Coating with embedded abrasive particles

Abstract

The invention relates to a coating for arrangement on a substrate, comprising a matrix layer having a matrix made of an oxide material, characterized in that the matrix layer contains oxide particles which can be distinguished from the matrix made of an oxide material, the oxide particles cannot be identified as droplets formed during cathodic arc evaporation.

Description

[0001] This invention relates to coatings for reducing component wear, said coatings being used, for example, to engage with a break-in layer over a wide temperature range. Such a break-in layer is typically applied to the inside of a gas turbine housing (“casing”) using a spraying technique. Once the turbine blades rotate, the blade tips (“tips”, “crowns”) contact the break-in layer and are profiled therein by grinding. This high-precision cut achieves the necessary high gas compression, which is essential for the turbine's high efficiency.

[0002] Another trend in improving gas turbines to achieve higher efficiency is higher gas combustion temperatures. This development, in turn, affects the break-in layer materials, requiring them to maintain mechanical stability at higher temperatures. Break-in layers made of high-temperature resistant materials are particularly suitable here, being oxide-based or oxide-containing (e.g., wear-resistant or abrasive materials made of aluminum-magnesium spinel that have been developed). The development of break-in layers with high mechanical stability at high temperatures also necessitates improvements to the materials required for the cutting-in break-in material at the turbine blade tips (“blade tips”).

[0003] Existing technology US 9957629 B2 discloses an example of prior art. An MCrAlY coating is deposited by electroplating on the tip of a turbine blade made of a high-temperature alloy, and abrasive grains composed of cubic boron nitride (cBN), alumina, silicon carbide, or other nitrides, oxides, or carbides are embedded within this coating. This coating exhibits higher compressive stress than conventional MCrAlY coatings, achieved through a suitable MCrAlY coating composition. This compressive stress firmly embeds the abrasive grains within the coating. The MCrAlY coating also possesses oxidation resistance comparable to standard MCrAlY, as demonstrated by results in a cycling temperature test at 1133°C. This remains true even when the abrasive grains are embedded within the coating.

[0004] However, the proposed solution has limitations in two aspects. First, cBN is not resistant to oxidation, so oxidation occurs on the particle surface. Oxidative wear weakens the adhesion of cBN particles in the MCrAlY coating.

[0005] Secondly, another limitation of the proposed solution lies in the temperature stability of the MCrAlY matrix. At temperatures approaching or above 1200℃, the mechanical strength decreases significantly, the MCrAlY matrix softens, leading to the loss of cBN abrasive particles, and the coating system loses its function of penetrating the running-in layer.

[0006] Another patent (EP1743958B1) proposes using a self-healing coating to address the oxidation wear problem that occurs with cBN abrasive grains. The method involves coating the SiC particles before embedding them into the coating at the blade tip. MCrAlY material is again preferred as the coating at the blade tip.

[0007] However, this invention did not solve the problem of the decrease in mechanical strength of MCrAlY at high temperatures.

[0008] Invention Task Therefore, the objective of this invention is to at least partially eliminate the aforementioned disadvantages of known coatings for application on substrates and methods of manufacturing thereof. In particular, the objective of this invention is to provide a coating for application on a substrate that exhibits low abrasion, and especially high oxidation resistance, even at temperatures, for example, above 1200°C.

[0009] The above-described task is accomplished by a coating for application on a substrate according to claim 1 and a method for manufacturing such a coating according to claim 10. Further features and details of the invention are derived from their respective dependent claims, description, and drawings. Herein, the features and details described in relation to the coating for application on a substrate of the invention are equally applicable to the method of the invention, and vice versa; therefore, reference is always made to or permissible to each other in relation to the disclosure of each aspect of the invention. Summary of the Invention

[0010] In this case, the coating according to the invention for application on a substrate comprises a substrate layer having a matrix composed of an oxide material, wherein the substrate layer contains oxide particles that are distinguishable from the matrix and cannot be identified as droplets formed during cathodic arc evaporation.

