure on the optical properties at room temperature are then evidenced. This work is conducted in the framework of OPTISOL, project supported by the French National Agency (A.N.R.) [1] T. Fend, R.- Pitz-Paal, O. Reutter, J. Bauer, and B. Hoffschmidt, “Two novel high-porosity materials as volumetric receivers for concentrated solar radiation,” Sol. Energy Mater. Sol. Cells, vol. 84, no. 1–4, pp. 291–304, Oct. 2004. [2] B. Rousseau, S. Guevelou, G. Domingues, J. Vicente, C. Caliot, and G. Flamant, “Prediction of the radiative properties of reconstructed alpha-SiC foams used for concentrated solar applications,” in MRS Online Proceedings Library, 2013, pp. 1545:mrss13–1545–k01–07. [3] R. Lobo, C. Allançon, F. Gotor, J.-M. Bassat, L. Jean-Pierre, P. Odier, D. Krystoff, F. Gervais, C. Champeaux, P. Marchet, and A. Catherinot, “Analysis of infrared-visible-near-ultraviolet reflectivity of conducting and superconducting oxides,” Phys. C Supercond., pp. 1071–1072, 1994.

3:10pm C1-6 Smart Hybrid of Two Different Magnetron Sputtering Technologies to Enhance Electrical Properties of Highly Transparent Conductive Al-Doped ZnO Films with Well-Defined Single (0001) Orientation, Junichi Nomoto ([email protected]), H. Makino, T. Yamamoto, Kochi University of Technology, Japan We develop a technology to obtain Al-doped ZnO (AZO) polycrystalline films with a well-defined single (0001) orientation deposited by a directcurrent magnetron sputtering (DC-MS) to achieve low-resistivity AZO films. In this work, our aim is to clarify the characteristics of AZO films deposited by DC-MS and radio-frequency MS (RF-MS) and to develop novel technology to mix the benefits of the two different MS technologies. We deposited 500-nm-thick AZO films on glass substrates (@200 ºC). Al2O3 contents in the sputtering target was 2.0 wt.%. Firstly, we clarify the characteristics of AZO films deposited by DC-MS and RF-MS. We deposited the films with varying the ratio of the DC power (PDC) and RF power (PRF). We found the critical ratio, PRF/(PDC+PRF)=0.14, causing substantial changes in structural and electrical properties. The AZO films deposited with a ratio, PRF/(PDC+PRF), of 0.0, i.e., by only DC-MS, showed poor crystallinity: the (002) and (004) peak intensities were very weak compared with those of the other samples and a small peak of (006) diffraction could be observed. For the AZO films deposited with the critical ratio, we found that all the three peaks above had strong intensity and the (101) peak had diminished intensity. For the AZO films deposited with a ratio of 1.0, by only RF-MS method, we found not only a further increase in the intensities of the three peaks but also a complete absence of the (101) reflection. We obtained the following results of Hall effect measurements: (1) AZO deposited by RF-MS showed low carrier concentration (N) of 4.13×1020 cm-3; (2) AZO deposited by DC-MS showed low Hall mobility (μH) of 29.3 cm2/Vs; (3) AZO films deposited with the critical ratio exhibited low resistivity (ρ) of 2.47×10-4 Ωcm with N=6.88×1020 cm-3 and μH=36.8 cm2/Vs. Then, we develop smart technology for the achievement of AZO films with well-defined single (0001) orientation. We propose “critical layer (CL)” that extremely affects the growth orientation of AZO films deposited by DC-MS. We deposited 10-nm-thick AZO films as the CLs on glass substrates by RF-MS to successively deposit AZO films by DC-MS. For the AZO films with the CLs, we found not only a further increase in the intensities of the three peaks but also a complete absence of the (101) reflection. We obtained the following results in this study: the AZO films with the CLs exhibited the lowest ρ=2.32×10-4 Ωcm with the highest N=7.00×1020 cm-3 and highest μH=38.6 cm2/Vs. We will clarify key factors limiting carrier transport of AZO films theoretically. This work has been supported by JSPS (Kakenhi No.26790050), Grant-inAid for Young Scientists (B).

Wednesday Afternoon, April 22, 2015

4:10pm C1-9 Adhesion and Failure Pattern of Optical Coatings on Polymers and Glass, Uwe Beck ([email protected]), S. Hielscher, BAM Berlin, Germany Adhesion is a key functionality for any kind of coating/substrate system. For optical applications, metallic and dielectric coatings are of major interest, in particular for crucial materials such as silver on glass or dielectrics on polymers. Within an adhesion study, four different cases have

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been investigated in more detail: effect of substrate thickness on adhesion for dielectrics on polymers (1) and for metals on glass (2) as well as the effect of process parameters on adhesion for dielectrics on polymers (3) and for metals on glass (4). Adhesion, i.e. adhesive strength, is defined by definition as force per area as tensile stress with the unit N/mm2 = MPa. There are only two technologies for tensile stress application available, first the single-sample pull-off test in a tensile testing machine and second the multiple-sample pull-off test within a centrifuge. Both tests require bonded test stamps on the coating. The multiple-sample test within a centrifuge was chosen as it enables either the statistics or the ranking of samples under identical testing conditions. After testing, a microscopic inspection is required in order to determine the failure pattern according to ISO 10365 and to correlate the failure event to distinct interfaces, the effect of adhesion promoters or process parameters. It has been shown that there is a remarkable effect of the substrate thickness on the measured adhesive strength, at first astonishing, but in general unavoidable as adhesion is a coating/substrate system property. Delamination failure (DF) could be divided into DF-R (delamination of metallic reflector), DF-D (delamination of dielectric protection) and combined types. In case of good adhesion of the coatings either substrate failure or adhesive failure has been observed. Future investigations will address alternative adhesives and advanced bonding strategies.

Coatings for Biomedical and Healthcare Applications Room: Sunrise - Session D1 Anti-bacterial Coatings, Surface Functionalization, Surgical Instruments Moderator: Kerstin Thorwarth, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland, Argelia Almaguer-Flores, Universidad Nacional Autonoma de Mexico, Mexico 1:30pm D1-1 Mechanical Properties, Biocompatibility and Antibacterial Behaviors of Tunable TaOxNy and TaOxNy-Ag Thin Films, J.H. Hsieh ([email protected]), Yi-Hua Lai, Ming Chi University of Technology, Taiwan, C. Lee, National Yang Ming University., Taiwan Oxynitrides of transition metals show tunable optical, mechanical, electrical, and bio-related properties when the ratio of oxygen to nitrogen is varied. TaOxNy and TaOxNy-Ag nanocomposite films were deposited by reactive co-sputtering with the variation of O/N ratios. After deposition, the films' mechanical properties were first examined. Next, the samples were tested for their biocompatibility using 3-T-3 cells, as well as for their antibacterial behaviors against Escherichia coli. The results show that these films' hardness as well as the toughness could reach the maximum when the ratio of O/N was near 0.4. However, from the biocompatibility testing, it was found that the O/N ratio should be near the transition of semiconductor to conductor. It was also found that the antibacterial efficiency of TaOxNy-Ag film against Escherichia coli could be much improved, comparing with that of TaOxNy film. The effect of Ag on the biocompatibility of TaOxNy-Ag was found insigificant. The viability of the cells was examined using MTT assay.

4:30pm C1-10 Atomistic Driven Performance of TCO Films, Gregory Exarhos ([email protected]), Pacific Northwest National Laboratory, USA INVITED Transparent and Conducting oxide films owe their ubiquitous properties to the presence of resident chemical and structural defect states that are intentionally introduced by doping or that are created during post deposition thermal treatment, or irradiation. To achieve low resistivity in these films, both charge carrier density and carrier mobility must necessarily be maximized. However, these two variables are closely coupled and exhibit a somewhat inverse relationship with one another. The challenge is to discover optimum chemistries, compositions, and structures that will maintain high transparency under conditions of low film resistivity. A vast amount of phenomenological data in the literature supplemented by electronic structure simulations allows development of ad hoc guidelines for the rational identification of dopants and matrix systems. This information paired with innovative concepts for improving charge mobility can lead not only to improved film performance, but also to improved film robustness in operating environments. A conceptual picture of TCO films is presented here that is intended to germinate fresh ideas that will underpin subsequent development of these technologically important materials. Both PVD and solution deposited n-type free carrier and p-type polaron conducting films will be used as examples to illustrate these concepts.

1:50pm D1-2 PVD-grown Antimicrobial Thin Films on PVDF Substrates for Sensors Applications, SandraMariana Marques ([email protected]), University of Minho, Portugal, I. Carvalho, Czech Technical University in Prague, Czech Republic, S. Lanceros-Mendez, M. Henriques, University of Minho, Portugal, T. Polcar, Czech Technical University in Prague, Czech Republic, S. Carvalho, University of Minho, Portugal Electroactive polymers are the most interesting class of polymers used as smart materials in various applications, such as the development of sensors and actuators for biomedical applications in areas as smart prosthesis, implantable biosensors and biomechanical signal monitoring, among others. For acquiring or applying the electrical signal from/to the piezoelectric material, suitable electrodes can be produced from Ti based coatings with tailored multifunctional properties, as conductivity and antibacterial characteristics, obtained by the inclusion of Ag. This work reports on Ti 1xAgx electrodes and Ag-TiNy electrodes deposited by d. c. and pulsed magnetron sputtering at room temperature on poly(vinylidene fluoride)(PVDF). In the first system (Ti1-xAgx electrodes), silver content was varied from 0-100 at. %. For the second system (Ag-TiNy electrodes), the nitrogen content changed between 0 to 40.3 at. % by increasing the nitrogen gas flow between 0 sccm and 15 sccm and the ratio Ti/Ag changed from 13.4 to 2.2 being clearly the visible decrease on the Ti content in the reactive mode. The X-Ray Diffraction (XRD) results revealed that the deposition conditions preserve the polymer structure and suggested the presence of crystalline Tiβ phase in pure titanium coating and fcc-Ag phase in pure silver coating for the Ti1-xAgx system. For the Ag-TiNy system it is possible to detect a fcc TiN structure and a fcc Ag phase. Sheet resistivity values show a typical behavior of a binary alloy system, varying between 0.12 and 28.5 Ω/sq for the Ti1-xAgx electrodes. For the second system the sheet resistivity decrease with the nitrogen content from 12.0 Ω/sq with 0 at. % to 2.8 Ω/sq for 40.3 at. % of N. The piezoelectricity of the different samples show similar values, showing values from 19.6 to 27.6 pCN-1 for the Tix-1 1Agx system and 13.6 pCN as minimum for the Ag-TiNy system, achieved for the highest N content. In order to assess the mechanical behavior of the as-sputtered films, the film/substrate system was loaded unidirectionally using a tensile machine. The stress-strain curves were analyzed and correlated with the structural data. Moreover, the antibacterial activity of the samples was assessed and it was verified that samples from the second series (Ag-TiNy) present antibacterial activity, in contrast of the first series (Ti1-xAgx).

5:10pm C1-12 Optical and Antibacterial Properties of Silver Nanoparticles Embedded on Transparent-dielectric Films, G. Tafur, O. Varas, D. Vasquez, C. Benndorf, Arturo Talledo ([email protected]), Universidad Nacional de Ingenieria, Peru, D. Acosta, Universidad Nacional Autonoma de Mexico Silver nanoparticles were intercalated between layers of transparent dielectric films such as PTFE, titanium dioxide and amorphous carbon. All nanoparticles and films were produced by rf magnetron sputtering in the same vacuum chamber. Samples were analyzed by X- ray photoelectron Spectroscopy and X-ray diffraction. The nanoparticles size was determined by HRTEM. Optical properties, reflectance and transmittance, in the range 300-1100 nm were measured and the plasmon resonance frequency was related to the size of silver nanoparticles according to the Mie theory. Antibacterial effects were studied on Eschericia coli and Staphylococcus aureus.

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2:10pm D1-3 Anti-biofilm Strategies for Implanted Biomaterials, Jessica Jennings ([email protected]), University of Memphis, USA INVITED Biomaterial implants are susceptible to the attachment of contaminating bacteria, leading to bacterial biofilm formation. Biofilm microorganisms are highly resistant to antibiotic therapy, requiring up to 1000 times the concentration of antimicrobials to eradicate. The presence of multiple types of microorganisms in polymicrobial biofilm further increases the resistance of biofilm to antimicrobial therapy. Treatment of biofilm-based infection is often unsuccessful and may require removal of the implant and multi-stage revision processes to correct. Several strategies have been developed for the prevention and treatment of biofilm-based infection. Local delivery strategies to increase the concentration of antimicrobial at the site of the often poorly vascularized infected tissue include coatings on devices to slowly release antimicrobials and/or biofilm dispersal agents at a therapeutically effective concentration. These coatings may be prefabricated to specific implant materials or applied at the point of care with clinicianselected antibiotics. In preliminary in vitro and in vivo studies, combining antibiotics with specific biofilm inhibitors, such as cis-2 decenoic acid or Damino acids, has been found to have additive or synergistic effects in reducing biofilm. Incorporation of these anti-biofilm agents into and controlling release from traditional local delivery systems can be challenging due to the hydrophobic nature of many biofilm inhibitors. Controlling release of biofilm inhibitors as well as antibiotics from these delivery systems is essential not only to ensure therapeutic efficacy but also to prevent concentrations from reaching those that may induce toxicity or inhibit healing in affected tissue. Implant coatings under investigation for local delivery of biofilm inhibitors include chitosan, electrospun nanofiber membranes, and phosphatidylcholine coatings, among others. Modifications to common local delivery systems such as calcium sulfate or polymethylmethacrylate, controlling release of antibiotic through the application of coatings or enhancing porosity, have demonstrated efficacy in treating established infections in animal models of osteomyelitis. Degradable local delivery systems can be useful as an adjunct to systemic antibiotic therapy to prevent and treat implant-associated biofilm infection.

3:10pm D1-6 Influence of Hybrid Current Modes During Plasma Electrolytic Oxidation of Magnesium: Possible Implications on Biodegradable Implant Applications, Sankara Narayanan, M.H. Lee ([email protected]), Chonbuk National University, Republic of Korea Development of biodegradable implants is indeed fascinating and among them magnesium and its alloys assume significance. Nevertheless, rapid corrosion, generation of a large volume of hydrogen gas, accumulation of hydrogen bubbles in gas pockets adjacent to the implant and an increase in local pH of the body fluid, limit their utilization. Surface medication by plasma electrolytic oxidation (PEO) is a viable approach since it delays the rate of corrosion attack during the initial periods of implantation and decreases the extent of hydrogen evolution. However, the higher pore density facilitates quicker infiltration of the corrosive medium into the inner regions of the PEO coating and subsequently down to the substrate, thus deteriorating its corrosion resistance by changing its local pH. During PEO, the choice of suitable current modes could produce significant changes in the discharge events, both in terms of discharge intensity and density. Any change in the discharge events would alter the coating microstructure, thickness, roughness, porosity, all of which is likely to influence the corrosion resistance. This leads to the questions that will it be possible to choose hybrid current modes (combination of unipolar and bipolar) to optimize the characteristics of the PEO coatings? If so, which type of hybrid current mode (unipolar followed by bipolar or bipolar followed by unipolar) is better? Will the characteristics of the coatings prepared by the hybrid current modes are better than those prepared only under unipolar or bipolar current modes? The present work aims to get a better understanding of these aspects. The PEO coatings were prepared using an alkaline silicate-fluoride electrolyte under unipolar, bipolar and hybrid current modes. The morphological features of the coatings were characterized by scanning electron microscopy while their structural characteristics were evaluated by X-ray diffraction measurements. Corrosion resistance of the coatings in Hank’s balanced salt solution (HBSS) was evaluated by potentiodynamic polarization studies. The findings of the study reveal that by a careful choice of hybrid current modes, it is possible to alter the characteristics of the PEO coatings and their corrosion resistance in HBSS, thus making them suitable for biomedical applications. (This work was supported by the National Research Foundation of Korea (NRF), South Korea Grant funded by the Korean government (MEST) (2011-0028709, 2013R1A1A2012322 & 2014R1A4A1005309. This paper was supported by the research funds of Chonbuk National University, South Korea in 2014).

2:50pm D1-5 Silver Activation as a Trigger Element of the Silver Ionization for Antibacterial Activity in Multifunctional Coatings, Isabel Ferreri ([email protected]), S. Calderon, M. Henriques, S. Carvalho, University of Minho, Portugal Knee and hip joint prosthesis are being widely used worldwide, as a result of the increase of life expectancy, with concerns about the quality of life of patients and costs involved in the treatment of patients requiring placement of orthopedic prostheses. However, even with the advanced materials used today, the failure of medical devices is still a concern in the medical field. One of the major causes of failure is the microbial colonization, being Staphylococcus epidermidis one of the major nosocomial pathogens associated with orthopedic prostheses infections. Therefore, the introduction of multifunctional coatings in the biomaterial could be a step to improve their physical, mechanical, tribological and biological properties and consequently to avoid the revision surgeries by microbial infection. The main goal of this work was to produce multifunctional Ag-ZrCN for antibacterial coatings for hip prostheses. Although silver is described as having a potent antibacterial effect in the history of medicine, studies concerning Ag-ZrCN biomaterial’s coatings, showed no antibacterial effect, since silver is present on its metallic form. Indeed antibacterial activity depends of the released Ag+ from metallic silver. Therefore, the proposed challenge of this work is to enhance the ionization of silver, in order to achieve their release to the biological environment and promote its action on microorganisms, preventing its development. Silver antibacterial activity of these coatings was achieved by an activation procedure, by immersion of the samples in an oxidizing solution for 5 minutes. Metallic silver (content up to 20 at. %) in ZrCN matrix, was deposited onto stainless steel 316L, by DC reactive magnetron. ICP-OES technique was used to quantify silver ion release on the samples and the antibacterial activity was assessed by the halo test, using Staphylococcus epidermidis IE 186 strain. Previously to activation the results showed no antibacterial activity and no significant release of silver ions, in opposition to activated samples, that show significant changes in morphology, which may be related with the formation of oxidized nano silver based masses, that allow improving biocidal Ag+ formation and mobility, providing a constant concentration of Ag+ ions in aqueous environments, killing or inhibiting bacteria growth . Silver activation ensures the silver oxidation and consequently silver ion release, translating in antibacterial effect.

Wednesday Afternoon, April 22, 2015

3:30pm D1-7 Attachment and Proliferation of Neurons on Ultrananocrystalline Diamond Films with Different Surface Terminations, A. Voss, H. Wei, M. Giese, University of Kassel, Germany, G. Ceccone, Inst. for Health and Consumer Prot., European Comm. Joint Res. Ctr., Italy, M. Stengl, J.P. Reithmaier, Cyril Popov ([email protected]), University of Kassel, Germany Diamond is a promising material for different biomedical and biotechnological applications due to its outstanding properties, including high chemical stability and biocompatibility combined with excellent mechanical properties, electrical properties adjustable by doping, wide electrochemical potential window, etc. The properties of the diamond surface (wettability, conductivity, etc.) can be tailored by modification techniques in order to promote or suppress interactions with cells, proteins, RNA or DNA. In the current work we have investigated the interaction of neurons with ultrananocrystalline diamond (UNCD) films with different surface properties. The UNCD layers were prepared by microwave plasma chemical vapor deposition (MWCVD) from methane/nitrogen mixtures on silicon and glass substrates. The resulting coatings were composed of diamond nanocrystallites with a diameter up to 10 nm embedded in an a-C matrix with a grain boundary width of 1-1.5 nm. They were closed, uniform and relatively smooth with rms roughness of 12-14 nm, as revealed by atomic force microscopy (AFM). The intrinsic H-termination of the asgrown UNCD films was replaced by O-termination upon O2 plasma or UV/O3 treatment or by NH2-termination after NH3 plasma modification. Contact angle measurements and X-ray photoelectron spectroscopy (XPS) were used to study the differently prepared surfaces. Finally, the UNCD films with different terminations were applied as platforms for the attachment of circadian pacemaker and olfactory receptor neurons. The results for the proliferation and the viability of the cells in a period up to 14 days, expressed by the cell density, the KCl response and their spontaneous activity, were compared to those obtained for neurons on glass substrates with concanavalin A as an adhesion agent. An improved adhesion of the neurons on the modified UNCD without the application of adhesion proteins was demonstrated and applied for improvement of the cell culture preparation technique.

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3:50pm D1-8 Super-hydrophobic AISI 304 Stainless Steel Surface Prepared by Electrochemical Treatment and Fluorocarbon Coating for Orthodontic Application, Cheng-Wei Lin, Feng Chia University; Central Taiwan University of Science and Technology, Taiwan, C.M. Chou, Taichung Veterans General Hospital; National Yang-Ming University, Taiwan, C.J. Chung ([email protected]), Central Taiwan University of Science and Technology, Taiwan, J.L. He, Feng Chia University, Taiwan Dental arch wires are frequently used in orthodontics nowadays. The accumulated food debris adhered to such orthodontic appliance in oral cavity may lead to overgrowth of bacteria and subsequently results in dental caries. A super-hydrophobic surface of such dental appliances is believed to reduce these risks. Unfortunately, those super-hydrophobic surfaces based on the nano/micro morphology recently prepared by various routes are unsatisfactory in mechanical strength or bio- incompatible. In this study, an electrochemical technology was used to develop nano/micro morphology on AISI 304 stainless steel, which is mostly used for dental arch wires. Through careful control of the anodic electrochemical dissolution process, nano/micro morphology was developed showing hydrophobic characteristic. Following a fluorocarbon coating, superhydrophobic property was measured, which can be attributed to the synergistic effect of the nano/micro morphology and low surface energy of the fluorocarbon coating. It retains super-hydrophobic characteristic after being worn down 50 times using steel wool. Keywords: super-hydrophobic; AISI 304 stainless steel; electrochemical; fluorocarbon; orthodontic.

work as drug reservoirs and release them in controlled fashion. The results related to silica microparticles with drug Cephalexin would be elaborated, which show promising controlled release of the drug for a duration of 48 hours. In another attempt a nano-porous self-assembled therapeutic bandage is synthesised using doctor-blade method. Drug curcumin is incorporated into it and is studied for drug release, antimicrobial property and radicalscavenging properties. These results drive us to a niche prototype of such medicinal topical patches for antimicrobial-anti-inflammatory and cellrejuvenating bandage product. These results would be elaborated.

