Ultra-high temperature resistant and anti-oxidation ceramic coating and preparation method thereof

Abstract

The present application relates to the technical field of composite ceramic coatings, specifically to an ultra-high-temperature resistant, anti-oxidation ceramic coating and its preparation method. The preparation method comprises the following steps: preparing a transition layer: mixing amorphous silica, crystalline silica, an adhesive, and a solvent in proportion to obtain a transition layer slurry; adhering the slurry to a substrate and pressurizing and curing to obtain A; preparing a sealing layer: mixing a mixture of SiO2 and B2O3, a phenolic resin, and alcohol in proportion to obtain a sealing layer slurry; adhering the slurry to A and curing to obtain B; preparing an oxygen barrier layer: mixing Si3N4 or SiC, or a mixture of the two, a phenolic resin, and alcohol in proportion to obtain an oxygen barrier layer slurry; adhering the slurry to B and curing to obtain C; preparing an anti-erosion layer: mixing a mixture of ZrSiO4 and SiC, a phenolic resin, and alcohol in proportion to obtain an anti-erosion layer slurry; adhering the slurry to C and curing to obtain D; and performing oxygen-free, high-temperature sintering. The present application relates to an anti-oxidation ceramic coating capable of withstanding temperatures of 2000°C.

Description

Technical Field

[0001] The present application relates to the technical field of composite ceramic coatings, and more specifically, to an ultra-high temperature resistant and anti-oxidation ceramic coating and a preparation method thereof. Background Art

[0002] Carbon / carbon or carbon-ceramic composites are composite materials with a carbon fiber-reinforced carbon matrix. They possess exceptional properties unmatched by other structural materials, including high-temperature resistance, low density, high specific modulus, high specific strength, thermal shock resistance, corrosion resistance, good friction properties, excellent vibration absorption, and a low thermal expansion coefficient. In particular, at temperatures exceeding 1500°C, the strength of carbon / carbon or carbon-ceramic composites does not decrease but instead tends to increase, leading to their widespread application in aviation, aerospace, metallurgy, and medical fields. However, carbon / carbon or carbon-ceramic composites are susceptible to oxidation at high temperatures, severely limiting their performance. With the continuous advancement of aerospace technology, high-performance aircraft are moving towards high speeds, high-pressure resistance, and high-temperature resistance, placing higher demands on the oxidation resistance, erosion resistance, and ablation resistance of carbon / carbon or carbon-ceramic composites.

[0003] Currently, methods for anti-oxidation of carbon / carbon or carbon-ceramic composites fall into two main categories: internal matrix modification techniques, which rely on the material itself to counteract oxidation reactions, and external anti-oxidation coating techniques, which rely on preventing oxygen contact and diffusion. Compared to matrix modification techniques, anti-oxidation coatings offer longer-term oxidation protection and higher-temperature ranges. They are the most direct and effective method for improving the antioxidant properties of composites, and are currently one of the most promising and widely researched approaches.

[0004] However, the current oxidation resistance temperature of carbon / carbon or carbon-ceramic composite materials is below 1500°C, and they cannot achieve the purpose of oxidation resistance in an ultra-high temperature environment of 2000°C. Summary of the Invention

[0005] In order to improve the temperature resistance of the anti-oxidation coating, the present application provides an ultra-high temperature resistant anti-oxidation ceramic coating and a preparation method thereof.

[0006] In a first aspect, the present application provides a method for preparing an ultra-high temperature resistant and anti-oxidation ceramic coating, which adopts the following technical solution:

[0007] A method for preparing an ultrahigh temperature resistant and anti-oxidation ceramic coating comprises the following steps:

[0008] (1) Preparation of transition layer

[0009] Prepare a transition layer slurry: mix amorphous silica, crystalline silica, adhesive, and solvent in a ratio of (2-4):(1-2):(1-2):(0.5-1), stir and disperse evenly to obtain a transition layer slurry;

[0010] The transition layer slurry is adhered to the substrate, placed in a curing furnace, and pressurized to obtain A;

[0011] (2) Preparation of sealing layer

[0012] Preparation of sealing layer slurry: Mixing a mixture of SiO2 and B2O3 in a ratio of (1-2): (2-3), phenolic resin, and alcohol in a ratio of (1-2): (0.5-1): (0.5-1) and stirring uniformly to obtain a sealing layer slurry;

[0013] Adhere the sealing layer slurry to A and solidify it to obtain B;

[0014] (3) Preparation of oxygen barrier layer

[0015] Preparing an oxygen barrier layer slurry: mixing Si3N4 or SiC or a mixture of Si3N4 and SiC, phenolic resin, and alcohol in a ratio of (1-2):(0.5-1):(0.5-1) and stirring uniformly to obtain an oxygen barrier layer slurry;

[0016] The oxygen barrier layer slurry is adhered to B and solidified to obtain C;

[0017] (4) Preparation of anti-erosion layer

[0018] Preparation of anti-erosion layer slurry: Mixing a mixture of ZrSiO4 and SiC in a ratio of (0.5-1):(1-2), phenolic resin, and alcohol in a ratio of (1-2):(0.5-1):(0.5-1) and stirring uniformly to obtain an anti-erosion layer slurry;

[0019] The anti-erosion layer slurry is adhered to C and solidified to obtain D;

[0020] (5) Sinter D at high temperature in an oxygen-free environment.

[0021] By employing this technical solution, the transition layer is composed of SiO2; the sealing layer is composed of SiO2-B2O3; the oxygen barrier layer is composed of Si3N4 or SiC; and the anti-erosion layer is composed of ZrSiO4-SiC. By using materials with similar thermal expansion coefficients to form the anti-oxidation coating layer by layer, cracks and coating shedding caused by large differences in thermal expansion coefficients between layers can be avoided, thereby ensuring the durability of the high-temperature resistant anti-oxidation coating.

[0022] The two elements of silicon nitride have similar electronegativity, making it a strongly covalently bonded compound. Silicon nitride has a complex and diverse molecular structure, with each silicon atom forming an equivalent Si-N chemical bond with eight nitrogen atoms, creating an octahedral structure. This atomic crystal is resistant to oxidation at high temperatures and can withstand thermal shocks. It can be heated to over 1500°C in air, rapidly cooled, and then rapidly heated again without breaking.

[0023] The molecular structure of silicon carbide is formed by covalent and ionic bonds between carbon and silicon atoms. It has two common crystal structures: cubic β-SiC and hexagonal α-SiC. This structure enables silicon carbide to maintain excellent physical and chemical properties at high temperatures, and has high hardness and wear resistance.

