The coatings In the late of the 70s of last century, that is, about 40 years ago, began the era of coatings with titanium nitride (TiN) on the tools for chip removal. Then began a revolution that has changed, in some respects, the same philosophy of many types of production of mechanical parts. At the beginning were only covered carbide inserts, with the CVD method (chemical vapor deposition), which we will discuss shortly, and after a few years it has gone to coat even with the HSS method PVD (physical vapor deposition). The coating consists in the deposition on the surfaces of tools or other components of a thin layer of a compound that, in origin, was the Titanium Nitride (TiN) and which was subsequently complemented by other compounds such as Carbo Titanium Nitride (TiCN), Titanium Nitride and Aluminum (AlTiN), Chromium Nitride (CrN) and many others. All of these films, with a thickness of a few micrometers, have the purpose of improving in a consistent way the physical characteristics of the surface, such as hardness, corrosion resistance, coefficient of friction, etc.. in order to increase the wear resistance and thus to increase the life of the tools or other mechanical parts subjected to this treatment. Limiting ourselves to only talk of cutting tools, the results were so important that some companies have been forced to diversify their production because the demand for traditional tools has collapsed due to their greater longevity. To talk about a specific case involving the world of gears, let's see what happened to the hobs: if in certain operations using not coated hobs were cut, for example, 200 pieces before having to sharpen the tool, with the coated hobs it was possible tod cut 1000 pieces under equal conditions of work and wear. This has meant a 80% reduction of hobs need. A striking case that explains this trend well, is that the creators of the blade shows that had invaded the market, due to their higher profitability compared to the hobs grains, but are then quickly disappeared, unable to be coated. Then, let's enter a little more in detail about the coating methods and their characteristics. Coating method CVD This technique transforms the elements to be deposited in the vapor state and brings them in contact with the work-piece to be coated in an environment where the pressure is of 10 100 mbar and the temperature is between 800 and 1000 ° C. In these conditions are developed chemical reactions that allow the adhesion of the elements to the work-piece surface. The first, and also the most widespread applications of this method, were those of the TiN coating of carbide inserts used in turning and milling. Since the temperature in which the process takes place is relatively high, however above the tempering limit of high-speed steels, this process has remained restricted, for a certain limited time, only to the coating of carbide tools. High speed steels, therefore, cannot be coated with the CVD method, because they would lose their hardness at temperatures between 800 ° C and 1100 ° C, to which the process is realized. Additionally the process temperature would cause deformations which could be recovered only with grinding operations, but also they will remove the covering. In summary, the CVD method therefore presents the following characteristics:  excellent adhesion of the film on all surfaces;  good coating also on complex shapes and in blind holes;  temperatures too high to be able to cover the steel, so it is limited to carbide tools. Coating method PVD The great advantage of this method of coating is that it can take place at temperatures below 520 ° C (generally the limit of tempering of high speed steels), with the added advantage that it could also take place at lower temperatures, which practically does not involve deformation of the processed parts.

This allowed to apply this process to almost all the high speed steel tools and the components used, in extreme conditions, in the aircraft and automotive industry. This particular coating technology is highly developed also because it is a physical process, not chemical, and therefore does not use reagents which are difficult to dispose of. In summary, the CVD method has the following characteristics:  increased flexibility of the process with the possibility of coating nearly every type of metal;  possibility of coating for industrial use and for decorative purposes;  absence of structural and dimensional variations which allow the coating process on finished products;  no ecological problems. The coatings made with the PVD method are of various kinds and this will be discussed later; however, must bear in mind that these different types do not exhaust the theoretical possibilities of this deposition system, as it could use many other coating elements on pieces of various nature. The only constraint would be that the piece or, how do you use to call it, the substrate, bear without alteration the temperature of the process. However, the wider diffusion of the PVD coating, in addition to the decorative sector, took place in an industrial sector, where the demands of materials performance are increasingly higher and where the large-scale adoption of the coating has brought very great benefits. To understand how great was the impact on the world of mechanics due to the introduction of the coating material of TiN type, suffice to say that it has stimulated the creation of a new generation of high-speed gearing, which has allowed us to reduce the processing time to a fraction compared to the existing situation. The success of the PVD coating process is mainly due to the following general characteristics of the coating layer:     

great hardness and then high resistance to wear and craterization; very low coefficient of friction; poor chemical affinity with the other elements, which results in a good resistance to corrosion and adhesive wear; resistance to high temperatures; better aesthetic appearance of the piece.