4:10pm D1-9 Triode Plasma Nitriding of Austenitic Manganese Steels, Xiao Tao, J. Kavanagh, A. Matthews, A. Leyland ([email protected]), University of Sheffield, UK Plasma nitriding can significantly improve both wear and corrosion resistance of austenitic stainless steels, if appropriate treatment conditions are chosen. Nickel, as an austenitic stabilizer for steel, can be replaced by manganese at lower cost. The absence of chromium in such alloys can also present the potential to beneficially suppress nitride precipitate formation during plasma nitriding, enabling a more efficient nitriding treatment, where a deep and highly supersaturated (expanded austenite) layer can form, without nitride precipitation, after a relatively short treatment time. In this study, Hadfield austenitic manganese steels (traditional Mn-12 and a low-carbon weldable grade, with higher Mn content) were nitrided under low-pressure triode plasma conditions. Nitrided cross-sections were etched and examined by optical microscopy to characterize material core and treated surface microstructures. Glancing-angle XRD analysis was applied before and after nitriding to characterise surface phase evolution. Knoop microindentation hardness tests were also applied on nitrided cross-sections to obtain hardness-depth profiles. Tribological behaviour was evaluated by sliding wear and microabrasion testing. Open circuit potential and potentiodynamic polarization corrosion tests in 3.5wt% NaCl solution were applied before and after nitriding, to identify any changes in material corrosion properties.

1:30pm E3-2-1 Influence of the Physicochemical Structure of a SiCx:H Interlayer on the Tribological Behavior of a-C:H Thin Films Grown on Steel by EC-PECVD, F. Cemin, L. Bim, C. Menezes, L. Leidens, M. Maia da Costa, C. Aguzzoli, F. Alvarez, Carlos Figueroa ([email protected]), Universidade de Caxias do Sul, Brazil Hydrogenated amorphous carbon (a-C:H) thin films can be used in mechanical applications due to its strident properties such as high wear resistance and ultra-low friction. However, a widespread use regarding energy efficient issues in the automobile industry is neglected due to the poor adhesion of a-C:H on steel and/or expensive technologies. a-C:H adhesion on steel can be achieved by nanometric bonding interlayers containing silicon, which are particularly beneficial to mitigate the high compressive stress and the thin film mismatching, promoting stronger chemical bonds between the interfaces. Although the use of such a siliconcontaining interlayers is well established in current industrial processes, there is a lack of systematic works reporting the influence of the physicochemical structure of the interlayer on the tribological behavior of aC:H thin films on steel, mainly from a chemical point of view. The aim of this study is to investigate the influence of the physicochemical structure of a silicon-containing interlayer on the tribological behavior of aC:H thin films on steel, through the different chemical bonds and species formed on both interfaces of the same interlayer. The interlayers were grown from tetramethylsilane (TMS) at different deposition temperatures (100 to 550°C) and the a-C:H thin films were grown from acetylene at 80°C. Both interlayer and thin film were deposited on AISI 4140 plain steel by pulsed direct current PECVD process assisted by electrostatic confinement (EC-PECVD). The bi-layers were characterized by SEM, EDX, GDOES, XPS, Raman scattering spectroscopy, and nanoindentation and nanoscratch tests. The results show that the silicon-containing interlayer is formed by a non-stoichiometry SiCx:H compound. The a-C:H thin films show compact and uniform layer structures, while the SiC x:H interlayer thickness and chemical composition are temperature-dependent following a thermally activated kinetic process according to the Arrenhius equation. AC:H thin films have adhesion on the SiC x:H-steel system when the interlayer is grown at deposition temperatures higher than 300°C. Moreover, the higher deposition temperature, the high the critical load to wedge spallation. Whereas C–C and C–Si bonds are formed on the SiCx:H/a-C:H interface, the steel/SiCx:H interface is constituted by Si–Fe bonds. The interlayer growth temperature controls the type of chemical bonding and oxygen degrades the adhesion of a-C:H thin films. Finally, a tribological mechanism to explain the a-C:H thin film failure will be proposed and the chemical function of each interface in the same interlayer will be discussed in details.

Tribology and Mechanical Behavior of Coatings and Engineered Surfaces Room: San Diego - Session E3-2 Tribology of Coatings for Automotive and Aerospace Applications Moderator: Astrid Gies, Oerlikon Balzers, Oerlikon Surface Solutions AG, Gary L. Doll, The University of Akron, USA, Pantcho Stoyanov, Kennametal Incorporated, USA

4:30pm D1-8 Functional Nanomaterials for Healthcare Applications, Sangeeta Kale ([email protected]), Defence Institute of Advanced Technology, India INVITED Using nanoforms of inorganic metal oxides (and their complexes with polymeric and biomolecular systems) with fine conjugation strategies, one can explore extremely interesting and promising applications in the area of Healthcare: especially for development of smart biosensors, MRI agents, magnetic hyperthermia agents, wound-healing patches, drug delivery agents, antimicrobial agents and in wide-range of pharmaceutical formulations. This can be achieved via careful materials study to engineer them for establishment of their efficacy in such multiple applications. In this presentation, two such applications would be elaborated, namely: a) Iron oxide nanoparticles as efficient cancer-hyperthermia-cum-drugdelivery agent and b) mesoporous, self-assembled nanostrcutures for controlled-drug-release. Magnetic nanoparticles have been investigated for their applications in cancer hyperthermia. If an appropriate drug is further conjugated to it, then the system can serve dual strategy to approcah the cancer cells, and lead them to destruction. Out of many systems explored by us, namely, manganites, iron oxides and nickel-cobaltites, the work related to iron oxide will be focused. Fe3O4 (Fe) nanoparticles have been conjugated to curcumin (CU) molecules via a citrate (CA) linker (Fe-CA-CU) and have been explored for superoxide scavenging, tumor suppression, and cancer hyperthermia. These studies promise Fe-CA-CU as a good cancer hyperthermia-cum-tumor suppressant and antioxidant agent. These results would be discussed. Second part of presentation would be on the use of various inorganic (silica) and organic (natural gel, aloevera) self-assembled nanostructures which

1:50pm E3-2-2 Development and Tribological Characterization of Nidoped Vanadium Nitride Coatings, Giovanni Ramirez ([email protected]), O.L. Eryilmaz, Argonne National Laboratory, USA, R. Mirabal, O. Depablos-Rivera, S.E. Rodil Posada, Universidad Nacional Autónoma de México, México, Y. Liao, A. Erdemir, Argonne National Laboratory, USA A series of nickel-doped vanadium nitride composite coatings were prepared using high power impulse magnetron sputtering (HPIMS) system. Ni content was adjusted by varying Ni target power while keeping V target

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power constant during deposition. In order to achieve better adhesion of the coating to steel substrate, HPIMS was used for metal ion etching. The films were grown on 52100 steel substrates and 9.5 mm diameter ball samples for tribological tests. Si wafers were also coated for coating characterization studies. X-Ray Diffraction (XRD), x-ray photoelectron spectroscopy (XPS), ellipsometry, Raman Spectroscopy, nano-indentation, and transmission electron microscopy (TEM) techniques were used to characterize the structural, mechanical and chemical nature of the resultant Ni-VN nanocomposite coatings. The tribological performance of the coatings was evaluated in poly alpha olefin (PAO) oil using a high frequency reciprocating test rig over a wide range of test conditions covering both the boundary and hydrodynamic regimes. Nickel addition to VN system improves the tribological performance up to an amount and the higher nickel addition from this point reverses the tribological performance of the coating system. Overall, the optimum amount of nickel containing VN coated surfaces showed 95% reduction in wear and 40% reduction in coefficient of friction compared to baseline (uncoated) steel in PAO oil. With the use of a combination of surface analytical techniques, we confirmed the formation of a carbon-rich boundary film on sliding surfaces which may explain the much superior friction and wear performance of NiVN coated surfaces.

and sustain the performance including the application of a hard coating on the piston rings. Currently, thick CrN (50-70 µm) is commonly used for diesel engines. The COF of CrN coatings is generally high (0.5-0.7 for dry sliding). Diamond-like carbon (DLC) coating is also being explored due to its low COF, but its current thickness of 2-10 µm is deemed to be insufficient. The main aim of this study is to develop a coating that has both low COF and high wear resistance. Another goal of the development is to reduce the coating thickness (coating time) and hence the coating production cost. In this paper, we report the preliminary results from the development of TiSiCN-based nanocomposite coatings. Plasma enhanced magnetron sputtering (PEMS) was used to sputter Ti in a mixture of Ar, hexamethyldisilazane (HMDSN), N2 and C2H2 to form the coatings. Various techniques were used to characterize the coating microstructural, mechanical and tribological properties including SEM, XRD, nanoindentation, ball-on-disc test, Plint 77 (ring-on-cylinder linear) test, and ultimately single cylinder engine tests. The TiSiCN coatings (15-20 µm) exhibited a nanocrystalline phase of TiCN and an amorphous phase of SiCN, or nc-TiCN/a-SiCN, and showed excellent mechanical properties with high H/E ratios, good adhesion, low dry COF and excellent wear resistance from ball-on-disc tests. Optimized TiSiCN coatings were then deposited on actual piston rings and tested on the Plint TE77, and the results showed a 10% reduction of the COF (0.058) as compared to the baseline (0.065). Based on the Plint tests, the best TiSiCN coating was finally deposited on a set of piston rings and then tested in a single cylinder engine. The results showed that the uncoated piston rings contributed to 25% and 34% of the total COF in two separate baseline tests. In contrast, the coated piston rings contributed to 18% of the total COF in the test, indicating that the coating on the piston rings reduced the COF by 39%. Furthermore, the durability engine test showed a 28% and 40% reduction in weight loss for the coated top and second rings, respectively, from the baseline. Finally, the coating on the piston rings also showed a reduction in cylinder liner wear by ~50% compared to the baseline, even thought it was not coated.

2:10pm E3-2-3 Wear Resistant Zirconium Based Coatings, Javier Barriga ([email protected]), IK4-TEKNIKER, Spain A great effort has been done in the development of carbon based coatings for tribological applications. As a consequence, the slip-rolling resistance of DLC thin films was improved considerably. On the other side, zirconium has been used widely in the decorative industry because of its corrosion resistance and wide range of metallic colors. But the use of Zr in tribological thin films is not very broad. However, recent developments show that zirconium based coatings could perform better than DLC films in tribological contacts under severe contact conditions. In the present work, zirconium carbonitride multilayered films have been developed on AISI M2 and 52100 steels by cathodic arc evaporation under a wide range of deposition parameters: BIAS voltage (from 0 to 400 V) and processing temperatures (from 100 to 700ºC aprox.), in order to study the possibility of doing the deposition at low temperatures opening the range of substrate steels and energy savings (lower costs). A wide characterization campaign has been carried out with the resulting ZrCN/ZrN coatings: Calotest, SEM, X-Ray analysis, Raman, XPS, adhesion tests and, finally, a battery of sliding tribological tests. With this we have analyzed the influence of deposition parameters on the films. We have seen that adhesion improves with higher processing temperatures but bias voltage has to be selected for each tribological application: best adhesion does not lead directly to lowest abrasive wear. Under some sliding conditions it is not necessary to process coatings at higher temperatures as life expectancy of components seem to be unaffected. Only for specific coatings (and testing conditions) there is a reaction between lubricating additives and coating, forming a tribofilm. This could be related to the contents of elements on the surface and their bonding state. Raman analysis shows more carbon content in the coatings with higher processing temperatures and lower bias voltages.

3:10pm E3-2-6 Wear Mechanism of HIPIMS Mo-W Doped Carbon Coatings in Dry and Boundary Lubrication Conditions, Papken Hovsepian ([email protected]), P. Mandal, A.P. Ehiasarian, Sheffield Hallam University, UK Mo-W doped Carbon coatings were deposited by a combined non-reactive High Power Impulse Magnetron Sputtering (HIPIMS) and Unbalanced Magnetron Sputtering (UBM) technique. The Mo-W doped C coatings showed nanohardness of 16.5 GPa. In scratch adhesion test critical load values, Lc exceeding 80 N were acieved due to the effective HIPIMS substrate pretreatment. GAXRD patterns indicated that the overal structure was nanocrystalline almost amorphous like. The coating friction coefficient was measured by room and high temperature pin-on-disc tests under dry and boundary lubrication conditions using 6 mm diameter 100Cr6 steel ball counterpart. Highly viscous nonformulated engine oil (Mobill 10W-60) was used as lubricant. The friction coefficient in dry sliding conditions was measured to be μ=0.35, which was somewhat higher when compared to state-of-the-art DLC coatings produced by Plasma Assisted Chemical Vapour Deposition or Arc Evaporation techniques. In lubricated conditions however, the Mo-W doped C coatings showed friction coefficient of μ=0.033. which was lower that these reported for a number of state-of-the art DLCs. Raman spectroscopy of the wear debris was employed to better understand coating wear mechanism in dry and boundary lubrication conditions. In dry sliding conditions the wear debris consisted of MoO3 and WO3 as well as debris of graphitic nature as indicated by the well pronounced D and G bands in the Raman spectra. In these conditions the Me-dopants react with the oxygen from the environment due to the high flash temperatures at the asperity contacts to form oxides, which is typical for the oxidative wear mechanism. In oil lubrication conditions at elevetaed temperatures, (200 oC) the wear product was a mixture of MoS2 and WS2, with Mo and W being the Medopants in the coating and sulphur being an element in the oil formulation. Both MoS2 and WS2 compounds have a graphite-like layered crystallographic structure, therefore act as solid lubricants. Thus it can be stated that in boundary lubrication condition the tribological behaviour of the Mo-W doped C coatings is goverened by tribochemical reaction wear mechanism.

2:30pm E3-2-4 Diamond-like Carbon for Sliding Components in Heavy Machinery Drive Train, Bao Feng ([email protected]), H. Yoon, W. Tian, Caterpillar Inc., USA Rolling bearing and sliding bearing are alternatively selected based on the outcome of trade-off analysis for component designs of heavy duty equipment. Evidence showed sliding bearings sometimes offered much better reliability than roller bearings under this context. However, sliding bearings cause efficiency loss outside of the hydrodynamic regime and are also subject to unpredictable scuffing failure. The undesirable characteristics of sliding bearings limit them from being considered for high load applications. Candidate materials were compared in a full size drive train sliding component test simulator. The test results suggested the capability of sliding bearings can be significantly extended by using diamond-like carbon (DLC). The working mechanism of DLC in highly loaded sliding bearing systems is discussed. The design parameters of DLC coated components are proposed. 2:50pm E3-2-5 Development of Low Friction and Wear Resistant Nanocomposite Coatings for Piston Rings, J. Liang, Ronghua Wei ([email protected]), D. Bitisis, P. Lee, Southwest Research Institute, USA To meet the future US Corporate Average Fuel Economy (CAFE) standards (54.5 mpg or 4.34 liter/100km in 2025), all efforts are being made to increase the fuel efficiency of vehicles, in which lowering the coefficient of friction (COF) of any moving components including the piston rings is one key area. In addition, efforts are also being made to increase the reliability

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3:30pm E3-2-7 Lubrication of Steel and DLC Contacts by MoDTCContaining Lubricant. Effect of Lubricant Degradation, Modestino De Feo ([email protected]), M.-I. De Barros Bouchet, C. Minfray, T. Le-Mogne, B. Vacher, LTDS - Ecole Centrale de Lyon, France, L. Yang, F. Meunier, Oerlikon Sorevi, France, B. Thiebaut, TOTAL Solaize Researcher Center, France, J.-M. Martin, LTDS - Ecole Centrale de Lyon, France Nowadays, the control of energy consumption is a priority, especially for the automotive industry due to the problems generated by the global earth warming. The reduction of energy consumption of diesel engines can be reached through the minimization of friction losses in some engine parts, like the piston-ring liner. Indeed, some authors blame this part to be responsible for 40% of friction losses in the diesel engine, particularly under mixed and boundary lubrication regimes. To address this problem, various chemical additives can be added to the engine oil to optimize its friction reduction performance. These additives are supposed to react with steel sliding surfaces to form tribofilms able to reduce friction coefficient. To go further in reducing friction losses and in the protection against mechanical wear, the introduction of Diamond-Like Carbon (DLC) coatings on the mechanical parts is being considered. A large amount of research has been addressed on the study of the effect of molybdenum dithiocarbamate (MoDTC) additives on the lubricating performances of carbon-based coatings, showing that high wear rate is produced when the MoDTC is blended to the base oil. However, the mechanisms leading to the coating removal are not fully understood yet. On the other hand, the effect of lubricant degradation on the tribological properties of DLC coatings has been poorly investigated although it can provide more information about undue wear of the coatings in the presence of MoDTC-containing base oil. In this work, the friction and wear performances of different kinds of DLC coatings, in terms of hydrogen content and metallic doping agents, have been analysed for fresh and aged 1% wt. MoDTC-containing oils. The tribological tests have been carried out with DLC/steel and steel/steel contacts under boundary lubrication conditions, using a ball-on-flat tribometer. The wear of the sliding surfaces, steel balls and DLC coatedflat, were evaluated using an interferometer. In order to understand the changes in tribological behaviour as a function of ageing time, tribofilm composition was investigated by X-ray Photoelectron Spectroscopy (XPS). Transmission Electron Microscopy (TEM) technique has been used to observe and analyse the wear particles produced during the friction experiments.

New Horizons in Coatings and Thin Films Room: Sunset - Session F2-2 High Power Impulse Magnetron Sputtering (HiPIMS) Moderator: Stephanos Konstantinidis, University of Mons, Belgium, Tomas Kubart, Uppsala University, Angstrom Laboratory, Sweden 1:30pm F2-2-1 Laser Diagnostics of Particle Dynamics in HiPIMS Plasmas, Catalin Vitelaru ([email protected]), National Institute for Optoelectronics-INOE 2000, Romania, D. Lundin, Université Paris-Sud 11, France, V. Tiron, Alexandru Ioan Cuza University, Romania, N. Brenning, Royal Institute of Technology, Sweden, G. Popa, Alexandru Ioan Cuza University, Romania, T. Minea, Université Paris-Sud 11, France INVITED The continuous development of new versions of the magnetron process is pushing towards novel technological applications, also bringing forward the need of fundamental understanding. The High Power Impulse Magnetron Sputtering (HiPIMS) is gathering great interest in the last years. The HiPIMS specificity resides in its temporal behavior, on a time scale of nanoseconds for electrons instabilities (‘spokes’), ranging from microsecond to hundreds of microseconds for heavy species, during the high power pulse, and extending to milliseconds in the afterglow phase. The temporal dimension of the process requires time resolved measurements to get an insight on the undergoing processes. Laser spectroscopy is generally used to diagnostic the density, the temperature or the velocity distribution function of investigated species. Its formidable effectiveness comes from the narrowness of this radiation and the ability to deliver the exact energy required for probing the desired transition, usually implying the ground state or metastables. The main types of laser sources used so far for this purpose are tunable diode lasers, optical parametric oscillators (OPO-s) and dye lasers. The investigation of inhomogeneous time evolving discharges, like the HiPIMS, requires a different approach compared to continuous and/or homogeneous plasmas, and specific techniques have been adapted for it. This contribution focuses on the main developed methods to perform time and space resolved measurements by laser based diagnostics, using different types of laser sources, pointing out the main advantages and weaknesses of each technique illustrated by typical results. Hence, the temporal and spatial behavior of the most relevant species is revealed, e.g. metal atoms and ions, inert or reactive gas atoms, etc. It is shown that the high dynamics of density and temperature of metal atoms is mainly related to transport phenomena, occurring mostly in the afterglow phase. The dynamics of metal ions is related to atom transport and ionization phenomena in the discharge volume. The density and temperature of gas metastable atoms are governed by the production and loss mechanisms through electron impact and to gas rarefaction during the pulse. The main focus involves the processes occurring during the high power pulse and immediately after it. As for the reactive species it is shown that both volume and surface phenomena play an important role, with different weights in different discharge regions.

3:50pm E3-2-8 Atomistic Simulations of Tribo-induced Phase Transitions in Coatings, Michael Moseler ([email protected]), Fraunhofer Institute for Mechanics of Materials IWM, Germany INVITED The tribological behavior of technically relevant coatings is closely related to the formation of a third body between two first body surfaces. Usually third bodies form during running-in. A successful running-in results in a long-lived tribo system with low friction and wear, while a system with a third body that evolves towards the “wrong” tribo material results in early failure. Therefore, it is essential to understand the tribo-induced phase transitions that govern third body formation. Despite intense experimental research, many details and most of the underlying mechanisms of the phase transitions that produce third bodies are barely understood. In this contribution, classical molecular dynamics employing realistic bond-order potentials is used as a descriptive and predictive tool to study phase transitions in carbon coatings and simple metallic tribo systems. For carbon films, emphasis is laid on phase transitions that are responsible for the slow wear of these protective coatings. Despite the fact that diamond and diamond-like carbon coatings (DLC) are used in an increasing number of applications, not much is known about the atomic scale processes that cause wear of these films. In our molecular dynamics simulations Diamond and DLC exhibits a mechanically driven phase transformation into a weak sp 2 phase that can be easily removed from the sliding interfaces. The talk will end with atomic scale insights into third body formation in metals.

2:10pm F2-2-3 Correlation Between Ion Transport and Plasma Oscillations in DC and HiPIMS Discharges, Ante Hecimovic ([email protected]), V. Schulz-von der Gathen, J. Winter, A. von Keudell, Ruhr-Universität Bochum, Germany Recent findings show that plasma oscillations are commonly found in magnetrons, regardless of the power supply and power levels obtained. We present a comprehensive investigation of the oscillation properties in terms of amplitude, frequency and rotation direction using the 12 flat probes, installed azimuthally around the circular magnetron. The investigated discharge conditions encompass both DC and HiPIMS discharges with current density ranging from 0.5mA/cm2 to 5A/cm2. The results exhibit a wide spectrum of frequencies ranging from 250 Hz to 200 kHz. When the flat probes are negatively biased, the ion saturation current is collected and measured. The correlation between the observed oscillations and the ions transported away from the target allows establishing a qualitative understanding of the ion transport for wide range of discharge currents in DC and HiPIMS discharges. The results are compared with the Hall parameter, a measure commonly used to evaluate the cross-field transport, reducing from 16 in DC discharges to values of around 2 in HiPIMS discharge.