[0024] Zirconium silicate is a complex silicate structure formed by silicon-oxygen tetrahedra and zirconium ions connected in a specific manner, which gives it excellent oxidation resistance. Coatings made by mixing ZrSiO4 and silicon carbide in a specific ratio have very low oxygen permeability and can exist stably at temperatures above 1500°C without undergoing phase changes or reactions, thus providing excellent resistance to oxygen erosion corrosion.

[0025] Preferably, the adhesive is an inorganic adhesive, the inorganic adhesive is silica sol, the solvent is water, and a dispersant is added and stirred evenly to prepare the transition layer slurry.

[0026] Preferably, the adhesive is an organic adhesive, the organic adhesive is phenolic resin, and the solvent is alcohol.

[0027] By adopting the above technical solution, the adhesive can be either an organic adhesive or an inorganic adhesive, corresponding to different solvents, to achieve uniform dispersion and then adhesion.

[0028] Preferably, the transition layer slurry is adhered to the substrate by dipping, painting or electrophoresis, and the sealing layer, oxygen barrier layer and anti-erosion layer slurry are adhered by dipping or painting.

[0029] The above-mentioned technical solution provides a more uniform adhesion method using electrophoresis. However, electrophoresis is only suitable for the substrate when adhering the first coating layer, also known as the transition layer. For other coatings, the substrate is already dried after the previous coating layer is applied. Electrophoresis requires immersing the entire substrate in liquid, which can destabilize the dried coating. Therefore, dipping and brushing can meet the adhesion requirements of various coatings.

[0030] Preferably, the curing method is: heating from room temperature to a first temperature, keeping warm for 30 minutes; heating to a second temperature, keeping warm for 30 minutes; heating to a third temperature, keeping warm for 20 minutes; heating to a fourth temperature, keeping warm for 20 minutes; heating to a fifth temperature, keeping warm for 30 minutes for curing;

[0031] Wherein: first temperature: 80°C; second temperature: 100°C; third temperature: 120°C; fourth temperature: 150°C; fifth temperature: 200°C;

[0032] The pressurized curing method is: pressurizing 1.5-1.8 MPa at room temperature, and the fifth temperature is 180°C.

[0033] By adopting the above technical solution, the coating can be dried, making it stable and non-shedding, and enabling stable transfer between devices. The transition layer adopts a unique pressurized curing process. Pressurization can force the material in the transition layer into the pores of the carbon-carbon composite material, reducing the mismatch in the thermal expansion coefficient between the transition layer and the substrate, and between the transition layer and the sealing layer, and strengthening the bonding between the coating and the substrate.

[0034] It is cured at high temperature under pressure in a curing furnace. During the high-temperature curing process, part of the SiO2 is pressurized to penetrate into the pores of the carbon-carbon material. Finally, when sintered at 2000℃-2400℃ in a high-temperature furnace, the SiO2 forms a dense glassy structure under high temperature conditions. The crystal phase is tetragonal, which can effectively prevent the chemical reaction between the sealing layer and the base material.

[0035] Preferably, the substrate is pretreated before preparing the coating. The substrate is a carbon / carbon composite material. The carbon / carbon composite material is polished with SiC sandpaper, ultrasonically cleaned, and then dried in an oven.

[0036] By adopting the above technical solution, the pretreatment can increase the roughness of the surface of the carbon-carbon composite material and enhance the bonding strength between the carbon-carbon composite material matrix and the transition layer.

[0037] The amorphous silicon dioxide has a mesh size of 300-400, and the crystalline silicon dioxide has a mesh size of -200.

[0038] By employing this technical solution, crystalline silica becomes glassy, ​​pore-free, and more dense. While amorphous silica maintains a regular arrangement of adjacent atoms, the overall structure is distorted, making it less dense than crystalline silica. Only by mixing the two at the right mesh size and ratio can the transition layer achieve a tighter and more complete bond with the substrate.

[0039] Preferably, the high temperature sintering temperature in the oxygen-free environment is 2000°C-2400°C.

[0040] By adopting the above technical solution, high-temperature sintering can solidify the four layers of coating and solidify them together with the substrate without cracking or falling off.

[0041] In a second aspect, the present application provides an ultra-high temperature resistant and anti-oxidation ceramic coating, which adopts the following technical solution:

[0042] A super-high temperature resistant and anti-oxidation ceramic coating comprises a transition layer, a sealing layer, an oxygen barrier layer and an anti-erosion layer, wherein the transition layer comprises silicon dioxide, the sealing layer comprises SiO2 and B2O3, the oxygen barrier layer comprises Si3N4 or SiC or a mixture of Si3N4 and SiC, and the anti-erosion layer comprises ZrSiO4 and SiC.

[0043] By adopting the above technical solution and providing four layers of coating, each layer is made of a material having a specific thermal expansion coefficient, thereby obtaining an anti-oxidation ceramic coating capable of withstanding high temperatures of 2000°C.

[0044] Preferably, the thickness of the transition layer coating is 0.2-0.3 mm, the thickness of the sealing layer coating is 0.1-0.2 mm, the thickness of the oxygen barrier layer coating is 0.2-0.3 mm, and the thickness of the anti-erosion layer coating is 0.3-0.4 mm.

[0045] By adopting the above technical solution, the outermost anti-erosion layer that contacts oxygen is the thickest, and the other layers are thinner. This thickness combination makes it easier to achieve oxygen blocking without cracking or falling off.

[0046] In summary, this application has the following beneficial effects:

[0047] 1. The transition layer is composed of SiO2; the sealing layer is composed of SiO2-B2O3; the oxygen barrier layer is composed of Si3N4 or SiC; and the anti-erosion layer is composed of ZrSiO4-SiC. The anti-oxidation coating is prepared layer by layer using materials with similar thermal expansion coefficients. This can avoid cracks and coating shedding caused by large differences in thermal expansion coefficients between layers, thereby ensuring the durability of the high-temperature resistant anti-oxidation coating.

[0048] Due to the different oxidation mechanisms of carbon / carbon or carbon-ceramic composites in different temperature ranges and the different anti-oxidation behaviors of different coating materials, it is difficult to use the same coating material to effectively protect against different oxidation processes in the entire temperature range. Through the four-layer coating structure of transition layer, sealing layer, oxygen barrier layer and anti-erosion layer, while giving full play to the advantages of each coating material, they also improve and avoid their respective shortcomings through mutual coordination and complementation, thereby solving the current high-temperature oxidation problem of carbon / carbon or carbon-ceramic composites at 1500-2000℃.

