A method for preparing a c / c-sic composite material

Abstract

The application provides a preparation method of C / C-SiC composite material, which can effectively improve the preparation efficiency of C / C-SiC, and obtain C / C-SiC composite material with good mechanical properties and excellent oxidation resistance and friction performance. The process method is that after the preform is heat treated and degreased, a C matrix containing SiC is prepared through slurry impregnation and pyrolysis, and then the carbon matrix is reacted into a SiC matrix through a liquid silicon infiltration process. The slurry is made by dispersing SiC micropowder in medium-temperature coal pitch, after the slurry impregnation and pyrolysis to a certain density, the carbon matrix generated by the pitch impregnation and pyrolysis is partially reacted into a SiC matrix through the liquid silicon infiltration process. The application is suitable for preparing components with high requirements for material oxidation resistance and friction performance.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of composite materials, and particularly relates to a preparation method of wear-resistant and oxidation-resistant C / C-SiC composite material. BACKGROUND

[0002] Continuous carbon fiber reinforced silicon carbide (C / C-SiC) composite material has a series of excellent performances such as low density, high temperature resistance, high strength and toughness, thermal shock resistance, high chemical stability, low thermal expansion coefficient and high design tolerance, and is an excellent candidate material for rocket engine nozzles. In the 1970s, SEP (European Power Association) of France successfully developed a C / C-SiC composite material nozzle for the first time, and after that, the material has been widely used in the field of aerospace. For example, the European Ariane upper stage HM7 low temperature engine uses the material as the nozzle extension section, and the material nozzle has been successfully applied to multiple types of rocket engines represented by "Expedition Three" in China.

[0003] At the same time, the C / C-SiC composite material has a series of excellent performances such as good friction heat stability, low wear, small brake system volume and environmental adaptability, which makes up for the disadvantages of steel brake disc such as high temperature crack initiation, high temperature deformation and low wet friction coefficient of C / C composite brake material, and is a new generation of friction material with strong competitiveness, which has a wide application prospect in the field of high-speed trains, automobiles, airplanes and the like.

[0004] At present, the main methods for preparing C / C-SiC at home and abroad include chemical vapor deposition process (CVI), precursor impregnation and pyrolysis process (PIP) and reaction melt infiltration process (RMI) and the like. The comprehensive performance of C / C-SiC composite material prepared by chemical vapor deposition and precursor pyrolysis method is higher, but the long preparation cycle, high cost and the like limit the wide application of C / C-SiC in aviation and civil use. The reaction melt infiltration method for preparing C / C-SiC composite material has the advantages of simple process, low cost, high density and easy near net shape forming and the like, and is a process route with outstanding advantages. The inventors have found that, in order to make the C matrix be converted into SiC as much as possible, a sufficient amount of silicon material needs to be added in the RMI process, but a certain amount of Si will be left in the prepared C / C-SiC friction material, the high temperature stability of Si is poor, which will reduce the working temperature and the creep resistance of the material, the hardness of the residual Si is high, which is easy to cause cutting effect on the friction surface to form the furrow effect of micro convex body. At the same time, the melting point of Si is relatively low (about 1411℃), and plastic deformation is easy to occur in the friction process, which causes adhesive wear on the surface of the friction object, resulting in unstable friction factor, thereby adversely affecting the performance of the C / C-SiC friction material. The excessive or locally excessive addition of silicon will also cause siliconization corrosion to carbon fibers. Therefore, the inventors believe that the key to the preparation of C / C-SiC friction material by RMI method is to reasonably control the content and distribution of residual Si, and reducing the addition of silicon material is an effective way to control the content of residual silicon. SUMMARY

[0005] In view of the above analysis, the present application aims to provide a preparation method of C / C-SiC composite material, which can significantly improve the efficiency of material preparation, and effectively avoid the problems of excessive Si material leading to residual silicon and siliconization corrosion to carbon fibers, resulting in performance decline.

[0006] The present application provides a method for rapidly preparing C / C-SiC composite material by slurry impregnation and pyrolysis combined with RMI. SiC powder is added to molten pitch to prepare a slurry, and a C matrix containing a certain amount of SiC is prepared outside the preform fiber by slurry impregnation and pyrolysis process; in the subsequent RMI process, a small amount of silicon material is added to participate in the reaction to prepare a SiC matrix. The slurry impregnation and pyrolysis combined with RMI process can significantly shorten the preparation cycle, and the reduction of the amount of silicon material added in the RMI process can effectively avoid the problems of excessive Si material leading to residual silicon and siliconization corrosion to carbon fibers, resulting in performance decline.

