Ablation-resistant organic modified C / C-SiC composite material and preparation method thereof

Abstract

The invention belongs to the technical field of preparation of carbon fiber reinforced carbon-based composite materials, and discloses an ablation-resistant organic modified C / C-SiC composite material and a preparation method thereof. The preparation method comprises the following steps: preparing turbid liquid by using SiC particles and absolute ethyl alcohol as raw materials, and preparing slurry by using phenolic resin and absolute ethyl alcohol as raw materials; introducing SiC in the turbid liquid into the C / C composite material through a vacuum filtration process to obtain a first sample; and impregnating the first sample with the phenolic resin slurry through a vacuum impregnation process, curing, and repeating the steps to obtain the organic modified C / C-SiC composite material. The ceramic particles and the resin matrix are uniformly introduced into the matrix, so that the overall consistency of the composite material is ensured, the ablation resistance and the heat insulation performance of the material are improved, and the oxidative damage of the matrix is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of preparation of carbon fiber reinforced carbon-based composite materials, and in particular relates to an ablation-resistant organically modified C / C-SiC composite material and a preparation method thereof. Background Art

[0002] Carbon / carbon (C / C) composite materials have the advantages of low density, low thermal expansion coefficient, high specific strength, and excellent high-temperature mechanical properties. They have become the commonly used nozzle throat lining materials. However, their high cost, long preparation cycle, complex process, and easy oxidation in an aerobic environment at around 400°C have restricted their further development in the high-temperature field. Phenolic resin has the advantages of excellent machinability, high residual carbon rate, and low cost. It can absorb a large amount of heat during the pyrolysis process, which makes it widely used in thermal protection systems. In the patent "Yan Kefei, Li Ting, Zhang Chuan et al. A method for preparing a low-cost and low-ablation dual-base composite material, CN116023162A. 2023.", phenolic resin is introduced into the material with an initial density of 1.30-1.55g / cm through an impregnation-curing process. 3 A carbon and phenolic resin dual-matrix composite material was obtained by adding a carbon / C composite matrix. The ablation rate during ground thermal testing was 0.32 mm / s. However, the phenolic resin shrinks in volume after thermal decomposition, which can easily produce microcracks and other defects during the ablation process. These cracks provide pathways for oxygen penetration, accelerating oxidation within the material and affecting its anti-ablation performance.

[0003] SiC ceramics have the advantages of low density, high strength, high modulus, low thermal expansion coefficient, and excellent high-temperature stability. Reference 1: "WANG S, HUANG H, TIAN Y, et al. Effects of SiC content on mechanical, thermal and ablative properties of carbon / phenolic composites[J]. Ceramics International, 2020, 46(10): 16151-16156." Wang et al. prepared modified carbon / phenolic composites with different SiC contents (mass fraction of 0% to 11%) by vacuum impregnation. The introduction of SiC particles improved the thermal stability, thermal conductivity, and ablation resistance of the composites. Reference 2: "Yin Huan, Peng Ke, Rao Fei, et al. Preparation and Properties of C / C-SiC Composites by High-Solid Content Slurry Infiltration [J]. Powder Metallurgy Materials Science and Engineering, 2018, 23(5):539-546." Yin et al. used a combination of solid-phase composite technology and PIP process to prepare C / C-SiC composites with excellent mechanical properties. Under oxyacetylene ablation conditions at 2000°C, the SiO2 generated by SiC oxidation can fill defects such as pores and cracks, preventing further oxidation of the material, making the C / C-SiC composite exhibit good ablation resistance.

[0004] However, the PIP process is costly and requires a long material densification cycle. The vacuum impregnation process easily causes the solvent and powder to separate, and the powder often accumulates on the surface of the material, making it difficult to evenly distribute it into the matrix, resulting in uneven composite structure and inconsistent performance. Therefore, there is an urgent need to develop a combined process to uniformly introduce ceramic particles and resin matrix into the matrix to achieve the preparation of organically modified C / C-SiC composites. Summary of the Invention

[0005] In view of the problems existing in the prior art, the purpose of the present invention is to provide an ablation-resistant organically modified C / C-SiC composite material and a preparation method thereof. The present invention uniformly introduces ceramic particles and a resin matrix into the interior of the matrix to ensure the overall consistency of the composite material.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: A method for preparing an ablation-resistant organically modified C / C-SiC composite material comprises the following steps: Immersing the C / C composite material in a suspension of SiC ceramic powder and a volatile solvent, and performing vacuum filtration to introduce SiC ceramic particles into the C / C composite material to obtain a first sample; The first sample is vacuum impregnated in a first slurry and then cured to obtain a second sample; the first slurry is prepared by mixing phenolic resin and solvent in a mass ratio of (70-75):100; The second sample is vacuum impregnated in the second slurry and then cured to obtain a third sample; the second slurry is prepared by mixing phenolic resin and solvent in a mass ratio of (50-55):100; The third sample is vacuum impregnated in a third slurry and then cured to obtain the ablation-resistant organically modified C / C-SiC composite material; the third slurry is a slurry prepared by mixing phenolic resin and solvent in a mass ratio of (40-45):100.

