The present invention relates to the field of the hard coating films. In particular the present invention relates to a coating system formed by a plurality of AlCr-based layers deposited forming a multilayer architecture. The present invention relates furthermore to articles coated with the inventive coating system and methods for producing the inventive coating systems.

In the context of the present invention the inventive coating system is an AlCr-based protective multilayer coating system (hereafter also called coating scheme)that provides improved protection to articles that are coated with it, for example longer life of the respective coated article in a broad range of different applications, which are covering in particular the application fields of cutting and forming tools, as well as wear components.

Exemplary coated articles in this context include without limitation cutting tools, forming tools and wear components.

State of the art

US10184187B2 discloses a method for the production of layers including M-AI-N wherein Al > 0.64. Moreover, both US 9,168,664 B2 and US 9,896,767 B2 disclose the M-AI-N layers with their properties, where the said layers can have residual compressive stress only less than 2.5 GPa, what limit an application range. The same stress limitation is given in US20150050490A1 for M-i-xAlxN wherein x > 0.68.

In addition, in the cutting tools proposed in Japanese Unexamined Patent Publication No. 2014-69258 coated tools such as drills and the like are coated by the first and the third hard coating films, both of which are made of TiAICrSiN; and the second coating film made of TiSiN. The film thickness of the first coating film is thicker than thicknesses of the second and the third coating films. By having the hard coating film with the above-described coating structure, the film stress of each hard coating film constituting the multilayer hard film is reduced. It is understood that even a cutting tool with a small diameter such as drills can be coated with the multilayered film; and such a tool shows an excellent wear resistance in the given application of drills with small diameter.

US9103036B2 discloses M-i-xAlxN wherein x > 0.5 and M is titanium or chromium, the refractory layer having 0.5 to 15 weight percent hexagonal phase, and the cubic phase forming nanolayer has a thickness only in the range of 2 nm to 20 nm.

US20190017162A1 discloses the hard coating layer being made of an alternate laminated structure, in which at least one A layer and at least one B layer are alternately laminated, where said layers A and B are made from different targets.

Anders et al. propose in WO 2016/102170 A1 a coating system for reducing crater wear of cutting tools during machining operations, which is expected to be particularly beneficial in dry machining operations such as hobbing.

In summary, numerous prior art coatings show good protective performance, especially wear protective performance for more or less special applications. Moreover, numerous prior art coatings show properties that limit its application range, and/or the method to produce said coatings is complex and often includes the use of different target types, that limit the efficiency of the production process. However, steady new increased demands for the increased performance and the highly efficient fabrication method by the use of only one target type need to be met. Therefore, in spite of the benefits attained with the above mentioned coatings as well as with other currently available coatings, it still remains a need to provide a new protective coating for a broad range of different applications that shows an improved protection i.e. life of the respective coated article in a broad range of different applications, which are covering the application fields of cutting and forming tools, as well as wear components.

In particular in the case that the coated article is a cutting tool, for mentioning one example of a coated article, a coated cutting tool typically comprises a substrate with a coating scheme (also called coating system) thereon. Coated cutting tools are useful for the removal of material in a chip forming material removal operation. Depending on the workpiece material, machining process and cutting parameters, a great amount of both wear, especially abrasive wear, and crack formation and propagation (especially in wet machining) and/or transfer of the heat (especially in dry machining) can exist at the interface of cutting tool and chip. Therefore, both wear, especially abrasive wear, and crack formation and propagation (especially in wet machining) and/or transfer of the heat (especially in dry machining) at the cutting chip interface into the substrate and the interface between the coating scheme and the substrate (i.e. coating-substrate interface) can be detrimental to cutting tool performance.

The coating scheme typically influences wear, crack formation and propagation and the extent of heat transfer from the cutting tool-chip interface to the substrate and coating-substrate interface. Both physical and chemical properties of the coating scheme strongly influence all wear, crack formation and propagation and the extent of such heat transfer.

The coated articles and the coating methods according to state of the art and numerous available market benchmarks already lead to good results. However, there is still a strong market-driven need for new coatings exhibiting a combination of enhanced properties such as outstanding wear resistance, especially abrasion resistance, thermal barrier properties and enhanced resistance against generation and propagation of cracks, where said coating would be produced by as more efficient as possible method.

Objective of the present invention

The main objective of the present invention is to provide a coating solution to overcome or at least to reduce the drawbacks of the coatings according to the state of the art.

In particular the coating solution should provide a combination of enhanced properties such as outstanding wear resistance, especially abrasion resistance, thermal barrier properties and enhanced resistance against generation and propagation of cracks. A further objective of the present invention is to provide a method for applying the coating solution, where said coating solution can be produced as efficiently as possible.

In particular the method should allow applying a coating scheme according to the present invention to different kind of articles, where the method should be highly efficient and especially it should allow a high productivity for the manufacture of the coated articles.

In particular the present invention should provide a new coating system (also called coating scheme) that exhibits enhanced properties which can be suitable to meet the growing demands in a broad range of different applications, which are covering the application fields of cutting, such as milling, both roughing and finishing, and forming tools (such as for example fineblanking, punching, trimming, piercing, hot and cold forging) as well as wear components.

Description of the present invention

The objectives of the present invention are attained by providing a coating system as described below and also claimed in the claims 1 to 19, coated articles as described below and also claimed in the claims 20 to 28, and a method as described below and also claimed in the claims 29 to 35. The Figures 1 to 6 as well as the examples described below are used for facilitating explanation of the present invention and should not be understood as a limitation of the present invention but only as showcases.

The coating system provided by the present invention is deposited on a surface of a substrate and comprises three essential coating films, an upper coating film, an under coating film that is deposited closer to the substrate than the upper coating film, and an interjacent coating film deposited in between the under coating film and the upper coating film. The inventive coating system can optionally comprise further coating films, in particular an interfacial film deposited between the substrate and the under coating film for improving adhesion of the under coating film of the coating system to the substrate and/or retention of the under coating film of the coating system at the substrate.

A first preferred embodiments of a coating system according to the present invention is schematically shown in Figure 1 a. In this embodiment, the coating system 200 comprises an upper coating film 240, an under coating film 220 that is deposited closer to the substrate 100 than the upper coating film 240, and an interjacent coating film 230 deposited in between the under coating film 220 and the upper coating film 240. The coating system 200 shown in Figure 1 further comprises an interfacial film 210, however this interfacial film is not an essential feature of a coating system according to the present invention and therefore can be optionally included. In this first preferred embodiment the under coating film 220 exhibits a multilayer architecture formed of individual layers 220. i with i varying from i=1 to i=n, where i and n are natural numbers and n is at least two, i.e. n>2.

A second preferred embodiments of a coating system according to the present is similar to the first preferred embodiment but differs from the first preferred embodiment in that the multilayer architecture of the under coating film 220 comprises additionally transitional coating layers 221 .i with i varying from i=1 to i=n- 1 , where the transitional coating layers 221. i are deposited between the individual layers 220. i as it is schematically shown in Figure 1 b.

The upper coating film 240 in any embodiment of a coating system according to the present invention, can be deposited as monolayer, preferably as top layer of the coating system.

The interjacent coating film 230 in any embodiment of a coating system according to the present invention, is deposited as a transition film, beginning at the end of the under coating film and ending at the beginning of the upper coating film.

An interfacial film 210 (as it is shown in Figure 1 a) is optionally included in any embodiment of a coating system according to the present invention for improving adhesion of the under coating film of the coating system to the substrate and/or retention of the under coating film of the coating system at the substrate. The interfacial film 210 is deposited in-between substrate 100 (the substrate can be any article, in particular any article mentioned in the present description) and the under coating film 220, where said interfacial film is preferably made by:

- depositing a film comprising one or more metals,

- depositing a film comprising one or more metals and nitrogen (N),

- modifying the substrate surface on which the coating system is deposited for example by subjecting the substrate surface to be coated to a nitriding process and/or a carbonitriding process and/or a metal ion etching process, or

- a combination of one or more of the above mentioned possibilities

The multilayer architecture of under coating films 220 according to the first preferred embodiment, as mentioned above, does not content transitional coating layers 221 .i but only individual layers 220. i.