Figure N°1- Load of tools for spur gears cutting exiting the coating facility

But these technical features, which certainly increase the efficiency of the tools, would not be sufficient to ensure a performance consistency; in fact, it is also necessary that the deposited film (substrate) is such that it can follow, as closely as possible, the deformation of the work-piece, i.e. the substrate, without damage or detach from the piece itself. The various coatings must be therefore designed so that the coefficient of thermal expansion and elastic modulus are closer to those of the work-piece to be coated. Cycle of PVD coating The coating cycle comprises several stages, all very important, which depend very much on the conditions of the part to be coated. First of all the tools must be absolutely free of burrs and the cutting edges shall be properly homogeneous. There are several techniques to achieve these requirements. The parts then must be thoroughly washed, for example with water and alkaline cleaners, and sometimes also acids, to eliminate possible oxides. The mechanical action of cleaning is realized through ultrasonic or spray jets. The rinsing is done with demineralized water with a conductivity monitored in microSiemens. Finally, the parts are loaded into vacuum chambers on a rotating carousel as that shown in Figure N°1. The coating room has a plan view which is schematically represented in Figure N°2, but which may have other layouts, in relation to the choices made by the manufacturer. The first phase is the heating, combined with the extraction of all the air, until reaching an ultimate vacuum of the order of magnitude of 10-4 Pa. This is necessary to remove virtually all the air and oxygen that may generate the formation of surface oxides. The temperature may vary according to the type of coating, but is typically between 100 and 600 ° C. At this point begins the operation by ION etching. It consists in a phase of "cleaning" where the parts are bombarded by ions with high potential. This is done to prepare the surface of the parts to be coated, removing every little impurities in order to increase the adhesion of the covering layer and activate the surface, preparing it for the coating. In practice it is carried out by entering in the chamber an inert gas, typically argon appropriately ionized and directing the flow of ions against the surface to be cleaned. The pressure in this phase may vary from 5:10 -4 to 5.10 -2 mbar. The process takes place in an electric field generated by a potential difference (bias), which can vary from 200 to 1000 V depending on the various procedures utilized. Once this phase is completed, in the chamber are entered one or more reactive gases, for example nitrogen or acetylene, which have the purpose of reacting chemically with the vaporized metals chosen for the coating. The pressures reached in these phases are ranging from 0.05 to 5 Pa, with bias voltages ranging from 20 to 200 V. The room temperature during deposition can be up to 600-620 ° C and in general, the higher the temperature the better the characteristics of the coatings in terms of hardness, adhesion and modulus of elasticity. Obviously the temperature must take account of the substrate which must not be damaged. For example, the limit for high speed steels is indeed 520°C, otherwise the danger of a certain tempering. Note that the bombing of the filler material generates localized overheating. At this point we can talk about a differentiation of the coating methods. A first technology involves the use of sputtering to erode the material of the target to be deposited, through to a plasma in a vacuum. In the diagram of Figure N°2 there are four and are indicated by numbers 1 to 4.

The material thus eroded is attracted towards the central zone in which are placed the parts to be treated. The force that accelerates the ionized atoms is always given by a potential difference between the cathode (target) and the anode (part). This method produces a very fine coating because it is exempt from the phenomenon of droplets, described later, but it has the disadvantage of being very slow and therefore expensive.

