Method for synchronously preparing silicon carbide ceramic-based composite material and ablation-resistant coating and method

Abstract

The invention discloses a method for synchronously preparing a silicon carbide ceramic-based composite material and an ablation-resistant coating, and the method comprises the following steps: carrying out ball milling on solid phenolic resin powder, silicon carbide powder, ablation-resistant powder and short carbon fibers, and uniformly mixing to form ablation-resistant composite powder; carrying out hot-pressing connection on the fiber-reinforced carbon-based composite material and the composite powder; carbonizing the connected sample to obtain a fiber-reinforced carbon-based intermediate with a pre-coating layer; and placing the carbon-based intermediate with the ablation-resistant precoating on silicon powder or silicon alloy powder, carrying out vacuum reaction infiltration, and synchronously preparing the silicon carbide ceramic-based composite material with the ablation-resistant coating. Synchronous preparation of densification of the silicon carbide ceramic-based composite material and the ablation-resistant coating is realized, the bonding strength of the coating and the silicon carbide ceramic-based composite material is enhanced, the content of ablation-resistant powder in the coating can be accurately regulated and controlled, the bonding property and the compactness of the coating are improved, and the preparation period of the ablation-resistant coating is shortened.

Description

Technical Field

[0001] The present invention belongs to the technical field of ablation-resistant coatings, and in particular relates to a method for simultaneously preparing a silicon carbide ceramic-based composite material and an ablation-resistant coating. Background Art

[0002] Carbon fiber reinforced silicon carbide ceramic matrix composites (CSMCs) boast a range of excellent properties, including low density, high specific strength, high fracture toughness, oxidation resistance, thermal shock resistance, corrosion resistance, and high temperature resistance. They have been widely used in aerospace, metallurgy, and other fields, becoming one of the most promising high-temperature thermal structural materials. However, CSMCs exhibit poor ablation resistance at temperatures above 1600°C, and the carbon fibers are easily oxidized, severely limiting the composites' potential at high temperatures. With the continuous development of aerospace technology, higher requirements are being placed on the oxidation resistance and ablation resistance of CSMCs. Developing technologies to resist oxidation and ablation for CSMCs can advance their application in aerospace and is of great practical significance.

[0003] The preparation of ablation-resistant coatings on silicon carbide ceramic-based composites can effectively improve their ablation resistance. Currently, the main preparation methods include chemical vapor deposition (CVD), embedding, plasma spraying, and slurry brushing. The paper "Ablation Performance of ZrC Coatings and ZrC-TaC Co-deposited Coatings Prepared by CVD. Powder Metallurgy Materials Science and Engineering, 2016" reported the preparation of ZrC coatings and ZrC-TaC by chemical vapor deposition (CVD) using the reaction systems ZrCl₄-CH₄-H₂-Ar and ZrCl₄-TaCl₅-CH₄-H₂-Ar. After a 60-second oxygen-acetylene flame ablation test, the ZrC-TaC composite coatings exhibited excellent thermal shock resistance and overall integrity, with good adhesion to the substrate and excellent ablation resistance. The CVD method allows for relatively low preparation temperatures, avoiding the loss of mechanical properties of the substrate material caused by high-temperature preparation. The resulting coatings are denser in structure and can also be controlled in terms of coating composition and structure. However, the deposition rate of chemical vapor deposition is low, the preparation cycle is long, the preparation process is relatively complex, and the preparation cost is high.

[0004] In a Chinese invention patent (Ultra-high temperature ceramic matrix composite material with La / Y-doped ZrC-SiC coating and preparation method, 202210266664.7), a gradient embedding method is used to set embedding powders of different components in a gradient, and a C / ZrC-SiC ultra-high temperature ceramic matrix composite material with a La / Y-doped ZrC-SiC coating is prepared in a one-step reaction. The embedding method is easy to prepare and can produce a dense coating. However, the uniformity, component content, and thickness of the prepared coating are difficult to control, which can easily affect the performance stability of the material. In addition, the high-temperature chemical reaction process can easily cause fiber damage and weaken the mechanical properties of the matrix material. The infiltration temperature in this patent is 1700-2100°C, which is relatively high and causes greater damage to the fibers.

