Preparation method of high-temperature-resistant carbon fiber reinforced quartz ceramic matrix composite material

Abstract

The application discloses a preparation method of a high-temperature-resistant carbon fiber reinforced quartz ceramic matrix composite material. The preparation method comprises the following steps: firstly, carbon fiber fabric is sequentially placed in ethanol and high-purity water for washing, and then air drying is performed to obtain pretreated carbon fiber fabric; secondly, the pretreated carbon fiber fabric is immersed in a mixed solution of silica sol and boron nitride powder for first-round immersion composite; then, the blank after the first-round composite is mixed with silica sol, and repeated immersion is performed for at least 6 times to complete blank composite; finally, vacuum hot-pressing sintering is performed to obtain the carbon fiber reinforced quartz ceramic matrix composite material. When the carbon fiber reinforced quartz ceramic matrix composite material is prepared by the method, the carbon fiber can be protected from oxidation under a high-temperature state, and the interface bonding capacity between the carbon fiber and the quartz ceramic matrix can be ensured.

Description

Technical Field

[0001] This invention relates to the field of fiber-reinforced ceramic matrix composites, and more specifically to a method for preparing a high-temperature resistant carbon fiber reinforced quartz ceramic matrix composite. Background Technology

[0002] Traditional methods for preparing carbon fiber reinforced quartz ceramic composites (C f / SiO2) is prepared by winding short carbon fibers with ceramic powder or unidirectional continuous carbon fibers to form a ceramic preform, which is then densified by hot pressing sintering. C prepared using traditional methods... f / SiO2 composites still suffer from brittleness and struggle to meet the reliability requirements of complex-shaped components. Significant breakthroughs have been achieved in the preparation of this material in recent years, primarily focusing on the construction of three-dimensional preforms and optimization of sintering processes. To address these issues, three-dimensional fabric reinforcement technology has become a research hotspot. By introducing continuous three-dimensional carbon fiber preforms (fiber volume fraction 25%-55%), such as 2.5D needle-punched structures and fine-woven puncture structures, the isotropy and anti-delamination ability of the composite material have been significantly improved. In terms of pretreatment processes, researchers have employed silica sol pre-impregnation (concentration 5%-10%) combined with nitrogen-protected heat treatment (800-900℃) to effectively remove organic wetting agents from the carbon fiber surface and form a transitional interface layer, preventing oxidative damage to the carbon fibers during subsequent high-temperature processes.

[0003] Controlling the interfacial behavior between carbon fibers and the quartz ceramic matrix is ​​a core scientific issue and technological challenge for this material system. Under high-temperature service conditions (>800℃), a harmful interfacial reaction occurs between carbon fibers and the SiO2 matrix, generating a brittle silicon carbide transition layer. This reaction process can be described as: SiO2(s) + 3C(s) → SiC(s) + 2CO(g). While this in-situ generated SiC can improve interfacial bonding to some extent, excessive reaction leads to interfacial embrittlement and fiber strength degradation. Studies have shown that when the thickness of the interfacial reaction layer exceeds 200 nm, the fracture toughness of the composite material decreases by 30%-40%. Summary of the Invention

[0004] To address the problems existing in the background technology, the present invention provides a method for preparing high-temperature resistant carbon fiber reinforced quartz ceramic matrix composite material. When preparing carbon fiber reinforced quartz ceramic matrix composite material by this method, the carbon fiber can be protected from oxidation at high temperature and the interfacial bonding ability between the carbon fiber and the quartz ceramic matrix can be guaranteed.