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2:30pm F2-2-4 Dynamics and Potential Structure of Ionization Zones in Magnetron Discharges, Matjaž Panjan ([email protected]), Y. Yang, J. Liu, A. Anders, Lawrence Berkeley National Laboratory, USA Organization of plasma into so-called ionization zones or spokes has been first observed in HiPIMS discharges [1-3]. Measurements of charge transport in continuously operated magnetron suggested that ionization zones also form in DCMS discharges [4]; indeed this was recently observed by imaging with high-speed camera [5]. DCMS discharges run at very low currents (few mA on 3 inch target) form a single ionization zone with elongated arrowhead shape that points in the direction of electron drift. The number of zones increases sequentially from two to three and more as discharge current and/or pressure are increased; in some cases multiple zones form symmetrical patterns. In the present work we used two high-speed ICCD cameras triggered in sequence to study dynamics of ionization zones in DCMS discharges (limited studies were also performed for HiPIMS discharges). Images were correlated with probes positioned around the perimeter of magnetron's racetrack, which measured time-dependent floating potential and ion current. Analysis of images and probe measurements shows that the speed of ionization zone and the direction of their movement depends on the discharge current and gas pressure. At very low discharge currents ionization zones rotate in the direction opposite to the E×B electron drift. At particular discharge conditions almost stationary, standing wave plasma configuration forms. Only at very high discharge currents (several amperes) ionization zones move in the E×B direction as was previously reported for HiPIMS discharges. In our previous work we suggested that ionization zones are regions of negative-positive-negative space charge distribution, which results in formation of potential hump and electric fields parallel to the target [6]. It is believed that traveling electric fields play important role in anomalous transport of charge across magnetic field lines [4, 6]. Probe measurements and images acquired in this work will therefore be discussed in the context of traveling potential hump model. [1] A. Kozyrev, N. Sochugov, K. Oskomov, A. Zakharov, A. Odivanova, Plasma Phys. Rep., 37 (2011) 621 [2] A. Anders, P. Ni, A. Rauch, J. Appl. Phys., 111 (2012) 053304 [3] A.P. Ehiasarian, A. Hecimovic, T. de los Arcos, R. New, V. Schulz-von der Gathen, M. Boke, J. Winter, Appl. Phys. Lett., 100 (2012) 114101 [4] M. Panjan, R. Franz, A. Anders, Plasma Sources Sci. Technol., 23 (2014) 025007 [5] A. Anders, P. Ni, J. Andersson, IEEE T Plasma Sci., (2014) 1 [6] A. Anders, M. Panjan, R. Franz, J. Andersson, P. Ni, Appl. Phys. Lett., 103 (2013) 144103

3:10pm F2-2-6 Controlled Reactive High-power Impulse Magnetron Sputtering - Experiments and Modelling, Jaroslav Vlcek ([email protected]), T. Kozak, J. Rezek, University of West Bohemia, Czech Republic High-power impulse magnetron sputtering (HiPIMS) with a pulsed reactive gas (oxygen) flow control was used for high-rate reactive depositions of densified, highly optically transparent, stoichiometric zirconium dioxide films. The depositions were performed using a strongly unbalanced magnetron with a planar zirconium target of 100 mm diameter in argonoxygen gas mixtures at the argon pressure of 2 Pa. The repetition frequency was 500 Hz at the deposition-averaged target power density from 5 Wcm -2 to 53 Wcm-2 with the duty cycles from 2.5% to 10%. Typical substrate temperatures were less than 130°C during the depositions of films on a floating substrate at the distance of 100 mm from the target. Usual deposition rates, being around 10 nm/min, were achieved for the target power density of 5 Wcm-2. An optimized location of the oxygen gas inlets in front of the target and their orientation toward the substrate surface made it possible to improve quality of the films due to minimized arcing on the sputtered target and to enhance their deposition rates up to 120 nm/min for a deposition-averaged target power density of 52 Wcm-2 and a voltage pulse duration of 200 µs[1,2]. To understand complicated processes during reactive HiPIMS of dielectric films, we have developed a parametric model. The model takes into account specific features of the HiPIMS discharges, namely gas rarefaction in front of the sputtered target, backward flux of the ionized sputtered metal atoms and reactive gas atoms onto the target, and high degree of dissociation of reactive gas molecules in the flux onto the target and substrate. Moreover, a local overfilling of the reactive gas in front of the reactive gas inlet is considered. The model makes it possible to calculate the time-dependent compositions of the compound layers on the target and substrate surfaces in a pulse period, and the number of metal atoms, forming the compound layers, which are deposited onto the substrate per second. We used this model to clarify the experimental results achieved by us for the controlled reactive HiPIMS of zirconium dioxide films. References [1] J. Vlcek, J. Rezek, J. Houska, R. Cerstvy, R. Bugyi, Process stabilization and a significant enhancement of the deposition rate in reactive high-power impulse magnetron sputtering of ZrO2 and Ta2O5 films, Surf. Coat. Technol.236 (2013) 550. [2] J. Vlcek, J. Rezek, J. Houska, T. Kozák, J. Kohout, Benefits of the controlled reactive high-power impulse magnetron sputtering of dielectric oxide films, Vacuum(2014, submitted). 3:30pm F2-2-7 Analysis of Ion Energy Distribution at the Substrate during a HPPMS (Cr, Al)N Process using Energy Resolved Mass Spectrometer and Retarding Field Analyser, K. Bobzin, T. Brögelmann, R. Brugnara, Stephan Chromy ([email protected]), RWTH Aachen University, Germany The ion energy is known to have a strong influence on the properties of coatings deposited by physical vapor deposition (PVD). Therefore, the ion energy distribution (IEDF) specially measured at the substrate side is of great interest for understanding the coating growth. In PVD coating processes the ion energy at the substrate can be adjusted by applying a negative voltage (bias) to the substrate table. In the present work, mass integrated measurements of the IEDF were carried out during a high power pulse magnetron sputtering (HPPMS) (Cr,Al)N process using a Cr-target with 20 plugs of Al within an industrial scale PVD coating unit. The HPPMS cathode was operated with different average powers (1, 3 and 5 kW) and pulse lengths (40 and 200 µs) at constant frequency of 500 Hz. In a first step, measurements of the IEDF using mass spectrometer (MS) and retarding field energy analyser (RFEA) were carried out. By comparing the measured IEDFs with these two different methods some differences had been found. At high peak power, i. e. short pulse duration and high average power, a much greater high energetic fraction in the IEDF between 10 and 50 eV were found in the results of the RFEA in comparison to the MS measurements. However, the effective ion temperatures between 10 and 50 eV calculated relatively from RFEA and MS measurements show a slight difference of a factor of approx. 1.3. In a second step, measurements were done using biased RFEA with a substrate bias of -100 V. The comparison of the IEDF measurements with and without substrate bias using the RFEA shows a significant change in the shape of the IEDF. Using a substrate bias the IEDF showed a nearly gaussian shape, while without a substrate bias the shape of the IEDF is asymmetric and in the high energetic range of 10 to 50 eV it showed a maxwellian distribution.

2:50pm F2-2-5 Plasma Characterization of Sputtered Aluminum with a MF Superimposed HIPIMS Process from Industrial Sized Rotatables, Holger Gerdes ([email protected]), R. Bandorf, Bräuer, Fraunhofer Institute for Surface Engineering and Thin Films, Germany, M. Mark, MELEC GmbH, Germany, T. Schütte, PLASUS, Germany High power impulse magnetron sputtering HIPIMS is often referred to suffer from low deposition rates. To compensate the rate loss, the parallel use of another target running with a conventional discharge is reported. Alternatively superposition of conventional and HIPIMS operation for one cathode is available. The question for such combination is: how much influence has the ionized part of the process on the plasma and film properties? Within this presentation a novel approach for combining Mid-frequency and HIPIMS will be presented. The set-up consists of a dual rotatable (length 550 mm, equipped with aluminum) and a mid-frequency (MF) power generator connected to them. This MF generator is running in a bipolar mode. Furthermore two HIPIMS power supplies are connected to one of the rotatables and to a separated anode. These power supplies are running in a unipolar mode. This setup is giving a high deposition rate (MF-process) and can influence the growth of the film by supporting a higher flux of ionized particles to the substrate (HIPIMS process). Different operating modes on the target and at resulting properties at the substrate were investigated. At the target site electric properties like voltage and current, as well as optical emission spectroscopy were investigated. The results will be correlated with the measurement of the ion and electron density, investigated by Langmuir probe. No significant reduction in deposition rate with respect to the applied average power to the cathode was observed, even by adding HIPIMS. For a moderate peak current density of up to 0.2 A/cm² significant modifications of the resulting electron and ion current was observed. While the MF process showed an electron density of 0.3*1017/m3, the superimposed process led to a density of 1.6*1017/m3. Similar behavior was observed for the ion density, increasing from 0.8*1017/m3 in MF operation to 3.8*1017/m3 with superimposed HIPIMS.

Wednesday Afternoon, April 22, 2015

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3:50pm F2-2-8 Electronic Properties Correlated to Vacancy Model in Nickel Oxide Thin Films Deposited by Reactive HiPIMS Discharge, Julien Keraudy ([email protected]), IRT Jules Verne, France, A. Ferrec, A. Goullet, P.Y. Jouan, IMN Jean Rouxel, France Nickel Oxide (NiO) is a p-type semiconductor which has recently attracted a great deal of attention. Indeed, despite his simple crystallographic structure, NiO have proven to be an attractive material for hot topics: 1) renewable energy as a holes extractor in solar cells; 2) new generation of nonvolatile resistive random access memory devices as a prototypical Mott Insulator and 3) gas sensor as a result of his excellent chemical response. Among the numerous methods to synthesize NiO films, reactive magnetron sputtering discharge is considered to be the most widely used. Recently, D. T. NGuyen et al [1] have showed the feasibility to synthesized NiO films with HiPIMS. Based on Ellipsometry and XPS characterization, the authors show that by varying the pulse duration, they can control precisely the stoichiometry and the opto-electronic properties of the films. However, despite the large number of research focus on this material, no investigations have been reported on the correlation between plasma and films properties. The first part of this talk is dedicated to detect precisely the transition from metallic to oxide regime. Surprisingly, by using optical emission spectroscopy (OES) and EDX/XPS measurements, we have estimated four distinct regions (plasma composition and chemical composition of the film) reported by the oxidation curve measured with time-integrated voltage waveforms. This first result proves the good synergy between plasma diagnostic and thin film characterization. In a second part, influence of oxygen partial pressure on the electrical properties of the as-deposited materials was studied. Based on XPS and Ellipsometry measurements, we have well reconstructed the band diagram of all films. Indeed, by increasing the O2 ratio, we have observed a decrease of the EF-EV distance (from 0.92 eV to 0.68 eV) which leads to an improvement of the p-type behavior, confirmed by C-AFM measurements when the collected current increase exponentially with O2 partial pressure. Elevation of electrical conductivity with the O2 ratio was explained using vacancy model. Increase in the nickel vacancy results in an increase in the number Ni 3+ ions (confirmed by XPS) and the hole concentration of the nickel oxide films. Moreover, higher amount of nickel vacancy with O2 ratio was also confirmed by the presence of magnetic anomalies in NiO thin film deposited at higher oxygen content. NiO thin films (28%) exhibit a weak ferromagnetic behavior which is attributed to the presence of Ni3+ within the NiO lattice [2]. [1] D.T. Nguyen et al, Surf & Coat Technol 250 (2014) 21-25 [2] I. Sugiyama, Nature Nanotechnology 8, 266–270 (2013)

high plasma density induced by pulsed higher power applied to the target in magnetron sputtering. A Hipims process may be substantially enhanced by external magnetic field. In our Hipims system, a coil is equipped around the magnetron target to induce strong EXB effect. The substrate current may be increased by a factor of 2 or more if a proper current flows through the coil, accompanied by an intensified glow discharge. TiAl target is utilized for the deposition of AlTiN. The external magnetic field leads to a thicker film and smooth surface. This is an interesting and inspiring result. In conventional Hipims processes, a decreased deposition rate is often complained by the industrial users. The critical loads of 50N for AlTiN and 70N for TiN are easily achieved using this set up, even at a low processing temperature, e.g., 200oC. 4:50pm F2-2-11 Plasma Pretreatment of Tungsten Carbide and Steels by High Power Impulse Magnetron Sputtering, Arutiun P. Ehiasarian ([email protected]), A.W. Oniszczuk, T.J. Morton, Sheffield Hallam University, UK, C.F. Carlstrom, M. Ahlgren, Sandvik Coromant, Sweden Coated cutting tools are used for the majority of today's manufacturing operations. In a given cutting operation, the adhesion of the coating to the substrate is directly related to the lifetime of tools. Adhesion is commonly enhanced by the use of gaseous plasma to preclean the substrate and present a surface free of oxides for the growth of the coating. Metal plasmas are often more efficient due to the shallow implantation of metal into the substrate which enhances the wettability of the surface during nucleation of coatings of the same material. The effects of metal ion implantation on the depth and chemistry of the interface and the microstructure of the surface are not sufficiently understood due to the relatively constrained parameter space available from conventional metal ion sources. In this experiment tungsten carbide (WC), high speed steel and stainless steel were treated in the environment of a High Power Impulse Magnetron Sputtering plasma. The plasma chemistry was evaluated quantitatively by a combination of optical emission spectroscopy and plasma-sampling energyresolved mass spectroscopy. Ion fluxes and deposition rates were measured simultaneously to obtain ion-to-neutral ratios. The measurements confirmed a strong rarefaction of the gas and indicated that rarefaction of the metal species may take place as well. Both single- and double-charged metal ions were detected. No significant delay between the gas and metal plasma was observed within a pulse. The plasma diagnostics results were used as input to modelling calculations of penetration depth and chemistry near the substrate surface. Metal ions were found to penetrate approximately 4 nm into the WC substrate. The maximum implanted content of metal was found to increase as plasma became metal ion dominated and the metal ionisation degree increased. Surface roughness of polished substrates increased due to the pretreatment as observed by atomic force microscopy, whereas as-received surfaces showed negligible differences. The etching removed preferentially smaller grains leaving behind a stronger substrate. Grain boundaries were also preferentially etched and the waviness factor was used to quantify the difference between samples. The etching rates corresponded to the ion flux to the substrate. The mechanisms linking the plasma chemistry, surface chemistry and the adhesion of the coatings are discussed. Optimal parameters for improved adhesion are determined.

4:10pm F2-2-9 Investigation of Plasma Conditions and Film Growth during Reactive HiPIMS of HfO2 Films, Amber Reed ([email protected]), Air Force Research Laboratory and University of Dayton, USA, J. Hu, University of Dayton Research Institute and Air Force Research Laboratory, USA, J. Wohlwend, UTC; Air Force Research Laboratory, USA, R. Naguy, Air Force Research Laboratory, USA, J. Bultman, University of Dayton Research Institute; Air Force Research Laboratory, USA, C. Muratore, University of Dayton, USA, P. Shamberger, Texas A & M University, USA, A.A. Voevodin, Air Force Research Laboratory, USA Hafnium oxide thin films have been produced by reactive HiPIMS from a hafnium target in an oxygen-argon background. The effect of total pressure, oxygen partial pressure and target-substrate distance on film microstructure was investigated using X-ray diffraction (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) and scanning electron microscopy (SEM). Film microstructure was strongly dependent on total pressure, with pressures below 20 mTorr resulting in smooth (RMS roughness < 1.0 nm) amorphous films and higher pressures resulting in nanocrystalline films with the (-111) orientation parallel to the substrate surface. Growth of the HfO2 films in O2/Ar mixture was also sensitive to increases in O2 partial pressure. For oxygen/argon flow rates above 0.06, an onset of plasma instability was observed, likely caused by heating of the target due to oxide formation on its surface. This study explores the plasma conditions during deposition and their relationship to film growth. Timeresolved current measurements combined with energy-resolved mass spectroscopy and optical emission spectroscopy (OES) at the substrate are used to identify the flux of particles and their energies at the substrate surface. Time-resolved target current measurements and calculations of the heat of formations for HfO2 are applied to determine if the observed target heating is the result of runaway or surface chemical reaction. 4:30pm F2-2-10 Magnetically Enhanced Hipims, Xiubo Tian ([email protected]), J. Gao, C. Gong, Harbin Institute of Technology, China, P.K. Chu, City University of Hong Kong, China High power impulse magnetron sputtering (Hipims) has proven to be an effective tool to obtain smooth functional films. Hipims is characterized by

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Thursday Morning, April 23, 2015 CMAS compositions with and without CaSO4 were synthesized in the laboratory and their infiltration behaviours were investigated by depositing them on EB-PVD 7YSZ samples and subsequent heating at 1225 and1250°C. In addition, mass spectroscopy was applied on CaSO 4 containing CMAS and the vaporization behaviour of sulphur was studied at high temperature. XRD was applied on the molten CMAS compositions and differences in phase formation due to the presence of CaSO4 were analysed. Based on this information, it is proved that sulphur which was present in the form of anhydrite evaporates as SO3 during the high temperature heating and extra CaO adds to the CMAS composition. This CaO-enriched CMAS is found to be more destructive than the initial CMAS. Hence it can be emphasised that CaSO4 presence in CMAS has no direct effect on the infiltration, but rather an indirect effect in changing the CMAS composition.

Coatings for Use at High Temperature Room: Royal Palm 4-6 - Session A2-1 Thermal and Environmental Barrier Coatings Moderator: Kang Lee, Rolls Royce, USA, Prabhakar Mohan, Solar Turbines, USA, Kinga Unocic, ORNL, USA 8:00am A2-1-1 Elucidating the Mechanism of Bond Coat Cavitation under CMAS-infiltrated TBCs through Modeling and Experimentation, Kaylan Wessels ([email protected]), R.W. Jackson, University of California, Santa Barbara, USA, D. Konitzer, GE Aviation, USA, M. Begley, T. Pollock, C. Levi, University of California, Santa Barbara, USA Thermal barrier coatings (TBCs) are essential in advanced gas turbines that require higher operating temperatures for increased efficiency and performance. As operating temperatures rise TBCs are vulnerable to degradation by ingested siliceous contaminants; the deposits generally referred to as CMAS (calcium-magnesium-alumino-silicates) melt during engine operation and infiltrate the porous ceramic top coat, compromising its strain tolerance. The ensuing stiffening can lead to delaminations through the top coat and at the TBC/TGO interface. A recently identified mechanism that involves bond coat cavitation can also lead to spallation of the TBC with the delamination occurring entirely within the bond coat. While bond coat void formation is not a new phenomenon, the correlation between CMAS infiltration of the TBC and cavitation has not been studied previously. Examination of specimens displaying signs of this damage suggests that creep deformation of the bond coat material motivated by stresses associated with the stiffening of the TBC can lead to void nucleation, growth, and coalescence. Numerical modeling, complemented by laser gradient experiments, is used to understand the mechanism behind the degradation and the evolution of the stresses during thermal cycling and high temperature dwells.

9:20am A2-1-5 Effect of Yttria Content on the Spallation Resistance of Plasma Sprayed YSZ in the Presence of Volcanic Ash, Catalina Taltavull, W. Clyne ([email protected]), Cambridge University, UK This study concerns the effect of volcanic ash content on the microstructure, stiffness and spallation lifetime of plasma sprayed YSZ coatings. These were produced using two different YSZ powders, containing 8 mol% and 38 mol% of Y2O3, with the latter formulation being claimed to produce coatings more resistant to CMAS-induced degradation. Following previous work on the ingestion [1] of Volcanic Ash (VA) into aeroengines, and on their tendency to promote [2, 3] spallation of Thermal Barrier Coatings (TBCs), two types of Icelandic VA, from Laki and Hekla volcanoes, were deposited onto plasma sprayed YSZ, at different dosage levels. Microstructural interactions between the YSZ and the penetrating VA were studied using XRD and EDX element mapping, after heat treatment at 1500˚C for periods up to 60 h. Free-standing coatings were used to measure the Young modulus and coatings attached to alumina substrates were employed to measure spallation lifetimes (in a periodic quenching furnace). Penetration of the VA into YSZ samples accelerates the sintering and associated stiffening of these coatings, and hence promotes spallation by raising the strain energy release rate during quenching. It is clear from microstructural examination that this is the main mechanism responsible for the reduced spallation lifetime, rather than the VA reaching the interface and impairing its toughness. It was found that the yttria level did have an effect on the microstructural changes, and on the associated sintering effects, and the details of this are explained. References [1] Shinozaki, M. Roberts, K.A., van de Goor, B and T.W. Clyne, Deposition of ingested volcanic ash on surfaces in the turbine of a small jet engine. Adv. Eng. Mats., 2013. 15: p. 986-994. [2] Shinozaki, M. and T.W. Clyne, A methodology, based on sinteringinduced stiffening, for prediction of the spallation lifetime of plasma sprayed coatings. Acta Mater., 2013. 61: p.579-588. [3] Shinozaki, M. and T.W. Clyne, The effect of vermiculite on the degradation and spallation of plasma sprayed thermal barrier coatings. Surf. & Coating Techn., 2013. 216: p.172-177.