[0049] 2. A unique pressurized curing process is used for the transition layer to reduce the mismatch in thermal expansion coefficients between the transition layer and the substrate, as well as between the transition layer and the sealing layer, and to enhance the bonding force between the coating and the substrate.

[0050] 3. The multi-layer composite coating of the prepared ultra-high temperature anti-oxidation ceramic coating can achieve oxidation protection for carbon / carbon or carbon-ceramic materials for a longer time and at a higher temperature range, and at the same time can show good erosion resistance and thermal shock stability under ultra-high temperature airflow erosion conditions.

[0051] 4. This application solves the problem of rapid oxidation and erosion of carbon / carbon or carbon-ceramic composite materials at ultra-high temperatures of 1500-2000°C through a uniquely designed four-layer coating structure, ensuring that the performance of carbon / carbon or carbon-ceramic composite materials remains stable for a long time at temperatures of 1500-2000°C and in an oxygen environment, enabling them to be better applied in the aerospace field.

[0052] 5. Through the four-layer composite structure of anti-oxidation ceramic coating, carbon / carbon or carbon-ceramic composite materials can be resistant to oxidation for a long time in the ultra-high temperature range of 1500-2000℃, and at the same time can show good erosion resistance and thermal shock stability under ultra-high temperature airflow erosion conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 : A simplified structural diagram of the anti-oxidation ceramic coating of this application. DETAILED DESCRIPTION

[0054] The following examples and Figure 1 This application is described in further detail.

[0055] Carbon / carbon or carbon-ceramic composite anti-oxidation coatings can generally only withstand temperatures of 1500°C. Some of these anti-oxidation coatings are thinner and have poor oxygen barrier effects; others are thicker and have improved oxygen barrier effects, but have poor adhesion and thermal shock stability, and are prone to cracking or even falling off.

[0056] Example

[0057] Example 1

[0058] 1. Preparation of carbon / carbon composite material samples:

[0059] The matrix, i.e. the carbon / carbon composite material, was polished with SiC sandpaper, ultrasonically cleaned for 30 min, and then dried in an oven at 180° C. for 1 h.

[0060] 2. Add a transition layer

[0061] Amorphous silica (300 mesh): crystalline silica (-200 mesh): silica sol: water = 2:1:1:0.5 were mixed, stirred for 30 minutes, and sodium alginate was added as a dispersant. The mixture was stirred for another 30 minutes to obtain a transition layer slurry.

[0062] The prepared transition layer slurry was electrophoretically applied to the carbon / carbon composite substrate, achieving a transition layer thickness of 0.2 mm. The slurry was then transferred to a curing oven for pressurized curing. Pressurization to 1.8 MPa was completed within 15 minutes at room temperature. After pressurization, the pressure was maintained at 1.8 MPa, and the curing process was performed using a temperature ramp profile: room temperature to the first temperature (holding temperature for 30 minutes), the second temperature (holding temperature for 30 minutes), the third temperature (holding temperature for 20 minutes), the fourth temperature (holding temperature for 20 minutes), and the fifth temperature (holding temperature for 30 minutes).

[0063] Among them: the first temperature: 80°C; the second temperature: 100°C; the third temperature: 120°C; the fourth temperature: 150°C; the fifth temperature: 180°C.

[0064] The entire substrate with the transition layer attached obtained after pressurization and curing is designated as A.

[0065] 3. Add sealing layer

[0066] After SiO2 and B2O3 are evenly mixed in a ratio of 2:3, phenolic resin: alcohol = 1:0.5:0.5, the mixture is stirred for 1 hour to obtain a sealing layer slurry.

[0067] The resulting sealing layer slurry was adhered to the transition layer cured onto the carbon-carbon composite material by impregnation, that is, adhered to one side of the transition layer on A, so that the sealing layer thickness was 0.1 mm. The carbon-carbon composite material with the transition layer and sealing layer adhered was transferred to an oven. Curing was carried out according to a heating curve from room temperature to the first temperature, holding for 30 minutes; to the second temperature, holding for 30 minutes; to the third temperature, holding for 20 minutes; to the fourth temperature, holding for 20 minutes; and to the fifth temperature, holding for 30 minutes.

[0068] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0069] The obtained substrate with the transition layer and the sealing layer attached thereto is designated as B.

[0070] On the one hand, the SiO2 contained in the sealing layer can better compound with the transition layer to prevent the coating from cracking and falling off due to the large difference in thermal expansion coefficients of the two materials; on the other hand, it can increase the sealing temperature, and the added alkaline earth oxide B2O3 can improve the sealing effect.

[0071] 4. Add oxygen barrier

[0072] Si3N4:phenolic resin:alcohol=1:1:1 ratio was mixed and stirred for 1 hour to obtain the slurry of the sealing layer coating.

[0073] The prepared oxygen barrier slurry was applied by brushing to the carbon / carbon composite material after the cured sealing layer, specifically to one side of the sealing layer on upper B, to a thickness of 0.2 mm. The material was then placed in an oven and cured according to a heating profile: from room temperature to a first temperature (holding temperature for 30 minutes), then to a second temperature (holding temperature for 30 minutes), then to a third temperature (holding temperature for 20 minutes), then to a fourth temperature (holding temperature for 20 minutes), and finally to a fifth temperature (holding temperature for 30 minutes).

[0074] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0075] The resulting substrate with the transition layer, sealing layer and oxygen barrier layer attached is C.

[0076] Si3N4 has unique high-temperature oxidation resistance.

[0077] The two elements of silicon nitride have similar electronegativity, making it a strongly covalently bonded compound. Silicon nitride has a complex and diverse molecular structure, with each silicon atom forming an equivalent Si-N chemical bond with eight nitrogen atoms, creating an octahedral structure. This atomic crystal is resistant to oxidation at high temperatures and can withstand thermal shocks. It can be heated to over 1500°C in air, rapidly cooled, and then rapidly heated again without breaking.

[0078] 5. Add anti-erosion layer

[0079] After uniformly mixing ZrSiO4:SiC in a ratio of 1:2:phenolic resin:alcohol in a ratio of 1:1:1, stir for 1 hour to obtain an anti-erosion layer slurry.

[0080] The prepared anti-erosion layer slurry was adhered to the carbon / carbon composite material of the cured oxygen barrier layer by brushing, that is, adhered to one side of the oxygen barrier layer on C, so that the thickness of the anti-erosion layer was 0.3 mm, and then transferred to an oven for curing according to a heating curve of heating from room temperature to a first temperature, keeping warm for 30 minutes; heating to a second temperature, keeping warm for 30 minutes; heating to a third temperature, keeping warm for 20 minutes; heating to a fourth temperature, keeping warm for 20 minutes; heating to a fifth temperature, keeping warm for 30 minutes.