In both preferred embodiments mentioned above (the first preferred embodiment and the second preferred embodiment), the individual layers 220. i are produced in such a manner that each individual layer differs from the next deposited individual layer in at least one physical and/or chemical property. It means that for example, in an under coating film 220 comprising n individual layers with n > 4, the first individual layer 220.1 differs from the second individual layer 220.2 in at least one physical and/or chemical property, and the second individual layer 220.2 differs from the third individual layer 220.3 in at least one physical and/or chemical property and so on along the whole thickness of the under coating film 220, so that also the penultimate individual layer 220. n-1 differs from the last individual layer 220. n in at least one physical and/or chemical property.

The at least one physical and/or physical property in which the individual layers differ according to the present invention is preferably one of following: hardness, elastic modulus, texture, compressive stress, crystalline size, concentration of the chemical elements comprised.

In order to attain the above mentioned differences between the individual layers 220. i comprised in the under coating film 220, each individual layer is deposited by using a different set of coating process parameters. It means that for example, for the deposition of an under coating film 220 comprising n individual layers with n > 4, a first set of coating process parameters is used for depositing the first individual layer 220.1 and a second set of coating process parameters is used for depositing the second individual layer 220.2, and a third set of coating process parameters is used for depositing the third individual layer 220.3, and so on during the whole deposition of the under coating film 220, so that also a penultimate set of coating process parameters is used for depositing the penultimate individual layer 22O.n-1 and a last set of coating process parameters is used for depositing the last individual layer 220. n, where in each case the set of coating process parameters used for depositing a previous individual layer differs from the set of coating process parameters used for depositing the next individual layer in at least one coating process parameter, i.e.:

- the set of coating process parameters used for deposition of the individual layer

220.1 differs from the set of coating process parameters used for deposition of the individual layer 220.2 in at least one coating process parameter, and

- the set of coating process parameters used for deposition of the individual layer

220.2 differs from the set of coating process parameters used for deposition of the individual layer 220.3 in at least one coating process parameter, and so on during the whole deposition of the under coating film 220, so that also

- the set of coating process parameters used for deposition of the individual layer 220. n-1 differs from the set of coating process parameters used for deposition of the individual layer 220. n in at least one coating process parameter.

The at least one coating process parameter in which the set of coating process parameters differs for the deposition of the different individual layers according to the present invention is preferably one of following: substrate temperature, substrate rotation, substrate bias current, substrate bias voltage, substrate bias voltage settings (e.g. non-pulsed, pulsed), gas flow or pressure of specific gases (e.g. H2, Ar, He, Ne, N2, CH4, C2H2, O2), arc source current, arc source voltage.

An under coating film 220 deposited according to the first preferred embodiment mentioned above is preferably produced according to one of the following variants:

Variant A: depositing each one of the individual layers 220. i comprised in the under coating film 220 by using a respective constant set of coating process parameters, it means by maintaining the respective set of coating process parameters constant during the deposition of the respective individual layer, or

- Variant B: depositing each one of the individual layers 220. i comprised in the under coating film 220 by using a variable set of coating process parameters, it means by varying continuously at least one coating process parameter of the respective set of coating process parameters during the deposition of the respective individual layer, or

- Variant C: depositing at least one individual layer by using a respective constant set of coating process parameters as mentioned in Variant A, and depositing at least one individual layer by using a variable set of coating parameters as mentioned in Variant B, so that the whole multilayer structure of the under coating film 220 is formed by a combination of individual layers deposited by using a constant set of coating process parameters and individual layers deposited by using a variable set of coating process parameters.

The term “varying continuously” used in the description above in Variant B indicates that at least one coating process parameters varying continuously does not change abruptly but gradually.

However for producing coating systems according to the first embodiment of the present invention, the change from a previous set of coating process parameters used for depositing a respective previous individual layer to a directly next set of coating process parameters used for depositing a respective directly next individual layer needs to be abrupt in order to produce a clear difference between the previous individual layer and the directly next individual layer deposited atop of the previous individual layer.

Preferably, if the bias voltage is varied during deposition of a coating film or during deposition of a layer comprised in a coating film, then the bias voltage value is increased in absolute values, it means that the bias voltage in absolute value at the end of the deposition is higher than the bias voltage in absolute value at the begin of the deposition. Preferably negative bias voltages are used.

It means for example that in a case in which the different sets of coating process parameters only differ in the absolute value of the negative bias voltage applied, and the under coating film 220 only comprises two individual layers 220.1 and 220.2, then:

- According to Variant A: o A first absolute value U1 of negative bias is set and maintained constant for depositing the first individual layer 220.1 , and a second absolute value U2 of negative bias voltage is set and maintained constant for depositing the second layer 220.2, where U2>U1 , or

- According to Variant B: o A first absolute value U1 a of negative bias voltage is set at the begin of the deposition of the first individual layer 220.1 , and the bias voltage is varied continuously during deposition of the first individual layer

220.1 till finalizing the deposition of the first individual layer 220.1 at a second absolute value U1 b of negative bias voltage, and a third absolute value U2a of negative bias voltage is set at the begin of the deposition of the second individual layer 220.2, and the bias voltage is varied continuously during deposition of the second individual layer

220.2 till finalizing the deposition of the second individual layer 220.2 at a fourth absolute value U2b of negative bias voltage, where U1 a<U1 b and U1 b<U2a and U2a<U2b, or

- According to Variant C: o A first absolute value U1 a of negative bias voltage is set at the begin of the deposition of the first individual layer 220.1 , and the bias voltage is varied continuously during deposition of the first individual layer 220.1 till finalizing the deposition of the first individual layer 220.1 at a second absolute value U1 b of negative bias voltage, and a third absolute value U2 of negative bias voltage is set and maintained constant for depositing the second layer 220.2, where U1 a<U1 b and U1 b<U2, or o A first absolute value U1 of negative bias voltage is set and maintained constant for depositing the first individual layer 220.1 , and a second absolute value U2a of negative bias voltage is set at the begin of the deposition of the second individual layer 220.2, and the bias voltage is varied continuously during deposition of the second individual layer 220.2 till finalizing the deposition of the second individual layer 220.2 at a third absolute value U2b of bias voltage, where U1 <U2a and U2a<U2b.

For producing coating systems according to the second preferred embodiment of the present invention, the change from a previous set of coating process parameters used for depositing a respective previous individual layer to a directly next set of coating process parameters used for depositing a respective directly next individual layer is not abrupt as in the first preferred embodiment but includes the deposition of transitional layers 221. i in between two individual layers deposited one followed by the other as it is shown in Figure 1 b. The transitional layers 221. i have a layer thickness lower than the layer thickness of the individual layers 220. i and are provided to mitigate (to moderate) the impact in the mechanical stability of the under coating film 220, that can be caused by an abrupt change from a previous set of coating process parameters used for the deposition of a previous individual layer to a next set of coating process parameters used for the deposition of a next individual layer.

The transitional layers 221. i are provided in particular for increasing mechanical stability of the coating, more in particular for improving dissipation of mechanical load within the coating system structure and hereby increasing for example the resistance of the coating system to fatigue caused by repetitive impacts.

