Carbon / carbon composite material and preparation method therefor

Abstract

The present invention relates to the technical field of the preparation of materials and aims to solve the problems of interface separation and relatively weak oxidation resistance under complex working conditions caused by insufficient interfacial bonding force of existing carbon / carbon composite materials. To this end, the present invention provides a carbon / carbon composite material and a preparation method therefor. The carbon / carbon composite material comprises, in mass percentages, 40-55% of polyacrylonitrile-based carbon fibers, 10-25% of pitch-based carbon fibers, 8-20% of nano silicon dioxide-grafted carbon fibers, 8-20% of bio-pitch, 8-15% of a nanographene-modified phenolic resin, 3-6% of silicon carbide whiskers, 2-4% of zirconium boride nanoparticles, 2-4% of graphitized carbon fibers, and 1-3% of a natural plant extract antioxidant. The carbon / carbon composite material of the present invention can provide stable interfacial bonding force and significant oxidation resistance, thereby ensuring the structural integrity and mechanical property stability of the material when subjected to a variety of complex stresses such as tension, compression, bending, and shear, and broadening the application range of the material in the field of high-temperature oxidation resistance.

Description

A carbon / carbon composite material and its preparation method

[0001] Cross-referencing

[0002] This application is based on and claims priority to Chinese Patent Application No. 202510016386.3, filed on January 6, 2025, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to the field of materials preparation technology, specifically to a carbon / carbon composite material and its preparation method. Background Technology

[0004] With the rapid development of modern technology, the field of materials science is constantly facing new challenges and opportunities. Among many high-performance materials, carbon / carbon composites have attracted much attention due to their unique performance advantages.

[0005] The performance requirements for materials are becoming increasingly stringent in many industrial sectors, including aerospace, automotive manufacturing, and energy. For example, the aerospace industry requires materials with high strength, low density, high temperature resistance, and excellent oxidation resistance to meet the structural load-bearing and thermal protection needs of aircraft in extreme environments. The automotive industry seeks materials that can reduce vehicle weight to improve fuel efficiency while maintaining good mechanical and thermal stability in high-temperature components such as engines. High-temperature equipment in the energy sector, such as nuclear reactors and solar thermal utilization devices, also urgently requires materials that can operate stably for extended periods under harsh conditions such as high temperatures and radiation. Traditional single materials or conventional composite materials are no longer sufficient to fully meet these complex and diverse performance requirements; therefore, the development of novel high-performance composite materials has become an important direction in materials research.

[0006] Carbon materials possess unique properties, such as high strength and modulus of carbon fibers, and the ability of the carbon matrix to provide stability and support. However, pure carbon materials still have limitations in certain performance aspects. For example, the interfacial bonding between ordinary carbon fibers and the carbon matrix is ​​not ideal, making them prone to interfacial separation under stress or heat, thus affecting the overall mechanical and thermal properties of the material. Furthermore, in high-temperature oxidizing environments, carbon materials are susceptible to oxidation reactions, leading to a decline in material properties or even failure.

[0007] Therefore, there is a need in the art for a carbon / carbon composite material and a method for preparing it to solve the above problems. Summary of the Invention

[0008] In order to solve the above-mentioned technical problems, namely the problems of insufficient interfacial bonding force of existing carbon / carbon composite materials leading to interfacial separation under complex working conditions and weak oxidation resistance.

[0009] In a first aspect, the present invention provides a carbon / carbon composite material comprising, by weight percentage: 40%-55% polyacrylonitrile-based carbon fiber, 10%-25% pitch-based carbon fiber, 8%-20% nano-silica grafted carbon fiber, 8%-20% bio-asphalt, 8%-15% nano-graphene modified phenolic resin, 3%-6% silicon carbide whiskers, 2%-4% zirconium boride nanoparticles, 2%-4% graphitized carbon fiber, and 1%-3% natural plant extract antioxidant.

[0010] In some preferred embodiments, the carbon / carbon composite material comprises, by weight percentage: 42%-47% polyacrylonitrile-based carbon fiber, 10%-16% pitch-based carbon fiber, 10%-16% nano-silica grafted carbon fiber, 10% bio-asphalt, 10% nano-graphene modified phenolic resin, 4% silicon carbide whiskers, 3% zirconium boride nanoparticles, 3% graphitized carbon fiber, and 2% natural plant extract antioxidant.

[0011] In some preferred embodiments, the carbon / carbon composite material further includes 3%-6% rare earth oxides.

[0012] In some preferred embodiments, the rare earth oxide comprises 2%-4% cerium oxide and 1%-2% yttrium oxide.