8:20am A2-1-2 Pt Effect on MCrAlY Coatings for TBC System Applications, Aurélie Rouaix-Vande Put ([email protected]), M.C. Lafont, L. Laffont, Université de Toulouse, Institut Carnot CIRIMAT, France, E. Péré, Université de Pau et des Pays de l’Adour, IPREM, France, D. Oquab, Université de Toulouse, Institut Carnot CIRIMAT, France, A. Raffaitin, Turbomeca, France, D. Monceau, Université de Toulouse, Institut Carnot CIRIMAT, France INVITED Because of their high Cr- and Al-contents and the presence of the reactive element Y, MCrAlY coatings exhibit a great resistance to high temperature corrosion and oxidation. However, they are generally not perfect aluminoformers. This constitutes a key issue for thermal barrier coating system applications for which Pt-modified β-NiAl or Pt-rich γ-Ni+γ’-Ni3Al bondcoatings are often preferred. In the aim of overperforming these laters, NiCoCrAlYTa coatings were modified by a Pt overlayer and the effect of such Pt addition was investigated. This included the study of the influence of Pt on the coating microstructure, the impact on the oxidation resistance of the bond-coating as well as on the lifetime of thermal barrier coating systems. In addition, the influence of the manufacturing (NiCoCrAlYTa and Pt deposition processes, surface preparations) was analyzed after thermal cycling tests and degradation mechanisms were proposed. Due to an extensive Al diffusion toward the external Pt-rich zone during the bondcoating heat treatment, enrichment in Al occurred in the sub-surface and martensite formed. This favored Al selective oxidation, increased the oxide scale adherence, lead to a decrease in the oxidation rate and finally resulted in longer thermal barrier coating system lifetimes. Thermal cycling tests highlighted the relevance of manufacturing dense, well interdiffused and oxide-free NiCoCrAlYTa coatings, as well as suitably smoothing NiCoCrAlYTa surfaces before and after the modification by Pt.

9:40am A2-1-6 Calcium-Magnesium-Aluminosilicate (CMAS) Interactions with Ytterbium-Silicate Environmental Barrier Coatings, F. Stolzenburg, Northwestern University, USA, K. Lee, Rolls Royce, USA, Katherine Faber ([email protected]), Northwestern University, USA Although silicon-based ceramics (i.e., SiC, Si3N4) have been identified as some of the most promising materials systems for high-temperature structural applications in engine environments, a passivating SiO2 surface layer, which forms on SiC and Si3N4 in oxygen-containing environments, becomes unstable in combustion environments, resulting in the volatilization of the silica layer and component recession. Environmental barrier coatings (EBCs) have been identified as protection from these harsh turbine environments. In this study, the interaction of two candidate EBC topcoats, Yb2Si2O7 and Yb2SiO5, with CMAS was investigated in detail using quantitative laboratory-based X-ray diffraction, scanning electron microscopy, energy dispersive X-ray spectroscopy, and selected area electron diffraction. Of particular interest was the formation of a new phase, an ytterbium-silicate oxyapatite (Ca2Yb8(SiO4)6O2) in both ytterbium silicates.

9:00am A2-1-4 Understanding the Presence of CASO4 Within CMAS and its Effect on the Infiltration Behaviour in EB-PVD 7YSZ, Ravisankar Naraparaju ([email protected]), U. Schulz, P. Mechnich, M.G. Rodriguez, DLR Institute of Materials Research, Germany Infiltration of CaO-MgO-Al2O3-SiO2 (CMAS) in TBCs is an issue of concern for the aeronautical industry. From the existing research it is known that as soon as CMAS melts it infiltrates the TBC structure, chemically attacks the TBC, changes its phase composition and ultimately leads to the spallation of the TBC. Few investigations have shown the presence of anhydrite (CaSO4) within CMAS deposits. These investigations could not provide a complete understanding of the presence and the effect of CaSO4 on CMAS induced TBCs damage in this study. A systematic approach in understanding the effect of CaSO4 in CMAS has been taken. Five different

Thursday Morning, April 23, 2015

10:00am A2-1-7 Analysis of Ex-service Parts for the Development of TBC Lifetime Prediction Models, Gregoire Witz ([email protected]), D. Renusch, M. Schaudinn, B. Bordenet, H.-P. Bossmann, Alstom ltd., Switzerland INVITED Lifetime prediction of thermal barrier coatings (TBCs) is usually performed based on laboratory tests. Due to the multilayer structure of the TBC,

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standard fatigue tests are not well suited and some specific tests are used: like furnace cyclic tests, burner rig tests or thermoshock tests. While furnace cyclic tests can bring a good understanding of the behavior of the bondcoat TBC interface, they do not allow studying the effect of the thermal gradient on the coating lifetime. Burner rig tests allow to apply a thermal gradient in the system, but are usually carried out with very harsh condition such to bring a coating failure within a reasonable time. This leads to results that bring some qualitative information, but cannot be used to derive quantitative lifetime prediction models. Additionally, some models have been derived based on the coating field experience, but due to the limited information of the coating load during engine operation, it is difficult to generalize them. In Alstom, we have developed a TBC temperature mapping tool, which allows to gain some understanding of the thermal history of the coating during engine operation. Combining it with other tests performed on ex-service parts, some insight on the TBC degradation mechanisms can be gained, leading to the possibility to develop new TBC lifetime prediction models. Some examples will be provided showing how these methodologies have been used in Alstom. This ensures that the lifetime prediction models cover the various degradation mechanisms occurring in the gas turbine, allowing to design parts with a minimized risk of TBC spallation.

11:20am A2-1-11 Stability of Rare Earth Silicates in HighTemperature High-Velocity Water Vapor, Elizabeth Opila ([email protected]), R. Golden, C. Parker, University of Virginia, USA Both dense and air-plasma sprayed yttrium- and ytterbium-mono- and disilicates were exposed in a steam-jet furnace to evaluate the thermochemical stability of these EBC candidate materials in a simulated turbine engine environment. The steam-jet environment is controlled at 1 atm water vapor pressure, temperatures between 1200 and 1400°C, and gas velocities on the order of 170 m/sec. In the steam-jet furnace, a one millimeter diameter area of the test specimen surface experiences the high velocity condition. The rare earth disilicates show surface depletion of silica to form rare earth monosilicates. Key microstructural changes include porosity development, grain refinement, and grain fallout near the steam jet impingement site. Downstream of the steam impingement, non-uniform faceting is observed, most likely due to silica depletion that varies as a function of rare earth disilicate crystallographic orientation. Cross-sectional microstructural characterization reveals that the silica depletion depth of rare earth disilicates varies, likely due to surface defects, crystallographic orientation effects, and grain fallout. The time, temperature, and initial porosity dependence of rare earth disilicate depletion will be described. Strategies for thermochemical life prediction of rare earth disilicate EBCs based on these results will be discussed. Finally, early results for rare earth monosilicate stability in the steam-jet furnace environment will also be presented.

10:40am A2-1-9 Fracture Behavior and Lifetime Performance of Thermal Barrier Coatings in Thermally Graded Mechanical Fatigue Environments, Zhe Lu, S.W. Myoung, Y.G. Jung ([email protected]), Changwon National University, Republic of Korea The effects of bond coating species on the fracture behavior and lifetime performance of thermal barrier coating (TBC) systems were investigated through thermally graded mechanical fatigue (TGMF) tests. Two types of process, air plasma spray (APS) and high-velocity oxy-fuel (HVOF), were employed to prepare the bond coats of about 300 μm thickness, and then the top coat of about 600 μm thickness was coated on the bond coats by APS process. The TGMF tests with two tensile loads of 100 and 150 MPa were performed at a surface temperature of 850 and 1100 °C for a dwell time of 10 min, till 900 cycles. When the tensile load of 100 MPa was applied at 850°C in TGMF tests, the TBC with APS bond coat showed delamination phenomena at the interface between the top and bond coats and small cracks on the surface after about 250 cycles, while the TBC with HVOF bond coat showed a long crack at the interface without delamination phenomena after 900 cycles. As the tensile load in TGMF tests was increased to 150 MPa at 850°C, delamination and/or cracks were created at about 1 30 and 280 cycles for the TBCs of the APS and HVOF bond coats, respectively. When the surface temperature was increased to 1100°C at the tensile load of 100 MPa, the TBCs of the APS and HVOF bond coats showed delamination and/or cracks at about 50 and 120 cycles, respectively. These evidences indicate that the TBC with HVOF bond coat is more efficient in improving lifetime performance than that with APS bond coat, when the thermal and mechanical stresses are applied simultaneously, indicating that the thermal stress gives a more severe effect on the thermal durability of TBC that the mechanical stress.

11:40am A2-1-12 Hybrid EBC/TBC Coatings for Si-Based Ceramics in Corrosive Environments, Satish Dixit ([email protected]), Plasma Technology Inc., USA, S. Basu, J. Xu, V. Sarin, Boston University, USA SiC/SiC ceramic matrix composites (CMCs) are being used increasingly in the hot-sections of gas turbines, especially for aerospace applications. These CMCs are subject to recession of their surface if exposed to a flow of highvelocity water vapor, and to hot-corrosion when exposed to molten alkali salts. This research involves developing a hybrid system containing an environmental barrier coating (EBC) for protection of the CMC from chemical attack and a thermal barrier coating (TBC) that allows a steep temperature gradient across it to lower the temperature of the CMC for increased lifetimes. The EBC coating is a functionally graded mullite (3Al2O3*2SiO2) deposited by chemical vapor deposition (CVD), the TBC layer is yttria-stabilized zirconia (YSZ) deposited by air plasma spray (APS). The stability of this system is investigated, which includes the adhesion between the two coating layers and the substrate, the physical and chemical stability of each layer at high temperature, and the performance under severe thermal shock and during exposure to hot corrosion. The effect of vertical cracks in the TBC on the EBC layer below it is also examined. 12:00pm A2-1-13 Fracture Mechanics Based Lifetime Assessment of Bi-Layer Thermal Barrier Coatings, Mario Rudolphi ([email protected]), MC. Galetz, M. Schütze, DECHEMAForschungsinstitut, Germany, M. Frommherz, A. Scholz, M. Oechsner, IfW, Technische Universität Darmstadt, Germany, E. Bakan, R. Vaßen, Research Centre Jülich, Germany, W. Stamm, Siemens Energy, Germany Bi-Layer thermal barrier systems made of a bottom layer of standard yttria stabilized zirconia (YSZ) and a top layer of gadolinium zirconate (GZO) offer the potential to increase the operating temperature of gas turbines or aero engines beyond the temperature limit of single layer YSZ systems. This is due to the exceeding phase stability of gadolinium zirconate at temperatures above 1200°C compared with yttria stabilized zirconia. In this work, the mechanical stability of such novel thermal barrier coating systems prepared by atmospheric plasma spraying (APS) was investigated after isothermal oxidation at 1050°C. 4-point bend testing with in-situ acoustic emission measurement served for determining the critical strain to failure of the coating, while the use of the acoustic emission technique enabled distinction of individual failure modes in the bi-layer system, such as, shear failure of the top GZO-layer, delamination along the GZO/YSZ interface, or shear failure of the bottom YSZ-layer. The measured critical strain values in combination with careful metallographic inspection were used to establish a fracture mechanics based lifetime model in form of mechanical stability diagrams. With the use of these diagrams, the failure of each individual layer can be assessed with respect to the externally applied load. The developed lifetime model enables a lifetime assessment by comparing the critical strain to failure with component loading cycles. Key Words: Bi-layer thermal barrier coatings, gadolinium zirconate, 4-point bend testing, acoustic emission.

11:00am A2-1-10 Analysis of Interfacial Crack Growth in Pre-cracked Ceramic Coating Systems under Biaxial Loading, Hélène Sapardanis ([email protected]), V. Maurel, A. Köster, V. Guipont, S. Duvinage, Ecole des Mines, France Ceramic coatings processed by thermal spraying are involved in many industrial applications such as thermal barrier coatings (TBCs), electrical insulating and anti-corrosive systems. Due to the multilayered structure of TBCs, the mismatch of coefficients of thermal expansion (CTE) between each layer generates an equi-biaxial compressive stress state during thermal cycling. Usually, service loading conditions result in both thermal and mechanical loadings which conducts to the ceramic layer failure. The equibiaxial stress state due to thermal cycling could be modified by mechanical loading varying the biaxiality stress ratio underwent by the TBC. Hence, to clarify the mechanisms of failure, the influence of bi-axial loading on crack growth is investigated. To that end, pre-cracked ceramic coatings were prepared by applying a laser shock debonding process: LASAT technique (Laser Shock Adhesion Test). The advantage of this contactless method is to easily control the size of a crack at the metal/ceramic interface. For this study, a polycristalline cobalt base alloy substrate and an alumina coating deposited by Air Plasma Spraying (APS) are considered. A coplanar biaxial fatigue machine is employed to prescribe various biaxiality stress ratios to a cruciform specimen. Top surface observation enables crack growth measurement under mechanical loading. In order to discuss the influence of biaxial loading, both uniaxial and biaxial tensile/compression tests results are compared. Finally, analysis of observed interfacial cracking enables to discuss the relevance of existing FE models. Keywords: ceramic coating, biaxial loading, crack growth, interface

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sight to blind people, dental implants, hips, knees, and more) based on biocompatible UNCD coatings.

Coatings for Biomedical and Healthcare Applications Room: Sunrise - Session D2

9:00am D2-4 In Vitro Biological Response of Rhin Hydroxyapatitecoating Titania Coatings on Ti-alloy Produced by Plasma Electrolytic Oxidation for Dental Implant Applications, WingKiu Yeung, The University of Sheffield, UK, I. Suhorukova, D. Shtansky, E.A. Levashov, National University of Science and Technology "MISIS", Russian Federation, I. Zhitnyak, N. Gloushankova, N.N. Blokhin Russian Cancer Research Center of RAMS, Russian Federation, A. Matthews, A. Yerokhin ([email protected]), The University of Sheffield, UK Plasma electrolytic oxidation (PEO) is a common method to modify surface for Ti alloy dental implants because of their process nature which is beneficial for osseointegration. However, healing time still remains a problem, therefore PEO research shifts into incorporation osteoconductive hydroxyapatite (HA) powder to improve the bioactive response of the implant. Previous work [1] demonstrated the utility of a novel two-step PEO process, wherein the Ti alloy was treated in a sodium phosphate based electrolyte with additions of HA micro-powder and nano-powder. The treatments were carried out in a pulsed bipolar current mode with both potentiostatic and galvanostatic control and have resulted a bioactive HA micro- and nano-powder being successfully incorporated into PEO titania coatings. The aim of this study is to compare the surface characteristics and biological response of HA micro- and nano-powder containing PEO titania coatings. The surface characteristics were examined by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and optical profilometry. The adhesion of coatings was measured by scratch test. The biocompatibility and bioactivity of samples in vitro was evaluated using MC3T3-E1 osteoblastic cells. To evaluate the bioactivity of surfaces, the alkaline phosphatase (ALP) activity of was measured calorimetrically at day 14. The obtained results show that coatings produced in the novel twostep PEO process are bioactive . The incorporation of HA nano-powder show to improve ALP activity by almost 2.5 times when compared to the control. [1] W.K Yeung 2013 ‘Formation of thin hydroxyapatite-containing titania coatings on cp-Ti for dental implant applications by plasma electrolytic oxidation’ presented at International Vacuum Congress IVC-19

Surface Coatings, Micro/Nano Texturing, Nanotubes, Drug Delivery, Biodegradable Implants Moderator: Sankara Narayanan, Chonbuk National University, Korea, Yifeng Liao, Argonne National Laboratory, USA 8:00am D2-1 Biofilm Formation on Stainless Steel Substrates Covered with TiO2 Thin Films, V. García-Pérez, J. Amezcua-García, Argelia Almaguer-Flores ([email protected]), S.E. Rodil Posada, Universidad Nacional Autonoma de Mexico, Mexico Microbial infection on implant surfaces has a strong influence on healing and long-term outcome. Prevention and control of biofilms can be achieved by reducing the initial bacterial adhesion on surfaces of modified metallic implants. The aim of this study was to improve the coating-substrate adhesion and to evaluate the bacterial adhesion and biofilm formation on the stainless steel (SS316L) substrates covered with TiO2 thin films. The thin films were deposited by reactive radio frequency (RF) magnetron sputtering on SS316L substrates previously treated by sandblasting and acid etch in order to obtain an average roughness of 3 µm. The characterization includes X-ray diffraction (XRD), Energy-dispersive X-ray spectroscopy (EDX) and profilometer. The adhesion of the coatings was tested by the scratch method. The biofilm formation on the surfaces at 1, 3 and 7 days was analyzed using the XTT viability assay and Confocal Laser Microscopy. The strains used in this study were Staphylococcus aureus (ATCC 25923), Staphylococcus epidermidis (ATCC 14990) and a mix of eight anaerobic strains representative of the subgingival plaque. The EDX and XRD analysis shows a surface chemistry and structural composition of amorphous-titanium oxide. Changing the deposition parameters such as temperature (100°C) we reach a film adhesion of 19 Newtons. In the biofilm formation test at 7 days of incubation, reduce levels of S. aureus and S. epidermidis were observed on the TiO2 covered surfaces (24% and 52%, respectively) compared with the SS316L substrate (38% and 59%, respectively) and the SLA surface (44% and 61%, respectively). While using the oral anaerobic bacteria the percentage of growth on the TiO2 covered surfaces, SLA and SS316L surfaces was 56%, 54% and 93%, respectively. These results suggest that TiO2 thin films could be used as biofunctional coatings on stainless steel devices reducing the probability of device-associated infections. (Supported by PAPIIT IN118914 and CONACYT 152995).

9:20am D2-5 Anodizing of AZ31 Mg Alloy in Cerium Contained Ethanol Solution, Salah Salman ([email protected]), Nagoya University, Japan; Al-Azhar University, Egypt Magnesium is the lightest structural metal currently available, with a density equal to two-thirds that of Al, one-third that of Zn and one quarter that of steel. Therefore, magnesium alloys are recognized as alternatives to Al alloys and steel in reducing the weight of structural materials. In spite of these good features, there are some major limitations of magnesium alloys due to its extremely negative equilibrium potential and poor corrosion resistance. Magnesium and its alloys are usually treated with chromate conversion coatings. However, changing environmental regulations and pollution prevention requirements have led to a significant push to find a new alternative to the use of poisonous hexavalent chromate. In this research, we investigate the anodizing of AZ31 Mg alloy in ethanol solution contains cerium nitrate. The composition and structure of the anodic films were analyzed using SEM, EDS, and XRD. The corrosion resistance was examined using salt spray corrosion test, polarization tests. The anticorrosion property was improved with the treatment and the anodic film composed of magnesium oxide and cerium oxides/hydroxides.

8:20am D2-2 Science and Technology of Multifunctional Biocompatible Ultrananocrystalline Diamond (UNCD) Coatings and Applications to a New Generation of Medical Devices and Implants, Orlando Auciello ([email protected]), University of Texas at Dallas, USA INVITED R&D of novel multifunctional nanocarbon thin films are providing the bases for new physics, new materials science and chemistry, and their impact in a new generation of multifunctional medical devices. This talk will focus on discussing a new paradigm in multifunctional novel ultrananocrystalline diamond (UNCD) thin films and integration into a new generation of medical devices and implants as described below: UNCDfilms co-developed and patented by O. Auciello and colleagues are synthesized by novel microwave plasma chemical vapor deposition and hot filament chemical vapor deposition techniques using an Ar-rich/CH4 chemistry that produces films with 2-5 nm grains, thus the name UNCD to distinguish them from nanocrystalline diamond films with 30-100 nm grains. The UNCD films exhibit a unique combination of outstanding mechanical, trtibological, electrical, thermal, and biological properties, which already resulted in industrial components and devices currently commercialized by Advanced Diamond Technologies (a company cofounded by O. Auciello and colleagues in 2003). Devices and systems reviewed include: a) UNCD-coated mechanical pump seals, providing up to 20% energy cost saving via friction reduction, for the petrochemical, pharmaceutical and car industries (shipping to market); b) UNCD-coated bearings for mixers for the pharmaceutical industry (shipping to MerckMillipore market); c) new electrically conductive UNCD-coated metal electrodes for water purification system, which outperform all other electrodes in the market today (shipping to market); d) UNCD-based MEMS energy harvesting devices, biosensors and drug delivery MEMS devices; e) New generation of Li-ion batteries batteries with ≥ 10x longer life and reduced size, using UNCD-based coatings technology for new anodes, membranes and inner wall battery case chemically resistant coating; f) new generation of medical devices (e.g., artificial retina to restore partial

Thursday Morning, April 23, 2015

9:40am D2-6 Antimicrobial Nanostructured Alloys for Tattoo Machines, Emily M. Hunt, B. Allen ([email protected]), T. Kelly, West Texas A&M University, USA In the last decade, the tattoo industry has grown considerably and considerations for public health and safety have come to the forefront of this profitable market. Despite considerable research and development efforts, the problem of contaminations related to biomedical devices persists. Traditional cleaning methods, such as aerosolized disinfectant sprays or wipes have a limited effectiveness and timescale. These products attempt to eliminate the bacteria after it has been established on the surface. There is a strong need to mitigate bacterial colonization by engendering materials with properties that include surface chemistry and roughness which are unfavorable for bacterial attachment and growth. Recently, the authors created a novel, antimicrobial nanostructured alloy (ANA) coating that can be applied to a surface for prevention of bacteria. This coating is unique in its structure and efficacy and can be applied to existing surfaces to prevent the growth and spread of bacteria. This study examined the application of the ANA coating using the electroplating method for tattoo machines. Experiments were performed to evaluate the antibacterial efficacy and thickness of the plated coatings. Results show that the electroplated coating is effective at eliminated bacteria on the surface as

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well as preventing future growth. The kill curves formed from the cell plate counts show that there was a significant decrease in viable cell counts after 30 minutes of exposure to the coating. As the time of exposure increased, the number of viable cells in the solution decreased rapidly until there were no viable bacteria cells after 1.5 hours. The control samples showed significant bacteria and colonization as well as run-away spore formation for the same time sales. In addition to being antibacterial, the electroplated coating exhibited advanced mechanical and thermal properties such as hardness, abrasion resistance, and high-temperature performance that increase its viability as a commercial coating.

lead to a shift away from the ultra-low wear mode and subsequently the type and size of wear particle generated. In-vitro and in-vivo biological testing singled out biological events that lead to massive cell necrosis dependent on the particle type. Although it is too late to reverse the events that led to the massive implant failure, this example can inspire to design surfaces that not only minimize wear in biomedical bearing applications, but also control the wear particle type so as to prevent adverse tissue reactions. 11:00am D2-10 The Influence of the MAO Coating on the Biocompatibility Properties for NiTi Alloy, Suleyman Sukuroglu ([email protected]), Gümüşhane University, Turkey, Y. Totik, E. Arslan, E.E. Sukuroglu, I. Efeoglu, Atatürk University, Turkey By using micro-arc oxidation method (MAO) the structural and morphological properties of the oxide layer that grown on NiTi alloy determined by x-ray diffraction, EDS and scanning electron microscopy in order to examine the mechanical properties such as adhesion and hardness. The biocompatibility tests of oxide layer with suitable properties obtained by Taguchi optimisation method of expansion parameters performed. The results showed that the possible harmful effects of NiTi alloy for the body removed. The results also showed that MAO coatings on NiTi substrates increased the biocompatibility by acting as a barrier layer.