[0011] The coating according to the invention for application on a substrate can therefore have a carrier layer (substrate layer) composed of an oxide material, wherein the carrier layer (substrate layer) may further contain oxide particles distinguishable from the oxide material, which are not droplets (“droplets”) formed or potentially formed during cathodic arc evaporation. The carrier layer (substrate layer) is preferably disposed on the substrate.

[0012] The substrate layer can be configured to be oxidation resistant, and preferably has intermetallic compound and / or oxide components and / or abrasive particles.

[0013] A simple and effective adjustment of the coating properties can advantageously be achieved by specifying that the substrate surface has nucleation aid centers. Nucleation aids can be, for example, substances or materials that assist in the nucleation process, i.e., assist in the formation of small, stable nuclei or crystals within the material. This process is crucial for various physical and chemical processes, such as crystallization, crystal growth, and phase formation within materials.

[0014] To ensure thermal shielding or thermal barrier, the coating may be specified to be porous (having a large number of pores). In this case, the coating may preferably be porous, such that the thermal conductivity is reduced by at least 20%, preferably by at least 50%, compared to a non-porous coating.

[0015] To improve adhesion, it may also be advantageous to have an intermediate layer between the substrate and the base layer, wherein the intermediate layer is preferably made of a material with a melting point higher than that of the MCrAlY coating.

[0016] Alternatively, it can be conceived to include another intermediate layer containing MCrAlY, preferably composed of MCrAlY.

[0017] The coating may advantageously have an intermediate layer having a metallic matrix of an intermetallic compound that is elementally related to the abrasive grains to be embedded, and preferably belongs to the same group of elements in the periodic table.

[0018] In addition, to improve grinding capability, it can be advantageously specified that the coating contains additional particles in the form of droplets, wherein the droplets are preferably generated by cathodic arc evaporation, especially those that have already been generated.

[0019] These droplets can advantageously have different shapes and contain chromium and / or aluminum.

[0020] Furthermore, the subject of this invention is also a method for manufacturing a coating, preferably the aforementioned coating, for application on a substrate by means of cathodic arc evaporation. In this case, according to the method of the invention, a target is used as a material source, the target material of which is used to manufacture the matrix layer of the coating, wherein particles (preferably with a particle size of 0.01 µm to 100 µm) are embedded in the target material, the particles being at least partially transferred to the substrate and embedded therein in the matrix layer of the coating during coating. It goes without saying that the method according to the invention can also be used to manufacture coatings that do not contain oxides and / or contain oxides only in the matrix or particles (abrasive grains), although the method is advantageously used to manufacture oxide-containing coatings, and the oxides are preferably not only present in the matrix and / or particles (abrasive grains).

[0021] Regarding the simple and controllable introduction of particles, it can also be specified that the melting point of the particles is higher than the melting point of the target material constituting the coating substrate layer.

[0022] In this case, the target material may have Cr and / or Al and / or additional abrasive grains.

[0023] In addition, the target material can advantageously have a resistance of 0.05 ohms to 3 ohms.

[0024] Furthermore, this method can be advantageously implemented using a reaction gas, wherein oxygen is preferably used as the reaction gas, and in particular, only oxygen is used.

[0025] The subject of this invention is also a turbine blade comprising the aforementioned coating, wherein the coating is applied to the surface of the turbine blade.

[0026] Furthermore, the subject of this invention is also a tool for processing composite materials and / or borides and / or carbides, the tool comprising the aforementioned coating, wherein the coating is applied to the tool surface.