[0081] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0082] The resulting substrate with the transition layer, sealing layer, oxygen barrier layer and anti-erosion layer attached is D.

[0083] Zirconium silicate is a complex silicate structure formed by silicon-oxygen tetrahedra and zirconium ions connected in a specific manner, which gives it excellent oxidation resistance. Coatings made by mixing ZrSiO4 and silicon carbide in a specific ratio have very low oxygen permeability and can exist stably at temperatures above 1500°C without undergoing phase changes or reactions, thus providing excellent resistance to oxygen erosion corrosion.

[0084] 6. High temperature furnace sintering

[0085] The substrate and the resulting oxidation-resistant ceramic coating, D, are finally sintered in a high-temperature furnace at 2200°C, protected by argon. During the high-temperature curing process, the transition layer is pressurized, allowing some SiO2 to penetrate the pores of the carbon-carbon material. Finally, during the 2200°C sintering process, the SiO2 forms a dense, glassy structure with a tetragonal crystal phase, effectively preventing chemical reactions between the sealing layer and the substrate.

[0086] Example 2

[0087] 1. Preparation of carbon / carbon composite material samples:

[0088] The matrix, i.e. the carbon / carbon composite material, was polished with SiC sandpaper, ultrasonically cleaned for 30 min, and then dried in an oven at 180° C. for 1 h.

[0089] 2. Add a transition layer

[0090] Amorphous 400-mesh silica: crystalline -200-mesh silica: phenolic resin: alcohol were mixed in a ratio of 2:1:1:0.5 and stirred for 1 hour to obtain a slurry.

[0091] The prepared slurry was adhered to the carbon / carbon composite material by impregnation, with a transition layer thickness of 0.25 mm. The material was then transferred to a curing oven and pressurized to 1.5 MPa at room temperature within 10 minutes. After pressurization, the pressure was maintained at 1.5 MPa, and the curing process was carried out according to a temperature ramp profile: from room temperature to the first temperature, holding for 30 minutes; to the second temperature, holding for 30 minutes; to the third temperature, holding for 20 minutes; to the fourth temperature, holding for 20 minutes; and to the fifth temperature, holding for 30 minutes.

[0092] Among them: the first temperature: 80°C; the second temperature: 100°C; the third temperature: 120°C; the fourth temperature: 150°C; the fifth temperature: 180°C.

[0093] 3. Add sealing layer

[0094] After SiO2 and B2O3 are evenly mixed in a ratio of 2:3, phenolic resin: alcohol = 1:1:1, mixed and stirred for 1 hour to obtain a sealing layer slurry.

[0095] The resulting sealing layer slurry was applied to the transition layer of the carbon / carbon composite material by brushing, resulting in a sealing layer thickness of 0.15 mm. The material was then placed in an oven and cured according to a heating curve: from room temperature to the first temperature, holding for 30 minutes; to the second temperature, holding for 30 minutes; to the third temperature, holding for 20 minutes; to the fourth temperature, holding for 20 minutes; and to the fifth temperature, holding for 30 minutes.

[0096] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0097] 4. Add oxygen barrier

[0098] SiC: phenolic resin: alcohol were mixed in a ratio of 1:1:1 and stirred for 1 hour to obtain a sealing layer slurry.

[0099] The prepared oxygen barrier slurry was applied to the sealing layer of the carbon / carbon composite material by brushing, achieving an oxygen barrier thickness of 0.25 mm. The material was then placed in an oven and cured according to a heating profile: from room temperature to a first temperature (holding temperature for 30 minutes), then to a second temperature (holding temperature for 30 minutes), then to a third temperature (holding temperature for 20 minutes), then to a fourth temperature (holding temperature for 20 minutes), and finally to a fifth temperature (holding temperature for 30 minutes).

[0100] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0101] 5. Add anti-erosion layer

[0102] After uniformly mixing ZrSiO4:SiC in a ratio of 1:1:phenolic resin:alcohol in a ratio of 1:1:1, stir for 1 hour to obtain a slurry for the anti-erosion layer coating.

[0103] The prepared coating slurry of the erosion-resistant layer is adhered to the oxygen barrier layer of the carbon / carbon composite material by brushing, so that the thickness of the erosion-resistant layer is 0.35 mm. The layer is then transferred to an oven and cured according to a heating curve of heating from room temperature to a first temperature, keeping warm for 30 minutes; heating to a second temperature, keeping warm for 30 minutes; heating to a third temperature, keeping warm for 20 minutes; heating to a fourth temperature, keeping warm for 20 minutes; heating to a fifth temperature, keeping warm for 30 minutes.

[0104] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0105] 6. High temperature furnace sintering

[0106] The prepared anti-oxidation ceramic coating finally needs to be sintered in a high-temperature furnace at 2000°C, with nitrogen protection throughout the process.

[0107] Example 3

[0108] 1. Preparation of carbon / carbon composite material samples:

[0109] The matrix, i.e. the carbon / carbon composite material, was polished with SiC sandpaper, ultrasonically cleaned for 30 min, and then dried in an oven at 180° C. for 1 h.

[0110] 2. Add a transition layer

[0111] Amorphous silica (300 mesh): crystalline silica (-200 mesh): silica sol: water = 4:1:2:0.5 were mixed, stirred for 30 minutes, and sodium alginate was added as a dispersant. The mixture was stirred for another 30 minutes to obtain a transition layer slurry.

[0112] The prepared transition layer slurry was applied to the carbon / carbon composite material by brushing, achieving a transition layer thickness of 0.3 mm. The material was then transferred to a curing oven for pressurized curing. Pressurization to 1.8 MPa was completed within 15 minutes at room temperature. After pressurization, the pressure was maintained at 1.8 MPa, and the curing process was performed using a heating profile: room temperature to the first temperature, held at that temperature for 30 minutes; to the second temperature, held at that temperature for 30 minutes; to the third temperature, held at that temperature for 20 minutes; to the fourth temperature, held at that temperature for 20 minutes; and to the fifth temperature, held at that temperature for 30 minutes.

[0113] Among them: the first temperature: 80°C; the second temperature: 100°C; the third temperature: 120°C; the fourth temperature: 150°C; the fifth temperature: 180°C.

[0114] 3. Add sealing layer

[0115] After SiO2 and B2O3 are evenly mixed in a ratio of 1:3, phenolic resin: alcohol = 2:0.5:1, the mixture is stirred for 1 hour to obtain a sealing layer slurry.