[0005] To achieve the above-mentioned objectives, the present invention provides the following technical solution: A method for preparing a high-temperature resistant carbon fiber reinforced quartz ceramic matrix composite material includes the following steps: (1) Pretreatment of carbon fiber fabric: The carbon fiber fabric is placed in ethanol for alcohol washing to remove the organic wetting agent on the surface of the carbon fiber. After the alcohol washing is completed, the remaining ethanol solution is poured out. Then the product after alcohol washing is placed in high-purity water for water washing. After the water washing is completed, the carbon fiber fabric is taken out and placed in an oven for forced air drying to obtain the pretreated carbon fiber fabric. The carbon fiber fabric is selected from any one of 2.5D woven carbon fiber fabric, needle-punched woven carbon fiber fabric, and fine-knitted pierced woven carbon fiber fabric, wherein the fiber volume fraction is 25%~55%; The alcohol washing operation specifically includes: placing a mold containing an appropriate amount of ethanol in a pneumatic cleaning vessel at a temperature of 60~80℃ and a pressure of 0.5~1.5MPa; placing the carbon fiber fabric in ethanol and maintaining pressure and temperature for 2~6 hours; ensuring that the amount of ethanol covers the carbon fiber fabric by at least 2mm; furthermore, after the alcohol washing is completed, after the temperature drops to room temperature and the pressure returns to normal pressure, rinsing is performed at least twice with an ethanol solution. The alcohol washing operation shall be repeated at least 3 times; The water washing operation specifically includes: injecting high-purity water into the mold cavity, placing the alcohol-washed carbon fiber fabric in the high-purity water, and placing the mold in a pneumatic cleaning kettle at a temperature of 60~80℃ and a pressure of 0.5~1.5MPa for 2~6 hours to maintain pressure and temperature, ensuring that the high-purity water covers the carbon fiber fabric by at least 2mm; furthermore, after the water washing is completed, after the temperature drops to room temperature and the pressure returns to normal pressure, the high-purity water is used for at least two more rinses. The water washing operation shall be repeated at least twice; The blower drying temperature is 110~130℃, and the drying time is 2~6h; (2) First impregnation and composite of carbon fiber fabric: The adhesive solution after mixing silica sol and boron nitride (BN) powder is poured into a mold containing carbon fiber fabric pretreated in step (1) and the carbon fiber fabric is submerged for vacuum impregnation; then the mold is transferred to an aging kettle for pressure impregnation, and after pressure impregnation, the carbon fiber fabric is taken out of the adhesive solution for curing to obtain the blank of the first composite. The silica sol has a mass concentration of 20-30%, and the mass ratio of silica sol to boron nitride (BN) powder is 5-7:1. The boron nitride (BN) powder has a content of 90%~99% and a particle size of 1~5μm; The vacuum impregnation conditions are: maintaining pressure at room temperature and pressure ≤ 0.1 MPa for 3~7 hours; The pressure impregnation conditions are: maintaining pressure at 0~4MPa at room temperature for (12±0.2)h; The curing conditions are: 190~210℃ for 4~5 hours; (3) Repeated impregnation and lamination: The blank obtained in the first round of lamination in step (2) is mixed with silica sol, and the vacuum impregnation, pressure impregnation and curing operations in step (2) are repeated at least 6 times to complete the blank lamination; In step (3), ensure that the liquid level exceeds the upper surface of the fabric composite blank plate after the previous impregnation and curing during each repeated impregnation. The amount used should take into account the thickness of the plate. The mass concentration of the silica sol is 20-30%. (4) Preparation of composite material: After the composite blank is repeatedly impregnated in step (3), it is mechanically processed into a sample block and then vacuum hot-pressed and sintered at a temperature of 1445~1455℃ and a pressure of 15~25MPa for 1~3 hours to complete the preparation of carbon fiber reinforced quartz ceramic matrix composite material.

[0006] Compared with the prior art, the present invention has the following beneficial effects: To prevent carbon fiber oxidation at high temperatures and to improve the interfacial bonding between carbon fiber and the quartz ceramic matrix, it is proposed to add BN powder during the first impregnation process. Previous studies have shown that BN-SiO2 is a good composite system; the addition of BN can improve the anti-crystallization properties and mechanical properties of quartz ceramics. Furthermore, the density of BN-SiO2 can reach 1.95 g / cm³. 3 It can protect carbon fibers from oxidation at high temperatures, thereby improving the mechanical properties of the material. Detailed Implementation

