A self-healing environmental barrier coating resistant to high temperature oxidation for ceramic-based composite materials and a preparation method thereof

Abstract

The present invention provides a self-healing environmental barrier coating for ceramic-based composite materials that is resistant to high-temperature oxidation and a preparation method thereof. The coating is a double-layer structure, which includes a bonding layer and a self-healing coating from the inside to the outside. The bonding layer is prepared on the surface of the silicon carbide ceramic-based composite material, and the self-healing coating is prepared on the surface of the bonding layer. The material of the bonding layer is MoSi2 or (Mo x ,W 1‑x )Si2; the material of the self-healing coating is Re2SiO5-Si; the ceramic-based composite material is a silicon carbide ceramic-based composite material. The present invention effectively improves the service temperature of the environmental barrier coating, improves its anti-oxidation performance, improves the bonding strength between the coating and the substrate, effectively improves the seismic life of the coating, and effectively improves the service life of the environmental barrier coating.

Description

Technical Field

[0001] The present invention relates to the field of material technology, and in particular to a high-temperature oxidation-resistant self-healing environmental barrier coating for ceramic-based composite materials and a preparation method thereof. Background Art

[0002] Improving the thrust-to-weight ratio of aircraft engines requires increasing the gas inlet temperature before the turbine, but traditional nickel-based high-temperature alloys cannot meet the current service temperature. Therefore, ceramic-based composite materials with advantages such as low density, high melting point, and excellent high-temperature mechanical properties are the most promising materials to replace nickel-based high-temperature alloys for high-temperature parts of aircraft engines.

[0003] In a dry, high-temperature combustion environment, a dense SiO2 layer is formed on the surface of the ceramic-based composite material, which can effectively block the entry of oxygen and improve the antioxidant performance. However, during the actual operation of the aircraft engine, the aviation kerosene will produce 8-10vol% water vapor during the combustion process. SiO2 reacts with high-temperature water vapor to generate Si(OH) x , ceramic matrix composites suffer from severe corrosion and their mechanical properties are seriously reduced. Therefore, it is necessary to prepare an environmental barrier coating on its surface to isolate high-temperature water vapor and inhibit the occurrence of high-temperature water-oxygen corrosion, which is extremely important for the long service life of the hot end components of ceramic matrix composites.

[0004] Si is the most widely used bonding layer in environmental barrier coatings. It improves the bonding strength between environmental barrier coatings and ceramic matrix composites, and also provides excellent anti-oxidation properties for ceramic matrix composites. However, the stress generated by the phase change of Si's oxidation product SiO2 during the cooling process can cause the coating to fall off and fail. In addition, the melting point of Si is 1414℃, which limits the use of environmental barrier coatings at higher temperatures. Therefore, it is necessary to develop a new material to improve the service temperature and anti-oxidation and anti-corrosion properties of environmental barrier coatings.

[0005] Rare earth silicates, as ceramic layers of environmental barrier coatings, play a role in isolating oxygen, gas and combustion impurities and other harmful substances, and are usually prepared by atmospheric plasma spraying. Atmospheric plasma spraying is an economical and efficient coating preparation process and is widely used in coating preparation. However, the spraying conditions in the atmospheric environment can easily cause non-oxides such as silicon, silicides, and carbides to oxidize. Therefore, in the preparation process of the bonding layer, the coating is prepared by cold spraying, and the solid-phase sintering method under a protective atmosphere can effectively prepare an oxidation-free, high-bonding strength bonding layer. In addition, rare earth silicates decompose in the plasma flame, and the prepared coating produces cracks, pores and other defects due to quenching stress and thermal mismatch stress. Through the doping method, a composite coating with self-healing function can be prepared, which inhibits the generation of defects such as cracks and pores in the coating during service, and can effectively prevent the entry of oxygen and water vapor. Summary of the invention

[0006] According to the technical problems raised above, a self-healing environmental barrier coating for ceramic matrix composite materials with high temperature oxidation resistance and a preparation method thereof are provided. The present invention mainly prepares Mo-Si or Mo-W-Si mixed slurry, and adopts two different methods, more convenient cold spraying method and slurry impregnation method, to prepare MoSi2 or (MoW-Si) on the surface of ceramic matrix composite materials. x ,W 1-x )Si2 bonding layer, avoiding the oxidation produced during atmospheric plasma spraying; Re2SiO5-Si powder (wherein Re=Yb, Y, Gd, Lu, Nd) is prepared by spray granulation method, and Re2SiO5-Si self-healing environmental barrier coating is prepared on the surface of the bonding layer by atmospheric plasma method, which effectively improves the seismic life and antioxidant ability of the coating.