[0007] Preferably, the particle size of the SiC ceramic powder is 1-3 μm.

[0008] Preferably, in the suspension, the mass ratio of SiC ceramic powder to volatile solvent is 1:(3-4).

[0009] Preferably, the C / C composite material has a density of 1.1-1.25 g / cm 3 2.5DC / C composite material; The C / C composite material is firstly subjected to ultrasonic cleaning and drying, and then immersed in a suspension made of SiC ceramic powder and a volatile solvent.

[0010] Preferably, when preparing the first sample, after the vacuum filtration is completed, the C / C composite material introduced with SiC ceramic particles is dried and weighed, and the weight gain of the C / C composite material introduced with SiC ceramic particles is calculated. When the weight gain does not exceed 1%, the C / C composite material introduced with SiC ceramic particles at this time is used as the first sample. Otherwise, the vacuum filtration, drying and weighing processes are repeated until the weight gain does not exceed 1%.

[0011] Preferably, when preparing the first slurry, the second slurry and the third slurry, the phenolic resin is mixed with the solvent, heated in a water bath at 60-65° C., and stirred for 1-2 h to obtain the first slurry, the second slurry and the third slurry; Wherein, the solvent is anhydrous ethanol, and the volatile solvent is anhydrous ethanol.

[0012] Preferably, the first sample is vacuum impregnated in the first slurry and then cured to obtain the second sample, comprising the following process: placing the first sample in the first slurry, vacuum impregnating for 1-1.5 hours, and then curing at normal pressure at 175-185°C, then polishing the first sample to remove phenolic resin bubbles formed on the surface of the first sample, repeating the above process 1-2 times to obtain the second sample.

[0013] Preferably, the second sample is vacuum impregnated in the second slurry and then cured to obtain a third sample, comprising the following process: placing the second sample in the second slurry, vacuum impregnating for 1-1.5 hours, and then curing at normal pressure at 175-185°C, then polishing the second sample to remove phenolic resin bubbles formed on the surface of the first sample, repeating the above process 1-2 times to obtain the third sample.

[0014] Preferably, the third sample is vacuum impregnated in a third slurry and then cured to obtain the ablation-resistant organic-modified C / C-SiC composite material, comprising the following process: placing the third sample in a third slurry, vacuum impregnating for 1.5-2.0 h, and then curing at normal pressure at 175-185°C to obtain the ablation-resistant organic-modified C / C-SiC composite material.

[0015] The present invention also provides an ablation-resistant organically modified C / C-SiC composite material, which is prepared by the preparation method of the present invention as described above.

[0016] Compared with the prior art, the present invention has the following beneficial effects: In the preparation method of the ablation-resistant organically modified C / C-SiC composite material of the present invention, C / C composite material, phenolic resin, SiC ceramic particles, and a volatile solvent are used as raw materials. SiC is introduced into the interior of the C / C composite material through a vacuum filtration process, and then the C / C-SiC composite material is organically modified by using phenolic resin alcohol solutions of different concentrations through a vacuum impregnation process to densify the composite material and obtain the ablation-resistant organically modified C / C-SiC composite material. Among them, the organic phenolic resin has good fluidity and processability before curing. It can penetrate into the carbon fiber to form a uniform matrix, thereby ensuring the overall consistency of the composite material. At the same time, it has the advantages of simple process and low cost, and has great industrial development potential. It can be seen that through the above-mentioned method of the present invention, the ceramic particles and the resin matrix can be uniformly introduced into the interior of the matrix, thereby ensuring the overall consistency of the composite material.

[0017] The ablation-resistant organically modified C / C-SiC composite material prepared by the present invention comprises a matrix composed of an organic phenolic resin and pyrolytic carbon. A resin coating is formed simultaneously during the preparation process, achieving efficient formation of an integrated matrix-coating structure. During ablation, the resin coating on the surface of the material preferentially undergoes pyrolysis, absorbing significant amounts of heat. The resulting carbonized layer not only traps heat at the surface, mitigating the erosion of heat flow through the material's depth, but also exhibits lower thermal conductivity, enhancing the composite's thermal insulation properties. Since SiC ceramic particles are introduced into the C / C composite via a vacuum filtration process, the composite's wear resistance and impact resistance are enhanced. SiC, with its excellent high-temperature stability and oxidation resistance, effectively inhibits excessive pyrolysis of the organic resin. It also provides a supporting framework for the resin carbon formed after pyrolysis, reducing volume shrinkage during pyrolysis and increasing the resin's residual carbon content. During the ablation process, SiO2, generated by oxidation of SiC, undergoes viscous flow, filling defects such as gaps and micropores formed by the pyrolysis of the phenolic resin. At the same time, SiO2 with high oxygen barrier properties can act as a protective layer to further prevent oxygen from penetrating into the interior of the matrix, reducing oxidative damage to the matrix. Combined with about 15 wt% of organic phenolic resin in the matrix, this synergistic effect achieves the maintenance of the material's structural integrity and the improvement of its ablation resistance, showing the best enhancement effect under multiphase coupling conditions. The ablation-resistant organic modified C / C-SiC composite material of the present invention has a low-density carbon fiber skeleton and an organic resin matrix that can undergo pyrolysis, as well as more excellent heat-insulating properties, which can fully meet the performance requirements of lightweight and ablation-resistant throat lining materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 The present invention is a flow chart of the preparation method of the ablation-resistant organic modified C / C-SiC composite material.