[0007] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0008] A method for preparing a high-temperature resistant carbon fiber reinforced quartz ceramic matrix composite material includes the following steps: (1) Pretreatment of carbon fiber fabric: The carbon fiber fabric is placed in ethanol for alcohol washing to remove the organic wetting agent on the surface of the carbon fiber. After the alcohol washing is completed, the remaining ethanol solution is poured out. Then the product after alcohol washing is placed in high-purity water for water washing. After the water washing is completed, the carbon fiber fabric is taken out and placed in an oven for forced air drying to obtain the pretreated carbon fiber fabric. The carbon fiber fabric is selected from any one of 2.5D woven carbon fiber fabric, needle-punched woven carbon fiber fabric, and fine-knitted pierced woven carbon fiber fabric, wherein the fiber volume fraction is 25%~55%; The alcohol washing operation specifically includes: placing a mold containing an appropriate amount of ethanol in a pneumatic cleaning vessel at a temperature of 60~80℃ and a pressure of 0.5~1.5MPa; placing the carbon fiber fabric in ethanol and maintaining pressure and temperature for 2~6 hours; ensuring that the amount of ethanol covers the carbon fiber fabric by at least 2mm; furthermore, after the alcohol washing is completed, after the temperature drops to room temperature and the pressure returns to normal pressure, rinsing is performed at least twice with an ethanol solution. The alcohol washing operation shall be repeated at least 3 times; The water washing operation specifically includes: injecting high-purity water into the mold cavity, placing the alcohol-washed carbon fiber fabric in the high-purity water, and placing the mold in a pneumatic cleaning kettle at a temperature of 60~80℃ and a pressure of 0.5~1.5MPa for 2~6 hours to maintain pressure and temperature, ensuring that the high-purity water covers the carbon fiber fabric by at least 2mm; furthermore, after the water washing is completed, after the temperature drops to room temperature and the pressure returns to normal pressure, the high-purity water is used for at least two more rinses. The water washing operation shall be repeated at least twice; The blower drying temperature is 110~130℃, and the drying time is 2~6h; (2) First impregnation and composite of carbon fiber fabric: The adhesive solution after mixing silica sol and boron nitride (BN) powder is poured into a mold containing carbon fiber fabric pretreated in step (1) and the carbon fiber fabric is submerged for vacuum impregnation; then the mold is transferred to an aging kettle for pressure impregnation, and after pressure impregnation, the carbon fiber fabric is taken out of the adhesive solution for curing to obtain the blank of the first composite. The silica sol has a mass concentration of 20-30%, and the mass ratio of silica sol to boron nitride (BN) powder is 5-7:1. The boron nitride (BN) powder has a content of 90%~99% and a particle size of 1~5μm; The vacuum impregnation conditions are: maintaining pressure at room temperature and pressure ≤ 0.1 MPa for 3~7 hours; The pressure impregnation conditions are: maintaining pressure at 0~4MPa at room temperature for (12±0.2)h; The curing conditions are: 190~210℃ for 4~5 hours; (3) Repeated impregnation and lamination: The blank obtained in the first round of lamination in step (2) is mixed with silica sol, and the vacuum impregnation, pressure impregnation and curing operations in step (2) are repeated at least 6 times to complete the blank lamination; In step (3), ensure that the liquid level exceeds the upper surface of the fabric composite blank plate after the previous impregnation and curing during each repeated impregnation. The amount used should take into account the thickness of the plate. The mass concentration of the silica sol is 20-30%. (4) Preparation of composite material: After the composite blank is repeatedly impregnated in step (3), it is mechanically processed into a sample block and then vacuum hot-pressed and sintered at a temperature of 1445~1455℃ and a pressure of 15~25MPa for 1~3 hours to complete the preparation of carbon fiber reinforced quartz ceramic matrix composite material.

[0009] Example 1 High-temperature resistant C2000 fabrics were prepared using 2.5D woven carbon fiber fabrics. f / SiO2 composite material, with a fiber volume fraction of 40%; (1) Pretreatment of 2.5D braided carbon fiber fabric The 2.5D woven carbon fiber fabric plate was placed in a pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for alcohol washing three times. Then, the fabric plate was removed and placed in high-purity water in the pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for water washing twice. Then, the carbon fiber fabric was removed and placed in an oven and dried at 130℃ for 3 hours. (2) First round of compound 1800g of silica sol with a mass concentration of 30% was mixed with 300g of BN powder with a content of 99% and a particle size of 1μm. The pretreated carbon fiber sheet was then placed in the mixed solution and vacuum impregnated at -0.05MPa for 5h. It was then transferred to an aging kettle and pressure impregnated at 1MPa for 12h. After pressure impregnation, the fabric was removed from the sol and cured at 200℃ for 4.5h. (3) Six-wheel compound The carbon fiber sheet after the first round of lamination was placed in 1800g of silica sol with a mass concentration of 30%, and then vacuum impregnated at -0.05MPa for 5h; then it was transferred to an aging kettle and pressure impregnated at 1MPa for 12h; after pressure impregnation, the fabric was taken out of the sol and cured at 200℃ for 4.5h, for a total of six rounds of lamination; (4) Machining After the composite process, the flat blank is machined into a 60×40×5mm sample block. (5) Vacuum hot pressing sintering The processed 60×40×5mm sample block was vacuum hot-pressed and sintered at a temperature of 1450℃ and a pressure of 20MPa to complete the material preparation.

