PVD Coatings Containing Multi-Anionic High-Entropy Alloy Oxynitrides

Abstract

A method for producing a coating comprising at least one PVD coating layer, comprising evaporating material from one or more targets using PVD techniques in a coating chamber containing oxygen and nitrogen as reactive gases for the production of the at least one PVD coating layer, wherein during the deposition of the at least one PVD coating layer, a multi-anionic HEA oxynitride structure is formed comprising a cation lattice formed of five or more elements and an anion lattice formed of two or more elements, where if there are only two elements present in the anion lattice, these are oxygen and nitrogen.

Description

Technical Field

[0001] The present invention relates to a method for producing a new HEA coating material exhibiting thermal stability at high temperatures and a corresponding new HEA coating material.

Background Art

[0002] Prior Art High-entropy alloys are usually referred to as HEAs and are a new class of materials consisting of at least five components, exhibiting a configurational entropy of Sconf. > 1.4R, where R is known as the gas constant. The configurational entropy (Sconf.) is estimated using Equation [1] described below, assuming random solid solution formation between these components.

[0003]

Number

[0004] In the formula, R is the gas constant, x i is the mole fraction of the corresponding element, and n is the total number of constituent elements. The above-described equation indicates that the configurational entropy is proportional to the number of components (i.e., Sconf. increases as the total number of components increases).

[0005] On the other hand, whether solid solution formation preferentially occurs when five different components are mixed is given by the mixing enthalpy (ΔH mix ) and the mixing entropy (ΔS mix ) described below. The solid solution of the five components preferentially occurs when the ΔG mix value is the lowest among all possible arrangements.

[0006] ΔG mix = ΔH mix - TΔS mix [2] In the formula, ΔH mix is the mixing enthalpy, ΔSmix is the mixing entropy and T is the temperature. In high-entropy alloys, this positive ΔH mix is overcome by the high configurational entropy of mixing TΔS mix which means that the solid solution is preferentially formed over phase separation.

[0007] Based on the thermodynamic principles described above, Christina M. Rost et al. reported entropy-stabilized oxides at temperatures above 1000 °C using a powder metallurgy route. These entropy-stabilized oxides were synthesized as bulk materials rather than as coatings. The powder metallurgy route can be described as follows.

[0008] MgO(Rs)+Nio(Rs)+CoO(Rs)+Cuo(T)+ZnO(w)→(Mg,Ni,Co,Cu,Zn)(R S ) [3] where Rs corresponds to the rock-salt structure, T corresponds to the chalcopyrite structure, and W corresponds to the wurtzite structure, respectively.

[0009] According to the report, the energy penalty caused by the conversion of CuO and ZnO from the chalcopyrite and wurtzite structures to the rock-salt structure, respectively, is in the range of 0.1 eV / atom (ΔH mix ), which is overcome by the entropy component TΔS mix in Equation [2] at temperatures above 900 °C.

[0010] However, since this material system is inherently relatively low in hardness, it is not suitable for wear-resistant applications.

[0011] On the one hand, in nitride alloys, A. D. Pogrebnjak et al. have reported various high-entropy alloy nitrides deposited in cubic phases, such as (AlCrMoSiTi)N, (TiZrHfNbTa)N, (AlCrNbSiTiV)N, (TiVCrZrTa)N, (AlCrMoTaTiZr)N, etc. However, they have not been able to show entropy stabilization, i.e., that the solid solution is stable up to high temperatures such as 1100 °C.

[0012] However, K. Yalamanchili et al. investigated the entropy stabilization up to 1100 °C in the c-(AlTiVNbCr)N alloy and reported that the following was derived from the balance between (ΔH mix ) and TΔS mix as follows.

[0013] c-(AlTiVNbCr)N → w-AlN + c-(TiNbVCr)N [4] Such structural changes observed by K. Yalamanchili et al. are undesirable because they are usually associated with undesirable volume changes and, at the same time, a decrease in mechanical properties.