[0116] The resulting sealing layer slurry was adhered to the transition layer cured onto the carbon-carbon composite material by impregnation, resulting in a sealing layer thickness of 0.2 mm. The carbon-carbon composite material with the transition layer and sealing layer adhered thereto was then placed in an oven and cured according to a heating profile: from room temperature to a first temperature, held at that temperature for 30 minutes; to a second temperature, held at that temperature for 30 minutes; to a third temperature, held at that temperature for 20 minutes; to a fourth temperature, held at that temperature for 20 minutes; and to a fifth temperature, held at that temperature for 30 minutes.

[0117] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0118] On the one hand, the SiO2 contained in the sealing layer can better compound with the transition layer to prevent the coating from cracking and falling off due to the large difference in thermal expansion coefficients of the two materials; on the other hand, it can increase the sealing temperature, and the added alkaline earth oxide B2O3 can improve the sealing effect.

[0119] 4. Add oxygen barrier

[0120] Si3N4:phenolic resin:alcohol were mixed in a ratio of 2:0.5:1 and stirred for 1 hour to obtain a slurry for the sealing layer coating.

[0121] The prepared oxygen barrier slurry was applied to the carbon / carbon composite material after curing the sealant layer by brushing, achieving an oxygen barrier thickness of 0.3 mm. The composite was then placed in an oven and cured according to a heating profile: from room temperature to a first temperature (holding temperature for 30 minutes), then to a second temperature (holding temperature for 30 minutes), then to a third temperature (holding temperature for 20 minutes), then to a fourth temperature (holding temperature for 20 minutes), and finally to a fifth temperature (holding temperature for 30 minutes).

[0122] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0123] Si3N4 has unique high-temperature oxidation resistance.

[0124] The two elements of silicon nitride have similar electronegativity, making it a strongly covalently bonded compound. Silicon nitride has a complex and diverse molecular structure, with each silicon atom forming an equivalent Si-N chemical bond with eight nitrogen atoms, creating an octahedral structure. This atomic crystal is resistant to oxidation at high temperatures and can withstand thermal shocks. It can be heated to over 1500°C in air, rapidly cooled, and then rapidly heated again without breaking.

[0125] 5. Add anti-erosion layer

[0126] After uniformly mixing ZrSiO4:SiC in a ratio of 1:4, phenolic resin:alcohol in a ratio of 2:0.5:1, stir for 1 hour to obtain the anti-erosion layer slurry.

[0127] The prepared anti-erosion layer slurry is adhered to the carbon / carbon composite material of the cured oxygen barrier layer by brushing, so that the thickness of the anti-erosion layer is 0.4 mm. The layer is then transferred to an oven and cured according to a heating curve of heating from room temperature to a first temperature, keeping warm for 30 minutes; heating to a second temperature, keeping warm for 30 minutes; heating to a third temperature, keeping warm for 20 minutes; heating to a fourth temperature, keeping warm for 20 minutes; heating to a fifth temperature, keeping warm for 30 minutes.

[0128] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0129] Zirconium silicate is a complex silicate structure formed by silicon-oxygen tetrahedra and zirconium ions connected in a specific manner, which gives it excellent oxidation resistance. Coatings made by mixing ZrSiO4 and silicon carbide in a specific ratio have very low oxygen permeability and can exist stably at temperatures above 1500°C without undergoing phase changes or reactions, thus providing excellent resistance to oxygen erosion corrosion.

[0130] 6. High temperature furnace sintering

[0131] The resulting anti-oxidation ceramic coating is then sintered in a high-temperature furnace at 2200°C, protected by argon. During the high-temperature curing process, the transition layer is pressurized, allowing some SiO2 to penetrate the pores of the carbon-carbon material. Finally, during the 2200°C sintering process, the SiO2 forms a dense, tetragonal glassy structure, effectively preventing chemical reactions between the sealing layer and the substrate.

[0132] Example 4

[0133] 1. Preparation of carbon / carbon composite material samples:

[0134] The matrix, i.e. the carbon / carbon composite material, was polished with SiC sandpaper, ultrasonically cleaned for 30 min, and then dried in an oven at 180° C. for 1 h.

[0135] 2. Add a transition layer

[0136] Amorphous silica (400 mesh): crystalline silica (-200 mesh): phenolic resin: alcohol were mixed in a ratio of 2:2:1:1 and stirred for 1 hour to obtain a slurry.

[0137] The prepared transition layer slurry was electrophoretically applied to the carbon / carbon composite material, achieving a transition layer thickness of 0.2 mm. The material was then transferred to a curing oven for pressurized curing. Pressurization to 1.6 MPa was completed within 15 minutes at room temperature. After pressurization, the pressure was maintained at 1.6 MPa, and the curing process was performed using a heating profile: room temperature to the first temperature, held at that temperature for 30 minutes; to the second temperature, held at that temperature for 30 minutes; to the third temperature, held at that temperature for 20 minutes; to the fourth temperature, held at that temperature for 20 minutes; and to the fifth temperature, held at that temperature for 30 minutes.

[0138] Among them: the first temperature: 80°C; the second temperature: 100°C; the third temperature: 120°C; the fourth temperature: 150°C; the fifth temperature: 180°C.

[0139] 3. Add sealing layer

[0140] After SiO2 and B2O3 are uniformly mixed in a ratio of 1:1, phenolic resin: alcohol = 1:1:0.5, the mixture is stirred for 1 hour to obtain a sealing layer slurry.

[0141] The resulting sealing layer slurry was adhered to the transition layer cured onto the carbon-carbon composite material by impregnation, resulting in a sealing layer thickness of 0.1 mm. The carbon-carbon composite material with the transition layer and sealing layer adhered thereto was then placed in an oven and cured according to a heating profile: from room temperature to a first temperature, held at that temperature for 30 minutes; to a second temperature, held at that temperature for 30 minutes; to a third temperature, held at that temperature for 20 minutes; to a fourth temperature, held at that temperature for 20 minutes; and to a fifth temperature, held at that temperature for 30 minutes.

[0142] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0143] On the one hand, the SiO2 contained in the sealing layer can better compound with the transition layer to prevent the coating from cracking and falling off due to the large difference in thermal expansion coefficients of the two materials; on the other hand, it can increase the sealing temperature, and the added alkaline earth oxide B2O3 can improve the sealing effect.

[0144] 4. Add oxygen barrier

[0145] SiC: phenolic resin: alcohol were mixed in a ratio of 1:1:0.5 and stirred for 1 hour to obtain a slurry for the sealing layer coating.