[0010] Example 2 High-temperature resistant C2C fabrics were prepared by needle punching and stitching weaving. f / SiO2 composite material, with a fiber volume fraction of 25%; (1) Pretreatment of needle-punched and stitched carbon fiber fabric The needle-punched and woven carbon fiber fabric plate was placed in a pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for alcohol washing three times. Then, the fabric plate was removed and placed in high-purity water in a pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for water washing twice. Then, the carbon fiber fabric was removed and placed in an oven and dried at 130℃ for 3 hours. (2) First round of compound 1800g of silica sol with a mass concentration of 30% was mixed with 300g of BN powder with a content of 99% and a particle size of 1μm. The pretreated carbon fiber sheet was then placed in the mixed solution and vacuum impregnated at -0.05MPa for 5h. It was then transferred to an aging kettle and pressure impregnated at 1MPa for 12h. After pressure impregnation, the fabric was removed from the sol and cured at 200℃ for 12h. (3) Six-wheel compound The carbon fiber sheet after the first round of lamination was placed in 1800g of silica sol with a mass concentration of 30%, and then vacuum impregnated at -0.05MPa for 5h; then it was transferred to an aging kettle and pressure impregnated at 1MPa for 12h; after pressure impregnation, the fabric was taken out of the sol and cured at 200℃ for 4.5h, for a total of six rounds of lamination; (4) Machining After the composite process, the flat blank is machined into a 60×40×5mm sample block. (5) Vacuum hot pressing sintering The processed 60×40×5mm sample block was vacuum hot-pressed and sintered at a temperature of 1450℃ and a pressure of 20MPa to complete the material preparation.

[0011] Example 3 High-temperature resistant C2C fabrics were prepared using fine-knitted puncture-woven carbon fiber fabrics. f / SiO2 composite material, with a fiber volume fraction of 55%; (1) Pretreatment of fine-knitted puncture-woven carbon fiber fabric The finely woven carbon fiber fabric plate was placed in a pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for alcohol washing three times. Then, the fabric plate was removed and placed in high-purity water in a pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for water washing twice. Then, the carbon fiber fabric was removed and placed in an oven and dried at 130℃ for 3 hours. (2) First round of compound 1800g of silica sol with a mass concentration of 30% was mixed with 300g of BN powder with a content of 99% and a particle size of 1μm. The pretreated carbon fiber sheet was then placed in the mixed solution and vacuum impregnated at -0.05MPa for 5h. It was then transferred to an aging kettle and pressure impregnated at 1MPa for 12h. After pressure impregnation, the fabric was removed from the sol and cured at 200℃ for 4.5h. (3) Six-wheel compound The carbon fiber sheet after the first round of lamination was placed in 1800g of silica sol with a mass concentration of 30%, and then vacuum impregnated at -0.05MPa for 5h; then it was transferred to an aging kettle and pressure impregnated at 1MPa for 12h; after pressure impregnation, the fabric was taken out of the sol and cured at 200℃ for 4.5h, for a total of six rounds of lamination; (4) Machining After the composite process, the flat blank is machined into a 60×40×5mm sample block. (5) Vacuum hot pressing sintering The processed 60×40×5mm sample block was vacuum hot-pressed and sintered at a temperature of 1450℃ and a pressure of 20MPa to complete the material preparation.