[0019] Figure 2 This is a cross-sectional scattering image of the ablation-resistant organically modified C / C-SiC composite material obtained in Example 1 of the present invention and its element distribution diagram.

[0020] Figure 3 The surface temperature change curve of the sample obtained in Example 1 of the present invention is obtained by subjecting the ablation-resistant organically modified C / C-SiC composite material to an oxyacetylene ablation test for 60 seconds.

[0021] Figure 4 This is a surface scattering image and element distribution diagram of the ablation-resistant organically modified C / C-SiC composite material obtained in Example 1 of the present invention after ablation.

[0022] Figure 5 This is the SEM image of the cross section of the sample obtained in Comparative Example 1. DETAILED DESCRIPTION

[0023] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention. If specific conditions are not specified in the embodiments, they are carried out according to conventional conditions or the conditions recommended by the manufacturer. Herein, all features such as numerical values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are only for simplicity and convenience. Accordingly, the description of numerical ranges or percentage ranges should be deemed to have covered and specifically disclose all possible secondary ranges and individual values ​​(including integers and fractions) within the range.

[0024] The present invention proposes introducing SiC ceramic particles into a low-density C / C composite material, then further modifying the matrix with an organic phenolic resin. This results in an ablation-resistant organically modified C / C-SiC composite material containing a higher proportion of organic resin and possessing a certain degree of self-healing ability. The introduction of SiC ceramic particles increases the residual carbon content of the phenolic resin, while the SiO2 generated by oxidation during the ablation process can fill defects such as cracks and pores generated by the pyrolysis of the phenolic resin. This approach is expected to further enhance the material's ablation resistance.

[0025] See also Figure 1 The method for preparing the ablation-resistant organically modified C / C-SiC composite material proposed in the present invention comprises the following steps: S1: Weigh an appropriate amount of 1-3 μm SiC ceramic powder and anhydrous ethanol (a volatile solvent) in a mass ratio of 1:(3-4) into a beaker, add a stirring bar, and magnetically stir at room temperature for 1-2 h to form a suspension; S2: The density is 1.1-1.25 g / cm 3 The 2.5DC / C composite material was ultrasonically cleaned and then dried in an oven at 70-80°C for 10-12 h; S3: Install the filtration equipment, wet the organic filter membrane (pore size 0.1 μm), and place it on the sand core filter, ensuring a tight fit between the organic filter membrane and the sand core filter. Place the z-side of the C / C composite (the surface with alternating mesh and non-woven fabric layers) on the filter membrane and turn on the vacuum pump. Use a dropper to draw the suspension onto the sample surface. The pressure differential created by the vacuum pump draws the SiC ceramic powder into the material. Repeat this process until no further slurry can be drawn from the sample surface. Constantly stir the suspension during filtration to prevent sedimentation. Brush off any excess powder from the sample surface and dry in a 70-80°C oven for 12 hours before weighing.

[0026] S4: Repeat step S3 until the weight increase of the sample does not exceed 1%, thereby obtaining the first sample.

[0027] S5: Phenolic resin and anhydrous ethanol were weighed in the mass ratios of (75-70):100, (55-50):100, and (45-40):100, respectively, and magnetically stirred in a water bath at 60°C for 1-2 h to obtain slurry 1 (i.e., the first slurry), slurry 2 (i.e., the second slurry), and slurry 3 (i.e., the third slurry), respectively.

[0028] S6: Place the first sample obtained in S4 into Slurry 1 and immerse in a vacuum drying oven for 1-1.5 hours. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured first sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0029] S7: Repeat step S6 1-2 times to obtain a second sample.

[0030] S8: Place the second sample prepared in S7 into Slurry 2 and immerse in a vacuum drying oven for 1-1.5 hours. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured second sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0031] S9: Repeat step S8 1-2 times to obtain a third sample.

[0032] S10: Place the third sample prepared in S9 into Slurry 3 and immerse it in a vacuum drying oven for 1.5-2 hours. After immersion, place the sample in an oven at 180±5°C and cure it at normal pressure for 180 minutes at a heating rate of 1°C / min to obtain an ablation-resistant organically modified C / C-SiC composite.