[0007] The purpose of the present application is achieved by the following technical scheme: a preparation method for rapidly preparing C / C-SiC composite material, characterized in that it comprises the following steps:

[0008] A method for rapidly preparing C / C-SiC composite material, characterized in that it comprises the following steps:

[0009] S1: degumming treatment is performed on the carbon fiber preform to obtain a degummed preform;

[0010] S2: SiC micropowder is mixed into pitch, heated and melted, and fully stirred to prepare a slurry;

[0011] S3: the degummed preform of S1 is placed in the slurry of S2 for vacuum impregnation for 2-3 hours, and after the excess slurry is recovered, it is cooled and solidified;

[0012] S4: the solidified preform is carbonized, and after carbonization is completed, the excess carbon layer on the surface is removed and cleaned;

[0013] S5: S3-S4 is repeated 3-4 times until the density reaches 1.3-1.45 g / cm 3 , to obtain a sample, and the sample is heat treated to obtain a heat treated sample;

[0014] S6: the heat treated sample is placed in a tooling, covered with silicon material, and siliconized to obtain a C / C-SiC composite material.

[0015] Further, in S1, the degumming treatment is performed in a heat treatment furnace, the carbon fiber preform is placed in the heat treatment furnace, N2 is continuously passed for 3-5 hours to fill the inert atmosphere inside the cracking furnace, the temperature is raised to 750-850 DEG C at a rate of 20-25 DEG C / h and kept for 2-4 hours, and the furnace is cooled to room temperature.

[0016] Further, in S2, the SiC micropowder has a particle size of 200-500 nm.

[0017] Further, in S2, the pitch has a softening point temperature of 80-100 DEG C.

[0018] Further, in S2, the SiC micropowder is mixed with pitch at a mass ratio of 1:3-1:4.

[0019] Further, in S2, the slurry needs to be stirred for 2-3 hours.

[0020] Further, in S3, the vacuum impregnation is performed in a vertical impregnation tank with a storage tank, there is a material conveying pipeline between the storage tank and the impregnation tank for feeding and returning material, and the pitch slurry is stored in the storage tank.

[0021] Further, in S3, the process parameters of the vacuum impregnation are as follows: the impregnation tank is vacuumed to 100-200 Pa, heated to 200-220 DEG C, and kept for 30-90 min, while the storage tank is heated to 200-220 DEG C, and kept for 30-90 min, then the slurry in the storage tank is sucked into the impregnation tank, vacuum impregnation is carried out for 2-4 h, then the impregnation tank is pressurized to 0.8-1 MPa to make the slurry backflow into the storage tank, and the impregnation tank is naturally cooled to solidify the preform impregnated with the slurry.

[0022] Further, in S4, the carbonization is carried out in a cracking furnace, and the process parameters of the carbonization are as follows: N2 is continuously fed for 3-5 h to fill the cracking furnace with inert atmosphere, the temperature is raised to 400-450 DEG C at a rate of 20-25 DEG C / h and kept for 3 h, then the temperature is raised to 850-900 DEG C at a rate of 20-25 DEG C / h and kept for 4 h, and the furnace is cooled to room temperature.

[0023] Further, in S4, the heat treatment is carried out in a high-temperature heat treatment furnace, and the process parameters of the heat treatment are as follows: the vacuum is extracted to below 100 Pa, the temperature is raised to 900-950 DEG C at a rate of 25-30 DEG C / h and kept for 2-3 h, then the temperature is raised to 2100-2200 DEG C at a rate of 35-40 DEG C / h and kept for 2-3 h, and then the temperature is lowered to 1500-1600 DEG C at a rate of 70-80 DEG C / h and naturally cooled;

[0024] Further, when the temperature is raised to 1050-1100 DEG C, Ar is fed to 101-102 kPa as protective gas and the pressure is kept until the temperature is lowered to 300-350 DEG C;

[0025] Further, in S6, the silicon infiltration is carried out in a high-temperature heat treatment furnace, and the process parameters of the silicon infiltration are as follows: the temperature is raised to 1600-1650 DEG C at a rate of 300-360 DEG C / h and kept for 2-3 h, and then the furnace is cooled to room temperature;

[0026] Further, in S6, the amount of the silicon material is 1 / 5-1 / 3 of the mass of the sample after the heat treatment.