[0012] Example 4 High-temperature resistant C2000 fabrics were prepared using 2.5D woven carbon fiber fabrics. f / SiO2 composite material, with a fiber volume fraction of 40%; (1) Pretreatment of 2.5D braided carbon fiber fabric A 2.5D woven carbon fiber fabric plate was placed in a pneumatic cleaning autoclave and kept at 60℃ and 1.5MPa for 6 hours for 4 alcohol washes. After cooling to room temperature and restoring the pressure to normal, it was rinsed twice with ethanol solution. Then, the fabric plate was removed and placed in a pneumatic cleaning autoclave with high-purity water and kept at 60℃ and 1.5MPa for 6 hours for 3 water washes. After cooling to room temperature and restoring the pressure to normal, it was rinsed twice with high-purity water. Finally, the carbon fiber fabric was removed and placed in an oven and dried at 110℃ for 6 hours. (2) First round of compound 2100g of silica sol with a mass concentration of 20% was mixed with 300g of BN powder with a content of 99% and a particle size of 2μm. The pretreated carbon fiber sheet was then placed in the mixed solution and vacuum impregnated at -0.05MPa for 3h. It was then transferred to an aging kettle and pressure impregnated at 4MPa for 12h. After pressure impregnation, the fabric was removed from the sol and cured at 190℃ for 5h. (3) Six-wheel compound The carbon fiber sheet after the first round of lamination was placed in 2100g of silica sol with a mass concentration of 20%, and then vacuum impregnated at -0.05MPa for 3h; then it was transferred to an aging kettle and pressure impregnated at 4MPa for 12h; after pressure impregnation, the fabric was taken out of the sol and cured at 190℃ for 5h, and a total of six rounds of lamination were performed. (4) Machining After the composite process, the flat blank is machined into a 60×40×5mm sample block. (5) Vacuum hot pressing sintering The processed 60×40×5mm sample block was vacuum hot-pressed and sintered at a temperature of 1455℃ and a pressure of 15MPa to complete the material preparation.

[0013] Example 5 High-temperature resistant C2000 fabrics were prepared using 2.5D woven carbon fiber fabrics. f / SiO2 composite material, with a fiber volume fraction of 40%; (1) Pretreatment of 2.5D braided carbon fiber fabric A 2.5D woven carbon fiber fabric plate was placed in a pneumatic cleaning autoclave at 70°C and 1 MPa for 2 hours, and then washed with alcohol four times. After cooling to room temperature and restoring the pressure to normal, it was rinsed three times with an ethanol solution. Then, the fabric plate was removed and placed in a pneumatic cleaning autoclave at 70°C and 1 MPa for 2 hours, and then washed with water four times. After cooling to room temperature and restoring the pressure to normal, it was rinsed three times with high-purity water. Finally, the carbon fiber fabric was removed and placed in an oven to be dried at 130°C for 2 hours. (2) First round of compound 1500g of silica sol with a mass concentration of 25% was mixed with 300g of BN powder with a content of 99% and a particle size of 5μm. The pretreated carbon fiber sheet was then placed in the mixed solution and vacuum impregnated at -0.05MPa for 7h. It was then transferred to an aging kettle and pressure impregnated at 1MPa for 12h. After pressure impregnation, the fabric was removed from the sol and cured at 210℃ for 4h. (3) Six-wheel compound The carbon fiber sheet after the first round of lamination was placed in 1500g of silica sol with a mass concentration of 25%, and then vacuum impregnated at -0.05MPa for 7h; then it was transferred to an aging kettle and pressure impregnated at 1MPa for 12h; after pressure impregnation, the fabric was taken out of the sol and cured at 210℃ for 4h, and a total of seven rounds of lamination were performed. (4) Machining After the composite process, the flat blank is machined into a 60×40×5mm sample block. (5) Vacuum hot pressing sintering The processed 60×40×5mm sample block was vacuum hot-pressed and sintered at a temperature of 1445℃ and a pressure of 25MPa to complete the material preparation.

[0014] Comparative Example 1 (without BN powder) High-temperature resistant C2000 fabrics were prepared using 2.5D woven carbon fiber fabrics. f / SiO2 composite material, fiber volume fraction 40%, fabric flat sheet size: 249×142×6.44mm; (1) Pretreatment of 2.5D braided carbon fiber fabric The 2.5D woven carbon fiber fabric plate was placed in a pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for alcohol washing three times. Then, the fabric plate was removed and placed in high-purity water in the pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for water washing twice. Then, the carbon fiber fabric was removed and placed in an oven and dried at 130℃ for 3 hours. (2) Composite The pretreated carbon fiber needle-punched fabric was placed in 1800g of silica sol with a mass concentration of 30%, and then vacuum impregnated at -0.05MPa for 5h; then it was transferred to an aging kettle and pressure impregnated at 1MPa for 12h. After pressure impregnation, the fabric was taken out of the sol and cured at 200℃ for 4.5h. A total of six composite cycles were performed. (3) Machining After the composite process, the flat blank is machined into a 60×40×5mm sample block. (4) Vacuum hot pressing sintering The processed 60×40×5mm sample block was vacuum hot-pressed and sintered at temperatures of 1250℃, 1350℃ and 1450℃ and a pressure of 20MPa to complete the material preparation.