[0027] The proposed features enable the provision of a coating for application on a substrate, the coating being: It has abrasive grains with low oxidation wear embedded in the coating. Its surface is mechanically stable at high temperatures, and its temperature stability is higher than that of MCrAlY coatings. It has grain boundaries to close the interface between itself and abrasive grains during oxidation, and to cause the particles embedded in the coating to consolidate. It has an oxidation-resistant matrix, which, in addition to intermetallic compounds, also contains oxide components or abrasive material components. An intermediate layer, configured as an oxide barrier layer, is provided between the substrate and the functional layer. It has an intermediate layer consisting of a metallic matrix of an intermetallic compound that has an elemental affinity with the abrasive grains to be embedded (e.g., they are in the same group of the periodic table). The coating according to the invention is also described as being manufactured in the following manner: By using a target made of a conductive metal substrate embedded with abrasive grains, The target preferably includes a target material with a specific particle size, and preferably has a resistance of 0.05 ohms to 3 ohms. A material with elemental affinity to the abrasive grains to be embedded is synthesized through a reactive cathode spark evaporation method, wherein a metal matrix vapor and a reactive gas react to form the abrasive grains. Among them, intermetallic compounds with melting points above 1000℃ are generated through the process of electric sparks traveling on the target surface.

[0028] This invention can be applied, for example, to turbine blades by applying the coating of this invention to the tip of the turbine blade, thereby achieving a clean cut in a running-in layer made of abrasive material.

[0029] Detailed Description of the Invention This invention provides a solution to the aforementioned problems of the prior art. The prior art can be optimally combined with the features of patent US9957629B2. Figure 1 The coating system is described in this way, wherein abrasive particles (1) are embedded in a metal substrate (2). This coating system is deposited on the blade tip (3) by the method described, i.e., the tip of the turbine blade, which is the area of ​​the wear-in material (“abrasive material”) that cuts into the inner side of the turbine housing. The metal substrate here is made of MCrAlY material, which is also made of a high-temperature alloy like the blade tip material, but with a different composition, particularly a higher aluminum content, to improve the oxidation resistance of the substrate. However, the mechanical strength of the MCrAlY substrate has reached its limit in the prior art at temperatures below 1200°C, i.e., it softens and can no longer hold the embedded abrasive particles. Furthermore, for the cBN particles described therein, oxidation begins at their surface at this temperature, which further exacerbates the decrease in the bonding strength of the embedded particles.

[0030] Figure 2 An exemplary coating (11) according to the invention is shown on a high-temperature alloy substrate (10). This coating is based on a non-high-temperature alloy matrix material (12) that has a greater mechanical strength than MCrAlY at temperatures of 1000°C and above, and may at least partially possess oxide properties. The coating is deposited on a substrate material, such as a Ni-based, Co-based, or Ni-Co-based high-temperature alloy, or a SiC-based, C-based, or other substrate material, for example, deposited on a blade tip, using a PVD or CVD method, preferably a combined PVD-CVD method. The coating (11) according to the invention exhibits higher temperature stability than prior art MCrAlY coatings.

[0031] However, it may be advantageous to apply another coating (13) between the high-temperature alloy substrate (10) and the coating (11) of the present invention to achieve a better match between the substrate and the coating (11) of the present invention.

[0032] As an example, a coating of the present invention will be described herein, which mainly comprises elements aluminum and chromium, and is prepared by cathodic spark evaporation of an aluminum-chromium target in an oxygen-containing atmosphere. Furthermore, the coating also contains oxygen, i.e., a portion of the coating comprises Al-Cr-O. Al-Cr-O is X-ray amorphous after deposition at approximately 500°C using the method described above, but gradually crystallizes at annealing temperatures in an ambient atmosphere from approximately 900°C, exhibiting X-ray diffraction peaks corresponding to a corundum-type structure of Al-Cr-O mixed crystals. This mixed crystal structure, unlike MCrAlY, remains stable at temperatures of 1400°C and above. During annealing, a thin layer of alumina, also exhibiting a corundum-type structure, is formed on the surface of the coating.

[0033] The substrate layer (12) of the coating of the present invention is also characterized in the deposited state by droplets (“splatters”) (14, 15) of different sizes and shapes. The spherical droplets (14) have a metallic chromium core with a high chromium content, while the flat droplets (15) are mainly composed of aluminum, with at most a small amount of chromium. These droplets originate from the melting process initiated by the cathodic electric spark acting on the corresponding area of ​​the target material. They form characteristic shapes as they solidify on the substrate surface, which reflect the melting point: high melting point corresponds to spherical geometry, and low melting point corresponds to flat geometry. During the coating process, the spherical droplets embedded in the coating form grain boundaries (16) when they are covered by multiple layers during the coating process. Oxygen can diffuse along the grain boundaries to the center of the spherical droplets during subsequent annealing or use, resulting in the gradual oxidation of the droplets. This oxidation process is accompanied by volume increase, resulting in stress in the coating. This is certainly the desired effect in order to clamp hard and advantageously oxidation-inert heterogeneous particles (i.e., abrasive particles) (17) in the coating. With gradual oxidation, the stress even increases further. According to the present invention, this effect is used to firmly fix the abrasive particles (17) in the coating.