[0007] The technical means adopted by the present invention are as follows:

[0008] A high-temperature oxidation-resistant self-healing environmental barrier coating for a ceramic-based composite material. The coating is a double-layer structure, which includes a bonding layer and a self-healing coating from the inside to the outside. The bonding layer is prepared on the surface of the silicon carbide ceramic-based composite material, and the self-healing coating is prepared on the surface of the bonding layer.

[0009] Furthermore, the material of the bonding layer is MoSi2 or (Mo x ,W 1-x )Si2;

[0010] The material of the self-healing coating is Re2SiO5-Si, wherein Re=Yb, Y, Gd, Lu or Nd;

[0011] The ceramic-based composite material is a silicon carbide ceramic-based composite material.

[0012] Furthermore, the thickness of the bonding layer is 50-100 μm; the thickness of the self-healing coating is 100-200 μm; the size of the ceramic-based composite material is 50×50×5 mm 3 .

[0013] The present invention also provides a method for preparing a high temperature oxidation resistant self-healing environmental barrier coating for a ceramic-based composite material, comprising the following steps:

[0014] S1. Using a silicon carbide ceramic-based composite material continuously toughened by silicon carbide fibers as a matrix, the silicon carbide ceramic-based composite material matrix is ​​polished, surface sandblasted, ultrasonically cleaned, alcohol soaked, and dried in sequence for standby use;

[0015] S2, preparing a bonding layer on a silicon carbide ceramic-based composite material substrate by a cold spraying method or a slurry impregnation method;

[0016] S3, preparing a self-healing coating on the surface of the bonding layer by an atmospheric plasma spraying method, thereby preparing a composite coating with a self-healing function, namely, a self-healing environmental barrier coating;

[0017] S4. Sample performance assessment: The prepared self-healing environmental barrier coating samples are subjected to oxidation test, thermal shock test and flame thermal cycle test.

[0018] Furthermore, in the step S1, a diamond grinding head is used to grind the silicon carbide ceramic-based composite material substrate into rounded corners; under a pressure of 0.3 MPa, the ground surface of the silicon carbide ceramic-based composite material substrate is sandblasted using 220-mesh corundum particles for a duration of 15 to 20 seconds; using anhydrous ethanol as a solvent, the sandblasted silicon carbide ceramic-based composite material substrate is ultrasonically treated for 5 minutes to remove impurities, then immersed in anhydrous ethanol for 60 minutes to remove oil stains, and then dried in an oven at ~60°C for 2 hours for coating preparation.

[0019] Furthermore, in step S2, the method of preparing the bonding layer by cold spraying is:

[0020] S21, weighing according to the mass ratio of Mo:Si:binder=64:35:1, or weighing according to the mass ratio of Mo:W:Si:binder=32:32:36:0.5, using anhydrous ethanol as solvent and zirconium oxide balls as ball milling media, performing ball milling at a ball milling speed of 500 r / min and a ball milling time of 4 h to prepare a Mo-Si or Mo-W-Si mixed solution;

[0021] S22, cold spraying a Mo-Si or Mo-W-Si mixed solution on the surface of a silicon carbide ceramic-based composite material substrate by a cold spraying method, and then drying it in an oven in two steps, first at 60°C for 24h, and then at 110°C for 12h, to prepare MoSi2 or (Mo x ,W 1-x )Si2 bonding layer.

[0022] Further, the MoSi2 or (Mo x ,W 1-x )Si2 bonding layer is solid-phase sintered at 1500°C for 2 hours in a hot press furnace in an argon atmosphere to better bond the coating to the silicon carbide ceramic-based composite material matrix; the process is repeated many times to obtain an ideal thickness (50-100 μm).