[0146] The prepared oxygen barrier slurry was applied to the carbon / carbon composite material after curing the sealant layer by brushing, achieving an oxygen barrier thickness of 0.2 mm. The composite was then placed in an oven and cured according to a heating profile: from room temperature to a first temperature (holding temperature for 30 minutes), then to a second temperature (holding temperature for 30 minutes), then to a third temperature (holding temperature for 20 minutes), then to a fourth temperature (holding temperature for 20 minutes), and finally to a fifth temperature (holding temperature for 30 minutes).

[0147] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0148] SiC has unique high-temperature oxidation resistance.

[0149] The molecular structure of silicon carbide is formed by covalent and ionic bonds between carbon and silicon atoms. It has two common crystal structures: cubic β-SiC and hexagonal α-SiC. This structure enables silicon carbide to maintain excellent physical and chemical properties at high temperatures, and has high hardness and wear resistance.

[0150] 5. Add anti-erosion layer

[0151] After uniformly mixing ZrSiO4:SiC in a ratio of 1:1:phenolic resin:alcohol in a ratio of 1:1:0.5, stir for 1 hour to obtain an anti-erosion layer slurry.

[0152] The prepared anti-erosion layer slurry is adhered to the carbon / carbon composite material of the cured oxygen barrier layer by brushing, so that the thickness of the anti-erosion layer is 0.3 mm. The layer is then transferred to an oven and cured according to a heating curve of heating from room temperature to a first temperature, keeping warm for 30 minutes; heating to a second temperature, keeping warm for 30 minutes; heating to a third temperature, keeping warm for 20 minutes; heating to a fourth temperature, keeping warm for 20 minutes; heating to a fifth temperature, keeping warm for 30 minutes.

[0153] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0154] Zirconium silicate is a complex silicate structure formed by silicon-oxygen tetrahedra and zirconium ions connected in a specific manner, which gives it excellent oxidation resistance. Coatings made by mixing ZrSiO4 and silicon carbide in a specific ratio have very low oxygen permeability and can exist stably at temperatures above 1500°C without undergoing phase changes or reactions, thus providing excellent resistance to oxygen erosion corrosion.

[0155] 6. High temperature furnace sintering

[0156] The resulting anti-oxidation ceramic coating is then sintered in a high-temperature furnace at 2200°C, protected by argon. During the high-temperature curing process, the transition layer is pressurized, allowing some SiO2 to penetrate the pores of the carbon-carbon material. Finally, during the 2200°C sintering process, the SiO2 forms a dense, tetragonal glassy structure, effectively preventing chemical reactions between the sealing layer and the substrate.

[0157] Example 5

[0158] 1. Preparation of carbon / carbon composite material samples:

[0159] The matrix, i.e. the carbon / carbon composite material, was polished with SiC sandpaper, ultrasonically cleaned for 30 min, and then dried in an oven at 180° C. for 1 h.

[0160] 2. Add a transition layer

[0161] Amorphous silica (300 mesh): crystalline silica (-200 mesh): phenolic resin: alcohol were mixed in a ratio of 2:2:1:1 and stirred for 1 hour to obtain a slurry.

[0162] The prepared transition layer slurry was electrophoretically applied to the carbon / carbon composite material, achieving a transition layer thickness of 0.3 mm. The material was then transferred to a curing oven for pressurized curing. Pressurization to 1.8 MPa was completed within 15 minutes at room temperature. After pressurization, the pressure was maintained at 1.8 MPa, and the curing process was performed using a heating profile: room temperature to the first temperature, held at that temperature for 30 minutes; to the second temperature, held at that temperature for 30 minutes; to the third temperature, held at that temperature for 20 minutes; to the fourth temperature, held at that temperature for 20 minutes; and to the fifth temperature, held at that temperature for 30 minutes.

[0163] Among them: the first temperature: 80°C; the second temperature: 100°C; the third temperature: 120°C; the fourth temperature: 150°C; the fifth temperature: 180°C.

[0164] 3. Add sealing layer

[0165] After SiO2 and B2O3 are evenly mixed in a ratio of 1:1, phenolic resin: alcohol = 1:1:0.5, the mixture is stirred for 1 hour to obtain a sealing layer slurry.

[0166] The resulting sealing layer slurry was adhered to the transition layer cured onto the carbon-carbon composite material by impregnation, resulting in a sealing layer thickness of 0.2 mm. The carbon-carbon composite material with the transition layer and sealing layer adhered thereto was then placed in an oven and cured according to a heating profile: from room temperature to a first temperature, held at that temperature for 30 minutes; to a second temperature, held at that temperature for 30 minutes; to a third temperature, held at that temperature for 20 minutes; to a fourth temperature, held at that temperature for 20 minutes; and to a fifth temperature, held at that temperature for 30 minutes.

[0167] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0168] On the one hand, the SiO2 contained in the sealing layer can better compound with the transition layer to prevent the coating from cracking and falling off due to the large difference in thermal expansion coefficients of the two materials; on the other hand, it can increase the sealing temperature, and the added alkaline earth oxide B2O3 can improve the sealing effect.

[0169] 4. Add oxygen barrier

[0170] Si3N4:SiC:phenolic resin:alcohol were mixed in a ratio of 1:1:1:0.5 and stirred for 1 hour to obtain a slurry for the sealing layer coating.

[0171] The prepared oxygen barrier slurry was applied to the carbon / carbon composite material after curing the sealant layer by brushing, achieving an oxygen barrier thickness of 0.3 mm. The composite was then placed in an oven and cured according to a heating profile: from room temperature to a first temperature (holding temperature for 30 minutes), then to a second temperature (holding temperature for 30 minutes), then to a third temperature (holding temperature for 20 minutes), then to a fourth temperature (holding temperature for 20 minutes), and finally to a fifth temperature (holding temperature for 30 minutes).

[0172] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0173] Si3N4 or SiC has unique high-temperature oxidation resistance.

[0174] The two elements of silicon nitride have similar electronegativity, making it a strongly covalently bonded compound. Silicon nitride has a complex and diverse molecular structure, with each silicon atom forming an equivalent Si-N chemical bond with eight nitrogen atoms, creating an octahedral structure. This atomic crystal is resistant to oxidation at high temperatures and can withstand thermal shocks. It can be heated to over 1500°C in air, rapidly cooled, and then rapidly heated again without breaking.

[0175] The molecular structure of silicon carbide is formed by covalent and ionic bonds between carbon and silicon atoms. It has two common crystal structures: cubic β-SiC and hexagonal α-SiC. This structure enables silicon carbide to maintain excellent physical and chemical properties at high temperatures, and has high hardness and wear resistance.

[0176] 5. Add anti-erosion layer

[0177] After uniformly mixing ZrSiO4:SiC in a ratio of 1:1:phenolic resin:alcohol in a ratio of 1:1:0.5, stir for 1 hour to obtain an anti-erosion layer slurry.