[0014] WO2020 / 084166A1 describes a PVD coating process for producing a multifunctional coating structure that exhibits phase stability up to a high temperature of 1100 °C. However, the procedure according to WO2020 / 084166A1 has the drawback of including an additional step of introducing a controlled precipitate structure into the HEA ceramic matrix formed on the substrate in the first step. This additional step requires additional equipment such as a laser light source or other heat source, which must be placed in each coating chamber. This not only increases the coating production cost but also minimizes the available space in the coating chamber. Also, the method according to WO2020 / 084166A1 is inconveniently applicable only locally, usually.

Summary of the Invention

Problems to be Solved by the Invention

[0015] Object of the Invention The present invention aims to improve or overcome one or more problems related to the prior art. In particular, the present invention aims to provide a highly efficient, preferably simple, rapid, and inexpensive method for producing a new HEA coating material that exhibits thermal stability at high temperatures, i.e., at temperatures of 700 °C or higher, particularly 800 °C or higher, more particularly 900 °C or higher, for example 1000 °C or 1100 °C.

Means for Solving the Problems

[0016] Description of the Invention To overcome the problems described above, the present invention provides a method for producing a thermally stable coating comprising or consisting of a multi-anion high entropy alloy (HEA) oxynitride.

[0017] The method according to the present invention is preferably carried out by producing the coating according to the present invention by using any PVD (Physical Vapor Deposition) technique, particularly cathodic arc evaporation, sputtering, or HiPIMS. Thus, the present invention relates to a new HEA material synthesized as a PVD coating by using cathodic arc evaporation, sputtering, or any other PVD technique, wherein the PVD coating according to the present invention comprises or consists of a multi-anion HEA oxynitride.

[0018] According to the present invention, a PVD coating material is produced that includes a cation sublattice designed as a multi-principal alloy formed by at least five elements (e.g., AlTaSiCrTi) and an anion sublattice formed by at least two elements, wherein at least two elements present in the anion sublattice are nitrogen and oxygen.

[0019] The term "multi-principal element alloy" is used to indicate that all alloying elements are present in contents in the range of 10 at.% to 40 at.%, and thus, no single element can be considered to be present in a dominant amount. This should be understood such that no element is considered to be in a dominant concentration if there is no element present at a concentration below 10 at.% or above 40 at.% (for example, if the elemental composition of the cation sublattice is Al 19 Ta 21 Si 11 Cr 11 Ti 38 ).

[0020] According to a preferred embodiment of the present invention, the PVD coating comprises or consists of a multi-principal element alloy containing TMN, AlN, and Si 3 N 4 , where TM is one or more transition metals, thus TMN is a nitride of TM, AlN is aluminum nitride, Si 3 N 4 is silicon nitride, the multi-principal element alloy is formed in a cubic phase, and at a temperature of 700 °C or higher, preferably 800 °C or higher, more preferably 900 °C or higher, for example, after annealing up to 1100 °C, etc., it is preferably generated to exhibit anion entropy stabilization that enables retention of the cubic phase for any use up to a temperature exceeding 1100 °C.

[0021] Thus, in a first aspect of the present invention, a method for producing a coating comprising at least one PVD coating layer is disclosed. For the production of at least one PVD coating layer, in a coating chamber containing oxygen and nitrogen as reactive gases, using PVD technology, materials from one or more targets are evaporated, and while at least one PVD coating layer is deposited, a multi-anion HEA oxynitride structure is formed that includes a cation lattice formed of five or more elements and an anion lattice formed of two or more elements, and if there are only two elements present in the anion lattice, these are oxygen and nitrogen.

[0022] The term "multianion HEA oxynitride structure" is preferably understood in the context of the present invention as a structure comprising an oxynitride anion sublattice formed of at least two atoms, in addition to a high-entropy alloy that constructs a cation sublattice, where these at least two atoms are oxygen (O) and nitrogen (N). Thus, it is understood that the oxynitride sublattice of the multianion HEA oxynitride structure may contain more than two atoms, for example, more than 10, particularly more than 15 atoms. To provide a suitable reactive atmosphere for generating the multifunctional coating structure according to the present invention, for example, a constant nitrogen partial pressure of preferably at least 2 Pa, particularly at least 5 Pa, can be provided. Then, a continuous amount of oxygen can be added to this partial pressure, preferably at an oxygen flow rate of at least 10 sccm, preferably at least 30 sccm.