Figure N°2 – Schematic layout of the coating room PVD Instead of sputter deposition is more frequently used the vaporization of the target material with the arc method. In the arc evaporation the ignition is caused by an electric arc in vacuum between a cathode (material to be deposited) and the walls of the room (anode). The very high current density (of the order of one million amperes per square millimeter) that is realized within the cathode spot, causes an intense evaporation combined with ionization of the material contained in it. The localization of the discharge on an area of modest dimensions means that the remaining part of the source is below the melting temperature. The substrates to be coated are, in turn, negatively polarized and attract the ionized vapors, accelerating them. It is generated, in this way, an intense ion bombardment that promotes adhesion of the coating on the substrate. The ions are accelerated up to a speeds of 104 ÷ 105 m / sec. This method has the considerable advantage of being relatively fast, but has the drawback that in the area affected by the arc where there has been the vaporization and ionization of the removed material, it also causes some fusion of the same material forming small droplets which will deposit on the surface to be coated. These droplets of molten material break the uniformity of the layer and therefore are damaging (Figure N°3). The size of the droplets are of the order 0.1 to 10 microns.

Figure N°3 - Formation of droplets The point of contact between the arc and the target is changed continuously also to have a uniform removal of the material of the target. About the material of the target, which we recall, is the metal material that will be deposited on the parts, may be different in each individual cathode positioned in the chamber. With reference to Figure N°2, for example, in position 1 may be titanium, in position 2 may be aluminum, in position 3 chromium, etc... By handling appropriately the direction of the arc, you can mix the various elements and form compounds or multilayer coatings with different characteristics. Are also available targets with mixed compositions, such as titanium-aluminum, titanium, chromium, etc.., but these solutions, even if more practical, do lose a little of the process flexibility. In Figure N°4 are shown different possible types of coatings.

Figure N°4 – Different types of coatings The coatings performed by miniToolsCoating generally have a thickness between 1 and 4 microns and perfectly follow the shape of the underlying surfaces. Sharp edges remain virtually unchanged and also the surface roughness can only get better. Coatings Control The cycle of treatment is managed by a numeric control system which uses a property software of miniToolsCoating, for which the process is extremely reliable: however there are some phases of the operation which depend on the care of the operator, as the

cleaning and decontamination of deposition chamber, the positioning of the pieces, the cleaning of the parts, etc.. and therefore it is necessary to check the results through rigorous testing on each load. In addition to an optical control which verifies the absence of macroscopic imperfections is performed, on a specimen that is placed in the chamber at every treatment, the check of the adhesion and the film thickness. For adhesion is used the so-called "Mercedes Test" that execute an impression with a indenter of a normal Rockwell device. By the type of impression you can understand the quality of the accession.

Figure N°5

Figure N°6

On Figure N°5 you can see schematically some impression features. The quality of the adhesion decreases from the imprint HF1 to the imprint HF6; up to the imprint HF4 the adhesion is acceptable, while imprint HF5 and HF6 indicate adhesion not acceptable. In Figure N°6 you can see instead the real impression of a layer with a good adhesion. Great importance to have a good adhesion has the phase of etching. It is evident that a good preparation of the surface to be coated increases the adhesion of ions and atoms on the surface. In Figure N°7 it can be noted the deleterious effect of the lack of phase etching.

Figure N°06.7

To check the thickness of the film is used instead of the "Calo Test". A sphere is rotated in contact with the test specimen up to the bare substrate. The thickness of the layer is determined based on the diameter of the sphere and the one of the imprint.

Figure N°8 With the data obtained from Figure N°8, we have:  Sphere diameter D = 30 mm (30.000 µm)  Outer diameter of the imprint D1 = 849,56 µm  Inner diameter of the imprint D2 = 433,77 µm Layer thickness

where

is obtained with

With the collected data we have in fact: that is

Tan α = 46,74267

and then

4,45 µm

These two types of tests however are not suitable for a control of very thin coatings (nanolayers) and then were developed other types of control, one of which is the scratch test. With reference to Figure N°9 the way to proceed is the following: A spherical diamond indenter, of the type used for the hardness control Rockwell, is pressed with a force which increases progressively on the surface to be checked while the piece to be checked moves at constant speed. During this phase, a sensor measures:  the acoustic emission;  the depth of penetration;  the tangential force required to move the piece. Reached a certain critical load, the film coating starts to break and this is detected, in addition of monitoring the three parameters mentioned above, also by observing the track with a microscope.