[0015] Comparative Example 2 (Number of rounds less than six) High-temperature resistant C2000 fabrics were prepared using 2.5D woven carbon fiber fabrics. f / SiO2 composite material, with a fiber volume fraction of 30%; (1) Pretreatment of 2.5D braided carbon fiber fabric The 2.5D woven carbon fiber fabric plate was placed in a pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for alcohol washing three times. Then, the fabric plate was removed and placed in high-purity water in the pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for water washing twice. Then, the carbon fiber fabric was removed and placed in an oven and dried at 130℃ for 3 hours. (2) First round of compound 1800g of silica sol with a mass concentration of 30% was mixed with 300g of BN powder with a content of 99% and a particle size of 1μm. The pretreated carbon fiber sheet was then placed in the mixed solution and vacuum impregnated at -0.05MPa for 5h. It was then transferred to an aging kettle and pressure impregnated at 1MPa for 12h. After pressure impregnation, the fabric was removed from the sol and cured at 200℃ for 4.5h. (3) Three-wheel compound The carbon fiber sheet after the first round of lamination was placed in 1800g of silica sol with a mass concentration of 30%, and then vacuum impregnated at -0.05MPa for 5h; then it was transferred to an aging kettle and pressure impregnated at 1MPa for 12h; after pressure impregnation, the fabric was taken out of the sol and cured at 200℃ for 4.5h, and a total of three rounds of lamination were performed. (4) Machining After the composite process, the flat blank is machined into a 60×40×5mm sample block. (5) Vacuum hot pressing sintering The processed 60×40×5mm sample block was vacuum hot-pressed and sintered at a temperature of 1450℃ and a pressure of 20MPa to complete the material preparation.

[0016] Comparative Example 3 (without pressure impregnation) High-temperature resistant C2000 fabrics were prepared using 2.5D woven carbon fiber fabrics. f / SiO2 composite material, with a fiber volume fraction of 30%; (1) Pretreatment of 2.5D braided carbon fiber fabric The 2.5D woven carbon fiber fabric plate was placed in a pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for alcohol washing three times. Then, the fabric plate was removed and placed in high-purity water in the pneumatic cleaning autoclave and kept at 80℃ and 1.1MPa for 4 hours for water washing twice. Then, the carbon fiber fabric was removed and placed in an oven and dried at 130℃ for 3 hours. (2) First round of compound 1800g of silica sol with a mass concentration of 30% was mixed with 300g of BN powder with a content of 99% and a particle size of 1μm. The pretreated carbon fiber sheet was then placed in the mixed solution and vacuum impregnated at -0.05MPa for 5h. After impregnation, the fabric was removed from the sol and cured at 200℃ for 4.5h. (3) Six-wheel compound The carbon fiber sheet after the first round of lamination was placed in 1800g of silica sol with a mass concentration of 30%, and then vacuum impregnated at -0.05MPa for 5h. After impregnation, the fabric was removed from the sol and cured at 200℃ for 4.5h. A total of six rounds of lamination were carried out. (4) Machining After the composite process, the flat blank is machined into a 60×40×5mm sample block. (5) Vacuum hot pressing sintering The processed 60×40×5mm sample block was vacuum hot-pressed and sintered at a temperature of 1450℃ and a pressure of 20MPa to complete the material preparation.

[0017] Comparative Example 4 (without preprocessing) The difference from Example 1 is that there is no preprocessing operation (1).

[0018] The materials prepared in the above embodiments and comparative examples were subjected to performance tests, and the performance test results are shown in Table 1.

[0019] Table 1. Properties of carbon fiber reinforced quartz ceramic matrix composites prepared in each example and comparative example. From the data in Table 1, we can conclude that: Compared with Example 1, the density of the composite material prepared in Comparative Example 1 was reduced less when BN was not present, but the mechanical properties were significantly reduced. The addition of BN can improve the anti-crystallization properties and mechanical properties of quartz ceramics.

[0020] Compared with Example 1, the number of compounding cycles in Comparative Example 2 was less than six, and no pressure impregnation was performed in Comparative Example 3, resulting in a significant reduction in the density and mechanical properties of the prepared composite material.