[0178] The prepared anti-erosion layer slurry is adhered to the carbon / carbon composite material of the cured oxygen barrier layer by brushing, so that the thickness of the anti-erosion layer is 0.4 mm. The layer is then transferred to an oven and cured according to a heating curve of heating from room temperature to a first temperature, keeping warm for 30 minutes; heating to a second temperature, keeping warm for 30 minutes; heating to a third temperature, keeping warm for 20 minutes; heating to a fourth temperature, keeping warm for 20 minutes; heating to a fifth temperature, keeping warm for 30 minutes.

[0179] Among them: first temperature: 80℃; second temperature: 100℃; third temperature: 120℃; fourth temperature: 150℃; fifth temperature: 200℃.

[0180] Zirconium silicate is a complex silicate structure formed by silicon-oxygen tetrahedra and zirconium ions connected in a specific manner, which gives it excellent oxidation resistance. Coatings made by mixing ZrSiO4 and silicon carbide in a specific ratio have very low oxygen permeability and can exist stably at temperatures above 1500°C without undergoing phase changes or reactions, thus providing excellent resistance to oxygen erosion corrosion.

[0181] 6. High temperature furnace sintering

[0182] The resulting anti-oxidation ceramic coating is then sintered in a high-temperature furnace at 2300°C, protected by argon gas throughout the process. During the high-temperature curing process, the transition layer is pressurized, allowing some SiO2 to penetrate the pores of the carbon-carbon material. Finally, during the final sintering process at 2200°C, the SiO2 forms a dense, tetragonal glassy structure, effectively preventing chemical reactions between the sealing layer and the substrate.

[0183] The different proportions of the main raw materials of Examples 1-5 are shown in the table below. Blank spaces indicate that the substance is not present in the examples.

[0184]

[0185]

[0186] Comparative Example

[0187] Comparative Example 1

[0188] The steps of Comparative Example 1 are the same as those of Example 1, with the main difference being the following differences in the proportions.

[0189]

[0190]

[0191] Comparative Example 2

[0192] First, the substrate is ground and polished with 1000 mesh SiC sandpaper. The substrate is a high-purity graphite substrate (purity ≥ 99.99%). Then, the ground and polished substrate is ultrasonically cleaned and dried at 50° C. for 5 h for later use.

[0193] Weigh the Zr and Hf powders in a mass ratio of 0:1 and place them in a beaker. Then pour polyvinyl alcohol solution (model: PVA-124, concentration: 0.02g / mL) into the beaker so that the powder to solution ratio is 17g:10mL. Stir with a mechanical stirrer for 30 minutes to obtain a slurry. Apply the slurry evenly on the cleaned substrate by brushing 6 times. Place the substrate coated with the slurry in a blast drying oven and dry and cure at 200°C for 8 hours to form a pre-coated coating for later use.

[0194] In addition, two elemental powders of Zr and Si were weighed in a mass ratio of 7:3 and placed in a ball mill with a ball-to-material ratio of 5:1. Alcohol was used as the ball milling medium. They were wet-milled for 10 hours and dried in a blast drying oven. After 5 hours, they were sieved through a 200-mesh sieve to obtain a uniformly mixed vapor deposition masterbatch.

[0195] The evaporation masterbatch is evenly spread on the bottom of the graphite crucible, and the substrate with the pre-coated coating is placed 2-5 cm above the mixed powder. Finally, the graphite crucible is placed in a high-frequency induction graphitization furnace for heating. When the furnace chamber temperature reaches 500°C, the furnace is vacuumed until it is below 50 Pa; then Ar gas is filled to make the furnace reach one atmosphere of pressure. The heating is carried out at a rate of 10°C-15°C / min. When the temperature reaches 2100°C, the furnace chamber is vacuumed again until it is below 50 Pa; then Ar gas is filled to make the furnace reach one atmosphere of pressure. The temperature is continued to rise to 2200°C, and the furnace chamber is vacuumed for the third time. After it is vacuumed to below 50 Pa, Ar gas is filled to make the furnace reach one atmosphere of pressure. Then, it is kept at 2200°C for 2 hours, and finally cooled with the furnace at a cooling rate of 5°C / min.

[0196] A ZrC-HfC / SiC double-layer composite ceramic coating with a thickness of about 300 μm was prepared.

[0197] Test methods for oxidation-resistant coatings

[0198] 1. Thermal shock stability: Heat the sample in a muffle furnace to 1000℃, take it out, and immediately put it into cold water at 10℃. Repeat this process 6 times and observe whether the coating has any cracks or falls off.

[0199] 2. Weight loss rate after static oxidation for 2 hours: first weigh the sample to an accuracy of 0.0002g; place the sample in the center of the muffle furnace that has been raised to the position specified in the technical conditions, and burn it 20mm away from the bottom of the furnace for 2 hours. During the burning process, keep the observation hole of the muffle furnace open to maintain air circulation; take out the sample and place it in a desiccator, cool it for 60 minutes, and weigh it to an accuracy of 0.0002g.

[0200] Where: W-static oxidation 2h weight loss rate;

[0201] G1-mass of sample before burning, g;

[0202] G2-mass of sample before ignition, g.

[0203] 3. Coating adhesion test: Test the adhesion of ultra-high temperature anti-oxidation coating according to the national standard GB / T5210-2006.

[0204] 4. Post-High-Temperature Wear Test Method: After the sample is statically oxidized at 2000°C for 2 hours, the wear test is conducted on the sample. A grinding pit is created on the sample surface by a friction steel wheel under specified conditions. The thickness before and after grinding is measured, and the wear value of the filter plate is calculated.

[0205] δ=δ1-δ2

[0206] Where: δ - wear value of the sample under specified conditions, μm;

[0207] δ1 - thickness of the sample before grinding, μm;

[0208] δ2 - thickness of the sample after grinding, μm.

[0209] The friction steel wheel makes reciprocating motion on the surface of the sample. The linear running speed of the friction steel wheel is set to 0.1m / s. The grinding thickness of the sample is measured after 500 reciprocating times.

[0210] (5) Test method for wear value before high temperature: the same as the above method, except that the sample is before use. For the corresponding embodiment, it is after sintering.