[0005] In a Chinese invention patent (a ZrC-based high-temperature resistant and ablation-resistant composite coating and preparation method, 201810230323.8), plasma spraying is used to sequentially spray a ZrC-MoSi2 inner layer and a ZrC-SiC outer layer powder onto a substrate to produce an ablation-resistant coating. Plasma spraying has low requirements for coating materials and can spray high-melting-point materials. The experimental operation is simple, the coating preparation speed is fast, and the coating thickness can be controlled. However, the coating prepared by this method has a high porosity, and the bonding between the prepared coating and the substrate is mainly mechanical, resulting in weak bonding.

[0006] In a Chinese invention patent (An antioxidant coating for C / ZrC-SiC composite materials and preparation method thereof, 201911201327.4), a slurry brushing method is used to brush a ceramic slurry containing Hf powder, B powder, ethanol and phenolic resin on the surface of the C / ZrC-SiC composite material. After cracking, an HfC-HfB2 coating is formed, and then a SiC coating is deposited. The slurry brushing method is relatively simple and inexpensive, and the composition and structure of the coating can be controlled by adjusting the slurry, making it easy to prepare a gradient coating. However, the coating prepared by the brushing method has poor bonding with the substrate, and the density of the coating cannot be guaranteed.

[0007] When preparing ablation-resistant coatings on the surface of silicon carbide ceramic-based composite materials, the current mainstream methods either have long cycles and high costs, or the coatings are not dense enough, or it is difficult to control the thickness, content and composition uniformity of the coatings, or the prepared coatings have weak bonding with the substrate. Therefore, there is an urgent need for a method for preparing ablation-resistant coatings that has a short cycle, can precisely control the content of ablation-resistant components in the coating, and has strong bonding between the ablation-resistant coating and the substrate. Summary of the Invention

[0008] In order to solve the above-mentioned defects in the prior art, the purpose of the present invention is to provide a method for the simultaneous preparation of silicon carbide ceramic-based composite materials and ablation-resistant coatings, wherein the ablation-resistant powder is connected and combined with the fiber-reinforced carbon-based composite material by hot pressing of powdered phenolic resin, and then carbonized and vacuum reaction infiltrated, thereby realizing the simultaneous preparation of silicon carbide ceramic-based composite materials and ablation-resistant coatings, enhancing the bonding strength between the coating and the silicon carbide ceramic-based composite material, and being able to accurately control the content of ablation-resistant powder in the coating, thereby improving the bonding and density of the coating, shortening the preparation cycle of the ablation-resistant coating, and reducing the preparation cost.

[0009] The present invention is achieved through the following technical solutions.

[0010] One aspect of the present invention provides a method for simultaneously preparing a silicon carbide ceramic matrix composite material and an ablation-resistant coating, comprising the following steps:

[0011] a. The solid phenolic resin powder, silicon carbide powder, ablation-resistant powder and chopped carbon fiber are evenly mixed by ball milling in a mass ratio of (25 to 35): (10 to 35): (10 to 35): (20 to 30) to form an ablation-resistant composite powder;

[0012] b. Place the fiber-reinforced carbon-based composite material and the composite powder of the desired thickness in the mold, and transfer the mold to a flat vulcanizer for hot pressing;

[0013] c. Placing the connected sample in a carbonization furnace and carbonizing it to obtain a fiber-reinforced carbon-based intermediate with a pre-coated layer;

[0014] d. Placing silicon powder or silicon alloy powder of a fiber-reinforced carbon-based intermediate with a pre-coating in a graphite crucible, placing the carbon-based intermediate with an ablation-resistant pre-coating on the silicon powder or silicon alloy powder, and performing vacuum reactive infiltration to simultaneously prepare a silicon carbide ceramic-based composite material with an ablation-resistant coating.

[0015] Preferably, in step a, the average particle size of the solid phenolic resin powder is 25-35 μm, the average particle size of the silicon carbide powder is 5-10 μm, the average particle size of the ablation-resistant powder is 25-35 μm, and the average diameter of the chopped carbon fiber is 5-10 μm and the length is 2-6 mm.

[0016] Preferably, the ablation-resistant powder is one or more of ZrC, HfC, TaC, ZrB2, HfB2 or TaB2.