[0034] Based on the above description, the matrix layer thus possesses "self-healing" properties: on the one hand, it is due to the formation of corundum-type alumina on its surface, and on the other hand, it is due to the grain boundaries closing along the spherical droplets as the volume increases.

[0035] The oxidation-resistant layer (12) serves as a matrix for embedding abrasive particles (17) (e.g., oxide particles).

[0036] In this example, the matrix (when using an Al-Cr target in the case of spark evaporation) comprises Al-Cr intermetallic compounds, such as Al4Cr1, Al9Cr4, AlCr2, but primarily Al8Cr5, as well as Al-Cr-O, preferably in a composition that forms a corundum-type mixed crystal structure upon annealing in the environment. This matrix is ​​advantageously (see detailed below) prepared using a reactive cathode spark evaporation PVD method. The oxide-resistant layer (12) should contain a temperature-stable phase, i.e., a phase with a melting point higher than that of the substrate material to be protected. These phases can be either intermetallic or oxide phases. These phases can be formed from two elements as in the example, or they can contain only one element or more than two elements.

[0037] The examples described above, using Al-Cr as the target material to form intermetallic compounds in the deposited coating and to form oxides based on the target element, should not be construed as limiting. Other targets, coating phases, and abrasives are also exemplarily listed in Table 1, enabling the manufacture of coatings according to the invention for the applications exemplified herein and for corresponding applications in other fields requiring temperature-stable coatings with embedded abrasives. Such temperature-stable coatings with embedded abrasives according to the invention are also referred to hereinafter as functional layers. The table is merely illustrative and should not be considered exhaustive.

[0038] exist Figure 3 The section details the area between the high-temperature alloy substrate (20) and the functional layer (21), specifically the portion involving the optional intermediate layer (22). The intermediate layer (22) is responsible for ensuring good adhesion of the functional layer (21) to the high-temperature alloy substrate (20). It must maintain good adhesion over a wide temperature range, i.e., it must suppress undesirable diffusion processes that could weaken adhesion, and it must have sufficient flexibility to accommodate different coefficients of thermal expansion.

[0039] For the stability of the coating system of the present invention discussed in detail herein, it is advantageous that the surface of the high-temperature alloy substrate is not exposed to oxygen, especially reactive oxygen, during coating deposition to avoid the formation of mechanically unstable oxides (e.g., nickel oxide) and oxygen-driven diffusion processes. To achieve this, the surface of the high-temperature alloy substrate must not be exposed to reactive oxygen plasma, nor should oxygen diffuse to the interface of the high-temperature alloy substrate during coating deposition or subsequent use.

[0040] This leads to two favorable conditions for constructing the intermediate layer. First, no oxides should be deposited in the transition region between the surface of the high-temperature alloy substrate and the intermediate layer (22). Second, the intermediate layer should be a good oxygen barrier layer or form a good oxygen barrier layer, either by depositing subsequent layers or by playing a role in a specific application.

[0041] This (while continuing to use this exemplary coating system as an example) is achieved by depositing an intermetallic compound (preferably and primarily Al8Cr5 or AlCr2) composed of Al-Cr within the intermediate layer in the first step. These intermetallic compounds have a higher melting point than, for example, MCrAlY materials, and form a corundum-type Al-Cr-O mixed crystal, i.e., an oxide barrier layer, when exposed to a reactive oxygen atmosphere, thereby achieving a stable transition to the functional layer (21).