[0021] Compared to Example 1, in Comparative Example 4, the carbon fiber fabric was not pretreated, resulting in a smaller change in density, but a significant reduction in mechanical properties.

Claims

1. A method for preparing a high-temperature resistant carbon fiber reinforced quartz ceramic matrix composite material, characterized in that, Includes the following steps: (1) Pretreatment of carbon fiber fabric: The carbon fiber fabric is placed in ethanol for alcohol washing. After the alcohol washing is completed, the remaining ethanol solution is poured out. Then the product after alcohol washing is placed in high-purity water for water washing. After the water washing is completed, the carbon fiber fabric is taken out and placed in an oven for forced air drying to obtain the pretreated carbon fiber fabric. The carbon fiber fabric is selected from any one of 2.5D woven carbon fiber fabric, needle-punched woven carbon fiber fabric, and fine-knitted pierced woven carbon fiber fabric, wherein the fiber volume fraction is 25%~55%; The alcohol washing operation shall be repeated at least 3 times; The water washing operation shall be repeated at least twice; (2) First impregnation and composite of carbon fiber fabric: The adhesive solution after mixing silica sol and boron nitride powder is poured into a mold containing carbon fiber fabric pretreated in step (1) and the carbon fiber fabric is submerged for vacuum impregnation. The mold is then transferred into an aging kettle for pressure impregnation. After pressure impregnation, the carbon fiber fabric is removed from the adhesive and cured to obtain the blank for the first round of composite. (3) Repeated impregnation and lamination: The blank obtained in the first round of lamination in step (2) is mixed with silica sol, and the vacuum impregnation, pressure impregnation and curing operations in step (2) are repeated at least 6 times to complete the blank lamination; In step (3), ensure that the liquid level exceeds the upper surface of the fabric composite blank plate after the previous impregnation and curing each time it is repeatedly impregnated; (4) Preparation of composite material: After the composite blank is repeatedly impregnated in step (3), it is machined into a sample block and then vacuum hot-pressed and sintered to complete the preparation of carbon fiber reinforced quartz ceramic matrix composite material.

2. The preparation method according to claim 1, characterized in that, The alcohol washing operation described in step (1) specifically includes: placing the mold containing an appropriate amount of ethanol in a pneumatic cleaning kettle with a temperature of 60~80℃ and a pressure of 0.5~1.5MPa, and keeping the carbon fiber fabric in ethanol for 2~6 hours under pressure and temperature, ensuring that the amount of ethanol covers the carbon fiber fabric by at least 2mm. The water washing operation specifically includes: injecting high-purity water into the mold cavity, placing the alcohol-washed carbon fiber fabric in the high-purity water, and placing the mold in a pneumatic cleaning kettle at a temperature of 60~80℃ and a pressure of 0.5~1.5MPa for 2~6 hours to maintain pressure and temperature, ensuring that the high-purity water covers the carbon fiber fabric by at least 2mm.

3. The preparation method according to claim 2, characterized in that, After the alcohol washing in step (1) is completed, wait for the temperature to drop to room temperature and the pressure to return to normal pressure, and then rinse with ethanol solution at least twice more. After the water washing is completed, wait for the temperature to drop to room temperature and the pressure to return to normal pressure, then rinse with high-purity water at least twice.

4. The preparation method according to claim 1, characterized in that, The blowing drying temperature in step (1) is 110~130℃ and the drying time is 2~6h.

5. The preparation method according to claim 1, characterized in that, The silica sol concentration in steps (2) and (3) is 20-30% by mass. The mass ratio of silica sol to boron nitride powder in step (2) is 5~7:1; The boron nitride powder has a content of 90%~99% and a particle size of 1~5μm.

6. The preparation method according to claim 1, characterized in that, The vacuum impregnation conditions in step (2) are: maintaining pressure at room temperature and pressure ≤ 0.1 MPa for 3~7 hours; The pressure impregnation conditions are: maintaining pressure at 0~4MPa at room temperature for (12±0.2)h; The curing conditions are: 190~210℃ for 4~5 hours.

7. The preparation method according to claim 1, characterized in that, The vacuum hot pressing sintering parameters in step (4) are: temperature 1445~1455℃, pressure 15~25MPa, and vacuum hot pressing sintering time 1~3 hours.

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