[0017] Preferably, in step a, the ball milling is performed for 10 to 12 hours.

[0018] Preferably, in step b, the fiber-reinforced carbon-based composite material is a carbon fiber or silicon carbide fiber reinforced carbon-based material, which is a C / C or SiC / C intermediate obtained by brushing carbon fiber or silicon carbide fiber plain weave cloth with phenolic resin or epoxy resin, laminating and then curing, and then carbonizing; or it is a resin-based intermediate obtained by brushing carbon fiber or silicon carbide fiber plain weave cloth with phenolic resin or epoxy resin, laminating and then curing.

[0019] Preferably, in step b, the hot pressing connection is performed at 150-170° C. for 2 hours, and then at 190-210° C. for 5-7 hours after the temperature is raised.

[0020] Preferably, in step c, the carbonization process is carried out in a carbonization furnace under an argon atmosphere at a heating rate of 1 to 1.5°C / min from room temperature to 800 to 1000°C for carbonization, and the temperature is kept at this temperature for 2 to 4 hours.

[0021] Preferably, in step d, the mass of the silicon powder or silicon alloy powder is 1.5 to 2 times that of the fiber-reinforced carbon-based intermediate with the pre-coating layer.

[0022] Preferably, in step d, the vacuum reaction infiltration temperature is 1500-1600° C., the holding time is 40-60 min, the reaction infiltration vacuum degree is below 10 Pa; and the ablation-resistant coating thickness is 0.5-1 mm.

[0023] Another aspect of the present invention provides a simultaneously prepared silicon carbide ceramic-based composite material and an ablation-resistant coating prepared by the method.

[0024] The present invention adopts the above technical solution, which has the following beneficial effects:

[0025] 1. Solid phenolic resin powder is connected by hot pressing, thermally cured and formed with ablation-resistant powder and combined with fiber-reinforced carbon-based composite materials. It is then carbonized and reactively infiltrated. The coating and the substrate are combined by in-situ reaction to form SiC, which has a high bonding strength.

[0026] 2. The densification of silicon carbide ceramic-based composites and the preparation of ablation-resistant coatings on the composites were completed simultaneously, shortening the preparation cycle of the ablation-resistant coatings, reducing the preparation cost of the ablation-resistant coatings, and reducing the waste of resources and energy.

[0027] 3. The synchronous reaction infiltration of the ablation-resistant coating and the substrate is carried out at 1500-1600°C. Compared with the existing technology, the lower reaction temperature causes less damage to the substrate and the fibers in the coating.

[0028] 4. The substrate and coating prepared by reactive infiltration are simultaneously densified, with low open porosity, and by controlling the ratio of ablation-resistant powder to phenolic resin powder, the content of ablation-resistant components in the coating can be precisely controlled.

[0029] The density of the ablation-resistant coating prepared by this method is 2.5-2.7 g·cm -3 The open porosity is less than 3%, and the mass ablation rate is 2.71~3.80×10 after ablation at 1600℃ in oxyacetylene for 200s. -4 g / s, excellent ablation performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The drawings described herein are used to provide a further understanding of the present invention, constitute a part of this application, and do not constitute an improper limitation of the present invention. In the drawings:

[0031] Figure 1 Flowchart adopted by the present invention;

[0032] Figure 2 This is a physical cross-sectional view of the silicon carbide ceramic matrix composite material and the ablation-resistant coating in the embodiment;

[0033] Figure 3 This is a microscopic photograph of the coating before ablation in Example 1-3;

[0034] Figures 4(a)-(c) are microscopic photographs of the coatings after ablation in Examples 1-3;

[0035] Figure 5 This is the backscattered image of the cross section of the coating and substrate. DETAILED DESCRIPTION

[0036] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. The exemplary embodiments and descriptions of the present invention are used to explain the present invention but are not intended to limit the present invention.