10:00am D2-7 HiPIMS Titanium Coatings on PEEK for Medical Applications, Kerstin Thorwarth ([email protected]), Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland, G. Thorwarth, DePuy Synthes, Switzerland, P. Barker, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland, C. Voisard, M. Kraft, DePuy Synthes, Switzerland, J. Patscheider, Empa, Swiss Federal Laboratories for Materials Science and Technology, Switzerland PEEK (Polyetheretherketone) is a chemically and mechanically stable material for orthopaedic applications best suited as a bone replacement material. Yet, the integration of unconditioned PEEK surfaces is inferior to other implant materials like titanium [1]. Therefore, titanium coatings on PEEK are well established on the market by means of titanium plasma spray processes (VPS, APS). However, such thick coatings (30-800 microns) lead to a loss of topographical features favorable for primary implant stability and exact placing of the implant. Furthermore, plasma spray processes are only feasible for coating the outer faces of implants; as they cannot reach recessed surfaces, they potentially cause fibrous encapsulation. To enhance the osseointegration of PEEK medical implants - especially for spinal fusion cages - the chopped HiPIMS process is used to prepare Ti coatings, as standard PVD processes do not provide adequate adhesion of the titanium coating to the PEEK surface. This cost effective coating method with superior adhesion values allows for excellent replication of the surface structure due to the low thickness of the Ti coatings. High adhesion strength values (>30 MPa) can be obtained, including penetration into narrow trenches and to surfaces with a high inclination towards the sputter target. Finite element simulations are used to illustrate that standard adhesion testing according to ASTM D4541 is not applicable to polymer substrates, as strong deformations of the soft substrates during the tests lead to incorrect adhesion strength values. XPS and ToF-SIMS measurements confirm film qualities compliant to surgical grade II Titanium (ISO 5832-2). [1] J.J. Schimmel et al. J Spinal Disord Tech 2012. http://dx.doi.org/ 0.1097/BSD.0b013e31826eaf74. [aheadofprint]

Tribology and Mechanical Behavior of Coatings and Engineered Surfaces Room: San Diego - Session E1-1 Friction, Wear, Lubrication Effects, and Modeling Moderator: Michael Chandross, Sandia National Laboratories, USA, Giovanni Ramirez, Argonne National Laboratory, USA 8:00am E1-1-1 Friction Modification of Surfaces using Graphene and Graphene Composite Materials, James Batteas ([email protected]), B. Ewers, J. Spear, Texas A&M University, USA INVITED from medical implants, to engines, to micro- and nano-scaled machine technologies. A ubiquitous challenge in many of these applications is how to control the wear that occurs in sliding contacts, which are dominated by the interactions between nanoscaled surface asperities, where the high pressures and shear forces that are experienced can result in increased friction and ultimately lead to device failure. Obtaining an atomic/molecular scale understanding of the interactions and energy dissipation mechanisms in asperity-asperity contacts at such interfaces is paramount for the rational design of new materials or lubrication schemes. Here we have developed a model platform to investigate true nanoscaled asperity-asperity contacts using silica nanoparticles deposited on a Si support to form surfaces with asperities of controlled radius of curvature (ca. 5 – 20 nm), matching those found in most machined interfaces. Friction, adhesion and wear at these surfaces have been explored using atomic force microscopy (AFM) where the AFM tip, acting as a single mobile asperity, allows us to probe asperityasperity contacts. Molecular adlayers on silica, such as self-assembled monolayers (SAMs) can dramatically reduce friction in such interfaces, however they can be easily damaged during impact and shear. When examining such molecular adlayers on rough surfaces, it has been found that nanoscale surface roughness impacts both the formation and quality of the SAMs, as compared to those formed on atomically smooth surfaces, impacting overall film stability. Using a combination of AFM, IR spectroscopy and molecular dynamics (MD) simulations, we have explored how the interplay of high pressure, surface curvature and molecular forces come together to control friction at the atomic/molecular level in such asperity-asperity silica contacts. New approaches for friction modification of interfaces including the deposition of single and few-layer graphene and graphene-SAM composites have also been examined using AFM and Raman microspectroscopy and will be described. Here, tuning the surface roughness and chemical composition has been observed to modulate surface friction by altering the interactions between the graphene and the surfaces in sliding contact and suggests mechanisms by which this can be controlled.

10:20am D2-8 Wear Particles in Hip Replacements – Can We Make them Behave?, Robin Pourzal ([email protected]), Rush University Medical Center, USA INVITED Most technical bearings undergo wear. Usually it is the goal of engineers to enable ultra-low wearing conditions. Accordingly the wear particle size has to be sufficiently small to maintain low wearing conditions by avoiding the introduction of three-body wear. For biomedical applications the bioreactivity of wear particles adds an additional complication. As such, total hip and knee replacements have been the subject of tribological research for over 60 years. The most common material couple has been metal vs. polyethylene. For some time there has been great concern about biological cascades triggered by wear particles which lead to bone degradation (osteolysis). One of the alternatives has been metal-on-metal (MoM) articulations where both sliding partners are made from CoCrMo alloy. MoM hips exhibited initially promising clinical results linked to ultra-low wear rates. Particle analysis has shown that the majority of wear particles had a size in the nanometer range. In depth retrieval analysis has demonstrated that strain induced phase transformation enables the formation of a nanocrystalline subsurface zone. This zone could be identified as the location of nano-particle detachment. Furthermore, the formation of a carbonaceous tribofilm can be observed on the surface of many implant retrievals. This film adheres strongly to the surface and gets locally incorporated into the nanocrystalline surface by mechanical mixing. The formation of the film is the result of mechanical decomposition of joint fluid constituents, mainly protein, under load as well as complex interactions with the metal surface. Such tribofilm was shown to reduce friction as well as increase corrosion resistance. Despite the ability of CoCrMo alloy to operate under ultra-low wearing conditions, the orthopedic industry has been recently shaken by a large number of early implant failures of some MoM devices. The most common diagnosis is adverse local tissue reactions to metal debris. The occurrence of this problem cannot be attributed to a single factor, but rather the combination of several. It appears that certain changes in implant design

8:40am E1-1-3 Alignment and Wear Debris Effects Between Laserpatterned Steel Surfaces under Dry Sliding Conditions, Andreas Rosenkranz ([email protected]), L. Reinert, C. Gachot, F. Mücklich, Saarland University, Germany In this experimental study periodic line-like patterns with different periodicities (5, 9 and 18 µm) were fabricated by laser-interference patterning on stainless steel samples (AISI-304) and on 100 Cr 6 steel balls.

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Linearly reciprocating dry sliding tests with a ball-on-disk configuration were performed on patterned pairs and on patterned-substrate/unpatternedball pairs. Alignment effects were studied by means of a newly developed positioning method, which ensures an optimal alignment. The number of cycles was set to 200 and 20.000 to study the run-in and stability behaviour of the patterned surfaces, all of which exhibited a lower kinetic coefficient of friction than the unpatterned reference. Depending on the respective alignment, different friction and wear mechanisms can be distinguished. Differences in the real contact area, the possibility to store wear particles and the time needed to remove the native or laser-induced oxide layer can be well correlated with the temporal evolution of the coefficient of friction.

machined surface quality is hence identified at all scales from roughness to waviness. Results demonstrate the tribological effect of contact stiffness on NFRP surface finish and interfaces behaviors after profile milling process. 10:00am E1-1-7 Back from Space: Results from the Materials on the International Space Station Experiments (MISSE) Tribometers, Brandon Krick ([email protected]), Lehigh University, USA, WG. Sawyer, University of Florida, USA INVITED Satellites and other moving mechanical assemblies in the space environment have numerous mission-critical sliding interfaces. Low ambient pressures, ultraviolet radiation, atomic oxygen and hot and cold thermal extremes are critical aspects of the low earth orbit (LEO) space environment that collude to make traditional lubrication strategies difficult. As such there is an applied need to develop materials for viable lubrication and test these materials in the actual space environment. This opportunity was presented with the Materials on the International Space Station Experiments (MISSE) program. Eight pin-on-disk tribometers were delivered to the International Space Station in November 2009 to evaluate candidate space materials. They were exposed directly to the extreme conditions of Low Earth Orbit (LEO), including atomic oxygen, ultrahigh vacuum, radiation (including UV radiation), microgravity, micrometeoroids and thermal ranges from -40°C to 60°C. The experiments were returned from the space station to earth in May 2011 where postflight analysis began. As expected, these conditions proved extremely harsh on candidate space lubricant materials and coatings, including MoS2/Sb2O3/Au, MoS2/Sb2O3/C, YSZ/Au/MoS2/C, SiOx doped DLC, PTFE/alumina nanocomposite and gold. This research presents the effects of the LEO environment on the composition and tribological performance of resulting from the MISSE space tribometer experiments.

9:00am E1-1-4 A Universal Model for the Load-Displacement Relation in an Elastic Coated Spherical Contact, R. Goltsberg, Izhak Etsion ([email protected]), Technion, Israel A finite element analysis was used in order to investigate the elastic contact of a coated sphere compressed by a rigid flat. Different coating and substrate geometrical and mechanical properties were analyzed to obtain a universal dimensionless model for the load–displacement relation. Both hard and soft coatings were considered. Dimensionless parameters, which control the behavior of the elastically loaded coated sphere, were identified. A proper normalization of the dimensional load and displacement was found resulting in a universal model. This model also provides a universal expression for the effective modulus of elasticity that is based only on mechanical properties of the coating and the substrate. 9:20am E1-1-5 Modeling the Effect of Substrate on Load Bearing Capacity of Thin Hard Coatings, C.T. Wang, Nanjing University of Science & Technology, China, Timo J. Hakala ([email protected]), A. Laukkanen, H. Ronkainen, K. Holmberg, VTT Technical Research Centre of Finland, Finland, N. Gao, R. Wood, T. Langdon, University of Southampton, UK Load carrying properties of titanium nitride (TiN) and diamond-like carbon (DLC-7Zr) coatings were studied by scratch testing and by threedimensional finite element modelling. TiN and DLC coatings were deposited on titanium substrates without and with high-pressure torsion (HPT) processing. The high-pressure torsion process decreased the grain size of titanium from 8.6 µm to 130 nm and increased the hardness from 1.83 GPa to 3.05 GPa. The scratch tests were carried out with a spherical diamond tip sliding on a coated flat surface with increasing normal load. The contact was modelled with three-dimensional finite element method (3D FEM) and the generated stresses on and below the surface were simulated at the location where first principal cracks were formed . In the model, the diamond tip was considered as elastic and the coating behaved in an elastic-plastic manner. The scratch test results revealed that both TiN and DLC coatings had a higher critical load on HTP-processed titanium compared to those on the titanium substrates without HTP processing. The increased load-carrying property of hard coatings on harder titanium substrates is related to generated stresses inside the substrate and its deformation behaviour. The harder substrate carries greater stresses compared to the softer substrate which experiences more elastic and plastic deformations. The deformation of the substrate generates strain between the coating and the substrate which is most notable in the perpendicular direction to the scratch direction.

10:40am E1-1-9 Friction and Lubrication Contribution of Microscale Surface Roughness to Gear Contact Noise, Simon Jolivet ([email protected]), S. Mezghani, J. Isselin, A. Giraudeau, M. El Mansori, Arts et Métiers ParisTech, MSMP, France, H. Zahouani, LTDS Ecole Centrale de Lyon, France The contribution of the micro-scale roughness of the engineered surface tooth flanks, even though it is essential in the fundamental mechanics of gear contact, has not yet been well understood. This paper covers the study of the simultaneous effect of micro-finish tooth flank surface and lubricant on vibratory and wear behavior of gears contacts. Different gears were hence manufactured with using three industrial finishing processes (shaving, grinding and power-honing) while having the same macro-scale characteristics. Then, experimental tests of the vibration performances of the gears were carried out on an instrumented single-stage low power rig in both dry and wet conditions using two lubricants viscosities. Furthermore, a new non-destructive sensory measurement technique was developed to characterize the interfacial thin layer of the tooth flank surface at various length scales from micro to macro wavelength. Results show the ability of this new method to rate the contribution of the tooth flank asperities during the meshing of the teeth on the gear in terms of induced vibration responses and wear performances. 11:00am E1-1-10 Experimental Investigation on Lubrication Effect of Liquid Nitrogen Under Sliding Wear Conditions, S. Josyula, R. Gunda, Sureshkumarreddy Narala ([email protected]), BITSPilani, Hyderabad Campus, India Recent studies reveal that the liquid nitrogen (LN2) possesses a microhydrostatic lubrication effect owing to its lower friction and wear values when compared to dry environment. However, it is still uncertain whether the lubrication effect is responsible for reduction in friction coefficient or by its cooling effect at the contact interface. In order to ascertain the effect of LN2 as lubricant under tribological conditions, in this research work sliding wear tests are conducted on Al-TiC composite to characterize the friction coefficient, wear rate and heat transfer under a range of sliding velocities and loads. A customized setup has been proposed to supply the LN2 into sliding contact with a restricted flow rate and pressure for better cooling and lubrication. Comparative studies have been carried out between LN2, cryogenic compressed air cooling and dry environment. The results indicate that the presence of LN2 in sliding contact offers significant reduction in friction and wear values when compared to other environments. The positive results with LN2 could be due to the hydraulic pressure of trapped LN2 into the sliding contact which takes away a part of normal load resulted in reduced friction coefficient and wear rate.

9:40am E1-1-6 Experimental Study of Coatings and Interfaces in Dry Cutting of Natural Fiber Reinforced Plastics, Faissal Chegdani ([email protected]), S. Mezghani, A. Mkaddem, M. El Mansori, Arts et Métiers ParisTech, MSMP Laboratory, France Natural fiber reinforced plastics (NFRP) constitute a real challenge for academia and industry since they are becoming a viable alternative to synthetic fiber ones in many industrial applications which not require high structural performances. Machining of NFRP such as milling process is still practically an unavoidable operation to facilitate the parts assembly in addition to the finishing of final products. Unfortunately, the effect of tool surface, while had a significant impact on the tribological performance during machining had not yet studied. This work aims to investigate tool coating effect on NFRP surface finish and tool wear during profile milling process with particular emphasis on shearing mechanisms efficiency. The cutting experiments were carried out on two NFRP specimens with treated and untreated flax fibers using three different cutting tools. Uncoated carbide monograin (MG10), titanium diboride coated (TiB2) and diamond coated (Dia) were used to conduct profile milling tests. Cutting forces, cutting temperatures, and tool wear were measured during each test. Interfaces states and surface topography of both the insert and NFRP surfaces after machining process were acquired by Scanning Electronic Microscope (SEM) and White Light Interferometry (WLI). Machined NFRP surface finish is characterized using a multi-scale analysis based on wavelets decomposition. The tool coating signature on the

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11:20am E1-1-11 Micro-Abrasive Wear Resistance of CoB/Co2B Coatings Formed in CoCrMo Alloy, G.A. Rodríguez-Castro ([email protected]), CesárDavid Reséndiz-Calderón, L.F. JiménezTinoco, A. Meneses-Amador, E.A. Gallardo-Hernández, I.E. Campos-Silva, Instituto Politecnico Nacional, Mexico In this work, the micro-scale abrasion wear resistance of CoB/Co2B coating was evaluated by ball cratering test. The coating was formed on the surface of a CoCrMo alloy using the powder-pack boriding method. The boriding process was carried out at 1173 K during 6 h of treatment resulting in the formation of CoB/Co2B phases with a total thickness of 23 µm, approximately. The hardness–depth profile was obtained by Berkovich depth-sensing indentation across the boride layer using a load of 50 mN. The wear rate in the boride phases on CoCrMo alloy was evaluated by a Plint TE-66 micro-scale abrasion tester using SiC particles in distilled water as abrasive slurry. Different duration tests were performed in order to analyze the wear evolution. The cobalt boride improved wear resistance of CoCrMo alloy. Furthermore, a wear-mode map was developed to identify the two and three body abrasion regimens (grooving and rolling) and the mix wear zone.

Recently, high power impulse magnetron sputtering (HIPIMS) was reported to be the novel technique which combines high degree of ionization of the deposition flux as well as absence of micro-particles. In this work we report on the synthesis and properties of Al-Cr-O wear protective coatings for cutting tool applications by using S3p™ in an industrial deposition plant. S3p™ technology enables scalability of the pulse power density and pulse length in a wide range and expands significantly the choice of the deposition parameters and process stability as compared to conventional HIPIMS. Al-Cr-O coatings have been produced using AlxCr1-x targets, where x was varied from 0.5 to 1. The deposition process is discussed with respect to the special features for deposition of oxide layers. Advantages of S3p™ technology are emphasised. Crystal structure, morphology as well as hardness and elastic modulus of the coatings studied as a function of the coating composition. 8:40am F4-1-3 Optical Characterization of Amorphous Tungsten Oxynitride Thin Films Made by DC Sputtering, Chintalapalle Ramana ([email protected]), M. Vargas, E. Rubio, A. Tarango, University of Texas at El Paso, USA, B. Fletcher, University of California, Santa Barbara, USA, N. Murphy, Air Force Research Laboratory, USA Tungsten oxide (WO3), one among the transition metal oxides, is a wide band gap semiconductor with excellent physical, chemical and electronic properties. Recently, cation and anion doping of WO3 is gaining significant attention in order to design materials suitable for application in solar energy conversion, photo-catalysis, transparent electrodes, electrochromics, and flat panel displays in optoelectronics. This work was performed to understand the effect of variable nitrogen flow rate on the optical properties of amorphous W oxynitrides. Tungsten oxy-nitride films were deposited onto silicon and quartz substrates using direct current (DC) sputtering. A tungsten metal target of 99.99% purity and a 2 in. diameter was used in the sputtering process. All of the samples were deposited at room temperature (T=25 °C). The sputtering was carried until a film thickness of ~100 nm was obtained. All the films were amorphous. Nitrogen concentration was varied by varying the nitrogen gas flow rate from 0 to 20 sccm while keeping the total gas flow constant at 40 sccm. The optical properties, evaluated using spectrophotometry and ellipsometry measurements, indicate that the optical parameters, namely transparency, band gap and index of refraction are highly dependent on the nitrogen content in the reactive gas mixture. Films grown without any nitrogen exhibit a band gap of 3.2 eV, which corresponds to WO3. The band gap decreases continuously with increasing nitrogen content in the reactive gas mixture. Analyses indicate band gap reduction and/or tuning by 1 eV by varying the nitrogen gas flow from 0 to 20 sccm, balancing oxygen. Ellipsometry results will be presented alongside the spectrophotometric measurements to demonstrate that the controlled nitrogen doping allows tuning the optical properties of amorphous W-O-N films.

New Horizons in Coatings and Thin Films Room: California - Session F4-1 Functional Oxide and Oxynitride Coatings Moderator: Jürgen Ramm, Oerlikon Balzers, Oerlikon Surface Solutions AG, Liechtenstein, Michael Stüber, Karlsruhe Institute of Technology (KIT), Germany 8:00am F4-1-1 Surface Wettability Partitioning Between Chromium Oxide and Chromium Nitride Thin Films with Potential Industrial Wettability Gradient Applications, A. Ogwu ([email protected]), University of the West of Scotland, UK, John Kavanagh, University of Sheffield, UK, S. Urrahman, M. Oje, University of the West of Scotland, UK, A. Matthews, A. Leyland, University of Sheffield, UK We report an investigation into the origin of the hydrophilic/hydrophobic switch from chromium oxide to chromium nitride thin films in contact with water. The presence of surface entities and bonds in the films that are responsible for the switch from hydrophilic to hydrophobic behaviour is probed with Raman spectroscopy, FTIR and X-ray photoelectron spectroscopy (XPS) including XPS satellite peaks. The role of the surface energy is further probed through the dispersive, polar and acid-base components of the films using the Owens-Wendt (OW) and the Van OssChaudhury-Good (VOCG) methods. Kelvin probe investigations of the role of the surface entities on surface energy changes in the films are carried out through contact potential difference (CPD) measurements and evaluation of electron affinity changes. Electrochemical corrosion investigation in saline solution involving open circuit potential, Tafel plots and Potentiodynamic polarization indicates superior corrosion resistance by the chromium oxide phase compared with chromium nitride. Our investigations show the potential to use combined chromium oxide/nitride layers in aggressive environments for wettability gradient force generation applications. Potential application areas include Lab-on-a-chip, biotechnology, biomaterials and reduced gravity space experiments, when an appropriate plasma treatment is used to create combined chromium oxide/nitride layers.