It means for example that in a case in which the different sets of coating process parameters only differ in the absolute value of the negative bias voltage applied, and the under coating film 220 only comprises two individual layers 220.1 and 220.2, then the under coating film 220 needs only to comprise one transitional layer 221.1 deposited directly atop the first individual layer 220.1 , wherein the second individual layer 220.2 is deposited directly atop the transitional layer 221 .1 :

- According to Variant A: o A first absolute value U1 of negative bias voltage is set and maintained constant for depositing the first individual layer 220.1 , afterwards the bias voltage is varied continuously during deposition of the transitional layer 221.1 from the first value U1 till finalizing the deposition of the transitional layer 221 .1 at a second absolute value U2 of negative bias voltage, and this second value U2 is maintained constant for depositing the second layer 220.2, where U1 <U2, or

- According to Variant B: o A first absolute value U1 a of negative bias voltage is set at the begin of the deposition of the first individual layer 220.1 , and the bias voltage is varied continuously during deposition of the first individual layer 220.1 till finalizing the deposition of the first individual layer 220.1 at a second absolute value U1 b of negative bias voltage, afterwards the bias voltage is varied continuously during deposition of the transitional layer 221.1 from the second value U1 b till finalizing the deposition of the transitional layer 221.1 at a third absolute value U2a of negative bias voltage, and this third value is set at the begin of the deposition of the second individual layer 220.2, and the bias voltage is varied continuously during deposition of the second individual layer 220.2 till finalizing the deposition of the second individual layer 220.2 at a fourth absolute value U2b of negative bias voltage, where U1 a<U1 b and U1 b<U2a and U2a<U2b, or

- According to Variant C: o A first absolute value U1 a of negative bias voltage is set at the begin of the deposition of the first individual layer 220.1 , and the bias voltage is varied continuously during deposition of the first individual layer 220.1 till finalizing the deposition of the first individual layer 220.1 at a second absolute value U1 b of negative bias voltage, afterwards the bias voltage is varied continuously during deposition of the transitional layer 221.1 from this second value till finalizing the deposition of the transitional layer 221.1 at a third absolute value U2 of negative bias voltage, and this third value U2 is set and maintained constant for depositing the second layer 220.2, where U1a<U1 b and U1 b<U2, , or o A first absolute value U1 of negative bias voltage is set and maintained constant for depositing the first individual layer 220.1 , afterwards the bias voltage is varied continuously during deposition of the transitional layer 221.1 from the first value U1 till finalizing the deposition of the transitional layer 221.1 at a second absolute value U2a of negative bias voltage, and this second value U2a is set at the begin of the deposition of the second individual layer 220.2, and the bias voltage is varied continuously during deposition of the second individual layer 220.2 till finalizing the deposition of the second individual layer 220.2 at a third absolute U2b value of negative bias voltage, where U1 <U2a and U2a<U2b.

As it is explained above, the transitional coating layers 221. i in-between the individual layers 220. i within the under coating film 220 either not exist (according to the first preferred embodiment) when the coating process parameters between the individual layers (i.e. between the end of a previous individual layer and the begin of the next individual layer) are changed sharply (i.e. abruptly), or exist (according to the second preferred embodiment), when the coating process parameters between the individual layers 220. i (i.e. between the end of a previous individual layer and the begin of the next individual layer) are changed gradually (i.e. continuously),

According to the present invention at least the under coating film 220, the interjacent coating film 230 and the upper coating film 240 comprise aluminum (Al), chromium (Cr), nitrogen (N) as mainly components or as solely components.

In the case that the under coating film 220, the interjacent coating film 230 and the upper coating film 240 comprise Al, Cr and N as main components, then these layers preferably further comprise one or more chemical elements selected from the elements of periods 2, 3, 4, 5, 6 of the periodic system except Al, Cr and N. More preferably one or more chemical elements selected from boron (B), yttrium (Y), tantalum (Ta), silicon (Si), tungsten (W), titanium (Ti), calcium (Ca), magnesium (Mg), iron (Fe), cobalt (Co), zinc (Zn), niobium (Nb), vanadium (V) and neodymium (Nd). Preferably the chemical element composition within the interjacent coating film 230 varies step-wise or gradually for at least one of the elements present in the said film.

The chemical element composition within the upper coating film 240 is either constant or varies step-wise or gradually for at least one of the elements present in said film.

The chemical element composition within the under coating film 220 varies step- wise or gradually for at least one of the elements present in the said film.

The crystalline structure of the under coating film 220, the interjacent coating film 230 and the upper coating film 240 is predominantly cubic with a minimum of 80% of cubic fee phase in vol-%.

The under coating film 220, the interjacent coating film 230, and the upper coating film 240 differ in minimum one of and preferably more than one of following physical and/or chemical properties: hardness, elastic modulus, texture, compressive stress, crystalline size, concentration of the chemical elements comprised.

The respective concentration in atomic percentage of Al in the under coating film 220, in the interjacent coating film 230, and in the upper coating film 240, considering only the content of Al and the content of Cr in the respective coating film, is in a range from 65 at-% to 79 at-%. In other words, the ratio of concentration in atomic percentage of aluminum to chromium (Al/Cr) is maintained in a range from 65/35 to 79/21.

Preferably the upper coating film 240 comprises carbon (C) and/or oxygen (O), in particular for improving friction properties.

The upper coating film 240 is deposited in some preferred variants as a top run-in layer.

The under coating layer 220 optionally comprise carbon and/or oxygen, however the under coating layer 220 preferably does not comprise oxygen.

The interjacent coating layer 230 optionally comprise carbon and/or oxygen, but the sum of the concentration of carbon and the concentration of oxygen in the interjacent coating layer 230 must be lower than in the upper coating film 240 and higher than in the under coating film 220.

The respective sum of the concentrations in atomic percentage of C and O in the under coating film 220 if given, in the interjacent coating film 230 if given, and in the upper coating film 240 if given, considering all chemical elements contained in the respective coating film, is in a range from 0.1 at-% to 49 at-%.

The respective sum of the concentrations in atomic percentage of the main components, i.e. of the chemical elements Al, Cr and N, in the under coating film 220, in the interjacent coating film 230, and in the upper coating film 240, considering all chemical elements contained in the respective coating film, is in a range from 51 at-% to 100 at-%, preferably in a range from 51 at-% to 99.9 at-%, more preferably in a range from 51 at-% to 95 at-%.

According to a preferred embodiment of a method for producing coating systems according to the present invention, the same target material, it means that one or more targets of the same target type are used for the deposition of the under coating film 220, the interjacent coating film 230, and the upper coating film 240.

The term “the same target type” is used in the present description for referring to targets that have the same chemical element composition.

The method for producing the inventive coating systems is preferably conducted by using reactive arc evaporation physical vapor deposition techniques.

Preferably a nitrogen gas flow is entered in the coating chamber during arc evaporation of the targets to be used as reactive gas for incorporating nitrogen in the coating system as required for each one of the coating films comprised in the coating system.

Preferably an oxygen gas flow is entered in the coating chamber during arc evaporation of the targets to be used as a further reactive gas for incorporating oxygen in the coating system if required for the deposition of one or more of the coating films comprised in the coating system. A carbon-containing gas flow can be entered in the coating chamber during arc evaporation of the targets to be used as a further reactive gas for incorporating carbon in the coating system if required for the deposition of one or more of the coating films comprised in the coating system.

If all of the three essential coating films of the inventive coating system (i.e. the under coating film 220, the interjacent coating film 230, and the upper coating film 240) requires to comprise carbon, the targets to be used can be of a target type that comprises carbon. In this case the use of a carbon-containing gas flow as reactive gas is optional, and if a carbon-containing gas is used then it can be used for producing variations in the content of carbon in the respective coating films comprised in the coating system as required.

By using targets of the same target type as mentioned above, it is possible to attain a considerable very high efficiency and productivity by coating articles with the inventive coating systems.

Therefore, the target type used for producing the inventive coating systems must comprise at least Al and Cr in a suitable concentration, preferably in a ratio of concentration Al/Cr in a range from 65/35 to 80/20.

Any optional additional chemical elements that need to be contained in the three essential coating films of the inventive coating system and cannot be incorporated from a reactive gas that is entered in the coating chamber as reactive gas flow during arc evaporation of the targets, need to be contained in the targets.