[0037] like Figure 1 As shown, an embodiment of the present invention provides a method for simultaneously preparing a silicon carbide ceramic-based composite material and an ablation-resistant coating, comprising the following steps:

[0038] Step 1: Solid phenolic resin powder with an average particle size of 25-35 μm, silicon carbide powder with an average particle size of 5-10 μm, ablation-resistant powder with an average particle size of 25-35 μm, and chopped carbon fiber with a diameter of 5-10 μm and a length of 2-6 mm are ball-milled in a mass ratio of (25-35): (10-35): (10-35): (20-30) for 10-12 hours to obtain ablation-resistant composite powder, and the total mass percentage of the four raw materials is 1.

[0039] Among them, the ablation-resistant powder is one or more of ZrC, HfC, TaC, ZrB2, HfB2 or TaB2.

[0040] Solid phenolic resin powder, silicon carbide powder, ablation-resistant powder, and chopped carbon fibers are uniformly mixed together by ball milling according to the mass ratio to produce a composite coating that can achieve uniform distribution between the various phases. The average particle size and mass ratio of the solid phenolic resin powder are controlled. On the one hand, it acts as a binder to connect the coating raw materials to the substrate, and on the other hand, it serves as a carbon source for subsequent reactive infiltration. Silicon carbide powder, as an inert filler, can reduce the generation of residual silicon during the siliconization process. It can also serve as the structural phase of the coating with the silicon carbide phase generated by reactive infiltration, the ablation-resistant powder as the functional phase of the coating, and the chopped carbon fibers as the skeleton material to reduce the shrinkage of the coating during the preparation process.

[0041] Step 2: Place the fiber-reinforced carbon-based composite material of the required thickness in a mold, spread the ablation-resistant composite powder on top of the composite material, transfer the mold to a flat vulcanizer, and hot press at 150-170°C for 2 hours, or at 190-210°C for 5-7 hours.

[0042] Among them, the fiber-reinforced carbon-based composite material is a carbon fiber or silicon carbide fiber reinforced carbon-based material, which is obtained by brushing carbon fiber or silicon carbide fiber plain cloth with a thermosetting resin (such as phenolic resin, epoxy resin, etc.), stacking, solidifying and then carbonizing. It can be a porous C / C or SiC / C intermediate prepared by other methods, or it can be a resin-based intermediate obtained by brushing carbon fiber or silicon carbide fiber plain cloth with a thermosetting resin (such as phenolic resin, epoxy resin, etc.), stacking and solidifying.

[0043] Solid phenolic resin powder is heat-cured and bonded to ablation-resistant powder through hot pressing, and then combined with a fiber-reinforced carbon-based composite material. Controlling the process conditions of the thermosetting phenolic resin used as the coating raw material ensures complete curing and prevents expansion and deformation during the subsequent carbonization and siliconization processes.

[0044] Step 3: Place the connected sample in a carbonization furnace and carbonize it under flowing argon to obtain a carbon-based intermediate with a pre-coating layer. Raise the temperature from room temperature to 800-1000°C at a rate of 1-1.5°C / min and keep it warm for 2-4 hours.

[0045] Step 4: Place silicon powder or silicon alloy powder with a mass of 1.5 to 2 times that of the coated carbon-based intermediate in a graphite crucible, and place the carbon-based intermediate with an ablation-resistant pre-coating on the silicon powder or silicon alloy powder, and perform vacuum reactive infiltration. The infiltration temperature is 1500 to 1600°C, the holding time is 40 to 60 minutes, and the reactive infiltration vacuum is below 10 Pa. Simultaneously, a silicon carbide ceramic-based composite material with an ablation-resistant coating with a thickness of 0.5 to 1 mm is prepared.

[0046] Steps 3 and 4 simultaneously complete the densification of the silicon carbide ceramic-based composite and the preparation of the ablation-resistant coating on the composite. In step 3, controlling the carbonization process, such as the heating rate, completely cracks the phenolic resin in the coating, generating porous carbon, which provides a carbon source and a path for silicon infiltration in the next step.

[0047] In step 4, reactive infiltration is used to simultaneously densify the coating and substrate. This process is simple, has a short cycle, and is low-cost. Controlling the quality of the silicon powder or silicon alloy powder and the infiltration temperature effectively reduces the viscosity of the liquid silicon and improves its fluidity, facilitating complete infiltration of the liquid silicon and producing a highly dense composite material. A high vacuum also facilitates the infiltration of the liquid silicon. During the simultaneous densification process, the coating and substrate form a SiC bond through an in-situ reaction, resulting in a strong bond.