9:00am F4-1-4 Structure-Property Relations in Reactively Sputtered Molybdenum Oxide Thin Films, Julia Pachlhofer ([email protected]), C. Jachs, R. Franz, Montanuniversität Leoben, Austria, E. Franzke, J. Winkler, PLANSEE SE, Austria, C. Mitterer, Montanuniversität Leoben, Austria Oxide-based thin film materials are widely used in optical and electronic applications due to their unique properties, e.g. transmittance, refractive index, electrical resistivity and chemical stability. The range of materials used includes transparent conducting oxides, dielectrics, diffusion barriers, and optical filter materials. With changes in stoichiometry or by alloying or doping the base materials, it is possible to tune the material properties to the desired level. The current work aims to explore structure and properties of molybdenum oxide thin films as various phases exist in the Mo-O system, potentially enabling to tune thin film properties. Molybdenum oxide thin films were deposited by reactive dc magnetron sputtering from a molybdenum target on Si (100) and window glass. By varying the gas flows during deposition, the argon/oxygen ratio was changed from pure argon to pure oxygen. The total flow and the total pressure were kept constant at 40 sccm and at 0.5 Pa, respectively. The film growth rate decreased from 90 to 7 nm/min with increasing oxygen partial pressure. The optical appearance of the as-deposited films varied from metallic to transparent, which correlated well with the oxygen content changing from 35 up to 68 at.%. A detailed structural characterisation was done by X-ray diffraction and Raman spectroscopy. The dominating phases were MoO2, different polymorphs of Mo4O11 and α–MoO3, depending on the oxygen content in the film. Mechanical properties like hardness, Young’s modulus and residual stresses as well as electrical conductivity and optical properties like transmittance and reflectance also show a dependence on the oxygen content. In conclusion, structure and properties of the deposited molybdenum oxide thin films are tuneable by adjusting the argon/oxygen ratio in the background gas during deposition; these thin

8:20am F4-1-2 Al-Cr-O Coatings Deposited by S3p™, Denis Kurapov ([email protected]), S. Krassnitzer, T. Bachmann, J. Hagmann, W. Kalss, M. Arndt, Oerlikon Balzers, Oerlikon Surface Solutions AG, Liechtenstein, H. Rudigier, Oerlikon Balzers Coating AG, Liechtenstein During the last years the Al-Cr-O coatings are getting more important for cutting tool applications. Beside chemical vapour deposition (CVD) which requests deposition temperatures above 1000°C, physical vapour deposition (PVD) can be deployed for coating production at reduced temperature below 600°C. The most used PVD techniques are reactive arc evaporation and magnetron sputtering. Although, the arc evaporation method enables a stable coating process with a high degree of ionisation of the deposition flux, macro-particle incorporation into the growing film might reduce the coating quality and cutting performance. Utilization of magnetron sputtering improves coating quality with respect to the number of incorporated defects. However complicated and cost intensive regulation methods have to be used during magnetron sputtering in order to enable a stable production process for oxide coatings. Additionally, a low degree of ionization of the deposition flux might result in deteriorating wear resistance of the coating.

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films are, hence, promising materials for a wide variety of optical and electronic applications.

electronegativity of metal atoms in the film is of key importance for its hydrophobicity.

9:20am F4-1-5 Phase Stability of Transition Metal Aluminium Oxynitride Coatings, Moritz to Baben ([email protected]), K.P. Shaha, M. Hans, P.K. Gokuldoss, Y.T. Chen, J.M. Schneider, RWTH Aachen University, Germany INVITED Using oxygen as alloying element in transition metal aluminum nitride coatings has recently attracted significant attention [1-4]. In this talk, it is shown that oxygen incorporation on nitrogen lattice sites leads to metal vacancy formation in the transition metal oxynitride, irrespective of whether the deposition was done by cathodic arc or high power pulsed magnetron sputtering [3,4]. Similar vacancy formation has been observed in the Al-SiN system by metal doping [5]. Additionally, the impact of oxygen addition and metal vacancies on elastic properties will be discussed based on comparative ab initio and experimental data. Furthermore, initial experimental data on the composition dependence of the thermal stability will be presented. [1]: Stueber et al., Thin Solid Films 519 (2011) 4025. [2]: Khatibi et al., Acta Mater. 60 (2012) 6494. [3]: Shaha et al., Appl. Phys. Let. 103 (2013) 221905. [4]: Hans et al., J. Appl. Phys. 116 (2014) 093515. [5]: Pignedoli et al., Appl. Phys. Lett. 96 (2010) 071908.

Applications, Manufacturing, and Equipment Room: Golden West - Session G2-1 Advances in Deposition Eqiuipment and Processes Moderator: Mats Ahlgren, Sandvik Coromant, Sweden, Ladislav Bardos, Uppsala University, Sweden 8:00am G2-1-1 An Overview of Available PVD and PACVD Technologies for Specific Tool and Tribological Applications, M. Eerden ([email protected]), G. Negrea, I. Kolev, R. Jacobs, G. Fransen, Dave Doerwald, R. Tietema, IHI Hauzer Techno Coating B.V., Netherlands Over the last 30 years, many different PVD and PACVD technologies have been developed for general or specific tool and tribological applications. These technologies can all be incorporated and combined in the Hauzer Flexicoat equipment. In the presentation, an overview of available technologies, like Circular Arc CARC+, Dual Magnetron Sputtering and Microwave Assisted Chemical Vapour Deposition will be shown. Results in tool applications, like cutting of hardened steels, aluminium and carbon fiber reinforced plastics and tribological applications like valve train components will be presented as well.

10:00am F4-1-7 Formation of Duplex Oxide Layers on the Ti-13Nb13Zr Alloy, Agnieszka Ossowska ([email protected]), A. Zielinski, Gdansk University of Technology, Poland, D. Scharnweber, R. Beutner, Technische Universität Dresden, Germany The paper presents results of research of duplex oxide layers obtained on the Ti-13Nb13-Zr alloy. The d ouble layers were prepared in two steps by two different methods. The f irst method used the gas oxidation process to achieve thin oxide layer on which nanotubes were produced by an electrochemical method . In the second method, based on the fully electrochemical production of oxide layers, on the amorphous titanium layer the nanotube layer was formed . The gas oxidation process was conducted at air atmosphere, using three different temperatures of 700, 900 and 1100°C (1292, 1652, 2012°F ) during 5h . The electrochemical oxidation was achieved in the 1M H3PO4 ( orthophosphoric acid ) and 1 M H3PO4 with the addition of HF ( hydrofluoric acid ) over 0.5 h, at constant current values of 20V and 40V . The SEM ( Scanning Electron Microscope ), EDX (Energy Dispersive X - ray Spectroscopy), chemical analysis, AFM (Atomic Force Microscopy ), Raman Spectroscopy, and potentiokinetic corrosion tests at different pH studies were used to examine the oxide layers. The obtained results show the possibility of producing duplex layers on titanium alloy Ti- 13Nb - 13Zr. Electrochemical formation of nanotubular layer as a second one, is possible only to a specific thickness of the first layer. The different colonies of nanotubes are observed. The obtained results indicate significant decrease of the corrosion resistance of titanium alloy Ti13 -Nb- 13Zr following the appearance of duplex oxide layers on the surface of titanium alloy.

8:20am G2-1-2 HiPIMS Equipment for Dedicated Coatings for Indexable Inserts, Christoph Schiffers ([email protected]), T. Leyendecker, O. Lemmer, W. Kölker, CemeCon AG, Germany Indexable inserts represent about 60% of the worldwide cutting tool market. PVD coatings dominate the insert market for milling and threading applications. This paper will discuss how HiPIMS coating equipment raises insert coatings to the next level with regard to coating adhesion, film thickness distribution and morphology of the deposited material. Special focus will be given to integrating and fine tuning the preparation of the cutting edge and the surface of the inserts prior to the deposition with the HiPIMS process. Key to using HiPIMS for industrial cutting tools is an equipment design that delivers the pulse energy directly into the plasma. Process data show how the door assembly machine design which avoids any cable between the HiPIMS unit and the cathode gives the system’s user the full control of the various parameters of the HiPIMS discharge. Field data illustrate how this integrated approach unleashes the full performance of the HiPIMS technology for cutting tools. 8:40am G2-1-3 Advanced Coatings for Aerospace and Defense Applications, Keith O. Legg ([email protected]), Corrdesa LLC, USA INVITED The most widely used aerospace and defense coatings have have remained unchanged for many years, in large part because the coatings that we use work reasonably well, but also because of the high cost and complexity of making changes. However, the coatings used in aerospace and defense coatings are now changing quite rapidly, driven by a combination of new structural materials, the need for improved performance, and regulatory requirements to reduce or eliminate toxic materials. The speed of these changes is in turn requiring more efficient ways of testing, qualifying and moving them into production, including computational design and analysis. We will discuss the various drivers for coating replacement, the choices that users are making, and the technology gaps. We will discuss the broad range of aerospace and defense coatings, where vacuum coatings fit in this market, and what drives their adoption or rejection. We will also discuss how the development and qualification of new materials is being affected by advances in fundamental understanding and computational methods. All of this may be opening up new markets for greatly improved coating methods, but their acceptance requires a great deal more than simply newer, better technology. We will therefore also discuss what it takes to get these new technologies into use and where potential applications might be.

10:20am F4-1-8 Hydrophobicity of Thin Films of Compounds of LowElectronegativity Metals, Sergei Zenkin ([email protected]), S. Kos, J. Musil, University of West Bohemia, Czech Republic Oxide and nitride films of various low-electronegativity metals were prepared by dc reactive magnetron sputtering in an Ar+O 2 or Ar+N2 gas mixture. Hydrophobic (the water droplet contact angle (WDCA) and surface free energy) and mechanical (the hardness H, effective Young’s modulus E* and elastic recovery We) properties were investigated in detail. The hydrophobicity of the sputtered films was measured by the sessile drop method with polar and non-polar testing liquids. These tests demonstrated that the surfaces of all sputtered nitride and oxide films of lowelectronegativity metals (unlike those of most metals) are of non-polar nature. The van Oss-Good-Chaudhury approach, based on the Lifshitz-van der Waals/acid-base theory, was selected for the calculation of the film surface free energy. It was found that: (1) All studied nitride and oxide films of low-electronegativity metals are hydrophobic with WDCA’s ranging from 94o to 105o, i.e. the obtained WDCA’s are comparable with those achieved for fluoropolymers, (2) The nitrides of low-electronegativity metals exhibit greater WDCA’s than the corresponding oxides, which is explained by the difference in the electronic structure of the oxygen and nitrogen anions and a different number of bonds of these anions with water molecules . (3) The hardness H of the nitride and oxide films of lowelectronegativity metals ranges from 8 GPa to 18 GPa, and (4) The hydrophobic properties of nitride and oxide films of low-electronegativity metals do not depend on the electronic structure of the metal cations. The main result of our investigation is the finding that the low value of

Thursday Morning, April 23, 2015

9:20am G2-1-5 Development of Rod Type Carbon Arc Source and Application for DLC Coating, S. Hirota, H. Fujii, J. Munemasa, S. Tanifuji, Koichiro Akari ([email protected]), Kobe Steel Ltd., Japan Among the deposition process for DLC(diamond like carbon), cathodic arc process has become a popular process and has been used especially for depositing ta-C films on many kinds of automotive components. But in the arc discharge of carbon target, arc spot movement is slower than other metal

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targets and the discharge is not even on the target surface. So the production scale equipment has still problem about the stability of carbon arc source. To improve this problem, new arc source for carbon discharge was developed. The feature of this new source are rod type carbon target with strong magnetic field and automatic feed mechanism of target. This new source showed the stable arc discharge on the whole area of target evenly because of faster movement of arc spot and longtime operation was confirmed using feed mechanism of target. As an application of this carbon arc source, the properties of DLC coating using this source were examined at several coating conditions and the synthesis of ta-C film with the hardness up to 90GPa and smoother surface was confirmed.

specific layer thickness (0.3 to 1 mm) depended on the energy input. The graphite was eliminated in the layer transformed by the EB, and complete coverage with PVD coatings could be achieved. In the case of Al alloys, the EB alloying was carried out using Co-based additives. The hardness of the layers could be increased up to 400 HV0.1, with thicknesses between 0.5 and 1.0 mm. Comparative studies of single (PVD hard coating of base materials) and duplex technologies (EB surface treatment with subsequent PVD hard coating) were carried out. The different load capacities resulting from the surface treatments were investigated, and the hardness, friction behavior, and wear behavior (ball-on-flat test) were measured. Apart from the influence of the EB layer configurations, the effect of different PVD coatings (TiN, TiAlN, TiCN) was taken into consideration. Special attention was focused on the influence of the temperature-time cycles during the subsequent PVD hard coating on the different materialspecific microstructures and hardness values of the EB-treated layers. In addition, the research activities were focused on specific aspects and effects of the chemical composition directly at the material surface on the formation, roughness, and adhesion of the PVD coatings, especially in the case of the Al alloys. For this purpose, XPS analyses and scratch tests under increased loading conditions were performed. Through a combined duplex EB surface treatment and PVD hard coating, cast irons and Al alloys can be used for applications with high demands in relation to friction and wear.

9:40am G2-1-6 Hollow Cathode Activated Magnetron, Hana Baránková ([email protected]), L. Bardos, Uppsala University, Sweden, M. Bernick, R. Newcomb, Angstrom Sciences, Inc., USA A new type of planar magnetron in which the target is coupled with a magnetized hollow cathode is presented. Detailed principles of such arrangements are explained. The hollow cathode activated magnetron produces intense and stable plasmas in a wider interval of the working gas pressures as compared to the conventional magnetrons at the same power. The close activation enhances sputtering of the magnetron target by highdensity hollow cathode plasma and increases the number of sputtered/evaporated species. Results of the first test experiments of this arrangement on a commercial planar magnetron with Ti target are presented and its capabilities are discussed.

8:20am G3-2 Pre-treatments and Post-treatments of Hard Coatings for Better Performance, Saleh Abusuilik ([email protected]), J. Nishida, Hitachi Metals, Ltd., Japan INVITED Hard coatings deposited using cathodic arc evaporation are widely used in forming and cutting tools industry. The hard coatings show good tribological and mechanical properties, which have improved the working life and performance of such tools. Nevertheless, improving coating adhesion and surface roughness are among the main challenging issues of the coatings. In this regard, pre-treatment and post-treatment processes, including variety of plasma and mechanical treatments are commonly used to enhance coating adhesion and surface roughness. In this talk, pretreatment and post-treatment methods used for hard coatings will be reviewed with concentration on industrial applications. Particularly, plasma nitriding and etching, shot peening, and micro-blasting finishing were studied and their role in improving adhesion and performance of CrN-based coatings were evaluated. In addition, tribological properties of the coatings were evaluated using ball-on-disk tests. Likewise, adhesion properties of the coatings were examined using HRC indentation and scratch tests. Furthermore, corrosion and erosion resistance of the coatings were tested in corrosive environments, including acidic aqueous solutions and molten aluminum. We found that plasma nitriding and intermediate post-treatment improved corrosion and erosion resistance of coated components against H2SO4 aqueous solutions and molten aluminum. Shot peening and microblasting finishing improved adhesion of the coatings. In conclusion, pretreatments and post-treatments of hard coatings showed good solutions for better performance of the coatings.

10:00am G2-1-7 Recent Developments of Hard Coatings Based on the Eifeler-Vacotec Alpha400P and Alpha900P PVD Coating Systems, Farwah Nahif ([email protected]), M. Schenkel, J. Blazek, M. Lartz, R. Scheibe, E. Voss, Eifeler-Vacotec GmbH, Germany The successful concept and flexibility of the eifeler-Vacotec alpha400P and alpha900P coating systems are demonstrated on recent examples of the several high-performance coatings offered by the eifeler group: The unique AlCrN based CROSAL® coating which has been developed with the focus on high temperature applications like e.g. dry cutting of steel and which exhibits high warm hardness, high oxidation resistance and excellent surface adhesion. Furthermore, the SPCS („strongly poisoned cathode surface“) technology developed at eifeler allows for the synthesis of smooth, well-adherent and hard cathodic arc coatings which do not require expensive post-finishing operations in many applications. These “ultrafine” coatings are obtained by an innovative control mechanism of the process gases and exhibit a similar surface quality as coatings deposited by filtered cathodic arc without the economical drawback of a reduced deposition rate. The talk will discuss the resistance against tribiogical wear and cutting test results in different materials.

Applications, Manufacturing, and Equipment Room: Sunset - Session G3

9:00am G3-4 Effect of Surface Roughness on Galling Behaviour of Steel on Hard Coatings, Thomas Klünsner ([email protected]), F. Zielbauer, S. Marsoner, Materials Center Leoben Forschung GmbH, Austria, M. Deller, Fritz Schiess AG, Switzerland, M. Morstein, PLATIT AG Advanced Coating Systems, Switzerland Galling, the transfer of workpiece material to tool surfaces, is an important factor known to influence both wear behaviour and loading conditions of metalworking tools such as deep-drawing, blanking or fine blanking punches or dies. In the current study, the states of a range of technically rough surfaces coated by AlCrN-based thin films using rotating cathodes arc evaporation PVD were characterized with regard to their galling behaviour. Furthermore, the influence of common post-treatment methods such as blasting or polishing on the early stages of galling of mild steel on coated surfaces was investigated in detail. Repeated dry-sliding contact, such as tool surfaces do encounter during operation, was physically simulated by a carefully selected ball-on-disc test setup with an applied contact pressure resembling the conditions between a steel sheet and the lateral surface of a fine blanking punch. The initial stages of galling were investigated by comparison of the development of the friction coefficient and the morphology of early iron adhesions to a range of differently post-treated coating surfaces. Depending on the surface roughness influenced by the applied post treatment method, hard coatings show a distinctively different galling behaviour in unlubricated contact conditions.

Coatings Pre-/Post Treatments Moderator: Tetsuya Takahashi, KCS Europe GmbH, Germany, Yin-Yu Chang, National Formosa University, Taiwan 8:00am G3-1 Duplex Electron Beam Surface Treatment and PVDHard Coating - the Key for Wear-resistant Cast Irons and Al Alloys, Rolf Zenker ([email protected]), A. Buchwalder, A. Jung, E. Zaulig, TU Bergakademie Freiberg, Germany PVD hard coating of steels is a well-known surface technology for significantly improving friction and wear behavior. In principle, hard coating can also be carried out on cast irons and Al alloys, but due to the insufficient load-supporting capacity of the soft base materials, i.e. of the microstructural constituents, this technology is inapplicable for wear protection of cast iron and Al alloys. This paper deals with research activities into using electron beam (EB) liquid-phase surface treatments both without additives (remelting) and with additives (alloying) to improve the conditions for the deposition of thin PVD hard coatings on these different groups of materials. The EB remelting of cast irons is already used for wear protection on an industrial scale. The ledeburitic microstructure of the remelted layer led to increased hardness up to a value of 700 HV0.1. Moreover, EB alloying using Ni-based additives allows the generation of a broad range of different microstructures, with hardness values ranging from 400 to 900 HV0.1. The

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Thursday Morning, April 23, 2015

The current work demonstrates a clear connection between the ratio of peaks to valleys on the investigated surfaces determined by atomic force microscopy and the kinetics of the early stages of galling illustrated by high-resolution scanning electron microscopy.

10:00am G3-7 Study of the Corrosion Behavior by the EIS Technique over the Surface of Borided and Non-borided AISI 316L Steels Immersed in a Simulated Body Fluid, Ivvone Mejia-Caballero, Instituto Politecnico Nacional, Mexico, M. Palomar-Pardave, Universidad Autonoma Metropolitana, Azcapotzalco, Mexico, J. Martínez-Trinidad, Instituto Politecnico Nacional, Mexico, M. Romero-Romo, Universidad Autonoma Metropolitana, Azcapotzalco, Mexico, R. Perez Pasten-Borja, Instituto Politecnico Nacional, ENCB, Mexico, C. Lopez-Garcia, I.E. Campos-Silva ([email protected]), Instituto Politecnico Nacional, Mexico The corrosion resistance of borided and non-borided AISI 316L steels was evaluated during 10 days of exposure in a simulated body fluid (Hanks’ solution). The boride layer was developed using the powder-pack boriding method at a temperature of 1223 K with 6 hours of exposure. The microstructure of the boride layer over the surface of the steel consisted in FeB/Fe2B phases with a flat and smooth morphology. Optical microscopy in clear field was used to estimate the thickness of the boride layer; the total boride layer thickness (FeB + Fe2B + diffusion zone) was approximately 52 ± 1 microns. The corrosion tests were performed over the surface of the non-borided and borided steels using the Electrochemical Impedance Spectroscopy (EIS) technique with a potentiostat (Zahner Zennium equipment) applied a frequency range from 8MHz to 2mHz (6-8 points per decade). After the corrosion tests, the surface of the borided and non-borided steels were analyzed by scanning electron microscopy (SEM), Energy Dispersive X-Ray Spectrometry (EDS) and X-Ray Photoelectron Spectroscopy (XPS) techniques to determine the corrosion mechanisms, the presence of the chemical elements on the surface of the borided and non borided steels, and the quantitative chemical composition of the specimens developed on the surface during the 10 days of exposition in the Hank’s solution. Based in the Nyquist plots estimated from the corrosion tests over the surface of borided and non-borided steels immersed in Hank’s solution during 10 days of exposure, the borided steel provided a reasonable corrosion resistance of approximately 45 KWcm2, while the corrosion resistance of the AISI 316 steel reached a maximum polarization resistance of 2138 KWcm2. In addition, according to the SEM and EDS results, pitting and crevice corrosion mechanisms were observed on the surface of the non-borided and borided steels respectively, whereas the phosphorus (or phosphates) content over the surface of borided steel increased as a function of the exposure time, and can be related by its low corrosion resistance compared with the values estimated in AISI 316 steel. Finally, equivalent electric circuits (EEC’s) were proposed for the analysis of the resulting impedance data for both borided and non-borided steels immersed in the simulated body fluid during 10 days of exposure.