For example AICrB targets can be used for producing inventive coating systems having an under coating film 220, an interjacent coating film 230, and an upper coating film 240 comprising AI,Cr and B. In this case a nitrogen gas flow would be used for providing the necessary nitrogen content and optionally a carbon- containing gas flow and/or an oxygen gas flow would be used for providing carbon content and/or oxygen content to one or more of the coating films comprised in the coating system as required. The above mentioned preferred embodiment of a method for producing coating systems according to the present invention is very efficient and allows a very high productivity in comparison with other methods in which more than one target type is used.

With the above mentioned embodiments of the present invention, coating systems (also called coating schemes) and very efficient and productive methods for producing such coating systems are provided, which in comparison to the state of the art allow attaining significantly higher wear resistance by simultaneous reduction of abrasive wear, crater wear, thermal crack formation and crack propagation, as well as suitable heat transfer (thermal load dissipation) from the cutting tool-chip interface to the coating-substrate interface and/or to the substrate and consequently significantly increasing cutting performance and life time of cutting tools used in different applications, which are covering the application fields of cutting and forming tools, as well as wear components; in the case of the cutting tools applications, such as machining operations, particularly in milling and gear cutting.

The thickness of the under coating film 220 is thicker than the thickness of the other coating films comprised in the inventive coating system 200.

Preferably the thickness of the under coating film 220 is at least 50% of the whole thickness of the coating system 200.

Preferably the thickness of the upper coating film 240 is maximal 25% of the whole thickness of the coating system 200.

Preferably the thickness of the optional interfacial layer 210 is maximal 10% of the whole thickness of the coating system 200.

The inventive coatings show considerable advantageous properties over numerous existing market benchmarks, in particular because of:

The combination of both physical and chemical properties, suitable elements and their concentrations, as well as fluctuation of those concentrations and other given properties, - The specially designed layout of the inventive coating system, which was explained above and will be explained below in more detail by using some examples. This special coating system design with adjusted number of interfaces along the whole thickness of the coating system, and reduced number of dissimilar interfaces, which would lead to significant increase of stress. In this context the term “dissimilar interface” is used for referring to interfaces between layers with big differences regarding physical and/or chemical properties, such as microstructure, texture, lattice constant, hardness, elastic modulus. For this reason the inventive coating systems are designed in such a manner that it is possible to relax stress, to enable simultaneous adjustment of mechanical energy dissipation and thermal energy (heat) dissipation in order to avoid that these energies dissipate towards the surface of the substrate (surface of the article being coated) for minimizing wear (reducing wear as much as possible).

Below the general design of the inventive coating systems is given:

(1 ) the upper coating film 240 of the coating system 200 (also called AlCr-based multilayer hard coating system) was produced by using reactive arc PVD, wherein doped or non-doped AlCr- targets were evaporated in a reactive nitrogen-containing atmosphere, for forming corresponding nitrides, wherein the properties of the upper coating film 240 were obtained by incorporating an optimized content of oxygen and/or carbon for optimizing both the physical and the chemical properties of the upper coating film 240 deposited as top layer of the inventive hard coating system that was deposited on a surface of an article;

(2) the under coating film 220 was produced consisting of a plurality of layers, where the minimum number of individual layers 220. i was two, and said individual layers were deposited by using only one target type and by using sets of coating process parameters that differ in one or more coating process parameters, such as pressure, temperature, bias voltage, arc source current and the like;

(3) optimizing the layer thicknesses and the layer number of the layers within the under coating film, as well as the layer properties and their change by the change of process parameters which can occur either sharply, or the process parameters between the layers are changed step-wise or gradually with in that case specially introduced the transitional coating layers in-between the layers within the under coating film; all this listed was optimized depending on the chemical composition used. The optimization implies an application dependent combination of properties such as thickness, chemical composition, microstructure, texture, stress, hardness, elastic modulus, etc.

General production of inventive articles, which are coated with inventive coating systems:

A coated article according to the present invention is coated with an inventive coating system (also called AlCr-based multilayer hard coating system) that satisfies the above-defined conditions (1 ) to (3), in this manner the inventive coated article exhibits a combination of excellent properties, for example the inventive coated article can exhibit simultaneously a combination of two or more of the following properties outstanding wear resistance, especially abrasion resistance, thermal stability, oxidation resistance, thermal barrier properties and enhanced resistance against generation and propagation of cracks.

The excellent wear resistance, in the example of an article being cutting tool, would be for instance without anomalous damages such as chipping, fracturing, or the like in different cutting applications and conditions. Furthermore, it is unlikely for the anomalous damages such as chipping, fracturing, or the like to occur. As a result, the coated article such as coated cutting tool exhibits excellent cutting performance for an extended usage time.

In addition to the three aspects (1 ) to (3) that were described above, in the general design of inventive coating systems, the inventors suggests following fourth aspect:

(4) in the case where both the physical and chemical properties of the coating films comprised in the coating system and/or only some layers comprised in the coating films are tuned (tuned means in particular that the corresponding properties are improved) in predetermined manner according to the present invention, in the case that only by change in the process parameters also including, if needed the change of the reactive gases while remarkably using only one target type, that those properties; such as composition fluctuation of an element amongst all others elements, are formed in a predetermined manner along the height of the coating system; consequently surprisingly simultaneously the stress relaxation effect, and also the wear resistance improving effects are obtained, where said optimized coating system exhibits a combination of simultaneously enhanced properties such as outstanding abrasion resistance, thermal barrier properties and enhanced resistance against generation and propagation of cracks. Thus, when a coated article is a cutting tool, wear resistance, such as the chipping resistance, the fracturing resistance, and the abrasive wear resistance are improved even more, and the tool life of the coated cutting tool is extended.

Coated articles coated with a coating system according to the present invention exhibit a considerable increased lifetime. Furthermore, the coating designs and methods for coating articles with a coating system according to the present invention allows attaining a sensational performance of the said coated article in a manner that is suitable for use in a very broad range of applications, it means coated articles (in particular cutting and forming tools or components) are suitable for attaining outstanding performance in application fields including use of cutting tools, forming tools and also wear components (components to be exposed to wear during use).

Therein, said applications may comprise continuous and interrupted cutting applications including, but not limited to drilling, milling, reaming, turning, tapping, threading and hobbing applications.

Therein, said workpieces may be used under various working conditions, such as, for example, dry cutting, cutting with emulsion and/or liquid coolants, cutting with minimal quantity lubrication (MQL) and cutting with gaseous coolants.

Therein, said article is at least one of the group consisting of: a machining tool; a milling tool; a cutting tool; a turning tool; a tapping tool; a threading tool; a reamer; an end mill; a drill; a cutting insert; a gear cutting tool; a hob; a clearing tool; and an insert for turning and milling.

Therein, said article has a body substantially made of one or more of the group consisting of a ferrous metal, a non-ferrous metal, a composite material, a cermet, a cemented carbide, a cubic boron nitride, a ceramic material, a steel, and a high speed steel.

Therein, said article is at least one of the group consisting of a forming tool of an upper die, a pierce punch, a die button, a fine blanking punch, a draw and forming insert, a roll forming, a form punch, a cold forging die, a fine blanking die, a draw ring, an extrusion die, a cold forging punch, a hot stamping insert, a hot forging punch, a hot forging die; a trimming insert, a monoblock die, a bottom swage, a drawing die, an ejector core, a thread former.

Therein, said article is an injection-molding tool for producing a molded plastic part or a data storage medium.

Therein, said article is a machine component, such as a sealing washer, a gear, a piston, a part of a valve drive or a needle for an injection nozzle, or that it is toothed.

Therein, said workpiece is suitable for application in machining of at least one of, preferably most of: ferrous and nonferrous materials, preferably hardened steel, annealed steel, alloyed steel, low carbon steel, stainless steel, titanium-based alloys, nickel-based alloys and composite materials.

Further preferred variants of embodiments of the present invention

The objectives of the present invention were achieved by providing a coating system for coating a substrate article as described in the present description, by using methods as described in the present description. Further variants of preferred embodiments as well as concrete examples are described below:.