[0048] Figure 2 This is a physical picture of the prepared silicon carbide ceramic-based composite material and ablation-resistant coating. Figure 3 This is a microscopic picture of the ablation-resistant coating in the example.

[0049] In this method, solid phenolic resin powder is connected by hot pressing, thermally cured and formed with ablation-resistant powder and combined with a fiber-reinforced resin matrix, and then carbonized and reacted and infiltrated together. The bonding strength between the coating and the matrix is ​​high, and the densification of the silicon carbide ceramic-based composite material and the preparation of the ablation-resistant coating on the composite material are simultaneously completed, shortening the preparation cycle of the ablation-resistant coating, reducing the preparation cost of the ablation-resistant coating, reducing resource and energy waste, and being able to accurately control the content of the ablation-resistant powder in the coating.

[0050] The densification of silicon carbide ceramic-based composite materials and the preparation of ablation-resistant coatings on the composite materials are simultaneously completed through reactive infiltration. The process is simple, the sintering temperature is low, the sintering speed is fast, and the preparation cycle is short, which can effectively reduce the preparation cost.

[0051] Through reactive infiltration, the substrate and the coating are simultaneously densified, with low open porosity, and by controlling the ratio of ablation-resistant powder to phenolic resin powder, the content of ablation-resistant components in the coating can be precisely controlled.

[0052] The ablation-resistant coating prepared by the method has a density of 2.5-2.7 g·cm-3, an open porosity of less than 3%, and a mass ablation rate of 2.71-3.80×10-4 g / s after ablation at 1600°C in oxyacetylene for 200s, showing excellent ablation performance.

[0053] The present invention is further illustrated below by means of specific examples.

[0054] Example 1

[0055] a. Solid phenolic resin powder with an average particle size of 30 μm, silicon carbide powder with an average particle size of 5 μm, ZrC powder with an average particle size of 30 μm, and chopped carbon fibers with a diameter of 7 μm and a length of 4 mm were ball-milled in a mass ratio of 25:35:10:30 for 12 hours to obtain an ablation-resistant composite powder.

[0056] b. Place a 5 mm thick CVI-densified 2.5DC / C intermediate in a mold, spread 3 g of ablation-resistant composite powder on top of the composite material, transfer the mold to a flat vulcanizer and hot press at 160 ° C for 2 h and 200 ° C for 6 h.

[0057] c. Place the connected samples in a carbonization furnace and simultaneously carbonize them under flowing argon to obtain a carbon-based intermediate with a pre-coated layer. Raise the temperature from room temperature to 800°C at a rate of 1.5°C / min and keep it there for 4 hours.

[0058] d. Place silicon powder or silicon alloy powder with a mass twice that of the coated carbon-based intermediate in a graphite crucible, and place the carbon-based intermediate with an ablation-resistant pre-coating on the silicon powder or silicon alloy powder. Vacuum reactive infiltration is performed at a temperature of 1550°C for 40 minutes. The reactive infiltration vacuum is maintained below 10 Pa. Simultaneously, a silicon carbide ceramic-based composite material with an ablation-resistant coating with a thickness of 1 mm is prepared.

[0059] The density of the prepared ablation-resistant coating is 2.52 g·cm -3 The open porosity is 2.5%, and the mass ablation rate is 3.80×10 -4 g / s.

[0060] Example 2

[0061] a. Solid phenolic resin powder with an average particle size of 25 μm, silicon carbide powder with an average particle size of 8 μm, HfC powder with an average particle size of 35 μm, and chopped carbon fibers with a diameter of 5 μm and a length of 4 mm were ball-milled in a mass ratio of 30:30:15:25 for 10 hours to obtain an ablation-resistant composite powder.

[0062] b. Place a 5 mm thick CVI-densified 2.5DSiC / C intermediate in a mold, spread 3 g of ablation-resistant composite powder on top of the composite material, transfer the mold to a flat vulcanizer and hot press at 170 ° C for 2 h and 190 ° C for 7 h.