[0027] Compared with the prior art, the embodiments of the present application have the following beneficial effects:

[0028] (1) The application aims at the problems of long preparation period of traditional CVI and PIP of oxidation-resistant wear-resistant C / C-SiC and possible performance damage of RMI, and proposes a preparation process of slurry impregnation and pyrolysis combined with RMI, SiC powder is added to molten pitch to prepare slurry for impregnation and pyrolysis, and the density of the C / C blank containing SiC can be increased to 1.3-1.45 in 3-5 cycles, and after heat treatment, only one step of RMI process can obtain the oxidation-resistant wear-resistant C / C-SiC composite material, and the preparation efficiency of the oxidation-resistant wear-resistant C / C-SiC is significantly improved.

[0029] (2) The silicon material used in the RMI process is reduced by 1 / 6-1 / 2 compared with the traditional PIP+RMI process, which can effectively avoid the friction performance decline caused by residual silicon, and can avoid the mechanical property damage caused by carbon fiber siliconization corrosion. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the application will be described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the application, not all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, but not as any limitation on the application and its application or use. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the application.

[0031] The technologies, methods and devices known to those skilled in the related art may not be discussed in detail, but should be considered as part of the authorized description when appropriate.

[0032] The test methods or test methods in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials are obtained from conventional commercial channels or prepared by conventional methods unless otherwise specified. Embodiment 1

[0033] A rapid preparation method of C / C-SiC plate material, comprising the following steps:

[0034] The non-woven fabric and the ultra-thin net tire are alternately stacked and needled to obtain a density of 0.45g / cm 3The carbon fiber plate preform is put into a heat treatment furnace, N2 is continuously passed for 3h to fill the inert atmosphere inside the furnace, the temperature is increased to 750℃ at a rate of 20℃ / h and kept for 3h, the furnace is cooled to room temperature, and a degummed preform is obtained; the degummed preform is put into an impregnation tank, vacuumized to below 200Pa, heated to 200℃, and kept for 1.5h; SiC powder with a particle size of 500nm and solid pitch are added into the storage tank at a mass ratio of 1:4, the pitch is melted by heating, and the slurry is fully stirred for 2h, the slurry is continuously heated to 200℃ and continuously stirred for 30min; the feeding valve is opened to make the slurry enter the impregnation tank, and vacuum impregnation is performed for 3h; after the impregnation is completed, the excess slurry is recovered, and the preform is naturally cooled and solidified; the solidified preform is taken out, put into a carbonization furnace, N2 is continuously passed for 3h to fill the inert atmosphere inside the furnace, the temperature is increased to 400℃ at a rate of 20℃ / h and kept for 3h, then the temperature is increased to 900℃ at a rate of 20℃ / h and kept for 4h, and the furnace is cooled; after cooling to room temperature, the preform is taken out, the surface carbon layer is removed, and the preform is cleaned; the above impregnation and carbonization process is repeated for 3 times, and the density reaches 1.32g / cm 3 , and a sample piece is obtained; the sample piece is put into a high-temperature heat treatment furnace, vacuumized to below 100Pa, heated to 900℃ at a rate of 25℃ / h and kept for 3h, then heated to 2100℃ at a rate of 35℃ / h, argon is introduced to 101kPa as a protective gas when the temperature is increased to 1100℃ and the pressure is kept, kept for 3h, then cooled to 1500℃ at a rate of 80℃ / h, and then naturally cooled to room temperature, and the sample piece is taken out and cleaned, and a heat-treated sample piece is obtained; the heat-treated sample piece is placed in a graphite tooling, silicon material with a mass of 1 / 3 of the mass of the heat-treated sample piece is covered, and the tooling is put into a high-temperature heat treatment furnace, vacuumized to below 200Pa, heated to 1650℃ at a rate of 300℃ / h and kept for 3h, and then cooled to room temperature with the furnace, and a C / C-SiC composite material with a density of 1.72g / cm 3 is obtained. Example 2

[0035] A rapid preparation method of a C / C-SiC plate, comprising the following steps:

[0036] The no-woven cloth and the ultra-thin net tire are alternately stacked and needled to obtain a C / C-SiC plate with a density of 0.42g / cm 3The carbon fiber plate preform is put into a heat treatment furnace, N2 is continuously passed for 3h to fill the inert atmosphere inside the furnace, the temperature is increased to 800℃ at a rate of 25℃ / h and kept for 4h, the furnace is cooled to room temperature, and a degummed preform is obtained; the degummed preform is put into an impregnation tank, vacuumized to below 200Pa, heated to 200℃, and kept for 30min; SiC powder with a particle size of 200nm and solid pitch are added into the storage tank at a mass ratio of 1:3, the pitch is melted by heating, and the slurry is fully stirred for 3h, the slurry is continuously heated to 220℃ and stirred for 1h; the feeding valve is opened to make the slurry enter the impregnation tank, and vacuum impregnation is performed for 3h; after the impregnation is completed, the excess slurry is recovered, and the preform is naturally cooled and solidified; the solidified preform is taken out, put into a carbonization furnace, N2 is continuously passed for 3h to fill the inert atmosphere inside the furnace, the temperature is increased to 400℃ at a rate of 20℃ / h and kept for 3h, then increased to 900℃ at a rate of 20℃ / h and kept for 4h, and the furnace is cooled; after cooling to room temperature, it is taken out, the surface carbon layer is removed, and it is cleaned; the above impregnation and pyrolysis process is repeated 4 times, and the density reaches 1.44g / cm 3 , and a sample piece is obtained; the sample piece is put into a high-temperature heat treatment furnace, vacuumized to below 100Pa, heated to 900℃ at a rate of 25℃ / h and kept for 3h, then heated to 2200℃ at a rate of 35℃ / h, argon is introduced to 100kPa as a protective gas when the temperature is increased to 1100℃ and the pressure is kept, kept for 3h, then cooled to 1600℃ at a rate of 80℃ / h, and then naturally cooled to room temperature, taken out and cleaned, and a heat-treated sample piece is obtained; the heat-treated sample piece is placed in a graphite tooling, silicon material with a mass of 1 / 5 of the heat-treated sample piece is covered, put into a high-temperature heat treatment furnace, vacuumized to below 200Pa, heated to 1600℃ at a rate of 330℃ / h and kept for 2h, then cooled to room temperature with the furnace, and a C / C-SiC composite material with a density of 1.71g / cm 3 is obtained. Example 3

[0037] A rapid preparation method of a C / C-SiC plate, comprising the following steps:

[0038] The no-woven cloth and the ultra-thin net tire are alternately stacked and needled to obtain a C / C-SiC plate with a density of 0.42g / cm 3The carbon fiber plate preform is put into a heat treatment furnace, N2 is continuously passed for 3h to fill the inert atmosphere inside the furnace, the temperature is increased to 800℃ at a rate of 25℃ / h and kept for 4h, the furnace is cooled to room temperature, and a degummed preform is obtained; the degummed preform is put into an impregnation tank, vacuumized to below 200Pa, heated to 200℃, and kept for 1h; SiC powder with a particle size of 300nm and solid pitch are added into the storage tank at a mass ratio of 1:3, the pitch is melted by heating, and the slurry is fully stirred for 3h, the slurry is continuously heated to 220℃ and stirred for 90min; the feeding valve is opened to make the slurry enter the impregnation tank, and vacuum impregnation is performed for 3h; after the impregnation is completed, the excess slurry is recovered, and the preform is naturally cooled and solidified; the solidified preform is taken out, put into a carbonization furnace, N2 is continuously passed for 3h to fill the inert atmosphere inside the furnace, the temperature is increased to 400℃ at a rate of 20℃ / h and kept for 3h, then increased to 900℃ at a rate of 20℃ / h and kept for 4h, and the furnace is cooled; after cooling to room temperature, it is taken out, the surface carbon layer is removed, and it is cleaned; the above impregnation and pyrolysis process is repeated for 3 times, and the density reaches 1.36g / cm 3 The sample is put into a high-temperature heat treatment furnace, vacuumized to below 100Pa, heated to 900℃ at a rate of 25℃ / h and kept for 3h, then heated to 2200℃ at a rate of 35℃ / h, argon is introduced to 100kPa as a protective gas when the temperature is increased to 1100℃ and the pressure is kept, kept for 3h, then cooled to 1600℃ at a rate of 70℃ / h, and then naturally cooled to room temperature, taken out and cleaned, and a heat-treated sample is obtained; the heat-treated sample is placed in a graphite tooling, 1 / 3 of the mass of the heat-treated sample is covered with silicon material, put into a high-temperature heat treatment furnace, vacuumized to below 200Pa, heated to 1600℃ at a rate of 330℃ / h and kept for 2h, then cooled to room temperature with the furnace, and a C / C-SiC composite material with a density of 1.75g / cm 3

[0039] Comparative Example 1

[0040] A C / C-SiC composite material is prepared by a traditional CVI+PIP process.