[0033] According to the test, the mass percentage of SiC particles in the ablation-resistant organically modified C / C-SiC composite material is 4.61%-6.26%, and the mass percentage of organic phenolic resin is 14.64%-16.99%.

[0034] Example 1: The method for preparing the ablation-resistant organically modified C / C-SiC composite material of this embodiment includes the following steps: S1: Weigh appropriate amounts of 1-3 μm SiC ceramic powder and anhydrous ethanol in a mass ratio of 1:3 into a beaker, add a stirring bar, and magnetically stir at room temperature for 1.5 h to form a suspension; S2: The density is 1.2 g / cm 3 The 2.5DC / C composite material was ultrasonically cleaned and then dried in a 70 °C oven for 10 h; S3: Install the filtration equipment, wet the organic filter membrane (pore size 0.1 μm), and place it on the sand core filter, ensuring a tight fit between the organic filter membrane and the sand core filter. Place the z-side of the C / C composite (the surface with alternating mesh and non-woven fabric layers) on the filter membrane and turn on the vacuum pump. Use a dropper to draw the suspension onto the sample surface. The pressure differential created by the vacuum pump draws the SiC ceramic powder into the material. Repeat this process until no further slurry can be drawn from the sample surface. Constantly stir the suspension during filtration to prevent sedimentation. Brush off any excess powder from the sample surface and dry in a 70°C oven for 12 hours before weighing.

[0035] S4: Repeat step S3, and increase the weight of the sample by 1% to obtain the first sample.

[0036] S5: Phenolic resin and anhydrous ethanol were weighed in a mass ratio of 75:100, 50:100, and 40:100, respectively, and magnetically stirred in a water bath at 60°C for 1 h to obtain slurry 1, slurry 2, and slurry 3, respectively.

[0037] S6: Place the first sample obtained in S4 into Slurry 1 and immerse in a vacuum drying oven for 1 hour. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0038] S7: Repeat step S6 once to obtain a second sample.

[0039] S8: Place the second sample prepared in S7 into Slurry 2 and immerse in a vacuum drying oven for 1.5 hours. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured second sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0040] S9: Repeat step S8 twice to obtain a third sample.

[0041] S10: The third sample prepared in S9 was placed in slurry 3 and immersed in a vacuum drying oven for 2 hours. After the immersion, the sample was cured in an oven at 180±5°C for 180 minutes at normal pressure, with the oven heating rate at 1°C / min. This yielded an ablation-resistant organically modified C / C-SiC composite.

[0042] Figure 2 This is a cross-sectional scattering image and element distribution diagram of the ablation-resistant organic-modified C / C-SiC composite material prepared in this example. It can be seen that there is a 25 μm thick organic resin coating on the surface of the material. Figure 2The left substrate is the non-woven fabric layer, and the right substrate is the mesh layer. According to the element distribution, SiC ceramics are concentrated in the mesh layer. Figure 3 The heat flux is 2.38 MW / m 2 The surface temperature curve during a 60-second oxyacetylene ablation test shows a sudden change in the material's surface temperature within the first 20 seconds of ablation. This sudden change in temperature is primarily due to the thermal decomposition of the organic resin during ablation, which absorbs a large amount of heat and forms a carbonized layer on the material's surface. Subsequently, both the carbonized layer and the SiC undergo oxidation reactions, accumulating heat on the sample surface and rapidly transferring it to the surrounding environment and the material's interior. This series of chemical reactions buffers the material's temperature rise during ablation, slowing the ablation process. Figure 4 This is a scattering image of the surface of the ablation-resistant organically modified C / C-SiC composite material after ablation in this embodiment. The SiO2 generated by the oxidation of SiC fills the defects generated during the ablation process of the composite material, proving that SiC can indeed further improve the ablation resistance of the composite material and reduce ablation damage.

[0043] After testing, the mass fraction of organic resin in the ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment is 16.99%, and the mass fraction of SiC is 6.26%. The density calculated by the Archimedean drainage method is 1.6346 g / cm 3 The porosity is 5.17%. The ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment was subjected to a 2.38 MW / m 2 During a 60-second oxyacetylene ablation test, the maximum ablation temperature reached 1932°C, and the mass and linear ablation rates were 16.94 mg / s and 0.0019 mm / s, respectively. Compared to Comparative Example 4, the ablation-resistant organically modified C / C-SiC composite prepared in this example exhibited a 20.32% lower mass ablation rate, a 53.66% lower linear ablation rate, and a 69°C lower maximum ablation temperature.