[0023] The PVD coating according to the present invention produced using the method according to the present invention can be used, for example, as a wear-resistant coating, or as a decorative coating, or as any other kind of functional coating. In the context of the present invention, the term "functional coating" is used to refer to a coating deposited on a substrate surface to provide one or more specific functions to the substrate surface.

[0024] The coating structure according to the present invention is preferably produced in one step by evaporating a target material (from one or more targets having the same or different elemental compositions) and depositing it on a substrate. Thus, no further steps such as thermal post-treatment are required to produce the coating according to the present invention. In other words, according to the present invention, a PVD coating having and exhibiting a multi-anion HEA oxynitride can be produced by reactively depositing the evaporated target material on a substrate placed in a vacuum chamber containing at least oxygen gas and nitrogen gas as reactive gases. This does not necessarily mean that no further steps such as depositing further layers as an adhesion layer or as an upper layer can be carried out to further improve the coating structure according to the present invention and / or to incorporate further properties thereof.

[0025] As described above, sputtering techniques, in particular HiPIMS (High Power Pulsed Magnetron Sputtering) or arc PVD (Cathodic Arc Evaporation PVD) processes, can be used as the PVD coating process for producing the coating according to the present invention.

[0026] Furthermore, in another example of the first aspect, the material of one or more targets is selected to include five or more elements that will be present in the cation lattice.

[0027] In another example of the first aspect, the material of one or more targets includes at least one transition metal from Group 4, Group 5, or Group 6 of the periodic table of elements and at least one element of Al, Si, or B, preferably including Al and Si.

[0028] In another example of the first aspect, the coating structure is deposited on the substrate by applying a negative bias voltage to the substrate during the coating process, and the bias voltage is less than 200V, preferably less than 150V, particularly less than 120V.

[0029] In another example of the first aspect, at least three different target materials are evaporated and deposited on a substrate, preferably simultaneously.

[0030] In another example of the first aspect, one or more of the targets used in the coating process include a target material that is to be evaporated to react with a reactive gas present in the vacuum chamber to form a coating, and this target material includes at least a total of five elements, which may be selected from the following: · Transition metals of Group 4, Group 5, or Group 6 of the periodic table of elements, and · Elements Al, Si, and B.

[0031] Thus, a controlled addition of Al, Si, or Ta can preferably be made in the form of these nitrides, which means that Al can be added by forming AlN (aluminum nitride), Si can be added by forming SiN (silicon nitride), and Ta can be added as TaN (tantalum nitride). By doing so, the following becomes possible: · By the addition of AlN, TaN, and / or SiN, high oxidation resistance is induced because the chemical composition diffuses slowly in the coating.

[0032] · By the addition of AlN and / or SiN, high fracture resistance is induced because local atomic strain causes crack branching.

[0033] Preferably, the substrate temperature during the formation of the coating structure is 100 °C to 400 °C, in some cases more preferably 150 °C to 300 °C, particularly 200 °C to 250 °C.

[0034] In a second aspect, a coating structure produced by using the process according to the present invention described above is provided by the present invention, the coating comprising a multi-anion HEA oxynitride structure, wherein the high-entropy alloy in the HEA oxynitride structure comprises at least one transition metal from Group 4, Group 5, or Group 6 of the periodic table of elements and at least one element selected from Al, Si, and B, preferably Al and Si and optionally B.

[0035] One important aspect of the HEA (AlTiTaCrSi) oxynitride according to the present invention is that the cubic solid solution is retained even after annealing at 1100 °C or even above 1100 °C. It is noted that for each of these pseudo-binary alloys after high-temperature annealing, the immiscible components are separated, and AlN has a wurtzite structure, TaN has a hexagonal structure, and Si 3 N 4 has a stable crystal structure such as a trigonal structure. Furthermore, CrN becomes hexagonal Cr 2 N. Surprisingly, in the HEA oxynitride according to the present invention, the above-described undesirable phase change is suppressed, but a single solid solution having a cubic phase is retained.

[0036] Preferably, the high-entropy alloy in the HEA oxynitride structure of the coating comprises a total of at least five elements from a transition metal of Group 4, Group 5, or Group 6 of the periodic table of elements and one of the elements Al, Si, B. In a preferred design having this total of at least five elements, it is understood that at least one element must be a transition metal of Group 4, Group 5, or Group 6 of the periodic table of elements and at least one further element must be one element selected from Al, Si, and B.