[0042] like Figure 4 As illustrated, the intermediate layer (30) on the substrate (31) can also be achieved as a multilayer coating before the deposition of the actual functional layer (32). After depositing a sufficiently thick intermetallic compound layer (33) of Al-Cr as an oxygen barrier layer in the first step, another layer (34) based on this material is deposited with a moderate addition of oxygen, and then the oxygen supply is interrupted again. This cycle is repeated until a multilayer intermediate layer (30) of Al-Cr / Al-Cr-O material is formed, wherein the oxygen content in the Al-Cr-O film can vary. The multilayer coating scheme will be further discussed in the following paragraphs explaining the embedding of abrasive particles (35) into the functional layer.

[0043] The requirements for functional layers are primarily oxidation resistance and mechanical strength suitable for their respective applications, as well as the ability to retain embedded abrasive grains. When used as blade tips, the functional layer must remain stable in a temperature range of approximately 1100°C and above. The method for manufacturing abrasive-containing functional layers will then be described in detail.

[0044] The preferred method for embedding abrasive particles in a coating described herein is based on evaporation in a vacuum environment using a solid source. For example, known methods include electron beam evaporation of material, such as an evaporation ingot (“ingot”), from a crucible. If particles are intentionally embedded during the ingot manufacturing process, they are carried by the evaporating material and can be embedded into the deposited coating.

[0045] However, experiments have shown that embedding abrasive particles into the coating without other measures is insufficient, which may be due to the low kinetic energy of the particles and the insufficient fixation of the particles in the substrate layer.

[0046] Therefore, one of the objectives of this invention is to increase the abrasive kinetic energy during the evaporation of the substrate material (ingot) and to improve its fixation in the grown coating.

[0047] To this end, cathodic electric spark evaporation (CAE) was investigated. Unlike the methods described above, the target to be evaporated must be conductive in the CAE; that is, continuing with this example, the target is composed of Al and Cr, for example, having an Al composition expressed as an atomic percentage. 70 Cr 30In addition, abrasive particles were added to the target during the manufacturing process.

[0048] These processes for target manufacturing can include, for example, forging, melting, sintering, hot isostatic pressing, or spark plasma sintering. Targets can also be manufactured using other processes, such as simultaneously spraying metallic and oxide materials onto a substrate during processes like APS, HVOF, or LPPS.

[0049] exist Figure 5 The target (40) is schematically described as being made in this way. The target (40) comprises a conductive metallic substrate (41) in which abrasive grains (42) are embedded. For stability reasons, such a target, as is known to those skilled in the art, can be applied to a backing plate (43), provided that it cannot be manufactured as a single piece. Insulating abrasive grains are used in most cases, such as corundum, quartz, silicates, diamond, cubic boron nitride, and other nitrides, to name a few. Particles made of poorly conductive (semiconductor) materials (e.g., silicon carbide or boron carbide or other carbides or borides) are also suitable as abrasive grains due to their high hardness. Alternatively, hard alloys can be embedded in the target.

[0050] The number and size of the abrasive grains (42) embedded in the metal substrate (41) depend on the specific application of the coating to be synthesized and are typically determined through optimization. This is similar to abrasive applications, where the grain size within the abrasive grains is matched to the desired roughness of the substrate surface to be ground. Because the metal substrate (41) and the abrasive grains (42) can be materials with different densities and chemical compositions, it is impossible to give a specific concentration ratio of abrasive grains to the metal substrate within the target.

[0051] However, when designing the target, it must be ensured that the influence of the abrasive particles on the conductivity of the target substrate does not exceed the level required to perform RCAE. This level is measured by the resistance (impedance) exhibited by the cathode spark discharge when using a target with the appropriate abrasive particles, ranging from 0.05 ohms to approximately 3 ohms. Of course, those skilled in the art will understand that the resistance is not only determined by the embedding of insulating particles into the originally conductive target, but other parameters of the spark discharge, such as the anode area, the magnetic field at the target, or the reacting gases, also affect the discharge voltage.