Figure N°9 The behavior analysis of the impression (comparable to a scratch) observed under the microscope, allows an evaluation of the adhesion of the film on the substrate. Figure N°10 shows the various types of subsidence of the layer and the corresponding trend of the adhesion.

Figure N°10 This verification method of the adhesion is more accurate of the Mercedes Test and, moreover, in the nano-composite coatings the Mercedes test is not reliable. The Scratch Test is the only valid for check the adhesion of carbide tools. Another important parameter to be controlled is the hardness of the coating film. Since the thickness of the covering layer is small, the traditional methods (i.e. Brinell, Rockwell, Vickers etc...) are not valid for detecting the hardness.

Indeed, in the case of coating, the reliability of the measurement of the hardness depends on the ratio between the depth of measurement and the thickness of the coating itself, which should not exceed 1/10, otherwise the value found may be influenced by the hardness of the material on which the coating is deposited. In the case of "traditional" coatings (galvanic coatings, chemical nickel plating, chrome thickness plating, etc..), in which the thicknesses are of the order of a tenth of a millimeter, it is called micro-hardness (the indenter proceeds at depth of cents millimeter). In the case of PVD or CVD coating, where the thicknesses are in the order of a thousandth of a millimeter (microns), it is necessary to perform penetrations deep few thousandths of a micron (nanometers), thus measuring the nano-hardness. This is known as importance of nano-hardness expressed in GPa (Giga Pascal). This is based on measurement of the impression left by a pyramid-shaped diamond indenter (of the type used for the measurement Vickers), which penetrates the film for few nm. In particular, we refer to the analysis of the curve of the loading / unloading in which the value of the applied load is shown on a graph, according to the corresponding area of the produced impression. After having reached a predetermined maximum load (or a maximum depth) the load is reduced (and the depth of penetration decreases) because the material recovers elasticity. The elastic properties are determined by the slope of discharge curve, and the hardness is derived from the residual depth of the discharge curve. The nano-hardness, as has been said, is measured in GPa and is obtained from the following formula:

where A (hc) is the area of the impression permanent, that is, what remains after the release of the load F.

Figure N°11 FN is the normal component of the applied force; hmax is the maximum depth reached by the indenter during a measurement; hf is the depth of the permanent imprint after each measurement; hc is the height to which the material follows the shape of the indenter (in practice it is excluded the flaring of the imprint); hmax = hs - hc

Figure N°12 - Curves of loading and unloading of the depth of the imprint As can be seen the permanent imprint depth, in the case shown, is a little more than 600 nanometers (0.6 micrometers). As an example, Table N°1 shows the values of the nano-hardness of some materials. Table N°1 Material Stainless steel DLC in different combinations Natural diamond Pure DLC TiN (titanium nitride) TiCN (titanium carbonitride) TiAlN (titanium aluminum nitride) TiAlCN (titanium aluminum carbonitride)

Nano-hardness GPa 3 9 - 30 60 - 80 60 - 130 24 31 35 - 40 28

But let's see what it is, intuitively, a Giga Pascal. Literally it means one billion of Pascal. The Pascal is the measurement unit of pressure and, precisely, is one Newton per square meter (Pa = N/m2). It is a very little pressure; just to realize what it means it would be the pressure that exerts half pound of sugar spread evenly on a square meter. If we transform N in kg (weight force) and m2 mm2, we have:

So 1 GPa corresponds to 100 kg/mm2 Another very important consideration is the control of the surface in order to put in evidence an excessive amount of droplets. This analysis can be performed with a good three-dimensional microscope that can represent the surface in topological form.

Figure N°13 From the Figure N°13 you may have already an idea of the state of the surface and the presence of droplets, but even more evident is the representation of the same area where the Z axis is amplified by 10 times. (Figure N°14). We can see that this control also provides an estimate of the surface roughness.