[0037] Advantageously, the present invention may provide that the coating structure according to the present invention includes an anion sublattice containing more than two atoms, preferably more than five atoms, particularly more than ten atoms. Regarding significant structural strengthening, in particular, a multi-anion oxynitride structure of O20N35 may be provided in addition to a HEA sublattice composed of five elements including the elements Al, Ta, Si, Cr, and Ti.

[0038] Also, when the coating structure according to the present invention is formed including a multi-anion HEA oxynitride structure, it may be beneficial for its phase to be stable up to a temperature of 1100 °C or even beyond 1100 °C. The phase stability here is accompanied by a stable hardness up to the corresponding high temperature.

[0039] To better stabilize the cation sublattice, it may be preferable to generate the structure by selecting HEA elements of the cation sublattice such that the multifunctional coating structure according to the present invention has at least 5% lattice strain, preferably at least 10% lattice strain, particularly at least 20% lattice strain.

[0040] In another example of the second aspect, the layer thickness of the coating structure is less than 8 μm and greater than 500 nm.

[0041] In another example of the second aspect, the coating structure is formed in the form of a multilayer coating, and the total thickness of the multilayer coating exceeds 1 μm, preferably exceeds 2 μm, particularly exceeds 5 μm.

[0042] In a third aspect of the present invention, the use of the coating according to the present invention is disclosed, preferably as a functional coating, particularly for a wear-resistant coating or a decorative coating.

[0043] Detailed Description Here, based on examples, the present invention will be described in more detail with reference to the drawings.

Brief Description of the Drawings

[0044]

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Figure 8

DETAILED DESCRIPTION OF THE INVENTION

[0045] Figure 1 shows the calculated configurational entropy (at 1000 K) as a function of the number of components in an equimolar alloy. The equation described above shows that the configurational entropy is proportional to the number of components.

[0046] Figure 2 depicts the formation of a cubic phase consisting of TMN, AlN, and Si 3 N 4 enabled by entropy stabilization. As already described above, the object of the present invention is to provide a new material that can preferably be produced as a coating material (more preferably as a PVD coating). These coatings are also formed of a cubic phase that can maintain phase stability after high-temperature annealing up to 1100°C, enabled by entropy stabilization and depicted in Figure 2, of TMN, AlN, and Si 3 N 4 alloys. This example shows that the aforementioned entropy stabilization effect (by which a cubic solid solution composed of a plurality of components with different structures is retained under thermodynamic equilibrium conditions such as high-temperature annealing at 1100°C) may not be achieved if alloying elements are randomly selected.

[0047] In a further aspect of the present invention, due to entropy stabilization, the alloy design according to the present invention also takes into account the selection of elements that have a large difference in atomic size and thus induce the lattice strain shown in Figure 2. The induced lattice strain strengthens the alloy and inhibits the diffusivity of the alloy, for example, in an alloy according to the present invention. A mixture of Ta with an ionic radius of 170 pm and Si with an ionic radius of 111 pm creates a strain of approximately 20% as lattice strain very locally in the lattice.

[0048] Figure 3 shows the estimated S / R values for alloys consisting of one anion and two anion sublattices with two and five elements in the metal sublattice.

[0049] As already mentioned, the object of the present invention is achieved by providing a new material produced as a PVD coating preferably comprising or consisting of a multi-anion high entropy alloy oxynitride.

[0050] The new material produced according to the present invention is different from the prior art, in particular, at least in the following points.

[0051] 1) Design of a multi-principal element alloy having five elements in the cation sublattice and two or more anion sublattices (i.e., a nitride sublattice and an oxide sublattice as examples). Figure 3 compares the change in the S / R value for alloys having one anion or two anions and five elements in the metal sublattice. The S / R value further increases as the number of anions increases.