[0044] Example 2: The method for preparing the ablation-resistant organically modified C / C-SiC composite material of this embodiment includes the following steps: S1: Weigh an appropriate amount of 1-3 μm SiC ceramic powder and anhydrous ethanol in a mass ratio of 1:4 into a beaker, add a stirring bar, and magnetically stir at room temperature for 1 h to form a suspension; S2: The density is 1.1 g / cm 3 The 2.5DC / C composite material was ultrasonically cleaned and dried in an oven at 80°C for 10 h; S3: Install the filtration equipment, wet the organic filter membrane (pore size 0.1 μm), and place it on the sand core filter, ensuring a tight fit between the organic filter membrane and the sand core filter. Place the z-side of the C / C composite (the surface with alternating mesh and non-woven fabric layers) on the filter membrane and turn on the vacuum pump. Use a dropper to draw the suspension onto the sample surface. The pressure differential created by the vacuum pump draws the SiC ceramic powder into the material. Repeat this process until no further slurry can be drawn from the sample surface. Constantly stir the suspension during filtration to prevent sedimentation. Brush off any excess powder from the sample surface and dry in an 80°C oven for 12 hours before weighing.

[0045] S4: Repeat step S3 until the weight gain of the sample reaches 0.5% to obtain the first sample.

[0046] S5: Phenolic resin and anhydrous ethanol were weighed in a mass ratio of 70:100, 55:100, and 40:100, respectively, and magnetically stirred in a water bath at 60°C for 1 h to obtain slurry 1, slurry 2, and slurry 3, respectively.

[0047] S6: Place the first sample obtained in S4 into Slurry 1 and immerse in a vacuum drying oven for 1.5 hours. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0048] S7: Repeat step S6 once to obtain a second sample.

[0049] S8: Place the second sample prepared in S7 into Slurry 2 and immerse in a vacuum drying oven for 1.5 hours. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured second sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0050] S9: Repeat step S8 once to obtain a third sample.

[0051] S10: The third sample prepared in S9 was placed in slurry 3 and immersed in a vacuum drying oven for 2 hours. After the immersion, the sample was cured in an oven at 180±5°C for 180 minutes at normal pressure, with the oven heating rate at 1°C / min. This yielded an ablation-resistant organically modified C / C-SiC composite.

[0052] After testing, the mass fraction of organic resin in the ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment is 14.64%, and the mass fraction of SiC is 4.61%. The density calculated by the Archimedean drainage method is 1.6767 g / cm 3The porosity is 4.13%. The ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment was subjected to a 2.38 MW / m 2 During a 60-second oxyacetylene ablation test, the maximum ablation temperature reached 1988°C, and the mass and linear ablation rates were 17.28 mg / s and 0.0021 mm / s, respectively. Compared to Comparative Example 4, the ablation-resistant organically modified C / C-SiC composite prepared in this example exhibited an 18.72% lower mass ablation rate, a 48.78% lower linear ablation rate, and a 13°C lower maximum ablation temperature.

[0053] Example 3: The method for preparing the ablation-resistant organically modified C / C-SiC composite material of this embodiment includes the following steps: S1: Weigh an appropriate amount of 1-3 μm SiC ceramic powder and anhydrous ethanol in a mass ratio of 1:3 in a beaker, then place a stirring bar and magnetically stir at room temperature for 1-2 h to form a suspension; S2: The density is 1.15 g / cm 3 The 2.5DC / C composite material was ultrasonically cleaned and dried in a 70°C oven for 10 h; S3: Install the filtration equipment, wet the organic filter membrane (pore size 0.1 μm), and place it on the sand core filter, ensuring a tight fit between the organic filter membrane and the sand core filter. Place the z-side of the C / C composite (the surface with alternating mesh and non-woven fabric layers) on the filter membrane and turn on the vacuum pump. Use a dropper to draw the suspension onto the sample surface. The pressure differential created by the vacuum pump draws the SiC ceramic powder into the material. Repeat this process until no further slurry can be drawn from the sample surface. Constantly stir the suspension during filtration to prevent sedimentation. Brush off any excess powder from the sample surface and dry in a 70-80°C oven for 12 hours before weighing.

[0054] S4: Repeat step S3 until the weight of the sample increases by 0.8%, obtaining the first sample.

[0055] S5: Phenolic resin and anhydrous ethanol were weighed in a mass ratio of 75:100, 55:100, and 45:100, respectively, and magnetically stirred in a water bath at 60°C for 2 h to obtain slurry 1, slurry 2, and slurry 3, respectively.

[0056] S6: Place the first sample obtained in S4 into Slurry 1 and immerse in a vacuum drying oven for 1 hour. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0057] S7: Repeat step S6 twice to obtain a second sample.

[0058] S8: Place the second sample prepared in S7 into Slurry 2 and immerse in a vacuum drying oven for 1 hour. After immersion, place the sample in an oven at 180±5°C and cure at ambient pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured second sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0059] S9: Repeat step S8 once to obtain a third sample.

[0060] S10: The third sample prepared in S9 was placed in slurry 3 and immersed in a vacuum drying oven for 2 hours. After the immersion, the sample was cured in an oven at 180±5°C for 180 minutes at normal pressure, with the oven heating rate at 1°C / min. This yielded an ablation-resistant organically modified C / C-SiC composite.