[0023] Furthermore, in step S2, the method for preparing the bonding layer by slurry impregnation is:

[0024] S201, weighing the Mo and Si raw materials according to the mass ratio of Mo:Si:binder=64:35:1, or weighing the Mo, W, Si raw materials according to the mass ratio of Mo:W:Si:binder=32:32:36:0.5, preparing Mo-Si or Mo-W-Si mixed powder by mechanical mixing ball milling and spray drying, mixing the Mo-Si or Mo-W-Si mixed powder with the solvent using ethanol as solvent, adding a certain mass of binder to prepare slurry, and stirring in a constant temperature magnetic stirrer for 2 to 3 hours;

[0025] S202, immersing the silicon carbide ceramic-based composite material matrix in the slurry, slowly taking it out, putting it into a drying oven, drying it at 60°C for 24 hours and at 110°C for 12 hours, and then putting it into an argon atmosphere furnace for high-temperature sintering. The sintering condition is sintering at 1600°C for 2 hours to prepare MoSi2 or (Mo x ,W 1-x )Si2 bonding layer.

[0026] Furthermore, the specific steps of step S3 are as follows:

[0027] S31. Taking rare earth silicate as the main component, adding 10-20wt% Si, and adopting mechanical mixing and spray granulation methods, Re2SiO5-Si composite powders of different rare earth elements are prepared; the detailed preparation process is: Re2SiO5 powder, Si powder, deionized water, gum arabic binder, and ammonium citrate dispersant are mixed and ball-milled to obtain a slurry; and then the slurry is dried by spray drying to obtain spherical granulated powders of 32-125μm.

[0028] S32. Spray Re2SiO5-Si composite powder on the surface of the bonding layer by atmospheric plasma spraying to prepare a self-healing coating, thereby preparing a self-healing environmental barrier coating with self-healing function. Preparation parameters of atmospheric plasma: during the atmospheric plasma spraying process, the substrate temperature is preheated to 300°C-600°C, the spray gun power is 20-42kW, the spraying distance is 100-200mm, the powder feeding rate is 3-10%, and the spraying angle is 30°-60°.

[0029] Further, in step S4, the oxidation test specifically includes the following steps: placing the self-healing environmental barrier coating samples at 1400° C. and 1500° C. respectively, and statically oxidizing the samples at each temperature for 2 h, 16 h, 32 h and 64 h, and observing the microscopic morphology of the coating and the substrate;

[0030] The thermal shock test specifically includes the following steps: the sample is kept at 1400°C for 55 minutes, air-cooled for 5 minutes, and thermally shocked for 16, 32, and 64 times respectively until the coating shedding area reaches 20% of the total area and the thermal shock is stopped;

[0031] The flame thermal cycle test specifically includes the following steps: using a flame thermal cycler, the sample is heated for 5 minutes, then cooled for 2 minutes, and the cycle is repeated 200 times, 400 times, and 800 times respectively until the coating peeling area reaches 20% of the total area, and the thermal cycle test is stopped.

[0032] Compared with the prior art, the present invention has the following advantages:

[0033] 1. The self-healing environmental barrier coating for ceramic matrix composite materials provided by the present invention that resists high temperature oxidation and the preparation method thereof, MoSi2 or (Mo x ,W 1-x )The preparation of Si2 bonding layer effectively increases the service temperature of the environmental barrier coating, improves its anti-oxidation performance, and effectively increases the service life of the environmental barrier coating.

[0034] 2. The high-temperature oxidation-resistant self-healing environmental barrier coating for ceramic-based composite materials provided by the present invention and its preparation method, through the cold spraying method, slurry impregnation method combined with the solid phase reaction sintering method, avoids the oxidation of silicides during the coating preparation process and improves the bonding strength between the coating and the substrate.

[0035] 3. The self-healing environmental barrier coating for ceramic-based composite materials provided by the present invention and its preparation method, and the preparation of the self-healing composite coating, effectively improve the thermal shock life and oxidation resistance of the coating. During the service process of the coating at a temperature above 1400°C, the molten Si fills the pores, cracks and other defects to form a relatively dense coating, which inhibits the entry of harmful substances such as oxygen and water vapor. In addition, the oxygen entering the coating is first consumed by Si, and the reaction product SiO2 reacts with rare earth monosilicate to form pyrosilicate.

[0036] Based on the above reasons, the present invention can be widely promoted in the fields of aviation and the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0038] Figure 1 This is a schematic diagram of the coating structure design of the present invention.