[0211] Test results

[0212] The antioxidant coatings of the embodiment and the comparative example were subjected to the above test method, and the experimental data are shown in Table 1:

[0213] Table 1: Anti-oxidation coating experimental data

[0214]

[0215]

[0216] The above examples and comparative examples showed no cracks, indicating that the samples met the experimental testing conditions and that the oxygen causing the weight loss was not provided by the cracks, demonstrating the coating's insulation properties. The coating of the present invention achieved Grade 1 adhesion. Only with the composition and ratio of the present invention can the four layers exhibit similar thermal expansion coefficients after bonding, drying, and high-temperature sintering, with their respective functions working in concert to achieve excellent coating adhesion. The coating of the present invention maintained a weight loss rate below 0.09% after static oxidation at 1500°C for 2 hours, while the weight loss rates in the comparative examples were all above 0.15%. The coating of the present invention achieved a weight loss rate of 0.11%-0.13% after static oxidation at 2000°C for 2 hours, while the same indicator for the comparative examples was at least 0.22%. Furthermore, the difference in the experimental data between the weight loss rates at 1500°C and 2000°C for 2 hours shows that the smaller the difference, the less impact the coating has on its oxidation resistance, indicating a stronger antioxidant capacity. The wear value of the embodiment of the present application is about 0.02μm before high temperature after sintering. After static oxidation at 2000℃ for 2h, the wear value is only about 0.04μm. The wear value of the comparative example is twice that of the present application. The coating of Comparative Example 2 can only withstand 800℃-1000℃, while the present application can withstand 2000℃. Moreover, from the wear values ​​of the embodiment itself before and after high temperature, it can be seen that after static oxidation at 2000℃ for 2h, its wear value does not increase sharply, indicating that the coating still has good hardness and strength in a long-term high temperature environment. Therefore, the coating of the embodiment of the present application is an anti-oxidation ceramic coating that can withstand ultra-high temperatures of 2000℃.

[0217] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing an ultra-high temperature resistant and anti-oxidation ceramic coating, characterized in that: The following steps are involved: (1) Preparation of transition layer Prepare a transition layer slurry: mix amorphous silica, crystalline silica, adhesive, and solvent in a ratio of (2-4):(1-2):(1-2):(0.5-1), stir and disperse evenly to obtain a transition layer slurry; The transition layer slurry is adhered to the substrate, placed in a curing furnace, and pressurized to obtain A; (2) Preparation of sealing layer Preparation of sealing layer slurry: Mixing a mixture of SiO2 and B2O3 in a ratio of (1-2): (2-3), phenolic resin, and alcohol in a ratio of (1-2): (0.5-1): (0.5-1) and stirring uniformly to obtain a sealing layer slurry; Adhere the sealing layer slurry to A and solidify it to obtain B; (3) Preparation of oxygen barrier layer Preparing an oxygen barrier layer slurry: mixing Si3N4 or SiC or a mixture of Si3N4 and SiC, phenolic resin, and alcohol in a ratio of (1-2):(0.5-1):(0.5-1) and stirring uniformly to obtain an oxygen barrier layer slurry; The oxygen barrier layer slurry is adhered to B and solidified to obtain C; (4) Preparation of anti-erosion layer Preparation of anti-erosion layer slurry: Mixing a mixture of ZrSiO4 and SiC in a ratio of (0.5-1):(1-2), phenolic resin, and alcohol in a ratio of (1-2):(0.5-1):(0.5-1) and stirring uniformly to obtain an anti-erosion layer slurry; The anti-erosion layer slurry is adhered to C and solidified to obtain D; (5) Sinter D at high temperature in an oxygen-free environment.

2. The method for preparing an ultrahigh temperature resistant and anti-oxidation ceramic coating according to claim 1, characterized in that: The adhesive is an inorganic adhesive, which is silica sol. The solvent is water. A dispersant is added and stirred evenly to prepare the transition layer slurry.

3. The method for preparing an ultrahigh temperature resistant and anti-oxidation ceramic coating according to claim 1, characterized in that: The adhesive is an organic adhesive, the organic adhesive is phenolic resin, and the solvent is alcohol.

4. The method for preparing an ultrahigh temperature resistant and anti-oxidation ceramic coating according to claim 1, characterized in that: The transition layer slurry is adhered to the substrate by dipping, painting or electrophoresis, and the sealing layer, oxygen barrier layer and anti-erosion layer slurry are adhered by dipping or painting.

5. The method for preparing an ultrahigh temperature resistant and anti-oxidation ceramic coating according to claim 1, characterized in that: The curing method described in steps (2), (3) and (4) is: heating from room temperature to the first temperature, keeping warm for 30 minutes; heating to the second temperature, keeping warm for 30 minutes; heating to the third temperature, keeping warm for 20 minutes; heating to the fourth temperature, keeping warm for 20 minutes; heating to the fifth temperature, keeping warm for 30 minutes to perform the curing process; Wherein: first temperature: 80°C; second temperature: 100°C; third temperature: 120°C; fourth temperature: 150°C; fifth temperature: 200°C; The conditions for pressurized curing in step (1) are: pressurized at room temperature, 1.5-1.8 MPa, first temperature: 80°C; second temperature: 100°C; third temperature: 120°C; fourth temperature: 150°C; and the fifth temperature is 180°C.

6. The method for preparing an ultrahigh temperature resistant and anti-oxidation ceramic coating according to claim 1, characterized in that: The substrate is pretreated before preparing the coating. The substrate is a carbon / carbon composite material. The carbon / carbon composite material is polished with SiC sandpaper, ultrasonically cleaned, and then dried in an oven.

7. The method for preparing an ultrahigh temperature resistant and anti-oxidation ceramic coating according to claim 1, characterized in that: The amorphous silicon dioxide has a mesh size of 300-400, and the crystalline silicon dioxide has a mesh size of -200.

8. The method for preparing an ultrahigh temperature resistant and anti-oxidation ceramic coating according to claim 1, characterized in that: The high-temperature sintering temperature in the oxygen-free environment is 2000° C.-2400° C.

9. An ultra-high temperature resistant and anti-oxidation ceramic coating, characterized by: The preparation method according to any one of claims 1 to 8 is adopted, comprising a transition layer, a sealing layer, an oxygen barrier layer and an anti-erosion layer, wherein the transition layer comprises silicon dioxide, the sealing layer comprises SiO2 and B2O3, the oxygen barrier layer comprises Si3N4 or SiC or a mixture of Si3N4 and SiC, and the anti-erosion layer comprises ZrSiO4 and SiC.

10. The ultrahigh temperature resistant and anti-oxidation ceramic coating according to claim 9, characterized in that: The thickness of the transition layer coating is 0.2-0.3 mm, the thickness of the sealing layer coating is 0.1-0.2 mm, the thickness of the oxygen barrier layer coating is 0.2-0.3 mm, and the thickness of the anti-erosion layer coating is 0.3-0.4 mm.

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