[0061] After testing, the mass fraction of organic resin in the ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment was 15.47%, and the mass fraction of SiC was 4.98%. The density calculated by the Archimedean drainage method was 1.5760 g / cm 3 The porosity is 4.39%. The ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment was subjected to a 2.38 MW / m 2 During a 60-second oxyacetylene ablation test, the maximum ablation temperature reached 1925°C, and the mass and linear ablation rates were 16.99 mg / s and 0.0023 mm / s, respectively. Compared to Comparative Example 4, the ablation-resistant organically modified C / C-SiC composite prepared in this example exhibited a 20.08% lower mass ablation rate, a 43.90% lower linear ablation rate, and a 76°C lower maximum ablation temperature.

[0062] Example 4: The method for preparing the ablation-resistant organically modified C / C-SiC composite material of this embodiment includes the following steps: S1: Weigh appropriate amounts of 1-3 μm SiC ceramic powder and anhydrous ethanol in a mass ratio of 3:10 into a beaker, add a stirring bar, and magnetically stir at room temperature for 1 h to form a suspension; S2: The density is 1.25 g / cm 3 The 2.5DC / C composite material was ultrasonically cleaned and then dried in an oven at 80 °C for 12 h; S3: Install the filtration equipment, wet the organic filter membrane (pore size 0.1 μm), and place it on the sand core filter, ensuring a tight fit between the organic filter membrane and the sand core filter. Place the z-side of the C / C composite (the surface with alternating mesh and non-woven fabric layers) on the filter membrane and turn on the vacuum pump. Use a dropper to draw the suspension onto the sample surface. The pressure differential created by the vacuum pump draws the SiC ceramic powder into the material. Repeat this process until no further slurry can be drawn into the sample surface. Constantly stir the suspension during filtration to prevent sedimentation. Brush off any loose powder from the sample surface and dry in an oven at 70-80°C for 12 hours before weighing.

[0063] S4: Repeat step S3 until the weight gain of the sample reaches 0.8% to obtain the first sample.

[0064] S5: Phenolic resin and anhydrous ethanol were weighed in a mass ratio of 70:100, 50:100, and 40:100, respectively, and magnetically stirred in a 60°C water bath for 1.5 h to obtain slurry 1, slurry 2, and slurry 3, respectively.

[0065] S6: Place the first sample obtained in S4 into Slurry 1 and immerse in a vacuum drying oven for 1 hour. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0066] S7: Repeat step S6 once to obtain a second sample.

[0067] S8: Place the second sample prepared in S7 into Slurry 2 and immerse in a vacuum drying oven for 1 hour. After immersion, place the sample in an oven at 180±5°C and cure at ambient pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured second sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0068] S9: Repeat step S8 once to obtain a third sample.

[0069] S10: The third sample prepared in S9 was placed in slurry 3 and immersed in a vacuum drying oven for 1.5 hours. After the immersion, the sample was cured in an oven at 180±5°C for 180 minutes at normal pressure, with the oven heating rate at 1°C / min. This yielded an ablation-resistant organically modified C / C-SiC composite.

[0070] After testing, the mass fraction of organic resin in the ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment is 16.35%, and the mass fraction of SiC is 5.01%. The density calculated by the Archimedean drainage method is 1.5948 g / cm 3The porosity is 5.88%. The ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment was subjected to a 2.38 MW / m 2 During a 60-second oxyacetylene ablation test, the maximum ablation temperature reached 1978°C, and the mass and linear ablation rates were 17.01 mg / s and 0.0029 mm / s, respectively. Compared to Comparative Example 4, the ablation-resistant organically modified C / C-SiC composite prepared in this example exhibited a 19.99% lower mass ablation rate, a 29.27% ​​lower linear ablation rate, and a 23°C lower maximum ablation temperature.

[0071] Example 5: The method for preparing the ablation-resistant organically modified C / C-SiC composite material of this embodiment includes the following steps: S1: Weigh appropriate amounts of 1-3 μm SiC ceramic powder and anhydrous ethanol in a mass ratio of 3:10 into a beaker, add a stirring bar, and magnetically stir at room temperature for 2 h to form a suspension; S2: The density is 1.15 g / cm 3 The 2.5DC / C composite material was ultrasonically cleaned and then dried in an oven at 80 °C for 10 h; S3: Install the filtration equipment, wet the organic filter membrane (pore size 0.1 μm), and place it on the sand core filter, ensuring a tight fit between the organic filter membrane and the sand core filter. Place the z-side of the C / C composite (the surface with alternating mesh and non-woven fabric layers) on the filter membrane and turn on the vacuum pump. Use a dropper to draw the suspension onto the sample surface. The pressure differential created by the vacuum pump draws the SiC ceramic powder into the material. Repeat this process until no further slurry can be drawn from the sample surface. Constantly stir the suspension during filtration to prevent sedimentation. Brush off any excess powder from the sample surface and dry in a 70-80°C oven for 12 hours before weighing.

[0072] S4: Repeat step S3 until the weight gain of the sample reaches 0.9% to obtain the first sample.