[0013] The carbon / carbon composite material of the present invention has the following beneficial effects:

[0014] In the carbon / carbon composite material of this invention, the nano-silica grafted carbon fibers form a strongly interacting interface layer with the carbon matrix through chemical bonding and physical adsorption. This interface layer acts as an "anchor," effectively enhancing the connection strength between the carbon fibers and the carbon matrix, and greatly reducing the possibility of interface separation under complex stress conditions. Simultaneously, bio-asphalt and nano-graphene-modified phenolic resin can fully impregnate and encapsulate the carbon fibers during the formation of the carbon matrix, further filling the microscopic gaps between the fibers and the matrix, making the interface bonding tighter. Furthermore, the interweaving of different types of carbon fibers, such as pitch-based carbon fibers, polyacrylonitrile-based carbon fibers, and graphitized carbon fibers, forms a stable fiber network structure. When interacting with the carbon matrix, this increases the interfacial contact area and contact points, strengthening the overall interfacial bonding force from multiple dimensions. This ensures the structural integrity and mechanical performance stability of the material under various complex stresses such as tension, compression, bending, and shear. Additionally, zirconium boride nanoparticles can preferentially react with the carbon matrix at high temperatures. Reacting with oxygen, a dense and stable zirconium oxide protective film is formed on the material surface, effectively preventing oxygen from diffusing into the material. Cerium oxide nanoparticles and yttrium oxide nanoparticles, through their unique redox properties, construct a dynamic antioxidant defense system on the material surface, which can promptly capture and neutralize free radicals generated during high-temperature oxidation, inhibiting the progress of oxidation chain reactions. Natural plant extract antioxidants, as auxiliary antioxidant components, further enhance the material's antioxidant capacity at different temperature ranges. These antioxidant components, along with the carbon matrix and carbon fibers, work synergistically. On the one hand, the carbon matrix provides a stable adhesion base for the antioxidant components, enabling them to be evenly distributed and continuously exert their antioxidant effect. On the other hand, carbon fibers can disperse oxidative stress to a certain extent, reducing localized oxidative damage. Furthermore, there is a certain mutual protection mechanism between them and the antioxidant components, jointly improving the material's antioxidant performance under harsh environments such as high temperature and oxidation, significantly extending the material's service life, and broadening its application range in the field of high-temperature antioxidants.

[0015] In a second aspect, the present invention provides a method for preparing the above-described carbon / carbon composite material, the method comprising:

[0016] S1: Polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are woven in multiple layers according to an internal and external gradient structure to obtain a preform.

[0017] S2: Place the woven preform into a plasma treatment device for plasma treatment;

[0018] S3: Prepare a precursor solution containing bio-asphalt and nano-graphene modified phenolic resin. Add silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles and natural plant extract antioxidants to the precursor solution. Then, sequentially or simultaneously subject the mixed solution to ultrasonic treatment and stirring treatment.

[0019] S4: Place the preform into the impregnation container, inject the mixed solution and seal it, then fill the impregnation container with supercritical carbon dioxide;

[0020] S5: Place the impregnated preform into a microwave curing device for curing.

[0021] S6: Place the preform in a chemical vapor deposition reaction chamber for thermal gradient chemical vapor deposition;

[0022] S7: The preform after chemical vapor deposition is placed in a pressure impregnation device, and the mixed solution is injected into the pressure impregnation device to permeate the preform to densify the carbon matrix.

[0023] S8: The composite material that has undergone infiltration treatment is placed in a high-temperature heat treatment furnace for high-temperature heat treatment.

[0024] In some preferred embodiments, in step S2, the plasma power of the plasma processing device is 100-300 watts, the processing time is 10-30 minutes, and the gas is a mixture of oxygen and argon with an oxygen content of 10%-30%.

[0025] In some preferred embodiments, in step S3, the ultrasonic treatment time is 30-60 minutes, and the stirring treatment is carried out at 200-300°C and 1000-2000 rpm for 60-120 minutes.

[0026] In some preferred embodiments, in step S4, supercritical carbon dioxide is introduced at a set pressure of 8-15 MPa, a temperature of 40-60°C, and an impregnation time of 2-4 hours.

[0027] In step S5, the curing power is 500-1000 watts, the time is 10-20 minutes, and the temperature is 150-200℃.

[0028] In some preferred embodiments, in step S6, during the thermal gradient chemical vapor deposition of the preform, methane and hydrogen are used as gas sources, with a methane flow rate of 50-100 mL / min and a hydrogen flow rate of 200-400 mL / min. The center temperature of the thermal gradient is 800-1000°C, the edge temperature is 600-800°C, and the deposition time is 2-5 hours.

[0029] In step S7, the pressure of the pressure impregnation equipment is 2-5 MPa, the temperature is 80-120°C, and the permeation treatment time is 1-3 hours.

[0030] In some preferred embodiments, step S8 specifically includes:

[0031] S81: Place the composite material in a high-temperature heat treatment furnace, introduce argon gas, heat to 1500-1800℃ at a heating rate of 3-8℃ / min, and hold for 1.5-3.5 hours;

[0032] S82: Continue heating at a rate of 2-4℃ / minute to 2000-2500℃, and hold for 2.5-4.5 hours.