[0039] Figure 2 The following is a flow chart of the coating preparation process of the present invention. DETAILED DESCRIPTION

[0040] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0041] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0042] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0043] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, method and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, method and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0044] like Figure 1 As shown, the present invention provides a self-healing environmental barrier coating for ceramic matrix composite materials that resists high temperature oxidation. The coating is a double-layer structure, which includes a bonding layer and a self-healing coating from the inside to the outside. The bonding layer is prepared on the surface of the silicon carbide ceramic matrix composite material, and the self-healing coating is prepared on the surface of the bonding layer. The material of the bonding layer is MoSi2 or (Mo x ,W 1-x )Si2; the material of the self-healing coating is Re2SiO5-Si, where Re=Yb, Y, Gd, Lu or Nd; the ceramic matrix composite material is a silicon carbide ceramic matrix composite material. The thickness of the bonding layer is 50-100 μm; the thickness of the self-healing coating is 100-200 μm; the size of the ceramic matrix composite material is 50×50×5 mm 3 .

[0045] like Figure 2 As shown, the present invention also provides a method for preparing a high temperature oxidation resistant self-healing environmental barrier coating for a ceramic-based composite material, comprising the following steps:

[0046] 1. Silicon carbide ceramic matrix composite material with continuous toughening of silicon carbide fibers (50×50×5mm 3) was used as the substrate. In order to reduce stress concentration, a diamond grinding head was used to grind the substrate sample into a rounded corner. The ground substrate was sandblasted with 220-mesh corundum particles under a pressure of 0.3 MPa for 15 to 20 seconds. Anhydrous ethanol was used as the solvent to ultrasonically treat the sandblasted substrate for 5 minutes to remove impurities. Then it was soaked in anhydrous ethanol for 60 minutes to remove oil stains, and then dried in an oven at ~60°C for 2 hours for coating preparation.

[0047] 2. Bonding layer preparation: cold spraying and slurry impregnation

[0048] (1) Cold spray method: Mo:Si:binder=64:35:1 mass ratio and Mo:W:Si:binder=32:32:36:0.5 mass ratio were weighed respectively, and anhydrous ethanol was used as solvent and zirconium oxide balls were used as ball milling media. The ball milling speed was 500r / min and the ball milling time was 4h to prepare Mo-Si or Mo-W-Si mixed solution. f / SiC matrix (silicon carbide ceramic matrix composite material matrix) surface preparation bonding layer, that is, on the SiC f Mo-Si or Mo-W-Si mixed solution was cold sprayed on the surface of the SiC substrate, and then dried in an oven in two steps, first at 60°C for 24h and then at 110°C for 12h to prevent the coating from cracking, thereby preparing MoSi2 or (Mo x ,W 1-x )Si2 bonding layer. In order to make the coating better with SiC f / SiC matrix to form MoSi2 or (Mo x ,W 1-x )Si2 bonding layer, further solid phase sintering at 1500℃ for 2h in a hot press furnace in argon atmosphere. This process can be repeated many times to obtain the desired thickness (50-100μm).

[0049] (2) Slurry impregnation method: Mo, Si raw materials or Mo, W, Si raw materials are mechanically mixed and ball milled and spray dried (in the slurry impregnation method, the weight is weighed according to the mass ratio of Mo:Si:binder = 64:35:1, or the weight is weighed according to the mass ratio of Mo:W:Si:binder = 32:32:36:0.5), and Mo-Si or Mo-W-Si mixed powder is prepared. Ethanol is used as the solvent, and a certain amount of binder is added to prepare a slurry, which is stirred in a constant temperature magnetic stirrer for 2 to 3 hours. SiC fThe / SiC matrix is ​​immersed in the slurry, slowly taken out, placed in a drying oven, dried at 60°C for 24h and 110°C for 12h, and then placed in an argon atmosphere furnace for high-temperature sintering (vacuum sintering) at 1600°C for 2h, thereby preparing MoSi2 or (Mo x ,W 1-x )Si2 bonding layer.

[0050] 3. Preparation of composite coating

[0051] Re2SiO5-Si composite powders of different rare earth elements were prepared mainly with rare earth silicate and 10-20wt% Si added by mechanical mixing and spray granulation. Specifically, Re2SiO5 and Si powders were prepared into slurry by mechanical mixing and ball milling, and the slurry was spray granulated to obtain Re2SiO5-Si composite powder. The detailed preparation process was as follows: Re2SiO5 powder, Si powder, deionized water, gum arabic binder and ammonium citrate dispersant were mixed and ball milled to obtain slurry; and the slurry was dried by spray drying to obtain spherical granulated powder of 32-125μm. On the surface of the bonding layer, a composite coating with a self-healing effect is prepared by an atmospheric plasma spraying method, that is, Re2SiO5-Si composite powder is sprayed on the surface of the bonding layer by an atmospheric plasma spraying method to prepare a self-healing coating, thereby preparing a self-healing environmental barrier coating with a self-healing function; the preparation parameters of the atmospheric plasma are: during the atmospheric plasma spraying process, the substrate temperature is preheated to 300°C-600°C, the spray gun power is 20-42kW, the spraying distance is 100-200mm, the powder feeding rate is 3-10%, and the spraying angle is 30°-60°.