A basic embodiment of a coating system according to the present invention is shown schematically in FIG 1 a and FIG 1 b, where 100 denotes an article to be coated with a multilayer coating system, which is here denoted as 200.

Coating system 200 deposited on a surface of a substrate 100 comprising:

- an under coating film 220, deposited as a multi-layered film 220, consisting of a plurality of layers 220.1 to 220. n, where n > 2, and an upper coating film 240, and an interjacent coating film 230, as a transition film between the under coating film 220 and the upper coating film 240 and also as optional comprising:

- an interfacial film 210 in-between substrate, i.e. article, and the under coating film 220, where said interfacial film 210 can be metal, metal with nitrogen (N), or modified substrate for example by nitriding and/or metal ion etching,

- the transitional coating layers 221.1 to 221. n-1 , as seen in FIG 1 b, where n > 2 in-between the layers 220.1 to 220. n within the under coating film 220 either not exist when the process parameters between the layers 220.1 to 220. n are changed sharply, or exist when the process parameters between the layers 220.1 to 220. n are changed step-wise or gradually, where all said films and layers comprising minimum aluminum, chromium, nitrogen and optionally one or more elements, wherein:

- the under coating film 220 is deposited on the substrate surface to be coated or in any case closer to the substrate than the interjacent coating film 230 and an upper coating film 240.

- the interjacent coating film 230 is deposited between the under coating film 220 and the upper coating film 240.

- the upper coating film 240 is deposited more distant from the substrate than the interjacent coating film 230.

- the above given films and layers comprise aluminum (Al), chromium (Or) and nitrogen (N), and one or more elements selected from element of periods 2, 3, 4, 5, 6 of the periodic system except Al, Or and N, such as without limitation boron (B), yttrium (Y), tantalum (Ta), silicon (Si), tungsten (W), titanium (Ti), calcium (Ca), magnesium (Mg), iron (Fe), cobalt (Co), zinc (Zn), niobium (Nb), vanadium (V) and neodymium (Nd). wherein: - the elemental composition within the interjacent coating film 230 changes step- wise or gradually for at least one of the elements present in the said film

- the elemental composition within the upper coating film 240 in either constant or changes step-wise or gradually for at least one of the elements present in the said film

- the elemental composition within the under coating film 220 changes step-wise or gradually for at least one of the elements present in the said film

- crystalline structure of all said coating films and layers is predominantly cubic with minimum of 80% of cubic fee phase

- The layers of the under coating film 220, the interjacent coating film 230 and upper coating film 240 differ in minimum one of or more physical and/or chemical properties, such as hardness, elastic modulus, texture, compressive stress, crystalline size, the concentration of elements comprised; where the later differ by minimum one of following:

(a) concentration of Al with respect to total Al and Cr content in the range from 65 to 79

(b) the ratio of concentration in atomic percentage of aluminum to chromium (Al/Cr) in the range from 65/35 to 79/21

(c) the ratio of concentration of O and C together with respect to total element concentration in the range from 0.1 to 49 at.%.

Coating system 200 is further wherein the upper coating film is deposited as outermost layer of the coating system. Moreover, the individual film thickness of the under coating film 220 is greater than the individual film thickness of the upper coating film 240.

Coating system 200 exhibits preferably also following features:

- the thickness of the under coating film is preferably at least 50% of the total thickness of the coating system 200,

- the thickness of the upper coating film is preferably maximal 25% of the total thickness of the coating system 200.

- the thickness of the optional interfacial layer 210, if any, is preferably maximal 10% of the total thickness of the coating system 200 Preferably the coating system 200 or at least one of the coating films, preferably at least one of the two (the upper coating film 240 and the interjacent coating film 230), or at least one of the layers comprised in the coating system can optionally comprise in addition to nitrogen (N) also oxygen (O) and/or carbon (C). Moreover, the concentration in atomic percentage of carbon and oxygen in one coating layer or in one coating film forming the coating system is preferably between 1 at.% and 80 at. %, if only the concentrations of N, C and O are considered, it means, if the sum of the concentrations of N, C and O in the respective coating layer or coating film is considered as 100 at.%.

Preferably the coating system 200 has:

- a ratio of concentration in atomic percentage of aluminum to chromium (Al/Cr) that varies along the total thickness of the coating system, wherein the range of variation of the ratio of concentration Al/Cr is preferably between 65/35 to 79/21 ,

- a concentration in atomic percentage of the dopant elements in between films and/or layers along the coating height that is between 0.1 at.% and 35 at.%, preferably between 0.5 at:% and 25 at.%, if the concentrations of all elements are considered, it means, if the sum of the concentrations of all elements are considered as 100 at.%,

- a concentration in atomic percentage of the dopant elements in the individual coating films and/or layers varies along the total thickness of the coating, system, the range of variation is preferably between 0.1 % and 600% taking as base the lowest concentration of the respective dopant elements in the coating system (it is for example observed in an example, where the interfacial layer 210 comprises oxygen in a concentration of 0.3 at-% but in the top layer the oxygen concentration is of 25 at-%, in such a case the multiplication factor is about 83),

- the concentration of the dopant elements in the under coating film, if any, as well as in the upper coating film varies along the total thickness of the under coating film,

- the concentration of the dopant elements varies along the total thickness of the upper coating film of the coating system that the range of variation is between 0.1 % and 600% taking as base the lowest concentration of the respective dopant elements in the under coating film or in the upper coating film, respectively. The under coating film 220 consists of different layers from 220.1 to 220. n where the number of the layers n>2 (as seen in FIG 1a) and those layers do not necessarily have to be with the same thickness. All those layers are produced by using the same targets. However those layers are different in minimum one of physical chemical properties, such as predominant crystalline orientation, crystalline size and/or crystalline size distribution (as all calculated from peak intensities and areas below the peaks and the full width at the half maximum from X-Ray diffractograms), mechanical properties (e.g. hardness, elastic modulus), chemical composition. Those different physical chemical properties in between the layers 220.1 to 220. n are obtained by change in the process parameters (such as pressure, temperature, bias voltage, source current, magnetic field shape and or strength) and/or reactive gases, but by the use of the same targets in between the layers.

The transitional coating layers 221.1 to 221.n-1 in-between the layers 220.1 to 220.n within the under coating film 220, which exist when the process parameters between the layers 220.1 to 220. n are changed step-wise or gradually, where the number of the layers n>2 (as seen in FIG 1 ) do not necessarily have to be with the same thickness and the same physical and/or chemical properties. All those layers are produced by using the same targets, but not necessarily by the use of the same process parameters.

The upper coating film comprises the same elements as the interjacent coating film 230.

All coating films and layers are produced from the same target types but that does not mean that the chemical composition of the different coating films and/or layers over the coating height is the same.

The coating system 200 comprises at least one or more films and/or layers substantially being of cubic structure.

The coating system 200 or at least one of the coating films, preferably at least one of the two (the interjacent coating film 230 and the upper coating film 240), or at least one of the layers comprised in the coating system can optionally comprise in addition to nitrogen (N) also oxygen (0) and/or carbon (C). So that the coating films or some of the coating films, preferably at least one of the two (at least section of the upper coating film 230 and/or 240), or at least one of the layers forming coating system can comprise metal nitrides or metal oxynitrides or metal carbonitrides or metal carboxynitrides, meaning metal and N or CN or ON or CON.

The concentration in atomic percentage of carbon and/or oxygen in the coating system is preferably between 1 at.% and 80 at. %, if only the concentrations of N, C and 0 are considered, it means, if the sum of the concentrations of N, C and 0 in the respective coating layer or coating film is considered as 100 at.%.

The ratio of concentration in atomic percentage of aluminum to chromium (Al/Cr) preferably varies along the total thickness of the coating system. The range of variation of the ratio of concentration Al/Cr in this case is preferably between 65/35 to 79/21.

The inventive coating system (also called coating scheme in this context as already mentioned above) comprises as described above layers arrangements especially adjusted in inventive manner- which allow simultaneous fulfilment of following challenging requirements:

- reduction of abrasive wear,

- reduction of crater wear,

- reduction/suppression of thermal crack formation and propagation, and enabling heat transfer from the end mill-chip interface to the substrate and coatingsubstrate interface.