[0063] c. Place the connected samples in a carbonization furnace and carbonize them simultaneously under flowing argon to obtain a carbon-based intermediate with a pre-coated layer. Raise the temperature from room temperature to 900°C at a rate of 1°C / min and keep it there for 3 hours.

[0064] d. Place silicon powder or silicon alloy powder with a mass 1.5 times that of the coated carbon-based intermediate in a graphite crucible, and place the carbon-based intermediate with an ablation-resistant pre-coating on the silicon powder or silicon alloy powder. Vacuum reactive infiltration is performed at a temperature of 1500°C for 60 minutes. The reactive infiltration vacuum is maintained below 10 Pa. Simultaneously, a silicon carbide ceramic-based composite material with an ablation-resistant coating with a thickness of 0.5 mm is prepared.

[0065] The density of the prepared ablation-resistant coating is 2.69 g·cm -3 The open porosity is 1.4%, and the mass ablation rate is 2.71×10 -4 g / s.

[0066] Example 3

[0067] a. Solid phenolic resin powder with an average particle size of 35 μm, silicon carbide powder with an average particle size of 10 μm, phenolic resin TaC powder with an average particle size of 25 μm, and chopped carbon fibers with a diameter of 10 μm and a length of 4 mm were ball-milled in a mass ratio of 35:10:35:20 for 11 hours to obtain an ablation-resistant composite powder.

[0068] b. Place a 5 mm thick CVI-densified 2.5DC / C intermediate in a mold, lay 3 g of ablation-resistant composite powder on top of the composite material, transfer the mold to a flat vulcanizer and hot press at 150 ° C for 2 h and 210 ° C for 5 h.

[0069] c. Place the connected samples in a carbonization furnace and carbonize them simultaneously under flowing argon to obtain a carbon-based intermediate with a pre-coated layer. Raise the temperature from room temperature to 1000°C at a rate of 1.5°C / min and keep it there for 2 hours.

[0070] d. Place silicon powder or silicon alloy powder with a mass twice that of the coated carbon-based intermediate in a graphite crucible, and place the carbon-based intermediate with an ablation-resistant pre-coating on the silicon powder or silicon alloy powder. Vacuum reactive infiltration is performed at a temperature of 1600°C for 50 minutes. The reactive infiltration vacuum is maintained below 10 Pa. Simultaneously, a silicon carbide ceramic-based composite material with an ablation-resistant coating with a thickness of 0.7 mm is prepared.

[0071] The density of the prepared ablation-resistant coating is 2.53 g·cm -3 The open porosity is 2%, and the mass ablation rate is 2.91×10 -4 g / s.

[0072] The obtained products were characterized by field emission scanning electron microscopy (FESEM). Figure 3These are backscattered photographs of the coatings prepared in each case before ablation. The black phase is chopped carbon fiber, the gray phase is silicon carbide, and the bright white phase is a mixed phase of zirconium carbide, zirconium silicide, and some residual silicon. Figure 4(a)-Figure 4(c) The backscattered photos of the coatings after ablation of each embodiment are shown. From embodiment 1 to embodiment 3, the sum of the mass percentages of the four raw materials is 1, and the ratio of phenolic resin to chopped carbon fiber is fixed. As the zirconium carbide content increases, the mass ablation first decreases and then increases. When the zirconium carbide content is 15wt%, the ablation performance is the best. When the zirconium carbide content continues to increase, the coating density decreases slightly, so the ablation rate increases slightly. Figure 4(a)-Figure 4(c) It can be seen that after ablation, zirconium carbide is oxidized into zirconium oxide, silicon carbide is oxidized into glassy silicon dioxide, and carbon fiber leaves holes after oxidation.

[0073] Figure 5 This is a backscattered image of the cross-section of the coating and the substrate. The black phase in the substrate is chopped carbon fiber, the gray phase is the silicon carbide phase, and the bright white is the residual silicon phase. The black phase in the coating is chopped carbon fiber, the gray phase is the silicon carbide phase, and the bright white is a mixed phase of zirconium carbide, zirconium silicide and some residual silicon. The coating is well bonded to the substrate.

[0074] The present invention is not limited to the above-mentioned embodiments. On the basis of the technical solutions disclosed in the present invention, those skilled in the art can make some substitutions and modifications to some of the technical features therein according to the disclosed technical content without creative labor, and these substitutions and modifications are all within the protection scope of the present invention.