9:20am G3-5 Enhancement of the Gas Barrier Property of Polypropylene by γ-APS Coating after Plasma Treatment, Kazuhisa Tsuji, Keio University, Japan, A. Uedono, University of Tsukuba, Japan, A. Hotta ([email protected]), Keio University, Japan The improvement of the gas barrier properties of polypropylene (PP), one of the most frequently used materials in the packaging industry, has been greatly demanded to extend the shelf life of the packaging goods by preventing the rapid degradation of the contents. In this work, the gas barrier property of PP was significantly improved by a factor of 15 through the plasma treatment of gamma-aminopropyltrimethoxysilane (γ-APS), as compared with that of non-treated PP. It was also suggested that the γ-APS was effectively converted into crosslinked SiOx with high gas barrier characteristics after 60 s plasma treatment. γ-APS coating is one of the silane coupling agents with an amino functional group, which is often used for the complement of coating materials. Here, the γ-APS was spin-coated on the PP substrate (γ-APS/PP) to form 1.4 μm thick film followed by the oxygen plasma treatment to induce the chemical crosslinking. Eventually, the oxygen transmission rate (OTR) of γ-APS/PP was substantially reduced to 61.0 cc/m2/day/atm, whereas that of pure PP was 886.2. The structural analyses were conducted by the positron annihilation lifetime spectroscopy (PALS) and X-ray photoelectron spectroscopy (XPS). The PALS results revealed that S-parameters, which represent the density of vacancies in the structure, were decreased from 0.517 to 0.496 by the oxygen-plasma treatment at the very surface of the γAPS coating. The S-parameter is directly related with the size of the free volume that is actually connected to the density of the micro-vacancy in the structure, which could become an efficient transmission path for the gas molecules. Thus the smaller size of the free volume at the γ-APS surface could highly be responsible for the improvement of the gas barrier properties of γ-APS/PP. XPS also revealed that the Si and O fractions were increased from 40.2% up to 85.8% after the plasma treatment, indicating the generation of SiOx networks by the partial cut-off of the amino side-chains in γ-APS. The γ-APS method may highly be a new simplified and low-cost method to expand the industrial utility of PP especially in the packaging food or beverage fields. 9:40am G3-6 Dry-blasting of CVD α-Al2O3 Hard Coatings: Influence of Blasting Media Size, Hardness and Coating Texture on the Stressdepth Gradients Investigated by X-ray Nanodiffraction, Michael Tkadletz ([email protected]), Materials Center Leoben Forschung GmbH, Austria, N. Schalk, J. Keckes, Montanuniversität Leoben, Austria, I. Krajinović, Materials Center Leoben Forschung GmbH, Austria, C. Czettl, CERATIZIT Austria GmbH, Austria, C. Mitterer, Montanuniversität Leoben, Austria Recently it has been shown that the shape of the blasting media has a considerable influence on the magnitude and depth of the stress gradients introduced by dry-blasting into CVD α-Al2O3 hard coatings. Within this work, CVD α-Al2O3 coatings grown on cemented carbide cutting inserts were dry blasted with globular Al2O3 based blasting media with three different mesh grit sizes ( (002); both intensities tend to decrease as the C2H2 flowrate increases. BP-17 Structure and Mechanical Properties of Mo-Al-N hard Coatings, Fedor Klimashin ([email protected]), H. Euchner, H. Riedl, P. Mayrhofer, Vienna University of Technology, Austria Cubic molybdenum nitride coatings exhibit high hardness and thermal stability and thus have a high potential to be used as wear-protection for various high-demanding applications. However, the formation of volatile molybdenum oxides requires an improvement of their oxidation resistance. Here, alloying of MoNx thin films with aluminium is an ideal tool, since Al forms stable dense oxides preventing both, further oxygen inward and molybdenum outward diffusion. Although face centred cubic fcc-Mo2N (nitrogen deficient NaCl structure) and hexagonal close packed hcp-AlN (wurtzite ZnS structure) are thermodynamically not miscible, using non-equilibrium physical vapour deposition (PVD) techniques allows to synthesise their metastable solid solutions. We show, that by PVD single-phase fcc-Mo–Al–N coatings can be developed for Al-contents [x=Al/(Mo+Al)] up to 0.34, where also the hardness reached its maximum with 37.4 GPa. Furthermore, these coatings exhibit also a relatively high resistance against plastic deformation with H3/E*2 = 0.24 GPa. According to X-ray diffraction analysis and ab initio calculations these single-phase fcc-Mo–Al–N coatings crystallize along the quasi-binary Mo2N–AlN tie line.

BP-13 Pre-Deposition Oxygen Treatment on Electrical and Reliability Characteristics of HfO2 Gate Dielectrics, Yi-Lung Cheng ([email protected]), T.C. Bo, C.S. Wu, National Chi Nan University, Taiwan In the study, two different oxygen treatments (O3 thermal and O2 plasma treatments) before HfO2 dielectric film deposition were compared. The radio frequency (RF) power effect of pre-deposition O2 plasma treatment on the physical, electrical, and reliability characteristics of HfO2 dielectric films was also investigated in this study. The experimental results indicated that O3 thermal pre-treatment resulted in a better electrical performance and reliability for HfO2 dielectric films as compared to O2 plasma treatment. In case of O2 plasma pre-treatments with various RF powers, as RF power is less than 30W, a thinner interfacial layer and the formation of new Hf-Si bonds were observed, leading to a degrading electrical performance and reliability. Although O2 plasma pre-treatments with RF power exceeding 50W led to a thicker interfacial layer, the electrical performance and reliability of HfO2 dielectric films were continuously degrading due to plasma damage at the interface.

BP-18 Residual Stress Evolution and Microstructure on Ordering in FePt Thin Films with Different Initial Stress States, S.N. Hsiao ([email protected]), S.H. Liu, S.K. Chen, Feng Chia University, Taiwan, A.C. Sun, Yuan Ze University, Taiwan, F.T. Yuan, Sentek Ltd, UK, H.Y. Lee, National Synchrotron Radiation Research Center, Taiwan, ShihHsuan Su, Feng Chia University, Taiwan L10 FePt thin films have attracted considerable attention for application of high-density recording media due to its high magnetocrystalline anisotropy. L10 ordering accompanied with lattice distortion can induce extrinsic compressive stress in FePt thin films. In the previous study, we reported that densification reaction could induce a tensile stress, which facilitates the nucleation of L10 ordering for the films with small initial stress (σi). The purpose of this paper is to clarify the microstructure and internal stress evolution during the densification in the FePt films with different σi. A considerable variation in er was observed before L10 ordering for the films with different σi (Fig. 1). As annealing temperature (Ta) was increased, er increased dramatically to a maximum (emax) toward the tensile direction, then subsequently relieved to a local minimum, after that er gradually increased again with Ta to 700 oC. The accumulation of tensile stress results from the densification reactions during annealing, evidenced by microstructural observation (not shown here). Fig. 2 shows the TEM images of the samples with exhibiting emax at different σi. The SADs connect the drop of er to the nucleation of L10 phase for the FePt films with different σi, confirmed by the appearance of diffraction (110) spots. We also found a grain growth from about 5 nm for the as-deposited state to ~50 nm after nucleation for the films with σi < –0.5 GPa (fig. 2a and 2b). On the contrary, for the films with σi = –1.01 GPa, the grain size after nucleation is about 5 nm, similar to that of as-deposited films (Fig. 2d). This indicates the fact that compressive σi suppresses growth of the disordered grains, which leads to a smaller densification stress and further sluggish L10 ordering transformation.

BP-16 Effects On Optoelectronic Properties of AZO Thin Film by Doping Carbon, Chih-Chiang Wang, National Chung Hsing University, Taiwan, H.C. Shih ([email protected]), Chinese Culture University, Taiwan ZnO is a hexagonal n-type semiconductor with a band gap energy of 3.2eV; Al-doped ZnO (AZO) would increase the electron concentration via the substitution of Zn2+ by Al3+ (~1.6wt% Al of the AZO target). In this work, carbon-doped AZO thin films have been successfully deposited on glass substrates by reactive pulse-DC magnetron sputtering, using AZO ceramic target under flowrate of C2H2 (0, 3, and 5 sccm). AZO is one of the transparent conductive oxide (TCO) thin film and much stable in hydrogen plasma than ITO, low cost, and nontoxic. C-doped AZO would further increase the electron concentration through the dissolved carbon atoms, which creating more anion vacancies by the formation of CO bonding. Both substitutional Al atoms and interstitial C atoms could effectively increase the negative charge carrier in the C-doped AZO. Higher concentration of the mobile electrons would reduce the electronic resistivity, but still lower than the critical concentration for the visible light (400-800nm), nc ~1021cm3 according to the relation: nc=ω2ε0 me /e2≧ ne (~1020cm-3) thus facilitating the transmission of visible light through the C-doped AZO. There are two major peaks of (002) and (103) observed on the XRD pattern with a trend of decreasing intensities as the flowrate of C 2H2 increases, accounting for the gradual build-up of amorphous carbon films on the surface of AZO. Raman spectra clearly indicate the bonds of C-O, Zn-O, and C-Zn appearing at 275, 510, and 575 cm-1, respectively; no signals of disordered and/or graphitic carbon respectively on ~1300 and ~1500 cm-1 were detected. Intrinsic carbon is always detected in the high vacuum system, which appears at 284.1eV. However, a nearby extra peak of 285.1eV could be resolved when 5 sccm C 2H2 was admitted to the reactor. This result is apparently due to the incorporation of the interstitially dissolved carbon atoms to the AZO. Optoelectronic performances, as the results of characterization, were obtained and derived from the evaluation are: the optical transparency (400-800nm): 87%; carrier mobility and concentration: 19.5 cm2/V-s and 6×1020 cm-3; and resistivity: 5.58×10-4 ohmcm . It is worth noting that better optoelectronic properties appear at the

BP-19 Effect of the Deposition Conditions on Corrosion Resistance of ZrxOy Films Deposited by Reactive Sputtering, Jhon-Jairo OlayaFlorez ([email protected]), J.E. Alfonso, M. Pinzon, Universidad Nacional de Colombia, Colombia In this work were deposited zirconia (ZryOz) thin films on 316L stainless steel by r.f. magnetrón sputtering. The coatings were deposited by changing deposition parameters, such as: electrical power applied at the target, flux of the argon gas and the substrate temperature. The crystalline structure was characterized by X-ray diffraction (XRD) and the chemical composition was analyzed by Auger electronic spectroscopy (AES) and X ray fluorescence (XRF). The corrosion resistance of the coatings were studied by potentiodynamic polarization test (Tafel extrapolation) and electrochemical impedance spectroscopy (EIS). Preliminary results revealed a change in its microstructure as a function of the discharge power and substrate temperature, since they evolved from a amorphous phase to a polycrystalline phase. In general, the corrosion resistance was better in the system film-substrate with respect to the substrate. The failure mechanism of corrosion is discussed in this research.

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Thursday Afternoon Poster Sessions

BP-22 Effect of Various Cr-N Interlayers on Adhesion Strength of the CrZrN Coatings on Tungsten Carbide Substrate, HoeKun Kim, K.S. Kim, J.H. La, S.Y. Lee ([email protected]), Korea Aerospace University, Republic of Korea, J.J. Lee, Seoul National University, Republic of Korea, W.Y. Jeung, Korea Institute of Science and Technology, Republic of Korea, M.H. Lee, Korea Automotive Technology Institute, Republic of Korea, O.J. Kwon, K.DLC Corporation, Republic of Korea The CrZrN coatings have been paid much attention to cutting tool’s coating due to their high hardness, low surface roughness and excellent tribological property. The adhesion strength between substrate and coating is essential property to protect cutting tool, and could be improved by addition of interlayer. The Cr-N coatings were reported to show various crystalline phases and properties with various nitrogen contents in coatings. Therefore, the Cr-N coatings of various properties can be controlled with various nitrogen contents. In this study, the CrZrN coatings with the Cr-N interlayer with various N2 partial pressures in the range from 1.1×10-1 to 2.3×10-1 Pa were synthesized using the unbalanced magnetron sputtering system on WC-6wt.% Co disc type substrate. The crystalline phase, microhardness and elastic modulus, microstructure, and adhesion properties of the CrZrN/Cr-N coatings were evaluated by x-ray diffractometer, Fischer scope, field-emission scanning electron microscopy, scratch tester and optical microscopy, respectively. The crystalline phase of Cr-N interlayers varied from single-phase Cr2N to CrN+Cr2N, and then single-phase CrN with increasing N2 partial pressure. The microhardness and elastic modulus of all the coatings gradually decreased from 28.5 to 23.3 GPa and 357.5 to 340.2 GPa, respectively. The critical load (Lc3) of the CrZrN/Cr2N and CrZrN/(CrN+Cr2N) coatings ranging from 26.8 to 28.7 N showed similar values. However, the critical load (Lc3) of the CrZrN/CrN coating significantly increased to 46.1 N. It could be attributed to the interlayer’s hardness to elastic modulus ratio (H/E) between the WC and CrZrN coating. The H/E ratio that is related to elastic strain to failure influences to adhesion strength. In this case, the H/E ratio of the CrN interlayer (0.068) showed a suitable median value between the WC (H/E=0.045) and CrZrN coating (H/E=0.090) comparing with Cr 2N (H/E=0.079) and CrN+Cr2N (H/E=0.077). The results showed that the single-phase CrN interlayer reduced stress gradient effectively. Detailed experimental results will be presented.

[6] H. Kousaka and N. Umehara, Trans. Materials Research Soc. Jpn31 (2006) 487. [7] H．Kousaka, T. Okamoto, N. Umehara, IEEE Trans. Plasma Sci.41 (2013) 1830. [8] X. Deng, H. Kousaka, T. Tokorayama and N. Umehara, Surf. Coat. Technol. 238 (2014) 80. [9] X. Deng, H. Kousaka, T. Tokorayama and N. Umehara, Tribology Online8 (2013) 257. BP-24 First Step Towards a Multi-scale Modelling of the Sputter Growth of Molybdenum on Si(100) Surface : ab initio Investigations, C. Mastail, J. Durinck, R. Béjaud, Grégory Abadias ([email protected]), A. Michel, C. Jaouen, Université de Poitiers, Institut Pprime, France Nowadays, magnetron sputtering is a commonly used method for the deposition of thin films with industrial applications. Experimental observations reveal that deposition parameters, such as the substrate's nature, growth rate, deposited energy, interfacial effects [1], strongly influence the final material properties. In this framework, we performed a multi-scale modelling of the growth of thin Molybdenum film sputtered onto a silicon substrate, based on a Monte Carlo algorithm. This system (MoSi) is widely used as a back contact for CIGS-based (Copper-Indium-(Gallium)-Diselenide/Disulfide) solar cells or those based on Silicon. Thus, the multi-scale strategy used helps to shed light on the complex links between the crystalline nucleation of the metal layer and the deposition process in real experimental conditions. This contribution is focused on the first step of a kinetic Monte Carlo (kMC) code, i.e. a comprehensive ab initio study of the elementary mechanisms which occur during the first stages of the growth. We will first consider molybdenum adsorption and diffusion on Si (100) surface as well as on Mo (110) surface. The most reactive surface sites will then be found. They consist in strong binding sites such as interstitial sites of the first silicon layer. The influence of a second Mo atom on the possible diffusion pathways of the deposited atoms on the two surfaces will be also investigated. The high diffusion barriers found on the silicon surface confirm the low mobility of Mo atoms. The incorporation into the Si subsurface will also be discussed. Results show that, under experimental deposition conditions, Mo migration in the bulk is thermodynamically favorable. We will conclude with some preliminary kMC results. [1] A. Fillon, G. Abadias, A. Michel, C. Jaouen, P. Villechaise, Phys. Rev. Lett,104 (2010), 096101

BP-23 A Numerical Simulation of Microwave Sheath-voltage Combination Plasma Source Designed for Ultra High Speed DLC Coating, Satyananda Kar ([email protected]), L. Alberts, H. Kousaka, Nagoya University, Japan The development of plasma sources for various types of plasma processing, such as, etching and thin film deposition show that one important parameter for effective plasma processing is high plasma density [1]. One type of high density plasma source is Microwave sheath-Voltage combination Plasma (MVP) [2-6]. MVP allows a tremendous increase in productivity for the deposition of Diamond-like carbon (DLC) coatings [7-9] since hard coatings of Si-DLC can be deposited with more than 100 micrometer/hr. A design tool for optimizing the reactor is highly welcomed by the industry. The MVP device requires the combination of well known microwave surface wave plasma with a resolution of the superimposed DC-plasma sheath. We present a better design of MVP source, in which the input microwave power couples with plasma very efficiently through an extended antenna and over-dense plasma is generated for low input microwave powers. This design would replace the challenging of building ever bigger coatings tools by using eco-friendly and low budget fast one-to-one automated deposition systems. Also we report on first qualitative agreements of the plasma modeling using the commercial COMSOL multi-physics plasma module. The simulation results are agreed with experimental results. The results suggest that this MVP device can be used for ultra-high-speed DLC coating. Acknowledgement This work was supported partly by DAIKO Foundation RESEARCH FELLOWSHIP PROGRAM in FY2014 and a “Grant for Advanced Industrial Technology Development (No. 11B06004d)” in 2011 from the New Energy and Industrial Technology Development Organization (NEDO) of Japan. References [1] M. A. Lieberman and A. J. Litchenberg, Principles of Plasma Discharges and Materials Processing, Wiley, New York, 1994. [2] H. Kousaka, J. Q. Xu and N. Umehara, Jpn. J. Appl. Phys.44 (2005) L1054. [3] H. Kousaka, H. Iida and N. Umehara, J. Vac. Soc. Jpn. 49 (2006) 183 [in Japanese]. [4] H. Kousaka and N. Umehara, Vacuum80 (2006) 806. [5] H. Kousaka, J. Q. Xu and N. Umehara, Vacuum80 (2006) 1154.

Thursday Afternoon Poster Sessions

BP-25 Optimization of the Coil Design for the Induction Evaporation Process for the Zn-Mg Coating: Simulation and Experiment, J.H. La, K.T. Bae, Sang-Yul Lee ([email protected]), Korea Aerospace University, Republic of Korea, M.K. Song, Vector Fields Korea, Inc., Republic of Korea, K.H. Nam, Y.H. Jung, POSCO Technical Research Laboratories, Republic of Korea It is well known that the Zn-Mg coating has higher corrosion resistance compared with the pure Zn coating due to the formation of the simonkolleite phase on the surface of the Zn-Mg coating. Therefore the ZnMg coating has been studied extensively for the corrosive protection coating in the automobile applications. To obtain Zn-Mg coating, an induction evaporation process is considered to be one of the strong candidates due to its high deposition rate and low energy consumption. In this study, the effect of the design of the induction coil and size of droplet on the efficiency of high-frequency induction heating was investigated. This investigation first utilized electromagnetic and thermal simulation using MagNet, ThermNet software to predict the electric field and temperature distribution during the induction heating process. The finite element method was then adopted to determine the best combination of process parameters with various induction coils. The most efficient coils were produced for the application of the atmospheric evaporation test. The results of the atmospheric test were measured against the simulation results to draw the best induction heating condition. The simulation results indicated that the heat value of droplet and induction coil by high-frequency induction heating increased linearly with decreasing the coil gap of turns from 7 mm to 3 mm. When the coil and the droplet were similar size, the heating efficiency was the highest at all turns of coil. For the highest heating efficiency of droplet with reducing heat value of induction coil, the coil with medium gap were produced. At the atmospheric evaporation test, the heating efficiency increased by 50% or more with increasing the size of droplet. However, when the droplet was larger than induction coil, the efficiency decreased contrastively. The results for the atmospheric evaporation test corresponded well to those of the simulation results and the conditions of high-frequency induction heating for the highest efficiency could be utilized for the synthesis of Zn-Mg coating in high vacuum environment.

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Acknowledgement This work was financially supported by the Smart Coating Steel Development Center operating for the execution of WPM (World Premier Materials) Program funded by the Ministry of Trade, Industry and Energy, Republic of Korea.

BP-30 Effects of Nitrocarburizing Processing Times after Radical Nitriding for Surface Hardening of High-speed Tool Steel, Yusuke Kikuchi ([email protected]), Y. Sakamoto, Chiba Institute of Technology, Japan Duplex coating is one of the complex process and it forms a thin film above the diffusion layer for improvement of adhesion strength and coating lifetime. Radical nitriding is possible to form diffusion layer keeping the surface roughness smooth. Recently, Diamond-like carbon (DLC) film has been widely applied in the Industry. To obtain higher adhesion strength of DLC coating, carbonitrid layer is suitable formed between nitride diffusion layer and DLC film. Nitrocurbrized can be obtained low hardness and shallow modified layer. So it is necessary to process nitrocurbrizing after radical nitriding to improve the adhesion strength. Investigation was carried out effect of processing time when performing nitrocarburizing after radical nitriding to high-speed tool steel. The surface of substrates was cleaned by H2 etching before radical nitriding. The condition of the radical nitriding was follows: pressure; 133Pa, applied voltage; -380V, NH3 flowed rate; 50SCCM, H2 flowed rate; 50SCCM, external heater temperature; 843K and processing time; 60min, respectively. The condition of nitrocarburizing after radical nitriding was follows: pressure; 532Pa, applied voltage; -380V, N2 flowed rate; 1SCCM, CH4 flowed rate; 50SCCM, H2 flowed rate; 50SCCM, NH3 flowed rate; 50SCCM, external heater temperature; 843K and processing times were varied; 5,10,15min respectively. The hardness of substrates was measured by a micro-Vickers hardness tester, the friction coefficient of substrates was measured by a Ball-on-disk friction tester and observation of cross-sectional layers with nital corrosion by Optical microscope. The results of the Vickers hardness test, radical nitriding and nitrocarburizing after radical nitiriding to high-speed tool steel was harder than that of the untreated sample. As a result of ball-on-disk friction test, all samples obtained nitrocarburized after radical nitriding were showed lower friction coefficient than that of radical nitriding. Also,the wear amount of abrasion was decreased. Observation of cross-sectional of the sample after nital corrosion by optical microscopy, compound layer was not observed for radical nitriding and nitrocarburizing. The present result suggested that the hardness of nitrocaburizing after radical nitriding was same as radical nitriding to high-speed tool steel. Also, the friction coefficient of nitrocaburizing after radical nitriding was lower than that of radical nitriding.