[0073] S5: Phenolic resin and anhydrous ethanol were weighed in a mass ratio of 75:100, 50:100, and 45:100, respectively, and magnetically stirred in a water bath at 60°C for 1 h to obtain slurry 1, slurry 2, and slurry 3, respectively.

[0074] S6: Place the first sample obtained in S4 into Slurry 1 and immerse in a vacuum drying oven for 1 hour. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0075] S7: Repeat step S6 once to obtain a second sample.

[0076] S8: Place the second sample prepared in S7 into Slurry 2 and immerse in a vacuum drying oven for 1.5 hours. After immersion, place the sample in an oven at 180±5°C and cure at normal pressure for 180 minutes, heating the oven at a rate of 1°C / min. Place the cured second sample on a grinding wheel to remove any phenolic resin bubbles formed on the surface.

[0077] S9: Repeat step S8 twice to obtain a third sample.

[0078] S10: The third sample prepared in S9 was placed in slurry 3 and immersed in a vacuum drying oven for 2 hours. After the immersion, the sample was cured in an oven at 180±5°C for 180 minutes at normal pressure, with the oven heating rate at 1°C / min. This yielded an ablation-resistant organically modified C / C-SiC composite.

[0079] After testing, the mass fraction of organic resin in the ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment is 15.88%, and the mass fraction of SiC is 5.23%. The density calculated by the Archimedean drainage method is 1.5948 g / cm 3 The porosity is 5.88%. The ablation-resistant organic modified C / C-SiC composite material prepared in this embodiment was subjected to a 2.38 MW / m 2 During a 60-second oxyacetylene ablation test, the maximum ablation temperature reached 1899°C, and the mass and linear ablation rates were 17.69 mg / s and 0.0030 mm / s, respectively. Compared to Comparative Example 4, the ablation-resistant organically modified C / C-SiC composite prepared in this example exhibited a 16.79% lower mass ablation rate, a 26.83% lower linear ablation rate, and a 102°C lower maximum ablation temperature.

[0080] Comparative Example 1: To explore the specific process of curing the C / C composite material after impregnation with phenolic resin, the 2.5DC / C composite material was directly subjected to the same steps as S5-S10 in Example 1, that is, only organic modification was performed, but the normal pressure curing was replaced by vacuum curing. It was found that the organic resin in the material matrix produced microcracks during the vacuum curing process. Figure 5 The density of the organic modified C / C composite material was only 1.4756 g / cm 3 , the porosity is 11.84%. Therefore, the atmospheric pressure curing process has a higher density than the vacuum curing process.

[0081] Comparative Example 2: The other steps of this comparative example are the same as those of Example 1, except that the mass ratio of the slurry in S5 is unified to 75:100. After 5 cycles of impregnation and curing, the density of the obtained composite material is only 1.4578 g / cm 3The porosity is only 15.69%. Therefore, when performing organic modification of the resin, continuous impregnation with high-concentration resin alcohol solution will affect the density of the material.

[0082] Comparative Example 3: The other steps of this comparative example are the same as those of Example 1, except that the mass ratio of the slurry in S5 is unified to 40:100. After 5 cycles of impregnation and curing, the density of the obtained composite material is only 1.5037 g / cm 3 The porosity is only 15.95%. Therefore, when performing organic modification of the resin, continuous impregnation with low-concentration resin alcohol solution will also affect the density of the material.

[0083] Comparative Example 4: The 2.5DC / C composite material was directly subjected to the same steps as S5-S10 in Example 1, that is, only organic modification was performed without introducing SiC ceramic particles to prepare an organic modified C / C composite material. The organic modified C / C composite material had an organic phenolic resin mass fraction of 18.23%. The organic modified C / C composite material was subjected to a heat flux of 2.38 MW / m 2 The surface temperature of the sample reached a maximum of 2001°C during the 60 s oxyacetylene ablation test, and the mass ablation rate and linear ablation rate were 21.26 mg / s and 0.0041 mm / s, respectively.

[0084] Comparative Example 5: The other steps of this comparative example are the same as those of Example 1, except that in this comparative example, the particle size of the 1-3 μm SiC ceramic particles in S1 is replaced with 3-5 μm SiC particles, and the SiC content in the resulting composite material is only 1.3 wt %. This is because the porosity of the initial C / C composite material is low, and the larger SiC particle size affects the filtration effect, resulting in a larger mass ablation rate of the composite material.

[0085] Comparative Example 6: The other steps of this comparative example are the same as those of Example 1, except that in this comparative example, the particle size of the 1-3 μm SiC ceramic particles in S1 is replaced with SiC particles of 300-500 nm. The SiC content in the resulting composite material is only 2.6 wt %. This is because the SiC particles are too small and easily agglomerated, thereby affecting the filtration effect, resulting in a large mass ablation rate of the composite material.