[0052] 4. Sample performance assessment:

[0053] (1) Oxidation test: The self-healing environmental barrier coating samples were placed at 1400℃ and 1500℃, and the samples at each temperature were subjected to static oxidation for 2h, 16h, 32h and 64h, and the microstructure of the coating and substrate was observed. There are two oxidation test environments: (1) static oxidation environment: atmospheric environment; (2) water-oxygen corrosion environment: 90% H2O-10% O2.

[0054] (2) Thermal shock test: The sample was kept at 1400°C for 55 min, air-cooled for 5 min, and thermally shocked for 16, 32, and 64 times respectively until the coating peeling area reached 20% of the total area.

[0055] (3) Flame thermal cycle test: Using an existing flame thermal cycler, the sample was heated for 5 min and then cooled for 2 min, with the cycle repeated 200 times, 400 times, and 800 times respectively, until the coating peeling area reached 20% of the total area and the thermal cycle test was stopped.

[0056] The present invention adopts MoSi2 or (MoSi2) with a higher melting point x ,W 1-x )Si2 replaces the traditional Si coating as a bonding layer, allowing the coating to serve at 1600℃ and improving the coating's anti-oxidation performance.

[0057] The present invention prepares Mo-Si or Mo-W-Si mixed slurry, and adopts two different methods, namely, a more convenient cold spraying method and a slurry impregnation method, to prepare MoSi2 or (Mo) on the surface of the ceramic matrix composite material. x ,W 1-x )Si2 bonding layer avoids oxidation during atmospheric plasma spraying.

[0058] The present invention prepares Re2SiO5-Si powder (wherein Re=Yb, Y, Gd, Lu, Nd) by a spray granulation method, and prepares a Re2SiO5-Si self-healing environmental barrier coating on the surface of a bonding layer by an atmospheric plasma method.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a high temperature oxidation resistant self-healing environmental barrier coating for a ceramic matrix composite material, characterized in that: The coating is a double-layer structure, which includes a bonding layer and a self-healing coating from the inside to the outside, wherein the bonding layer is prepared on the surface of the silicon carbide ceramic-based composite material, and the self-healing coating is prepared on the surface of the bonding layer; The material of the bonding layer is MoSi2 or (Mo x ,W 1-x )Si2; The material of the self-healing coating is Re2SiO5-Si, wherein Re=Yb, Y, Gd, Lu or Nd; The ceramic-based composite material is a silicon carbide ceramic-based composite material; The method for preparing the high temperature oxidation resistant self-healing environmental barrier coating for ceramic-based composite materials comprises the following steps: S1. Using a silicon carbide ceramic-based composite material continuously toughened by silicon carbide fibers as a matrix, the silicon carbide ceramic-based composite material matrix is ​​polished, surface sandblasted, ultrasonically cleaned, alcohol soaked, and dried in sequence for standby use; S2, preparing a bonding layer on a silicon carbide ceramic-based composite material substrate by a cold spraying method or a slurry impregnation method; S3, preparing a self-healing coating on the surface of the bonding layer by an atmospheric plasma spraying method, thereby preparing a composite coating with a self-healing function, namely, a self-healing environmental barrier coating; S4. Sample performance assessment: The prepared self-healing environmental barrier coating samples are subjected to oxidation test, thermal shock test and flame thermal cycle test; The specific steps of step S3 are as follows: S31, mainly using rare earth silicate, adding 10-20wt% Si, using mechanical mixing and spray granulation methods to prepare Re2SiO5-Si composite powders of different rare earth elements; S32. Spray Re2SiO5-Si composite powder on the surface of the bonding layer by atmospheric plasma spraying to prepare a self-healing coating, thereby preparing a self-healing environmental barrier coating with self-healing function.

2. The method for preparing a high temperature oxidation resistant self-healing environmental barrier coating for a ceramic matrix composite material according to claim 1, characterized in that: The thickness of the bonding layer is 50-100 μm; the thickness of the self-healing coating is 100-200 μm; the size of the ceramic-based composite material is 50×50×5 mm 3 .