Figure N°14 - Topological representation of the surface with very large amplification of the Z axis As you can easily understand, the execution of a good coating and the control of the results obtained is the outcome of high specialization that only companies that are dedicated specifically in this area can provide.

Coating service miniToolsCoating miniToolsCoating performs thin film coatings in high vacuum PVD technology. PVD coatings are made with the use of the best and most up-to-date technologies. They are the result of a close technical cooperation with the manufacturers of the equipment used, the experience gained in daily relationship with our customers and the professionalism of our staff. The coating service is offered to a wide audience of clients operating in various fields of mechanics. As an example we can list:  Tools industry: in addition to the tools for the machining of gears, both cylindrical and conical (bevel), are coated all the tools used for the general mechanics (twist drills, milling cutters, taps, inserts, etc...), as well as the tools for high performance, even in carbide.  he field of molds and components for punching and forming, plastic molds, molds for castings, punches and molds for sintering. Here we must highlight that coating of miniToolsCoating reach very high hardness and a reduced surface roughness, and this facilitates the distribution of the powders, allowing to reach a higher density of the product in addition of reducing maintenance on dies and punches.  Organs and mechanical components that require a low coefficient of friction, or a strong resistance to wear or even elements that must resist corrosion, etc.. Basically, one can adapt the technologies and materials of the coating to the diverse needs of our customers. The coatings carried out by miniToolsCoating generally have a thickness between 1 and 4 microns and recopied perfectly the shape underlying surfaces. Sharp edges remain virtually unchanged and also the roughness of the coated surfaces remains practically unchanged. The coatings that we realize have special structures and compositions that provide to the treated surfaces the most suitable characteristics to be exploited in the specific applications. The table N°2 shows the basic characteristics of the various types of coatings executed by miniToolsCoating. Table N°2 Typical Thickness (µm)

Coating Temperaure. (°C)

Max Operating Temp. (°C)

Friction Coefficient on 100Cr6

Type

Hardness (HV0,05)

TiN

2900

0,5 - 7

300 – 480 °C

600 °C

0,4

TiCN

3200

0,5 – 3

450 °C

420 °C

0,3

AlTiN nano

3200

0,5 – 4

300 – 480 °C

900 °C

0,4

ComposAl

3200

2,0 – 6

450 °C

900 °C

0,6

ALTICROME

3400

0,5 – 5

480 °C

1100 °C

0,35

Grey

SILICUT

3200

0,5 – 2

480 °C

> 1100 °C

0,4

Purple

CrN

2000

0,5 – 15

250 – 450 °C

700 °C

0,3

Steel grey

CBC

3200

0,5 – 5

480 °C

400 °C

0,25

Dark grey

CROMVIC

2000

1-3

250 °C

400 °C

0,15

Black

Colour Yellow gold Grey / Blue Dark purple Dark purple

The current capacity of coating facilities allow to work parts that are contained within the maximum space of a cylinder with a diameter of 600 mm and height 800 mm, with a maximum weight of 500 Kg. The following are the main features and fields of application of the various coatings:

TiN - Titanium Nitride The TiN coating is the best known and most widely used among the PVD coatings; it manages to combine a good hardness value at an excellent toughness and adhesion to substrates. The TiN is also characterized by a reduced coefficient of friction and a high chemical inertness towards the materials with which it is put in contact. Its properties, that remain stable up to the oxidation temperature, allow the TiN to be used with success in all the processes with chips removal as well as in the various operations of molding, shearing and sintering. miniToolsCoating realize different customizations of TiN coating, each optimized for specific applications. Some example are:  TiN for Gleason-type solid mill cutter of our production, where the performance is almost doubled compared to traditional TiN;  LT (Low Temperature) version with coating temperature reduced to 300 ° C for special applications;  the realization of a TiN with improved corrosion resistance, for parts subject to stay in oxidizing environments;  the realization of TiN particularly smooth for the application to sintering dentate punches. TiCN - Titanium Carbo Nitride The TiCN coating is an evolution of TiN: in practice, it is used as Carbon interstitial element of the TiN lattice; this is tensioning the coating, increasing very much the hardness, but also its fragility. The TiCN coating produced by miniToolsCoating is characterized by a particular graduation of the percentage of carbon present in the layer, designed to obtain high toughness property, while preserving the characteristic hardness of this coating. The presence of Carbon allows a reduction of the friction coefficient, as well as the reduction of the chemical affinity of the coating in respect of non-ferrous material, and increases the resistance to corrosion. The presence of Carbon allows the effective use of TiCN until the operating temperature reaches, even locally, the 420 °C.. It is used mainly on HSS tools for drilling, tapping and milling, especially for machining of non-ferrous metals, such as aluminum or bronze, and light alloys. miniToolsCoating produces a special version, called TiCN BRONZE, specific for application on steel hobs for bronze worm wheel cut which, together with our sharpening precision, allows optimum tools performance. It is generally indicated in shearing and shaping operations of non-ferrous materials and metal sheets with galvanizing treatments, such as aluminized, galvanized or pre-tinned sheets. AITiN nano - Alluminum Titanium Nitride nanolayer Its formulation, is based on nanolayers of nitrides of titanium and aluminum, gives this coating characteristics of low friction coefficient and excellent toughness, combined with a high surface hardness. The particular deposition technology (LARC ® - Lateral Rotating Arc Cathods) allows to obtain a coating almost free from droplets, the micro-droplets characteristics of the electric arc technology, and then a particularly smooth surface. The very high percentage of aluminum, close to 70%, allows the formation of a layer of aluminum oxide (Al2O3), which creates a effective thermal barrier, up to temperatures of use next to 900 ° C. It is also realized the LT version (Low Temperature) with reduced deposition temperature, down to 300 ° C, for special applications.

AlTiN nano is used on drills and mill cutters of steel and carbide, for general applications but also for high-speed machining of ferrous materials with hardness up to 55-56 HRC. The characteristics of AlTiN nano make it suitable for applications in molds for shearing and shaping of ferrous materials. One application that is particularly effective in molds and punches for the sintering of metal powders, where the high hardness and the almost total absence of droplets allow a better sliding of the powders and a consequent increase in the density of the sintered products. The dark purple color of this coating also makes it suitable for decorative applications, where the characteristic resistance to scratching and matching to a particular substrate preparation in order to make it reflective, make AlTiN nano coating particularly appreciated ComposAl - Titanium Alluminum Nitride multilayer ComposAL is a textured coating in groups of nano-layers, each designed with specific characteristics which combine in a synergistic way. The produced layer is being both very hard and very tough, with characteristics unchanged up to high temperature. The revolutionary technology of deposition used (LARC-Lateral Rotating Arc Cathods) allows to obtain coating with excellent surface finish, limiting the phenomenon of precipitation of particles of unreached material (droplets), making superfluous the use of expensive top-layer self-lubricating. The experience gained by miniToolsCoating in the field of PVD coatings applied to tolls for gears, and the simultaneous development of nano-technology used for the production of the most innovative coating, have led us to make a specific coating for the application on hob and shaper cutters tools. ComposAL is a coating with outstanding performance that can be successfully used both in conventional processes realized on mechanical machines than in high-speed machining (HSC), or dry processes, with strong heat development. ALTICROME - Alluminum Titanium Cromium Nitride Nano-structured coating, highly resistant to abrasion and corrosion, with high strenght at elevated temperatures and excellent anti-adhesive properties. Thanks to its unique structure is also suitable to be easily polished (treatment PLUS), enabling a particularly smooth and non-stincking surface. ALTICROME was developed specifically for application to molds and components for the aluminum die casting , where you deal with high operating temperatures and the wear phenomena of abrasion and corrosion. Its low coefficient of friction and easy release property allow a better flow of the casting and a reduction of the phenomena of metalization, improving the quality and facilitating the extraction of the molded components. The molds' maintenance is drastically reduced. ALTICROME is used with excellent results on hobs and sharper cutters in HSS for the gears toothing, where its features allow an optimal chip flow even at high cutting speeds. The possibility of performing systematically de-coating, re-sharpening and new coating, allows very repetitive and reliable performance. This is an important fact for mass production. ALTICROME is suitable for applications on molds for shearing and shaping of high alloyed steel and stainless steels, on punches and dies for mint-aging and bending. In the molding of plastic materials loaded with glass fibers or carbon, is used because the excellent combination of hardness, smoothness and corrosion resistance.