BP-27 Mechanical Properties of AlCrN/VN Nanolayered Thin Films Tailored by Cathodic Arc Deposition, Mohammad Arab Pour Yazdi ([email protected]), IRTES-LERMPS-UTBM, France, F. Lomello, CEA Cross-Cutting program on Advanced Materials Saclay, France, M.F. Wani, National Institute of Technology Hazratbal, India, F. Sanchette, LRC CEA- UMR CNRS 6279-ICD LASMIS, France, F. Schuster, CEA Cross-Cutting program on Advanced Materials Saclay, France, A. Billard, Lrc Cea-Irtes-Lermps-Utbm, France In recent years, the application of AlCrN-type coatings in processes which involve attrition, chipping and/or cracking due to the impacts, such as the industrial metal forming has increased [1]. The cutting edge of coated tools may exceed 1000°C, therefore the oxidation resistance is a very important issue [2]. The oxidation resistance and high temperature mechanical properties of AlCrN are improved comparing with other ternary nitride such as AlTiN [3]. On the other hand, to increase the tribological properties of AlCrN, nanolayered coatings containing vanadium are an interesting solution [4]. Indeed, when vanadium-based coatings are submitted to high loads and high temperature conditions, the formation of so-called Magnéliphases VnO2n-1 is induced and the latter allow the reduction of friction coefficient (µ 5at.% Si, and the presence of Si3N4 and NbN was confirmed by the chemical analysis in all the thin films deposited. The hardness was improved from 18 GPa to 29 GPa for low Si concentrations. The analysis of the corrosion mechanism revealed that the thin films with the highest Si content have low corrosion current density, low porosity index, and high degree of passivation.

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Thursday Afternoon Poster Sessions

BP-46 Tribomechanical and Structural Properties of a-SiC:H Films Deposited Using Liquid Precursors on Titanium Alloy, K. Nass, Universidade Federal de São Paulo-ICT/UNIFESP, Brazil, P. Goncalves ([email protected]), Lucia Vieira, Universidade do Vale do Paraíba, Brazil, D. Leite, Instituto Tecnológico de Aeronáutica - ITA, Brazil, M. Massi, Universidade Federal de São Paulo-ICT/UNIFESP, Brazil, A. Sobrinho, Instituto Tecnológico de Aeronáutica - ITA, Brazil, R.C. Lazzarini Dutra, D. Reis, Universidade Federal de São PauloICT/UNIFESP, Brazil Hydrogenated amorphous silicon carbide (a-SiC:H) have several features that make it desirable for tribological applications, as high hardness, low friction coefficient, high corrosion resistance and high temperature resistance. These properties qualify it for use in strategic areas as aerospace, pharmaceutical, biomedical, microelectronics and many others [1-2]. Hydrogenated amorphous silicon carbide (a-SiC:H) films can be obtained by using PECVD at low temperature (< 700 C) [3,4]. This paper presents a study of deposition parameters and results of tribological and mechanical properties of a-SiC:H films deposited on titanium alloy (Ti-6Al-4V). The aim was to obtain films with high adhesion and high tribological performance. The film was deposited using Plasma Enhanced Chemical Vapor Deposition (PECVD) and organosilanes hexamethyldisiloxane (HMDSO), [Si-(CH3)3]2O and tetramethylsilane (TMS) Si-(CH3)4 as silicon, carbon and hydrogen precursors. The deposition temperature was varied from 400 to 600 °C and pressure from 0.5 Torr to 3Torr. The chemical composition and structural properties of the deposited SiC thin films were analyzed by FTIR, XRD and Raman spectroscopy. The mechanical and tribological properties were evaluated through scratching test, friction, wear. The HMDSO films at 500 °C (H5) showed higher deposition rate, critical load and worn volume of the sphere, which suggests that this film has higher hardness and adhesion. The films obtained with HMDSO presented less friction coefficient values. The results showed that the films presented amorphous structures (a-SiC:H) and those obtained with 500 °C and 3 Torr presented high adhesion and tribological performance. Acknowledgments: This work was supported by CNPq, CAPES and FAPESP (Grant no 2011/50773-0). References: [1] WADA, A.;OGAKI,T.;NIIBE, M. Local structural analysis of a-SiCx:H films formed by decomposition of tetramethylsilane in microwave discharge flow of Ar.Diamond & Related Materials, University of Hyogo, Hyogo, Japan, p. 364-367. 2011. [2] PORADA, O.K.; IVASHCHENKO, V.I.; IVASHCHENKO, L.A. aSiC:H films as perspective wear-resistant coatings. Surface & Coatings Technology, NAS of Ukraine, Avtozavodska str. 2, 04074 Kyiv, Ukraine, p. 122–126.2004. [3] RASHID, Nur Maisarah Abdul; RITIKOS, Richard; OTHMAN, Maisara. Amorphous silicon carbon films prepared by hybrid plasma enhanced chemical vapor/sputtering deposition system: Effects of r.f. power. Thin Solid Films, University Of Malaya, p. 459-463. 2013. [4] MAGUIREA, P.D.; LAUGHLINA, J.A.; OKPALUGOA, T.I.T. Mechanical stability, corrosion performance and bioresponse of amorphous diamond-like carbon for medical stents and guidewires. Diamond & Related Materials, N. Ireland, United Kingdom, p. 1277–1288, 2005.

BP-48 Microstructure and Mechanical Properties of Nanocomposite Ti-Al-Si-N Films Deposited by Inductively Coupled Plasma-Assisted Magnetron Sputtering, M.-J. Park, S.-B. Heo, Inoeck Baek, E. An, J.B. Jeon, E. Choi, I.-W. Park ([email protected]), Korea Institute of Industrial Technology (KITECH), South Korea Quaternary Ti-Al-Si-N films were deposited on AISI 304 stainless steel substrates by an inductively coupled plasma-assisted magnetron sputtering technique using Ti3Al and Si targets in an Ar/N2 gas mixture. The microstructure and mechanical properties for the films were investigated as a function of deposition variables such as Si content and substrate bias voltage. As the Si was incorporated into Ti-Al-N film, the microstructure of Ti-Al-Si-N films were changed from a columnar structure with coarse grains to a glass-like structure with fine grains, and the micro-hardness of the Ti-Al-Si-N films showed higher hardness values compared with Ti-AlN coating. The mechanical and tribological properties for the films were investigated in various Si contents. The microstructures of the synthesized films were characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), X-ray photoelectron spectroscope (XPS), highresolution transmission electron microscope (HRTEM), respectively. Nanoindentation was conducted to assess the hardness and Young’s modulus of the films. Wear resistance and coefficient of friction of these films were evaluated using a micro-tribometer. This paper will present the effects of Si content on the microstructure, mechanical and tribological properties of inductively coupled plasma-assisted magnetron sputtered Ti-Al-Si-N films. BP-49 The Effect of Pulsed Magnetron Sputtering on Corrosion Behavior of CNx Thin Films, K.-S. Kim, Jun-Ho Kim, Korea Institute of Industrial Technology (KITECH), South Korea, S.-B. Heo, Korea Institute of Industrial Technology (KITECH),South Korea, W. Kim, U.-C. Jung ([email protected]), Korea Institute of Industrial Technology (KITECH), South Korea Carbon nitride (CNx) is one of promising hard and chemically stable coating materials because of having similar or higher properties as compared with diamond. However, the high electrical resistance of CNx thin films led to arcing and target poisoning during reactive sputtering process. In this study, CNx thin films were deposited by asymmetric bipolar pulsed DC (ABPD) magnetron sputtering and direct current (DC) magnetron sputtering technique. The change of bonding characteristics and corrosion resistance were investigated as types of power generator. The microstructure of deposited CNx thin films showed columnar structures with regardless of power generators. But the CNx film synthesized by DC magnetron sputtering showed a lot of macro CNx particles on surface, beside those particles were significantly decreased by using ABPD. And surface roughness, residual stress and defects were also decreased in ABPD sputtered CNx thin films. From the results of corrosion test, CNx thin film synthesized by ABPD magnetron sputtering showed superior resistances and low corrosion rates compared with a DC sputtered CNx thin film. Authors concluded that bonding characteristics of CNx thin films were effectively changed from low to higher fraction of sp 3 bonding and more nitrogen contents in films by using asymmetric bipolar pulsed DC. BP-50 Microstructure and Corrosion Behaviour of Sputtered Al-Zr Coatings Deposited on High Strength Steel, M. Reffass, LRC CEA/UTBM LIS-HP, Site de Montbéliard, France, A. Billard, Lrc CeaIrtes-Lermps-Utbm, France, Frédéric Sanchette ([email protected]), LRC CEA- UMR CNRS 6279-ICD LASMIS, France, J. Creus, Université de La Rochelle, France Nanocrystalline Aluminium-Zirconium coatings with Zr content between 0 and 25 at.% were deposited on high strength steel (HSS) by dc magnetron sputtering. Microstructure, microhardness and corrosion behaviour of Al-Zr coated steel were investigated. For Zr content up 18 at.%, the characterisation of Al-Zr coatings by X-ray diffraction (XRD) shows the formation of fcc solid solution with nanocrystalline structure. From 18 at.% to 25 at.% Zr the Al-Zr coatings are amorphous single-phased. The increase of Zr content in coatings leads to a refinement of microstructure and to an increase of microhardness. The corrosion behaviour of Al-Zr coatings was studied in 5 wt % NaCl solution using potentiodynamic polarisation, linear polarisation resistance and electrochemical impedance spectroscopy (EIS). The results show an enhancement of corrosion resistance and a decrease of corrosion kinetic with Zr contents’ increase. Lower corrosion rates are obtained for highest Zr contents. EIS results confirm the enhancement of corrosion resistance with addition of Zr and this enhancement is ascribed to the blocking mechanism due to ultra-dense structure of coating at high Zr contents.

BP-47 Microstructure and Mechanical Properties of Lanthanum Alloyed CrAlN Coatings, Hao Du, H. Zhao ([email protected]), H. Liang, Sichuan University, China CrAl(La)N coatings with lanthanum content varying from 0 to 7.73at.% were deposited on cemented carbide substrates by using a plasma-assisted reactive magnetron sputtering process. The amounts of lanthanum were varied by controlling the sputtering rate of Cr30Al70 targets and lanthanum target. The effects of varying amounts of lanthanum addition on the microstructure and mechanical properties of CrAlN coatings were investigated. The results showed that cubic structure was formed in the coatings. The preferred orientation changed from (111) to (200) with lanthanum content increased. Much more sense and finer grained columnar crystals were observed with lanthanum addition, while amorphous morphology was detected in the Cr0.28Al0.64La0.08N, Cr0.28Al0.59La0.13N and Cr0.27Al0.57La0.16N coatings. The hardness increased from 27.4Gpa to 43.4Gpa when lanthanum was added; however, the hardness decreased to 29.4Gpa with a further increase in lanthanum content. According to the indentation adhesion test, Cr0.3Al0.07L0.03N showed the best adhesion strength.

Thursday Afternoon Poster Sessions

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BP-52 Tribocorrosion Properties of MAO/DLC Coatings Using a Duplex Process on Cp-Ti Alloys, E.E. Sukuroglu, Atatürk University, Turkey, Suleyman Sukuroglu ([email protected]), Gümüşhane University, Turkey, E. Arslan, Y. Totik, I. Efeoglu, Atatürk University, Turkey The combined micro arc oxidation (MAO) and closed field unbalanced magnetron sputtering (CFUBMS) process was used to deposit duplex MAO/DLC coating on Cp-Ti alloy. Analysis of the microstructures, morphology and crystallographic structure were performed by using a SEM, RAMAN and XRD. The wear, corrosion and tribocorrosion properties of the coatings were investigated using the pin-on-disc wear test, potentiodynamic polarization test and combining tribocorrosion test unit, respectively. It is found that the DLC thin film could be successfully deposited onto the MAO coating. The results of this study showed that duplex MAO/DLC coatings exhibit better wear, corrosion and tribocorrosion properties than the DLC or MAO monolayer on Cp-Ti alloy substrate. MAO/DLC coatings exhibited dense structure. The dense microstructure is an important factor for the hardness. This causes an increase in the wear resistance. Duplex coatings were uniform, compact, smooth, columnar and dense as the Ti-DLC films that were directly coated onto the substrate. The MAO /DLC duplex coated has the hardest hardness value. The results also showed that MAO /DLC duplex coatings on Cp-Ti substrates increased the tribocorrosion resistance by acting as a barrier layer.

Fundamentals and Technology of Multifunctional Thin Films Room: Grand Hall - Session CP Symposium C Poster Session CP-1 Immobilization of Phthalocyanines on Nanocrystalline Diamond Surfaces for Photoelectrochemical Applications, C. Petkov, P. Reintanz, University of Kassel, Germany, M. Veres, L. Himics, Hungarian Academy of Sciences, Hungary, R. Merz, M. Kopnarski, IFOS GmbH, Germany, U. Siemeling, J.P. Reithmaier, Cyril Popov ([email protected]), University of Kassel, Germany Diamond is a prospective electrode material for a number of applications providing efficient electron transport, high stability of electrolytic performance with time, a possibility for dye-sensitizing with photosensitive molecules, etc. It can be functionalized with electron-donor molecules, like phthalocyanines or porphyrins, for the development of light energy conversion systems. For effective attachment of such molecules, the diamond surface has to be modified by plasma- or photo-chemical processes in order to achieve the desired surface termination. In the present work we have investigated the immobilization of diverse phthalocyanines (Pc) on nanocrystalline diamond (NCD) surfaces with different terminations. The NCD films have been prepared by hot filament chemical vapor deposition (HFCVD) on silicon substrates and thereafter subjected to modification with O2 plasma for exchange of the H-termination of the asgrown surface. The effectiveness of the modification was studied by contact angle measurements and X-ray photoelectron spectroscopy (XPS). The asgrown and the modified NCD surfaces were exposed to phthalocyanines with different metal centers (Ti, Cu, Mn) or with different side chains. The results of the Pc grafting were characterized by XPS and Raman spectroscopy. XPS revealed the presence of the nitrogen stemming from Pc molecules and traces of the respective metal with ratios close to those in the applied Pc. As a next step the Raman spectra of Ti-Pc, Cu-Pc and Mn-Pc were obtained with two different excitation wavelengths (488 and 785 nm) from droplet samples on Si after evaporation of the solvent in order to establish their Raman fingerprints. The major differences in the spectra can be assigned to the effect of the size of the metal ion on the structure of the phthalocyanine ring. The obtained spectra were used as references for the Raman spectra of NCD surfaces grafted with Pc.

BP-53 Tribocorrosion Properties of Metal Doped-DLC Thin Films, E. Arslan, Y. Totik, K.V. Ezirmik, E.E. Sukuroglu, Hikmet Cicek, Atatürk University, Turkey, A. Keles ([email protected]), Ataturk University, Turkey, I. Efeoglu, Atatürk University, Turkey Carbide and nitride of transition elements are natural candidate materials for wear resistance applications as protective coatings. Extreme hardness, high wear resistance, low friction coefficient, chemicaly stability of transition metal(s) doped-diamond-like carbon (DLC) films make them popular. From this point of wiev, transition metals, Ti and Ta doped hydrogeneted DLC films were deposited by closed-field unbalanced magnetron sputtering system onto Ti6Al4V, Cp-Ti, AZ-91 magnesium and 2024 Aluminium alloys in Ar/N2/C2H2 atmosphere. The tribocorrosion properties of Ti:Tabased DLC coating were investigated. The coated specimens were characterizied by SEM, XPS and X-ray diffraction techniques. Hardness measurements was performed by microindendation. The results showed that Ti-Ta-doped DLC film shows very dense microstructure, high hardness and tribocorrosion resistance.

CP-2 A High-quality SrTiO3 Nanocrystal Thin film prepared by Spincoating method, XiaoHui Wang ([email protected]), Tsinghua University, China Perovskite oxides have been extensively studied due to their widespread applications in electronics, sensing, catalysts, and energy storage. SrTiO3 is a typical perovskite-type oxide with good electronic performance, high photocatalytic activity and tunable chemical and physical properties. In this paper, we successfully synthesized sub-10 nm SrTiO3 nanocubes and their hyperstable nanocrystal sol via a rapid sol precipitation method under atmospheric pressure. The nanocubes are quite uniform with narrow size distribution, good crystallinity and high dispersibility, and are expected to be a better support for catalysts. In this method, controlled hydrolysis was veried to be critical to the formation of the regular cubic shape. The solvent TEG acted as an important additive in controlling the hydrolysis rate and providing steric repulsive energy for the stabilization of the nanocrystal sol. The high-concentration SrTiO3 nanocrystal sols (0.4–0.8 M) can be adapted to a variety of solution-based methods. They were successfully applied to fabricate high-quality SrTiO3 thin film at 100–160 oC. This method has many advantages including mild reaction conditions without high pressure, rapid formation (2 h) and well controlled size and morphology of the product, which can be applied to large-scale industrial production and open up new opportunities for low-cost fabrication of perovskite oxides.

BP-54 Characterization and Study Layer Hard on Steel Grade Machinery, Noe Lopez-Perrusquia ([email protected]), M.A. Doñu Ruiz, Universidad Politécnica del valle de Mexico, México, C.R. Torres San Miguel, G.M. Urriolagoitia Calderón, Instituto Politecnico Nacional, Mexico, G. Urriolagoitia Sosa, Instituto Politécnico Nacional, México This paper presents the growth and formation of boride coating in steel AISI 9840 used in industry plastic; the growth of FeB and Fe2B hard layers, depend the effect and time of treatment paste dehydrated boron, also as the incubation time for FeB and Fe2B phases, besides the growth kinetics of the layers borided at the material surface in AISI 9840 steels with paste dehydrated boron. This technique generates hard coating on the material and two bilayers FeB/Fe2B/zone transition/substrate. The thermochemical treatments were used three different temperatures: 1173, 1223 and 1273 K, with treatment times of 2, 4, 6 and 8 h; using the law of growth parabolic; to show mobility of boron in study. The characterization of layers FeB/Fe2B formed by paste dehydrated boron, are obtained with the techniques optical microscopy (OP), scanning electron microscopy (EDS) and XRD analysis present the type of layer formation and presence FeB/Fe2B sawn and two phases FeB/Fe2B, for the steel grade machinery; On the other hand, by the nanoindentation technique is obtained modulus and nanohardness of the phases present steels boriding . The work shows the growth kinetics FeB/Fe2B and proprieties FeB/Fe2B obtained by paste dehydrated boron

CP-4 High-k Polymer Nanocomposites as Gate Dielectrics for Organic Thin Film Transistor Applications, Y.Y. Yu ([email protected]), Rih-Sheng Chiang, S.N. Liu, W.C. Chien, Ming Chi University of Technology, Taiwan We report on a systematic study of hydroxyl-containing polyimide (PI)TiO2 nanoparticles (NPs) hybrid dielectric materials, to determine the effects of TIO2 NPs loadings (X) for X = 0, 2, 5, 8, 10, 13 and 15 wt%, on p-type pentacene organic thin film transistors (OTFTs). A condensation reaction to produce well-dispersed TIO2 NPs within the PI matrix was followed by spin coating to form a dielectric thin film directly on a silicon substrate. The thermal, optical, surface, dielectric, and electrical properties of the PI-TiO2 hybrid dielectric composite correlated to TiO2 content for each sample. The hybrid dielectric composites exhibit tunable insulating properties, including high dielectric constant, high capacitances, and low leakage current densities. Bottom-gate top-contact OTFTs fabricated using

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Thursday Afternoon Poster Sessions

various PI-TiO2 hybrid dielectrics, exhibit low threshold voltages, moderately high field-effect mobility rates, and high ON/OFF ratios. This study opens a route towards transparent and highly stable hybrid dielectric materials with tunable dielectric properties, by careful selection of NPs and polymer matrix combinations.

The transparent conductive AZO films were prepared on glass (OA-10) substrates by direct current magnetron sputtering (dc-MS) and radio frequency power superimposed dc-MS (rf+dc-MS). We used four surface texture formation techniques as follows: (a) formation by post-etching caxis oriented AZO films deposited by MS, (b) formation during the crystal growth of AZO films deposited by MS under conditions suppressing c-axis orientation, (c) formation by post-etching the surface-textured AZO films grown in case (b), and (d) formation by post-etching the surface-textured AZO films resulting from the deposition of the case (b) AZO films onto the case (a) AZO films. In case (a), AZO films were prepared at a sputter Ar gas pressure of 0.6 Pa and a substrate temperature of 200 oC. In case (b), surface-textured AZO films were first prepared at a sputter Ar gas pressure of 12 Pa and a substrate temperature of 350oC, and then the films were heat treated in a H2 gas atmosphere for 30 min. In case (d), low resistivity AZO films with a thickness of 1μm were first deposited under the same conditions used in case (a), and then surface-textured AZO films were deposited onto the case (a) AZO films. The textured surface structure formed by case (a) features relatively large etch pits (crater-like) with diameters in the range of 1-2μm, resulting from a wet-chemical etching (in a 0.1% HCl solution at 25oC). In case (b), the rough textured surface structure resulting on AZO films features wedge-shapes (pyramidal) with an average size below 1μm, which increased as the film thickness was increased up to 3.5μm. In case (c), the resulting structure features a double texture that combines the crater-like and pyramidal surfaces. However, it should be noted that both the surface-textured AZO films formed in cases (b) and (c) were found to exhibit low optical transmittance (or high absorption) near the band edge. Although the transmittance of the surfacetextured AZO films was improved by decreasing the thickness, the resulting sheet resistance increased. The results of case (d) show that a double textured surface as well as a low sheet resistance could be achieved in surface-textured AZO films.

CP-7 AgNWs Embedded Transparent Conductive Oxide Films using a Facing Targets Sputtering Method, S. You, Gachon University, Republic of Korea, You Seung Rim, University of California, Los Angeles, USA, K.H. Kim ([email protected]), H.W. Choi, Gachon University, Republic of Korea Recently, metal nanowires embedded transparent conductive oxide films have been attracting attentions for highly durable flexible technology. However, exposed surface of silver nanowires (AgNWs) could be easily oxidized at low temperatures in air, and the conductivity is decreased. Here, we report a sandwich structure of aluminum doped ZnO (AZO)/AgNWs/AZO via a sequential deposition method with the facing targets sputtering (FTS) and spin coating process for the passivation of AgNWs. FTS-based deposition technique has several advantages such as low damages and temperatures on substrate surface throughout the suppressing of high-energy particles bombardment during the deposition. We confirmed that top and bottom side of FTS-based AZO films could protect AgNWs without electrical degradation, which indicated that low temperature (