3. The method for preparing a high temperature oxidation resistant self-healing environmental barrier coating for a ceramic matrix composite material according to claim 1, characterized in that: In the step S1, a silicon carbide ceramic-based composite material substrate is ground into rounded corners using a diamond grinding head; the ground silicon carbide ceramic-based composite material substrate surface is sandblasted using 220-mesh corundum particles under a pressure of 0.3 MPa for a duration of 15 to 20 s; the sandblasted silicon carbide ceramic-based composite material substrate is ultrasonically treated for 5 min using anhydrous ethanol as a solvent to remove impurities, then immersed in anhydrous ethanol for 60 min to remove oil stains, and then dried in an oven at ~60°C for 2 h for coating preparation.

4. The method for preparing a high temperature oxidation resistant self-healing environmental barrier coating for a ceramic matrix composite material according to claim 1, characterized in that: In step S2, the method of preparing the bonding layer by cold spraying is: S21, weighing according to the mass ratio of Mo:Si:binder=64:35:1, or weighing according to the mass ratio of Mo:W:Si:binder=32:32:36:0.5, using anhydrous ethanol as solvent and zirconium oxide balls as ball milling media, performing ball milling at a ball milling speed of 500 r / min and a ball milling time of 4 h to prepare a Mo-Si or Mo-W-Si mixed solution; S22, cold spraying Mo-Si or Mo-W-Si mixed solution on the surface of silicon carbide ceramic matrix composite material matrix by cold spraying method, and then drying in an oven in two steps, first drying at 60 ° C for 24 h, and then drying at 110 ° C for 12 h, to prepare MoSi2 or (Mo x ,W 1-x )Si2 bonding layer.

5. The method for preparing a high temperature oxidation resistant self-healing environmental barrier coating for a ceramic matrix composite material according to claim 4, characterized in that: The MoSi2 or (Mo x ,W 1-x )Si2 bonding layer, solid phase sintering at 1500℃ for 2h in a hot press furnace with argon atmosphere to make the coating better bonded to the silicon carbide ceramic-based composite material matrix; repeat this process many times to obtain a thickness of 50~100μm.

6. The method for preparing a high temperature oxidation resistant self-healing environmental barrier coating for a ceramic matrix composite material according to claim 1, characterized in that: In step S2, the method for preparing the bonding layer by slurry impregnation is: S201, weighing the Mo and Si raw materials according to the mass ratio of Mo:Si:binder=64:35:1, or weighing the Mo, W, Si raw materials according to the mass ratio of Mo:W:Si:binder=32:32:36:0.5, preparing Mo-Si or Mo-W-Si mixed powder by mechanical mixing ball milling and spray drying, mixing the Mo-Si or Mo-W-Si mixed powder with the solvent using ethanol as solvent, adding a certain mass of binder to prepare slurry, and stirring in a constant temperature magnetic stirrer for 2-3 hours; S202, immersing the silicon carbide ceramic-based composite material matrix in the slurry, slowly taking it out, putting it into a drying oven, drying it at 60°C for 24 h and 110°C for 12 h, and then putting it into an argon atmosphere furnace for high-temperature sintering. The sintering conditions are sintering at 1600°C for 2 h to prepare MoSi2 or (Mo x ,W 1-x )Si2 bonding layer.

7. The method for preparing a high temperature oxidation resistant self-healing environmental barrier coating for a ceramic matrix composite material according to claim 1, characterized in that: In step S4, the oxidation test specifically includes the following steps: placing the self-healing environmental barrier coating samples at 1400° C. and 1500° C. respectively, and statically oxidizing the samples at each temperature for 2 h, 16 h, 32 h and 64 h, and observing the microscopic morphology of the coating and the substrate; The thermal shock test specifically includes the following steps: the sample is kept at 1400°C for 55 min, air-cooled for 5 min, and thermally shocked for 16, 32, and 64 times respectively until the coating shedding area reaches 20% of the total area and the thermal shock is stopped; The flame thermal cycle test specifically includes the following steps: using a flame thermal cycler, the sample is heated for 5 minutes, then cooled for 2 minutes, and cycled 200 times, 400 times, and 800 times respectively, until the coating peeling area reaches 20% of the total area, and then the thermal cycle test is stopped.

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