CrN - Chromium Nitride Monolayer coating characterized by excellent adhesion to substrates and low structural tension .

Its characteristics are: high toughness, good corrosion resistance, anti-adhesive properties and mold release, as well as reduced coefficient of friction, all this together with a moderate hardness. It can be deposited at low temperature (about 250 °C). It is mainly used in the molding of plastics. The low deposition temperature and the excellent adhesion to the substrates make it particularly suitable for the application of copper alloys Beryllium and in general to materials that can not be coated at the normal temperatures of PVD coatings. It is also referred to the application of tools for chips removal in the machining of copper, beryllium-copper alloys, aluminum-titanium alloys or Ampco bronze. CBC It's part of the family of DLC coatings (Diamond Like Carbon). CBC is a coating structured in two layers: the first layer is a Carbo Nitride Titanium with a particular graduation of carbon to render the layer hard and tough at the same time; the second is a layer of amorphous carbon with a low coefficient of friction and with high chemical inertness. The mechanical properties remain unchanged up to the oxidation temperature of 400 ° C. CBC is a coating that has been specially developed for the use of hobs of large module, where the cutting speed is limited. It allows a good chip evacuation and a clean and brilliant cut. It is successfully used in the sharing and shaping of light alloys in general and pasty materials. CROMVIC - Chromium-Nitride Carbo It's part of the family of DLC coatings (Diamond Like Carbon). It is realized with electric arc technology and is composed of a layer of adhesion of Chromium Nitride and a layer of amorphous carbon. The main characteristics of this coating are the low coefficient of friction and high chemical inertia, combined with good hardness and good adhesion to the substrates. It is realized out at a temperature of 250 °C, this broadens a lot the field of applicability. CROMVIC is used in the molding of plastic materials, even in the absence of release agents, in the sheared and shaping of light alloys and, in genera, of pasty materials. It is frequently used to coat mechanical organs of various types, such as extractors for molds, trolleys and centering of molds, camshafts, valves and other, where the reduction of friction is crucial. SILICUT - Titanium-Aluminum-Silicon Nitride SILICUT is a nano-structured coating, obtained by incorporation of nano-crystals of nitrides of titanium and aluminum in a matrix of silicon nitride. The matrix forms a thin film around the nano-crystalline AlTiN, which act as strong interface and gives to the layer the typical structure of composite materials. The high percentage of aluminum present in the layer allows the formation of a thermal barrier efficiencies up to over 1100 °C. The silicon, present in different percentages in the layer, involves the formation of a ceramic coating with high hardness, low coefficient of friction of high resistance against abrasive wear. SILICUT has been developed for application to tools for chips removal in hard metal, used in high speed finishing operations, also dry and/or hardened materials up to 64 HRC. Excellent results are obtained in the application in steel punches and hard metal for stuffing stamping and deformation of ferrous materials.

The current capacity of the coating facilities allow the coating of parts that are contained within the maximum space of a cylinder with a diameter of 600 mm and height 800 mm, with a maximum weight of 500 Kg. They are strict controls on each load in the coating systems, even if the process cycle is controlled by a numeric control system which uses a property software of miniToolsCoating. However there are some phases of the operation which depend on the care of the operator, like the cleaning and decontamination of the deposition chamber, the positioning of the pieces, the cleaning of the parts, etc.. and therefore a check of the results is necessary.

Figure N°15