[0041] The weftless cloth and the ultra-thin net tire are alternately stacked and needled to obtain a C / C-SiC composite material with a density of 0.45g / cm 3 ​carbon fiber plate needle punching preform, the preform is placed in a gas deposition furnace, N2 is continuously passed for 3h to fill the inert atmosphere inside the cracking furnace, the temperature is raised to 700℃ at a rate of 20℃ / h and kept for 3h; then continue to raise the temperature to 900℃, pass in natural gas and nitrogen at a gas flow of 30L / min, keep the pressure in the furnace at 5kPa, deposit for 20h, after deposition, naturally cool to room temperature and take out; the deposited preform is placed in a tool barrel and put into a vacuum impregnation tank, vacuumized to below 200Pa, 50wt% polysilicon alkane xylene solution is added, impregnated for 3h; the impregnated blank is placed in a 130℃ oven for drying and curing for 6h, then put into a cracking furnace for cracking, the cracking parameters are: continuously pass N2 for 3h to fill the inert atmosphere inside the cracking furnace, raise the temperature to 1100℃ at a rate of 20℃ / h and keep for 3h, cool to room temperature with the furnace; repeat the impregnation and cracking process for 24 times, the density reaches 1.72g / cm 3 .

[0042] Comparative Example 2:

[0043] C / C-SiC composite material is prepared by pitch PIP+RMI process.

[0044] A carbon fiber plate needle punching preform with a density of 0.42g / cm 3 is obtained by using the alternate stacking of the weftless cloth and the ultra-thin net tire, the preform is placed in a heat treatment furnace, N2 is continuously passed for 3h to fill the inert atmosphere inside the cracking furnace, the temperature is raised to 800℃ at a rate of 25℃ / h and kept for 4h, and then cooled to room temperature with the furnace to obtain the degummed preform; the degummed preform is placed in an impregnation tank, vacuumized to below 200Pa, heated to 200℃, and kept for 1h; solid pitch is added to the storage tank, heated to 220℃ to melt the pitch, and continuously stirred for 2h; the pitch is introduced into the impregnation tank by opening the feeding valve, vacuum impregnated for 3h; after impregnation, the excess pitch is recovered, and naturally cooled and cured; the cured preform is taken out, placed in a carbonization furnace, N2 is continuously passed for 3h to fill the inert atmosphere inside the cracking furnace, the temperature is raised to 400℃ at a rate of 20℃ / h and kept for 3h, then the temperature is raised to 900℃ at a rate of 20℃ / h and kept for 4h, and then cooled with the furnace; after cooling to room temperature, it is taken out, the surface carbon layer is removed and cleaned; the above impregnation and cracking process is repeated for 5 times, and the density reaches 1.34g / cm 3A sample was obtained. The sample was placed in a high-temperature heat treatment furnace, evacuated to below 100 Pa, heated to 900℃ at a rate of 25℃ / h and held for 3 hours, then heated to 2200℃ at a rate of 35℃ / h. When the temperature reached 1100℃, argon gas was introduced to 100 kPa as a protective gas and maintained at this pressure for 3 hours. The temperature was then lowered to 1600℃ at a rate of 80℃ / h, and allowed to cool naturally to room temperature before removal and cleaning, yielding a heat-treated sample. The heat-treated sample was placed in a graphite fixture, covered with silicon material at 2 / 5 of its mass, and placed in a high-temperature heat treatment furnace. The furnace was evacuated to below 200 Pa, heated to 1600℃ at a rate of 330℃ / h and held for 2 hours, then cooled to room temperature with the furnace, yielding a sample with a density of 1.76 g / cm³. 3 C / C-SiC composite material.

[0045] The C / C-SiC composite material prepared according to the example process can achieve a density of 1.3~1.45 g / cm³ after 3~4 impregnation and pyrolysis with asphalt slurry. 3 After another silicon infiltration process, the density reaches 1.7 g / cm³. 3 The C / C-SiC composite material prepared according to the process of Comparative Example 1, after 24 PIP cycles, achieved a density of 1.72 g / cm³. 3 This invention can significantly improve the preparation efficiency of C / C-SiC. When preparing C / C-SiC composite materials according to the process of Comparative Example 2, the amount of silicon material used is 1 / 6 to 1 / 2 more than in the example. This invention can effectively reduce the amount of silicon material used in the RMI process, effectively avoid the decrease in frictional properties caused by residual silicon, and also avoid the mechanical property damage caused by carbon fiber silicide corrosion.