[0052] 2) The selection of metal elements includes elements of Group 4, Group 5, and Group 6 and involves controlled addition of Al, Si, and optionally B such that the high ΔHmix value is surely exceeded by TΔS at a finite temperature of about 900 °C. mix

[0053] Figure 4 shows the estimated ΔH mix and ΔT s mix for the (AlTaSiCrTi)N alloy with respect to their binaries. Notably, at a temperature of about ~700 °C (more precisely, approximately 650 °C, or a value of 600 °C - 700 °C), the entropy exceeds the enthalpy component. In particular, Figure 4 shows the balance estimated for the alloy of (Al 19 Ta 21 Si 11 Cr 11 Ti 38 )N. The ΔH mix values are from published literature, and TΔS mixThe value is estimated from Equation 1. The graph represents only two configurations, namely the cubic solid solution with respect to their binaries. However, principally, this consideration should include all other configurations or decomposition pathways. This consideration is a necessary criterion but not a sufficient one.

[0054] Figure 4 shows that entropy stabilization can occur in (Al 19 Ta 21 Si 11 Cr 11 Ti 38 )N alloys at temperatures higher than ~700 °C. Also, only a single anion lattice is presented in this consideration, and from the previous description, it can be seen that a two-anion sublattice alloy, namely (Al 19 Ta 21 Si 11 Cr 11 Ti 38 )ON, would be more favorable for improving entropy stabilization.

[0055] Figure 5a shows a schematic setup used to grow HEA nitrides and oxynitrides using an industrial-scale reactive arc evaporation system. As an example, a coating of (Al 19 Ta 21 Si 11 Cr 11 Ti 38 )N is grown using a combinatorial approach with a target of Al 56 Cr 24 Ta 20 at the bottom (R2) and Ti 70 Si 30 at the top (R18).

[0056] Figure 5b shows SEM images of the cross-sectional fracture of the coating at the bottom (R2), middle (R10), and top (R18) positions. The composition of the coating measured by EDS is shown in the annotation of Figure 5b. The target is N at 5 Pa 2Subject the arc discharge at the partial pressure, measure the resulting coating composition by EDS, and show the SEM micrograph of the coating destruction in Fig. 5b. In this arrangement, the high entropy alloy (Al 19 Ta 21 Si 11 Cr 11 Ti 38 )N is synthesized at the position R10 which is the middle part of the substrate holder.

[0057] Fig. 5c shows the hardness change as a function of the substrate position. Apart from the core of the present invention described above, there are further technical measures that guide the preferred embodiments of the present invention. For example, there are the following further technical measures.

[0058] 1) The multi-principal element oxynitride alloy composed of AlN, TaN, and SiN can exhibit high oxidation resistance because the chemical components diffuse slowly in the coating.

[0059] 2) The multi-principal element oxynitride alloy containing AlN and SiN can exhibit high fracture resistance because local atomic strain causes crack branching.

[0060] 3) Next, the controlled formation of AlN and SiN is induced to enable high oxidation resistance and high-temperature properties.

[0061] 4) The multi-principal element oxynitride alloy containing AlN and SiN and having an entropy-stabilized cubic phase does not cause phase separation at temperatures above 800 °C, more preferably above 900 °C or above 900 °C, such as 1100 °C. As a result of the cubic phase being stable at such high temperatures, the hardness is stable up to high-temperature annealing at 1100 °C and above.

[0062] Fig. 6a shows the as-deposited state (AD) and after high-temperature annealing of (Al 19 Ta 21 Si 11 Cr 11 Ti 38)The XRD pattern of (Al 19 Ta 21 Si 11 Cr 11 Ti 38 )N is shown. SEM images of the backscattered contrast of the coating after annealing to AD and 1100 °C are supplemented to the XRD. 19 Ta 21 Si 11 Cr 11 Ti 38 )N in the coating form pos10 is subjected to vacuum annealing up to 1100 °C. Figure 6a supplements the structural changes measured by XRD with the fracture cross-section of the coating in the SEM backscattered mode. The XRD image shows that the cubic solid solution of (Al

[0063] Figure 6b shows the H change of (Al 19 Ta 21 Si 11 Cr 11 Ti 38 )N as a function of the annealing temperature and compared to the reference Al 67 Ti 33 N coating. Notably, after annealing to 1100 °C, the coating precipitates Cr 2 N and Cr, which leads to a decrease in hardness. At temperatures above 1000 °C, the alloy (Al 19 Ta 21 Si 11 Cr 11 Ti 38 )N shows a sharp gradient of hardness decrease related to phase decomposition.