Illustrated below are examples of the advantageous applications of different inventive multilayer hard coating system - coated article on the example of coated cutting tools used in different cutting operations. In order to exemplary show the surprisingly benefit attained by using coating systems according to the present invention, some examples will, be described as following:

EXAMPLE #1 Milling of hardened steel (steel type 1 .2344) 38 HRC roughing and 45 HRC finishing in wet condition.

• 38 HRC roughing test is referred to as example test 1

• 45 HRC finishing test is referred to as example test 2.

Example test 1 comprises a test of coated cutting end mills labelled as: o State of the art as market benchmark 1 , 2, 3 o Exemplarily inventive coatings 1 , 2, 3 as given in this invention.

Test parameters for 38 HRC roughing: Here the performance of roughing using end to mills is tested. The workpiece material is 38 HRC hardened steel (1.2344). The tools are cemented carbide endmills with a diameter=10 mm, with 4 teeth. The cutting parameters are set forth below: cutting speed Vc=175 m/min; Feed rate f=0.05 mm/tooth; Depth of cut ap=5.0 mm; Width of cut ae=4 mm; external cooling: wet; and wear criterion: VBmax=120 pm. The tool life in % is given in FIG 2 comparing three state of the art as market benchmark and three inventive examples.

The wear and wear evolution of coated cemented carbide end mills (exemplary state of the art as market benchmark 1 and inventive example 3) is given in FIG 3 of examples shown in FIG 2. In FIG 3 one of the four main cutting edges is shown which is a representative example.

FIG 2 shows a comparison of the lifetime of coated cemented carbide end mills in the example test 1 , a wet milling cutting test of 38 HRC hardened steel (steel type 1.2344) application of a wear-resistant coating scheme of three exemplary (inventive examples 1 , 2, 3) inventions tested against three state of the art as market benchmark. It can be seen that inventive coatings have remarkable increase of tool life of up to 175% as compared to state of the art as market benchmark.

FIG 3 shows wear and wear evolution of coated cemented carbide end mills in the example test 1 given on the representative example chosen out of 2 tested tools per variant, a wet milling cutting test of 38 HRC hardened steel (steel type 1.2344) application of a wear-resistant coating scheme of the inventive example 3 tested against state of the art as market benchmark 1. It can be seen that the wear progression for the state of the art as market benchmark 1 is much faster. The wear of the state of the art as market benchmark 1 example is characterized by higher abrasive wear and more chipping compared to inventive example 3, which leads to a shorter tool life, meaning lower cutting tool performance as seen from the earlier fulfilment of the wear criteria VBmax for the state of the art as market benchmark 1 . This can also be seen by the wear images of state of the art as market benchmark 1 , which reached the wear criteria (VBmax) already at 51.2 m of test, whereby inventive example 3 the wear is at a much lower level, enabling longer tool life and higher performance of the inventive example 3. For the inventive example 3 it can be clearly seen that the wear progression remains very slow after 51.2 m tool life until the end of tool life at 76.8 m, respectively, when the wear criteria VBmax is reached.

EXAMPLE #2

Example test 2 comprises a test of coated cutting end mills labelled as:

- State of the art as market benchmark 1 , 2, 4

- Exemplarily inventive coatings 1 , 2, 3, 4 as given in this invention.

Test parameters for 45 HRC finishing: Here the performance of finishing using end mills is tested. The workpiece material is 45 HRC hardened steel (1 .2344). The tools are cemented carbide endmills with a diameter=10 mm, with 4 teeth. The cutting parameters are set forth below: cutting speed Vc=150 mn/min; Feed rate f=0.1 mm/tooth; Depth of cut ap=5.0 mm; Width of cut ae=0.5 mm; external cooling: wet; and wear criterion: VBmax =140 pm. The tool life in % is given in FIG 4 comparing three state of the art as market benchmark and four inventive examples. The wear and wear evolution of coated cemented carbide end mills ((exemplary state of the art as market benchmark 1 and inventive example 3) is given in FIG 5 of examples shown in FIG 4. In FIG 5 one of the four main cutting edges is shown which is a representative example.

FIG 4 shows a comparison of the lifetime of coated cemented carbide end mills in the example test 2, a wet milling cutting test of 45 HRC hardened steel (steel type 1 .2344) application of a wear-resistant coating scheme of four exemplary (inventive examples 1 , 2, 3, 4) inventions tested against three state of the art as market benchmark. It can be seen that inventive coatings have remarkable increase of tool life of up to 160% as compared to state of the art as market benchmark.

FIG 5 shows wear and wear evolution of coated cemented carbide end mills-in the example test 2 given on the representative, example chosen out of 2 tested tools per variant, a wet milling cutting test of 45 HRC hardened steel (steel type 1 .2344) application of a wear-resistant coating scheme of the inventive example 3 tested against state of the art as market benchmark 1. It can be seen that the wear progression for the state of the art as market benchmark 1 is much faster. The wear of the state of the art as market benchmark 1 example is characterized by higher abrasive wear and more chipping compared to inventive example 3, which leads to a shorter tool life, meaning lower cutting tool performance as seen from the earlier fulfilment of the wear criteria VBmax for the state of the art as market benchmark 1 . This can also be seen by the wear images of state of the art as market benchmark 1 , which reached the wear criteria (VBmax) already at 387.2 m of test, whereby inventive example 3 the wear is at a much lower level, enabling longer tool life and higher performance of the inventive example 3. For the inventive example 3 it can be clearly seen that the wear progression remains very slow and homogeneous after 211.2 m tool life until the end of tool life at 598.4 m, respectively, when the wear criteria VBmax is reached.

Experimental details of measurement of coating properties are given in the following part.

The film structural analyses were conducted by X-ray diffraction (XRD) using a PANalytical X'Pert Pro MPD diffractometer equipped with a CuKa radiation source. The diffraction patterns were collected in Bragg-Brentano geometry at the grazing incidence angle.

The hardness and indentation modulus of the as-deposited samples were determined using an Ultra-Micro-Indentation System equipped with a Berkovich diamond tip. The testing procedure included normal load of 10mN. The hardness values were evaluated according to the Oliver and Pharr method. Thereby, we assured an indentation depth of less than 10 % of the coating thickness to minimize substrate interference.

In TABLE 1 are given some of the mechanical properties of state of the art as market benchmark coatings and of the inventive coatings. Those properties are hardness (H), elastic modulus (E), ratios H/E; ratio H ³ /E ² and compressive stress. State of the art as market benchmark 1 is characterized by high hardness (ca. 40 GPa) and high stress (ca. -4 GPa) which is a good combination for high resistance against abrasive wear. State of the art as market benchmark 2 is characterized by higher hardness (ca. 43 GPa) but in combination with lower E and at the same time lower stress (ca. -2.4 GPa). For this state of the art as market benchmark 2 the higher hardness should allow higher resistance against abrasive wear on the other hand the lower stress can be detrimental. For state of the art as market, benchmark 3 significantly lower hardness (ca. 33 GPa) is shown but in combination with low H/E and H ³ /E ² ratio and a tress (ca. -3.1 GPa) which is in between state of the as market benchmarkl and 2. For state of the art as market benchmark 4 the hardness value is comparable to state of the art as market benchmark 1 but in combination with a much lower E, which is not beneficial for abrasion resistance. Therefore the tool life as shown in the example of the cutting tests as given in both FIG 2 and FIG 4 of state of the art as market benchmark 1 -4 are significantly lower as compared to the inventive coating systems, which are given by the representative examples of the new inventive examples 1 -4.