[0046] The scope of protection of this invention is not limited to the above embodiments. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this invention should be included within the scope of protection of this invention.

Claims

1. A method for producing a C / C-SiC composite material, characterized by, Includes the following steps: S1: Degumming the carbon fiber preform to obtain the degummed preform; S2: SiC micro powder with a particle size of 200~500nm is mixed with asphalt with a softening point temperature of 80~100℃ at a mass ratio of 1:3~1:4, heated to melt, and stirred thoroughly for 2~3 hours to obtain a slurry; S3: Place the degummed preform obtained in S1 into the slurry obtained in S2 and vacuum impregnate for 2-3 hours. After recovering the excess slurry, cool down to allow the preform to solidify. S4: Carbonize the cured preform. After carbonization, remove the excess carbon layer from the surface and clean it thoroughly. S5: repeat S3-S4 3-4 times until the density reaches 1.3-1.45 g / cm 3 obtained, and the sample is subjected to heat treatment, the process parameters of the heat treatment being: vacuumizing to below 100 Pa, heating to 900-950 DEG C at a heating rate of 25-30 DEG C / h and holding for 2-3 h, then heating to 2100-2200 DEG C at a heating rate of 35-40 DEG C / h and holding for 2-3 h, and then cooling to 1500-1600 DEG C at a rate of 70-80 DEG C / h and naturally cooling, to obtain the heat-treated sample; S6: Cover the heat-treated sample with silicon material of 1 / 5 to 1 / 3 of the mass of the heat-treated sample, heat it to 1600 to 1650°C at a heating rate of 300 to 360°C / h and hold it at that temperature for 2 to 3 hours, then cool it to room temperature in the furnace and perform silicon infiltration to obtain the C / C-SiC composite material.

2. The method for preparing a C / C-SiC composite material according to claim 1, characterized in that, In S1, the degumming process is carried out in a heat treatment furnace. The carbon fiber preform is placed in the heat treatment furnace, and N2 is continuously purged for 3-5 hours to fill the inside of the pyrolysis furnace with an inert atmosphere. The temperature is raised to 750-850°C at a heating rate of 20-25°C / h and held for 2-4 hours. The furnace is then cooled to room temperature.

3. The method for preparing a C / C-SiC composite material according to claim 1, characterized in that, In S3, the vacuum impregnation is carried out in a vertical impregnation tank with a storage tank. There is a material conveying pipe between the storage tank and the impregnation tank for feeding and returning material. The asphalt slurry is stored in the storage tank. The process parameters of the vacuum impregnation are as follows: the impregnation tank is evacuated to 100~200Pa, heated to 200~220℃, and kept at the temperature and pressure for 30~90min. At the same time, the storage tank is heated to 200~220℃ and stirred continuously for 30~90min. Then, the slurry in the storage tank is drawn into the impregnation tank. After vacuum impregnation for 2~4h, the impregnation tank is pressurized to 0.8~1MPa to return the slurry to the storage tank. The impregnation tank is allowed to cool naturally to solidify the preform impregnated with the slurry.

4. The method for preparing a C / C-SiC composite material according to claim 1, characterized in that, In S4, the carbonization is carried out in a pyrolysis furnace. The process parameters for carbonization are as follows: continuously purging N2 for 3-5 hours to fill the inside of the pyrolysis furnace with an inert atmosphere, raising the temperature to 400-450°C at a heating rate of 20-25°C / h and holding for 3 hours, then raising the temperature to 850-900°C at a heating rate of 20-25°C / h and holding for 4 hours, and then cooling the furnace to room temperature.

5. The method for preparing a C / C-SiC composite material according to claim 1, characterized in that, In S5, the heat treatment is completed in a high-temperature heat treatment furnace.

6. The method for preparing a C / C-SiC composite material according to claim 1, characterized in that, When the temperature is raised to 1050~1100℃, argon gas needs to be introduced to 101~102 kPa as a protective gas and this pressure should be maintained until the temperature is lowered to 300~350℃.

7. The method for preparing a C / C-SiC composite material according to claim 1, characterized in that, In S6, the silicon infiltration is carried out in a high-temperature heat treatment furnace.