[0064] Using the above-described explanation for multi-anion entropy stabilization, at an oxygen flow rate of 30 sccm and using similar deposition conditions, (Al 21 Ta 21 Si 9 Cr 13 Ti 36 )O20 N 35 The coating was grown. Also, as shown in FIG. 7, the thermal stability of the oxynitride coating was investigated.

[0065] FIG. 7a shows the XRD patterns of (Al 21 Ta 21 Si 9 Cr 13 Ti 36 )O 20 N 35 . SEM images of the coating's backscattered contrast after AD and annealing at 1100° C. are supplemented to the XRD.

[0066] FIG. 7b shows the change in H of (Al 21 Ta 21 Si 9 Cr 13 Ti 36 )O 20 N 35 as a function of the annealing temperature and compared to the reference Al 67 Ti 33 N coating. Notably, this coating surprisingly shows a thermally stable solid solution up to at least 1100° C., and thus exhibits a stable solid solution.

[0067] Surprisingly, XRD shows that the cubic solid solution is stable up to an annealing temperature of 1100° C., which is not the case for nitride alloys with an equivalent composition in the metal sublattice. SEM images show similar grayscale images for the as-deposited state and after annealing at 1100° C., supplementing the XRD results.

[0068] Alloy (Al 21 Ta 21 Si 9 Cr 13 Ti 36 )O 20 N 35The relatively high thermal stability and stable hardness behavior are considered to be due to entropy stabilization, thus providing an example for designing thermally stable TM-Al-Si-ON multi-principal alloys over a wide composition range. The composition range includes elements of Group 4, Group 5, and Group 6, as well as Al, Si, and B.

[0069] Figure 8 shows a cross-sectional SEM image of the coated substrate after being subjected to oxidation at 900 °C for 2 hours in an ambient atmosphere. The oxidation resistance of the cubic (Al 21 Ta 21 Si 9 Cr 13 Ti 36 )ON coating is compared with that of the industrial standard coatings of cubic Al 64 Ti 36 N and cubic Al 77 Ti 23 N.

[0070] Surprisingly, although the alloy according to the present invention has a relatively low Al concentration of 21 at.%, as shown in Figure 8, its oxidation resistance is significantly higher than that of the current standard Al-rich AlTiN coating. Notably, the oxide layer thicknesses of cubic Al 64 Ti 36 N, cubic Al 77 Ti 23 N, and the high-entropy oxynitride alloy according to the present invention are less than 3000 nm, 740 nm, and 100 nm, respectively.

Claims

1. 1. A method for producing a coating comprising at least one PVD coating layer, comprising the steps of: using PVD techniques to evaporate material from one or more targets in a coating chamber with oxygen and nitrogen as reactive gases, wherein during deposition of said at least one PVD coating layer, a multi-anionic HEA oxynitride structure is formed comprising a cation lattice formed of five or more elements and an anion lattice formed of two or more elements, where if there are only two elements present in said anion lattice these are oxygen and nitrogen; In a cation lattice formed by the five or more elements, all of the five or more elements are present in a content range of 10 at. % to 40 at. %, The method of claim 1, wherein the cation lattice formed of five or more elements includes at least the elements Al, Ti, and Si.

2. The method of claim 1 , wherein the PVD technique is a magnetron sputtering technique.

3. 3. The method of claim 1 or 2, wherein the one or more target materials are selected to contain five or more elements that will be present in the cation lattice.

4. 4. The method of claim 3, wherein the material of the one or more targets comprises, apart from Al, Ti, and Si, at least one transition metal from group 4, 5, or 6 of the periodic table of the elements, and optionally B.

5. The method of any one of claims 1 to 4, wherein the coating is deposited on the substrate by applying a negative bias voltage to the substrate during the coating process, the bias voltage being less than 200V.

6. The method of claim 5 , wherein at least three target materials are evaporated and deposited simultaneously on the substrate.

7. The method according to claim 5 or 6, wherein the substrate temperature during production of the coating is between 100°C and 400°C.