Compared to the state of the art as market benchmark 1 , all exemplary inventive examples 1 -4 are characterized by a higher hardness (up to 49.3 GPa) and in the same time increased E (up to 467 GPa) whereby the stress is a bit lower but sufficiently high to enable beneficial effect, also still higher than state of the art as market benchmark 2. Typically, if one coating has higher E and H for the same coating thickness, it also has higher compressive stress which goes along with increase of E and H. It is very challenging to increase E and H of the coating with a simultaneous decrease of compressive stress. Surprisingly, inventive coatings (e.g. inventive example 1 and 2) simultaneously have lower compressive stress then state of the art as market benchmark coating 1 . This is a very important coating property for this application because very high compressive stress is associated to more crack formation and consequently tool failure via few possible mechanisms. All these in combination with the simultaneously optimized layout of the coating system and dedicated chemistry including doping and fluctuation of elemental concentration along the coating height allows for simultaneous: reduction of wear, especially abrasive and crater wear, chipping, reduction/suppression of thermal crack formation and propagation, and enabling heat transfer from the end mill-chip interface to the substrate and coating-substrate interface of the here shown inventive coatings. Inventive example 3 is characterized by lower hardness (ca. 37 GPa) but on the other hand with a much higher stress (ca. -4.3 GPa) which compensates for the lower hardness and still gives high resistance against abrasive wear. These dedicated designs of the here shows inventive examples allow for a higher tool life and hence an increased performance of the coated system.

TABLE 1 shows properties (hardness, elastic modulus, their ratios, and compressive stress) of state of the art as benchmark coatings and of examples of inventive coatings; A method for manufacturing a coated article, meaning an article coated by an AlCr- based protective multilayer coating system, comprising the steps of:

(a) depositing on said article at least 2 layers of the under coating film 220 with or without the transitional coating layers 221.1 to 221.n-1 and/or interfacial film 210; and (b) depositing on said article obtained in (a) at least one layer of the interjacent coating film 230 and the upper coating film 240 different from the said under coating film 220; wherein said all films and layers are deposited by using targets of the same AlCr-based type, or using AlCr-based targets mutually differing in chemical composition of the constituent elements up to 10% in between the target type for the respective element.

The said method, wherein steps (a) and (b) are carried out using a physical vapor deposition (PVD) process. The said method, wherein steps (a) and (b) are carried out using a cathodic arc evaporation process within the PVD system.

The said method:

- comprising holding said article at a temperature below approximately 650°C while carrying out steps (a) and (b),

- comprising applying a bias voltage between +20 V and -300 V to said article while carrying out steps (a) and (b),

- comprising exposing said article to a reactive gas atmosphere with a total gas pressure between 0.1 Pa and 9.9 Pa while carrying out steps (a) and (b), where the said reactive gas atmosphere comprising predominantly N.

In summary, the process parameters used for the deposition of the inventive coating systems by the said method are preferably: o Range of pressure: 0.1 Pa to 9.9 Pa (N2 partial pressure controlled) o Range of substrate temperature: 200 °C to 650 °C o Range of bias voltage: +20 V to -300 V, preferably the bias voltage applied is negative. o Range of source current: 50 A to 200 A

For the deposition of the inventive examples coating parameters were selected from the above mentioned ranges and also varied for varying properties as required. The elements nitrogen, carbon and oxygen were provided in the coating chamber for the formation of the coating systems by presence of the respective reactive gases, such as N2 gas for providing nitrogen, 02 gas for providing oxygen, C2H2 or CH4 for providing carbon and the like, in the PVD chamber.

For providing Al, Cr and the dopant elements solid targets were used as cathode to be evaporated and in this manner being used as material source for the formation of the coating system.

The targets were preferably operated as cathode in arc evaporators used as arc PVD sources.

Meaning the process is reactive: reactive cathodic PVD coating process.

During the whole coating process for the deposition of the coating scheme 200 (FIG

1 ) only one target type was used. For different inventive coating different targets were used which are different with respect to minimum one of the following:

1 ) concentration of Al in total Al+Cr content (meaning AI/(AI+Cr) in at. %), and/or

2) total concentration of all dopants together with respect to the total metal concentration and/or

3) concentration of one of the dopant with respect to the total dopant concentration and/or total element concentration.

AlCr metallic targets were used in the present examples as Al and Cr source, the AlCr metallic targets having a concentration (AI/(AI+Cr) in at.%) of minimum 65% of Al with respect to Al and Cr.

All dopants (metal or semi-metal dopants) were provided directly as dopants in the AlCr targets.

In regard to the application of specific embodiments of the AlCr-based protective multilayer coating system of the invention by the above-referred PVD system, the deposition of the AlCr-based protective multilayer coating system were performed using an industrial coating system (such as type INNOVENTA, INNOVA, RCS, BAI1200, or the like) of the company Oerlikon Balzers Coating. For that purpose, the pre-cleaned articles were mounted, according to their diameter, either on double-rotating or on triple-rotating substrate carriers while doped AlCr-based targets were installed in usually six cathode arc sources on the walls of the coating system. Next, radiant heaters likewise installed in the coating system heated the article to a predetermined temperature, which is in the inventive example 2 about 480°C), with a bias voltage of -100 to -200 V applied in an Argon atmosphere at a pressure of about 0.5 Pa, the workpiece surfaces were subjected to etch-polishing with Ar ions.

The detail example of the deposition process for the inventive examples is given on for the inventive example 2 with the process parameters, such as process temperature and pressure, substrate bias voltage, source current, non-metal elements, metals, dopant, crystalline structure, hardness and elastic modulus for the individual coaling films and layers, as summarized in TABLE 2.

TABLE 2 In principle, the process pressure for each of these steps may be set in the range from 0.5 to about 8 Pa, preferably between 2.5 and 5 Pa, and for nitride films either a pure nitrogen atmosphere or a mixture of nitrogen and an inert gas such as argon may be used, for carbonitride films a mixture of nitrogen and a carbonic gas, with the admixture of an inert gas if necessary. Correspondingly it is possible, when depositing oxygenous coatings, to admix oxygen gas in conventional fashion. Moreover, an elemental composition of the upper coating film 240 in here given inventive example 1 is given in the TABLE 3:

TABLE 3

TABLE 4 shows for all 4 said inventive examples: metals and dopant of the targets employed, thickness of the given coating system, their crystallographic structure, as well as relative atomic percent of both Al and Cr with respect to the total Al and Cr content. TABLE 4

In FIG 6 diffractograms of the four inventive examples from TABLE 4 are given. It can be seen that they exhibit a clearly pre-dom inantly cubic fee phase and that texture as well as the crystalline size and crystalline size distribution depending on the given process parameters and chemical composition used varies in predetermined way to optimized coating system performance.

Concretely the present inventions provides in particular:

A coating system 200 deposited on a surface of an article comprising: - an under coating film 220, deposited as a multi-layered film, consisting of a plurality of layers, where the number of layers is minimum two, and

- an upper coating film 240, and

- an interjacent coating film 230, as a transition film between the under coating 220 film and the upper coating film 240, and also as optional comprising:

- an interfacial film 210 in-between substrate 100, i.e. article, and the under coating film 220, where said interfacial, film can be metal, metal with nitrogen (N), or modified substrate for example by nitriding and/or metal ion etching,

- transitional coating layers 221 in-between the layers within the under coating film (220) either not exist when the process parameters between the layers are changed sharply, or exist when the process parameters between the layers are changed step-wise or gradually, where all of said films and layers comprising aluminum, chromium, nitrogen and optionally one or more elements, wherein,

- the under coating film 220 is closer to the substrate than the interjacent coating film 230 and the upper coating film 240,

- the interjacent coating film 230 is deposited between the under coating film 220 and the upper coating film 240,

- the upper coating film 240 is deposited more distant from the substrate 100 than the interjacent coating film 230,

- at least the undercoating film 220, interjacent coating film 230 and upper coating film 240 comprise aluminum (Al), chromium (Cr) and nitrogen (N), and one or more elements selected from element of periods 2, 3, 4, 5, 6 of the periodic system except Al, Cr and N, in particular such as without limitation boron (B), yttrium (Y), tantalum (Ta), silicon (Si), tungsten (W), titanium (Ti), calcium (Ca), magnesium (Mg), iron (Fe), cobalt (Co), zinc (Zn), niobium (Nb), vanadium (V) and neodymium (Nd). wherein:

- the elemental composition within the interjacent coating film 230 changes step- wise or gradually for at least one of the elements present in the said film,

- the elemental composition within the upper coating film 240 is either constant or changes step-wise or gradually for at least one of the elements present in said film,

- the elemental composition within the under coating film 220 changes step-wise or gradually for at least one of the elements present in the said film,

- crystalline structure of all said coating films and layers is predominantly cubic with minimum of 80% of cubic fee phase in vol-%,

- the layers of the under coating film 220, the interjacent coating film 230 and upper coating film 240 differ in minimum one of and preferably more than one of physical and/or chemical properties, such as hardness, elastic modulus, texture, compressive stress, crystalline size, the concentration of elements comprised; where the later differ by minimum one of following:

(a) concentration of Al with respect to total Al and Cr content in the range from 65 to 79

(b) the ratio of concentration in atomic percentage of aluminum to- chromium (Al/Cr) in the range from 65/35 to 79/21

(c) the ratio of concentration of O and C together with respect to total element concentration in the range from 0.1 to 49 at:%.

Preferably the upper coating film 240 is deposited as outermost layer of the coating system 200.

Preferably the film thickness of the under coating film 220 is greater than the film thickness of the upper coating film 240.

Preferably the thickness of the upper coating film 240 is maximal 25% of the total thickness of the coating system 200.

Preferably the thickness of the under coating film 220 is at least 50% of the total thickness of the coating system 200. Preferably the thickness of the upper coating film 240 is maximal 25% of the total thickness of the coating system 200.

Preferably the coating system 200 or at least one of the coating films comprises in the coating system 200, more preferably at least one of the two the upper coating film 240 and the interjacent coating film 230, or at least one of the individual layers 220. i comprised in the coating system 200, comprises in addition to nitrogen (N) also oxygen (O). and/or carbon (C).

Preferably the concentration in atomic percentage of carbon and oxygen in one coating layer or in one coating film forming the coating system is preferably between 1 at.% and 80 at.%, if only the concentrations of N, C and O are considered, it means, if the sum of the concentrations of N, C and O in the respective coating layer or coating film is considered as 100 at.%.

Preferably the ratio of concentration in atomic percentage of aluminum to chromium (Al/Cr) varies along the total thickness of the coating system, wherein the range of variation of the ratio of concentration Al/Cr is preferably between 65/35 to 79/21 .

Preferably the concentration in atomic percentage of the dopant elements in between films and/or layers along the coating height is between 0.1 at.% and 35 at.%, preferably between 0.5 at.% and 25 at.%, if the concentrations of all elements are considered, it means, if the sum of the concentrations of all elements are considered as 100 at.%.

Preferably the concentration in atomic percentage of the dopant elements in the individual coating films and/or layers varies along the total thickness of the coating system, the range of variation is preferably between 0.1 % and 600% taking as base the lowest concentration of the respective dopant elements in the coating system.

The under coating film 220 comprises different individual layers 220. i, where the number of the individual layers 220. i is minimum two, and those layers do not necessarily have the same thickness. All those layers are produced by using the same targets. However those layers are different in minimum one of physical chemical properties, such as predominant crystalline orientation, crystalline size and/or crystalline size distribution (as all calculated from peak intensities and areas below the peaks and the full width at the half maximum from X-Ray diffractograms), mechanical properties (e.g. hardness, elastic modulus), chemical composition. Those different physical chemical properties in between the layers are obtained by change in the process parameters (such as pressure, temperature, bias voltage, source current, magnetic field shape and or strength) and/or reactive gases, but by the use of the same targets in between the layers.

The under coating film 220 can also comprise transitional coating layers 221. i inbetween the individual layers 220. i within the under coating film 220, which exist when the process parameters between the end of one previous individual layer and the begin of a next individual layer are changed step-wise or gradually, where the number of the individual layers is minimum two or more, do not necessarily have to be with the same thickness and the same physical and/or chemical properties. All those individual layers and transitional layers are produced by using the same targets, but not by the use of the same process parameters, because fir producing the different layers at least one coating process parameter must be different in order to produce a difference in at least one coating property.

Preferably the upper coating film comprises the same elements as the interjacent coating film, however not in the same concentration.

Preferably the coating system produced by depositing the upper coating film (240), the interjacent coating film (230) and all layers comprised in the under coating film (220) from the same target types but in such a manner that the chemical composition of the different coating films and/or layers over the coating height is not necessarily the same. In other words, in spite of all coating films and layers are produced from the same target types, that does not mean that the chemical composition of the different coating films and/or layers over the coating height is the same, because the chemical composition can be changed by changing the coating process parameters (e.g. process gas flows or reactive gas flows or other parameters).

Preferably the concentration of the dopant elements in the under coating film, if any, as well as in the upper coating film varies along the total thickness of the under coating film. Preferably the concentration of the dopant elements varies along the total thickness of the upper coating film of the coating system. The range of variation is preferably between 0.1 % and 600% taking as base the lowest concentration of the respective dopant elements in the under coating film or in the upper coating film, respectively.

Preferably at least one coating film comprised in the coating system exibits substantially cubic structure.

The present invention relates also to an article comprising a coating system as described above.

The article is preferably:

- one of the group consisting of: a machining tool; a milling tool; a cutting tool; a turning tool; a tapping tool; a threading tool; a reamer; an end mill; a drill; a cutting insert; a gear cutting tool; a hob; a clearing tool; and an insert for turning and milling, or

- one of the group consisting of a tool, a reamer, an end mill, a drill, a cutting insert, a hob, and an insert for turning and milling.

The article as mentioned above has preferably a body that is substantially made of:

- one or more of the group consisting of a ferrous metal, a non-ferrous metal, a composite material, a cermet, and a cubic boron nitride, or

- one or more of the group consisting of a non-ferrous metal, a composite material, a cemented carbide, a cubic boron nitride, a ceramic material, and a steel, or

- one or more of the group consisting of a non-ferrous metal, a composite material, a cemented carbide, a cubic boron nitride, a ceramic material, and a high speed steel.

The article can be also one of the group consisting of a forming tool of an upper die, a pierce punch, a die button, a fine blanking punch, a draw and forming insert, a roll forming, a form punch, a cold forging die, a fine blanking die, a draw ring, an extrusion die, a cold forging punch, a hot stamping insert, a hot forging punch, a hot forging die, a trimming insert, a monoblock die, a bottom swage, a drawing die, an ejector core, a thread former. The article can be for example an injection-molding tool for producing a molded plastic part or a data storage medium.

The article can be also a machine component, such as a sealing washer, a gear, a piston, a part of a valve drive or a needle for an injection nozzle, or that it is toothed.

A method for manufacturing a coated article, meaning an article coated by an AlCr- based protective multilayer coating system according to the present invention comprises preferably following steps: a) depositing on said article at least two layers of the under coating film with or without the transitional coating layers and I or interfacial film; and b) depositing on said article obtained in a) at least one layer of the interjacent coating film and the upper coating film different from the said under coating film; wherein said all films and layers are deposited by using targets of the same AlCr-based type, or using AlCr-based targets mutually differing in chemical composition of the constituent elements up to 10% in between the target type for the respective element.

The steps a) and b) are preferably carried out using a physical vapor deposition (PVD) process. Preferably a cathodic arc evaporation process.

The method is preferably conducted by holding said article at a temperature below 650°C or maximal 650°C during execution of the steps a) and b).

Preferably a negative bias voltage between -10 V and -200 V is applied to said article during execution of the steps a) and b).

Preferably the article is exposed to a reactive gas atmosphere with a total gas pressure between 0.1. Pa and 9.9 Pa during execution of the steps a) and b). Preferably the reactive gas atmosphere comprises predominantly nitrogen (N).