[0052] Particle size at Figure 6 The figure is schematically illustrated. It shows two typical shapes of particle cross-sections (50, 51), with their maximum cross-sectional dimensions (D1, D2) used to represent particle size. Both spherical and sharp-edged particles can be used for specific applications. Advantageously, commercially available powders with sizes between 50 nm and 10 µm can be used, where, for special applications, particles of approximately 10 nm and particles up to 100 µm can be embedded in the target.

[0053] The aforementioned target with embedded abrasive grains is used as the cathode for RCAE, as described above. This method yields excellent results in abrasive grain embedding. This is because the evaporation method generates numerous electric spark spots on the target surface, which melt small areas of the target surface in a very short time and explosively evaporate the target matrix material. If a particle is located within this area, it is carried and gains sufficient energy to reach the coating surface with the evaporated material. The choice of abrasive grains can be determined based on the coating application. In this example, the triboelectric cutting process of turbine blades in a wearable material is described, and corundum particles are added to the target. These particles retain their chemical composition during target evaporation and during embedding into the coating during deposition. This is because the melting point of the abrasive grains is higher than the melting point of the phase formed on the target surface during electric spark evaporation. This is a design principle for applications requiring abrasive action.

[0054] There are two other important reasons for the secure embedding of abrasive grains in the grown coating. First, RCAE allows for target designs in which the metal substrate can be selected such that the elements it contains are also present in the abrasive grains, for example, Al2O3 particles embedded in a target made of Al (Al matrix), or Al2O3 particles embedded in a target made of Al-Cr matrix; or, a Zr matrix embedded with ZrO2 particles or YSZ particles, or a Zr-Y matrix embedded with YSZ particles.

[0055] This type of matrix is ​​particularly advantageous when the addition of a reactive gas (e.g., oxygen in this case) to the CAE during RCAE can synthesize a coating with properties close to those of abrasive particles (e.g., in terms of thermal expansion coefficient). Again, taking an Al-Cr target containing embedded Al₂O₃ particles as an example, Al-Cr-O, as a mixed crystal, can be synthesized using the RCAE method, possessing a lattice constant similar to corundum-type Al₂O₃. In other words, for abrasive embedding, it is particularly advantageous to select a conductive matrix in the target design so that the coating material synthesized during the reaction is similar to the abrasive material. This is especially applicable to oxide synthesis accompanied by oxide particle embedding, but the same principle applies to nitrides and carbides and their mixtures, i.e., embedding TiC particles in a titanium target and adding C₂H₂ as a reactive gas during evaporation.

[0056] The second reason why RCAE is particularly suitable for introducing abrasive grains embedded in the target into the coating to be synthesized is that the reactive gas can be changed during the reactive evaporation process of the target, thereby preparing a multilayered coating, which consists of sublayers that react with the reactive gas to different degrees. Again, taking an Al-Cr target containing corundum (alumina) abrasive grains evaporated in reactive oxygen as an example: to prepare a multilayered coating, the oxygen flow rate is varied as follows: at a high oxygen flow rate, Al-Cr is completely oxidized to (Al,Cr)₂O₃, forming a stoichiometric ternary oxide; while at a low oxygen flow rate, a substoichiometric state of oxygen occurs, thereby forming at least one biphase layer consisting of oxide and metal components.

[0057] If this coating is exposed to higher temperatures in the atmosphere during use, oxygen diffuses along the grain boundaries and initiates oxidation along the grain boundaries in areas that were not fully oxidized during coating synthesis due to insufficient oxygen flow. This, in turn, leads to volume increase and compressive stress in these areas, ultimately resulting in better anchoring of the abrasive grains within the coating. Experience shows that when the particle size ( Figure 6 When the thickness of D1 and D2 in the coating is roughly the same as that of a single layer, the particles can be embedded particularly well in the multilayer coating.

[0058] exist Figure 7 This multilayer coating with embedded particles is shown. The multilayer coating was ground through to the underlying substrate using a ball-crater grinding method, and measurements were taken of the coating. The total thickness of the coating is approximately 4.2 µm, consisting of approximately 220 nm of Al-Cr-O. x Monolayer and approximately 320 nm Al-Cr-O y The structure consists of a single layer, namely Al-Cr monolayers with varying oxygen contents. Optical micrographs also show particles (60) of different sizes embedded in the multilayer structure. After crater grinding, particles (60) with sizes approximately equal to the thickness of the monolayers remain embedded, while larger particles (61) are removed by crater grinding.