Claims

1. A method for simultaneously preparing a silicon carbide ceramic matrix composite material and an ablation-resistant coating, characterized in that: The following steps are involved: a. The solid phenolic resin powder, silicon carbide powder, ablation-resistant powder and chopped carbon fiber are evenly mixed by ball milling in a mass ratio of (25 to 35): (10 to 35): (10 to 35): (20 to 30) to form an ablation-resistant composite powder; b. Place the fiber-reinforced carbon-based composite material and the composite powder of the desired thickness in the mold, and transfer the mold to a flat vulcanizer for hot pressing; c. Placing the connected sample in a carbonization furnace and carbonizing it to obtain a fiber-reinforced carbon-based intermediate with a pre-coated layer; d. Placing silicon powder or silicon alloy powder of a fiber-reinforced carbon-based intermediate with a pre-coating in a graphite crucible, placing the carbon-based intermediate with an ablation-resistant pre-coating on the silicon powder or silicon alloy powder, and performing vacuum reactive infiltration to simultaneously prepare a silicon carbide ceramic-based composite material with an ablation-resistant coating.

2. The method for simultaneously preparing a silicon carbide ceramic matrix composite material and an ablation-resistant coating according to claim 1, characterized in that: In step a, the average particle size of the solid phenolic resin powder is 25 to 35 μm, the average particle size of the silicon carbide powder is 5 to 10 μm, the average particle size of the ablation-resistant powder is 25 to 35 μm, and the average diameter of the chopped carbon fiber is 5 to 10 μm and the length is 2-6 mm.

3. The method for simultaneously preparing a silicon carbide ceramic-based composite material and an ablation-resistant coating according to claim 1, characterized in that: The ablation-resistant powder is one or more of ZrC, HfC, TaC, ZrB2, HfB2 or TaB2.

4. The method for simultaneously preparing a silicon carbide ceramic matrix composite material and an ablation-resistant coating according to claim 1, characterized in that: In step a, the mixture is ball milled for 10 to 12 hours.

5. The method for simultaneously preparing a silicon carbide ceramic matrix composite material and an ablation-resistant coating according to claim 1, characterized in that: In step b, the fiber-reinforced carbon-based composite material is a carbon fiber or silicon carbide fiber reinforced carbon-based material, which is a C / C or SiC / C intermediate obtained by brushing carbon fiber or silicon carbide fiber plain weave cloth with phenolic resin or epoxy resin, stacking and then curing, and then carbonizing; or it is a resin-based intermediate obtained by brushing carbon fiber or silicon carbide fiber plain weave cloth with phenolic resin or epoxy resin, stacking and then curing.

6. The method for simultaneously preparing a silicon carbide ceramic matrix composite material and an ablation-resistant coating according to claim 1, characterized in that: In step b, the hot pressing connection is performed at 150-170° C. for 2 hours, and then at 190-210° C. for 5-7 hours after the temperature is increased.

7. The method for simultaneously preparing a silicon carbide ceramic matrix composite material and an ablation-resistant coating according to claim 1, characterized in that: In step c, the carbonization system is to heat the temperature from room temperature to 800-1000° C. at a rate of 1-1.5° C. / min under an argon atmosphere in a carbonization furnace, and keep the temperature for 2-4 hours.

8. The method for simultaneously preparing a silicon carbide ceramic-based composite material and an ablation-resistant coating according to claim 1, characterized in that: In step d, the mass of the silicon powder or silicon alloy powder is 1.5 to 2 times that of the fiber-reinforced carbon-based intermediate with the pre-coating layer.

9. The method for simultaneously preparing a silicon carbide ceramic-based composite material and an ablation-resistant coating according to claim 1, characterized in that: In step d, the vacuum reaction infiltration temperature is 1500-1600° C., the holding time is 40-60 min, the reaction infiltration vacuum degree is below 10 Pa; and the ablation-resistant coating thickness is 0.5-1 mm.

10. A simultaneously prepared silicon carbide ceramic-based composite material and ablation-resistant coating prepared by the method according to any one of claims 1 to 8.

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