8. 1. A method for producing a coating comprising at least one PVD coating layer, comprising the steps of: using PVD techniques to evaporate material from one or more targets in a coating chamber with oxygen and nitrogen as reactive gases, wherein during deposition of said at least one PVD coating layer, a multi-anionic HEA oxynitride structure is formed comprising a cation lattice formed of five or more elements and an anion lattice formed of two or more elements, where if there are only two elements present in said anion lattice these are oxygen and nitrogen; The method, wherein the coating is deposited on the substrate by applying a negative bias voltage to the substrate during a coating process, the bias voltage being less than 200V.

9. 1. A method for producing a coating comprising at least one PVD coating layer, comprising the steps of: using PVD techniques to evaporate material from one or more targets in a coating chamber with oxygen and nitrogen as reactive gases, wherein during deposition of said at least one PVD coating layer on a substrate, a multi-anionic HEA oxynitride structure is formed comprising a cation lattice formed of five or more elements and an anion lattice formed of two or more elements, two elements present in said anion lattice being oxygen and nitrogen; A substrate temperature of 150°C to 300°C is used; The method, wherein the target material to be evaporated and deposited comprises at least five elements in total from the transition metals of groups 4, 5, or 6 of the Periodic Table of the Elements and the elements Al, Si, B.

10. The method according to any one of claims 1 to 9, wherein the PVD technique is a HiPIMS or cathodic arc PVD technique.

11. A coating obtainable by using the method according to any one of claims 1 to 10, the at least one PVD coating layer comprises a multi-anionic HEA oxynitride structure; The high entropy alloy in the HEA oxynitride structure comprises a cation lattice formed of five or more elements and an anion lattice formed of two or more elements, the cation lattice comprising Al, Si, and optionally B, and at least one transition metal from group 4, 5, or 6 of the Periodic Table of the Elements; In a cation lattice formed by the five or more elements, all of the five or more elements are present in a content range of 10 at. % to 40 at. %, wherein the cation lattice formed of five or more elements comprises at least the elements Al, Ti, and Si.

12. The coating of claim 11 , wherein the anion lattice comprises more than two atoms.

13. 13. The coating of claim 11 or 12, wherein the multianionic HEA oxynitride structure is phase stable up to temperatures of 1100°C.

14. The coating according to any one of claims 11 to 13, wherein the HEA elements of the cation lattice are selected such that the coating has a lattice distortion of at least 5%.

15. The coating according to any one of claims 11 to 14, wherein the coating has a layer thickness smaller than 8 μm and larger than 500 nm.

16. The coating according to any one of claims 11 to 15, wherein the coating is formed in the form of a multi-layer coating, the total thickness of the multi-layer coating being greater than 1 μm.

17. A coating obtainable by using the method according to any one of claims 1 to 10, at least one PVD coating layer comprises a multi-anionic HEA oxynitride structure; The high entropy alloy in the HEA oxynitride structure comprises a cation lattice formed of five or more elements and an anion lattice formed of two or more elements, the cation lattice comprising Al, Si, and optionally B, and at least one transition metal from group 4, 5, or 6 of the Periodic Table of the Elements; In a cation lattice formed by the five or more elements, all of the five or more elements are present in a content range of 10 at. % to 40 at. %, the cation lattice formed by the five or more elements includes at least the elements Al, Ti, and Si; The multianionic HEA oxynitride structure is phase stable up to temperatures of 1100° C., the coating.

18. A coating obtainable by using the method according to any one of claims 1 to 10, at least one PVD coating layer comprises a multi-anionic HEA oxynitride structure; The high entropy alloy in the HEA oxynitride structure comprises a cation lattice formed of five or more elements and an anion lattice formed of two or more elements, the cation lattice comprising Al, Si, and optionally B, and at least one transition metal from group 4, 5, or 6 of the Periodic Table of the Elements; In a cation lattice formed by the five or more elements, all of the five or more elements are present in a content range of 10 at. % to 40 at. %, the cation lattice formed by the five or more elements includes at least the elements Al, Ti, and Si; A coating, wherein the HEA elements of the cation lattice are selected such that the coating has a lattice distortion of at least 5%.

19. Use of a coating according to any one of claims 11 to 18 as a functional coating.

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