[0086] The above experimental results indicate that during the ablation process, the resin coating on the surface of the ablation-resistant organically modified C / C-SiC composite material obtained by the present invention preferentially undergoes pyrolysis, absorbing significant amounts of heat. This not only effectively reduces the surface temperature and mitigates the erosion of heat flow in the material's depth, but also results in a carbonized layer with lower thermal conductivity, enhancing the composite's thermal insulation properties. The SiC particles increase the residual carbon content of the phenolic resin, and the SiO2 generated by oxidation seals defects formed during the resin's pyrolysis, imparting a degree of self-healing ability and reducing oxidative damage to the substrate.

[0087] Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts should fall within the scope of protection of the present invention.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that the specific implementation methods of the present invention can still be modified or replaced by equivalents. Any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the scope of protection of the claims of the present invention.

Claims

1. A method for preparing an ablation-resistant organically modified C / C-SiC composite material, characterized in that: The process includes the following: Immersing the C / C composite material in a suspension of SiC ceramic powder and a volatile solvent, and performing vacuum filtration to introduce SiC ceramic particles into the C / C composite material to obtain a first sample; The first sample is vacuum impregnated in a first slurry and then cured to obtain a second sample; the first slurry is prepared by mixing phenolic resin and solvent in a mass ratio of (70-75):100; The second sample is vacuum impregnated in the second slurry and then cured to obtain a third sample; the second slurry is prepared by mixing phenolic resin and solvent in a mass ratio of (50-55):100; The third sample is vacuum impregnated in a third slurry and then cured to obtain the ablation-resistant organically modified C / C-SiC composite material; the third slurry is a slurry prepared by mixing phenolic resin and solvent in a mass ratio of (40-45):

100.

2. The method for preparing an ablation-resistant organically modified C / C-SiC composite material according to claim 1, characterized in that: The particle size of the SiC ceramic powder is 1-3 μm.

3. The method for preparing an ablation-resistant organically modified C / C-SiC composite material according to claim 1, characterized in that: In the suspension, the mass ratio of SiC ceramic powder to volatile solvent is 1:(3-4).

4. The method for preparing an ablation-resistant organically modified C / C-SiC composite material according to claim 1, characterized in that: The C / C composite material has a density of 1.1-1.25 g / cm 3 2.5DC / C composite material; The C / C composite material is firstly subjected to ultrasonic cleaning and drying, and then immersed in a suspension made of SiC ceramic powder and a volatile solvent.

5. The method for preparing an ablation-resistant organically modified C / C-SiC composite material according to claim 1, characterized in that: When preparing the first sample, after the vacuum filtration is completed, the C / C composite material introduced with SiC ceramic particles is dried and weighed, and the weight gain of the C / C composite material introduced with SiC ceramic particles is calculated. When the weight gain does not exceed 1%, the C / C composite material introduced with SiC ceramic particles at this time is used as the first sample. Otherwise, the vacuum filtration, drying, and weighing processes are repeated until the weight gain does not exceed 1%.

6. The method for preparing an ablation-resistant organically modified C / C-SiC composite material according to claim 1, characterized in that: When preparing the first slurry, the second slurry and the third slurry, the phenolic resin and the solvent are mixed, heated in a water bath at 60-65° C., and stirred for 1-2 hours to obtain the first slurry, the second slurry and the third slurry; Wherein, the solvent is anhydrous ethanol, and the volatile solvent is anhydrous ethanol.

7. The method for preparing an ablation-resistant organically modified C / C-SiC composite material according to claim 1, characterized in that: The first sample is vacuum impregnated in the first slurry and then cured to obtain the second sample, including the following process: placing the first sample in the first slurry, vacuum impregnating for 1-1.5 hours, and then curing at normal pressure at 175-185°C, then polishing the first sample to remove phenolic resin bubbles formed on the surface of the first sample, repeating the above process 1-2 times to obtain the second sample.

8. The method for preparing an ablation-resistant organically modified C / C-SiC composite material according to claim 1, characterized in that: The second sample is vacuum impregnated in the second slurry and then cured to obtain a third sample, including the following process: placing the second sample in the second slurry, vacuum impregnating for 1-1.5 hours, and then curing at normal pressure at 175-185°C, and then polishing the second sample to remove phenolic resin bubbles formed on the surface of the first sample, repeating the above process 1-2 times to obtain the third sample.

9. The method for preparing an ablation-resistant organically modified C / C-SiC composite material according to claim 1, characterized in that: The third sample is vacuum impregnated in a third slurry and then cured to obtain the ablation-resistant organic-modified C / C-SiC composite material, comprising the following process: placing the third sample in a third slurry, vacuum impregnating for 1.5-2.0 hours, and then curing at normal pressure at 175-185°C to obtain the ablation-resistant organic-modified C / C-SiC composite material.

10. An ablation-resistant organically modified C / C-SiC composite material, characterized in that: The ablation-resistant organically modified C / C-SiC composite material is prepared by the preparation method according to any one of claims 1 to 9.

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