[0059] Figure 8 A scanning electron microscope (SEM) cross-sectional image of the fracture surface of another multilayer coating is shown, with a relatively large layer thickness of approximately 13 µm. The image shows the embedding of abrasive grains larger than the individual layer thicknesses of the multilayer coating. The size of the particles (70) in the image ranges from approximately 1 µm to approximately 5 µm.

[0060] Figure 9 The grinding cut-in test results of two different multilayer coatings in abrasive materials were recorded. Both coatings manufactured according to the above description showed clean cut-in in abrasive materials, and uniform wear of the coating on the blade tip at a break-in temperature of 1200°C.

[0061] In general, this concept can be applied to many different substrates, such as high-temperature alloys, SiC CMC (composite materials), C / C composite materials, Ni-based alloys, various types of steel or cemented carbide.

Claims

1. A coating for application on a substrate, comprising a matrix layer having a matrix composed of an oxide material, characterized in that, The substrate layer contains oxide particles that can be distinguished from the substrate made of oxide materials, and these oxide particles cannot be identified as droplets formed during the cathodic arc evaporation process.

2. The coating for application on a substrate according to claim 1, characterized in that, The substrate layer is configured to be oxidation resistant, wherein the substrate layer preferably has intermetallic compounds and / or oxide-containing compounds and / or abrasive particles.

3. The coating for application on a substrate according to claim 1 or 2, characterized in that, The surface of the substrate has nucleation aid centers.

4. A coating for application on a substrate according to any one of the preceding claims, characterized in that, The coating has a large number of pores to reduce thermal conductivity.

5. A coating for application on a substrate according to any one of the preceding claims, characterized in that, An intermediate layer is provided between the substrate and the base layer, wherein the intermediate layer is preferably composed of a material with a melting point higher than that of the MCrAlY coating.

6. The coating for application on a substrate according to claim 5, characterized in that, There is another intermediate layer containing MCrAlY, preferably composed of MCrAlY.

7. A coating for application on a substrate according to any one of the preceding claims, characterized in that, An intermediate layer is provided, which has a metal matrix composed of an intermetallic compound, the intermetallic compound having an elemental affinity with the abrasive grains to be embedded, and preferably being in the same group of the periodic table.

8. A coating for application on a substrate according to any one of the preceding claims, characterized in that, The coating contains additional particles in the form of droplets, wherein the droplets are preferably generated by cathodic arc evaporation, especially those already generated by cathodic arc evaporation.

9. A coating for application on a substrate according to any one of the preceding claims, characterized in that, The droplets have at least some different shapes and sizes, and contain chromium and / or aluminum.

10. A method for manufacturing a coating, preferably the aforementioned coating, for application on a substrate by means of cathodic arc evaporation, characterized in that, Using a target as a material source, the target material is used to manufacture the substrate layer of the coating, wherein particles are embedded in the target material, and the particles are at least partially transported to the substrate and embedded therein in the substrate layer of the coating during coating.

11. The method according to claim 10, characterized in that, The melting point of the particles is higher than that of the target material that constitutes the matrix layer.

12. The method according to claim 10 or 11, characterized in that, The target material has Cr and / or Al and / or additional abrasive grains.

13. The method according to any one of claims 10 to 12, characterized in that, The target has a resistance of 0.05 ohms to 3 ohms.

14. The method according to any one of claims 10 to 13, characterized in that, This method is carried out using a reaction gas, wherein oxygen is preferably used as the reaction gas.

15. A turbine blade comprising a coating according to any one of claims 1 to 9, wherein, The coating is applied to the surface of the turbine blade.

16. A tool for processing composite materials and / or borides and / or carbides, comprising a coating according to any one of claims 1 to 9, wherein, The coating is applied to the surface of the tool.

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