[0033] The method for preparing the carbon / carbon composite material of the present invention has the following beneficial effects:

[0034] In the preparation method of the carbon / carbon composite material of the present invention, a multi-layered woven carbon fiber preform is first constructed according to an internal and external gradient structure, laying a structural foundation for subsequent enhancement of interfacial bonding. The rational layout of different types of carbon fibers allows each fiber to fully contact the matrix precursor and form a multi-layered bonding interface during subsequent processing. Plasma treatment activates the surface of the woven preform, introducing active sites on the carbon fiber surface, which greatly improves the reactivity and affinity of the carbon fibers with the subsequent carbon matrix precursor. The prepared precursor solution contains a variety of components that contribute to interfacial bonding, such as bio-asphalt and nano-graphene-modified phenol. In subsequent impregnation and infiltration processes, aldehyde resins and other components, under the influence of pressure (supercritical carbon dioxide pressure and pressure impregnation pressure) and temperature (impregnation and infiltration temperature), can fully fill the pores between carbon fibers and tightly bond with the carbon fiber surface, forming a strong interfacial bond. During microwave curing, which transforms the precursor into a carbon matrix, the uniform heating characteristics of microwaves reduce interfacial stress caused by uneven curing, further stabilizing the interfacial structure. During thermal gradient chemical vapor deposition (TCVD) of carbon on the surface and in the pores of the preform, the deposited carbon can integrate with the carbon fibers and the previously impregnated matrix components. Optimizing the interface microstructure synergistically enhances interfacial bonding from multiple aspects. Furthermore, the zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles, and natural plant extract antioxidants added in the preparation method are uniformly dispersed in solution. Through supercritical carbon dioxide-assisted impregnation, microwave curing, and pressure impregnation, they can be uniformly distributed in the preform and the formed carbon matrix. During high-temperature heat treatment, these antioxidant components exert their effects at different temperature ranges. The zirconium boride nanoparticles first form a protective film at high temperatures, while the cerium oxide and yttrium oxide nanoparticles participate in regulating the antioxidant reaction throughout the high-temperature process. The natural plant extracts provide antioxidant protection. The antioxidant enhances the antioxidant effect, and the cooperation between each step ensures that the antioxidant components, carbon matrix and carbon fibers form a good synergistic system. Plasma treatment not only enhances the interfacial bonding force, but may also improve the antioxidant properties of the carbon fiber surface to a certain extent, providing better conditions for the subsequent adhesion and action of antioxidant components. The carbon structure formed by thermal gradient chemical vapor deposition can provide certain physical support and diffusion channels for antioxidant components, which is conducive to the uniform formation and stable existence of the antioxidant protective film, thereby comprehensively improving the antioxidant properties of the material and enabling the material to operate stably for a long time in a high-temperature oxidizing environment. Attached Figure Description

[0035] The features and advantages of the invention will be more clearly understood by referring to the accompanying drawings, which are schematic and should not be construed as limiting the invention in any way. In the drawings:

[0036] Figure 1 is a flowchart of the preparation method of the carbon / carbon composite material of the present invention. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Based on the background art, which points out that the insufficient interfacial bonding force of existing carbon / carbon composite materials leads to interfacial separation under complex working conditions and weak oxidation resistance, this invention provides a carbon / carbon composite material and its preparation method. The aim is to enable carbon / carbon composite materials to provide stable interfacial bonding force and significant oxidation resistance, thereby ensuring the structural integrity and mechanical property stability of the material when subjected to various complex stresses such as tension, compression, bending, and shear, and broadening its application range in the field of high-temperature oxidation resistance.

[0039] The carbon / carbon composite material of the present invention comprises, by weight percentage: 40%-55% polyacrylonitrile-based carbon fiber, 10%-25% pitch-based carbon fiber, 8%-20% nano-silica grafted carbon fiber, 8%-20% bio-asphalt, 8%-15% nano-graphene modified phenolic resin, 3%-6% silicon carbide whiskers, 2%-4% zirconium boride nanoparticles, 2%-4% graphitized carbon fiber, and 1%-3% natural plant extract antioxidant. More preferably, the carbon / carbon composite material comprises, by weight percentage: 42%-47% polyacrylonitrile-based carbon fiber, 10%-16% pitch-based carbon fiber, 10%-16% nano-silica grafted carbon fiber, 10% bio-asphalt, 10% nano-graphene modified phenolic resin, 4% silicon carbide whiskers, 3% zirconium boride nanoparticles, 3% graphitized carbon fiber, and 2% natural plant extract antioxidant.

[0040] In the above, high-strength, high-modulus polyacrylonitrile-based carbon fiber is preferred, and the grade is preferably T1000. Pitch-based carbon fiber is preferred, and high thermal conductivity pitch-based carbon fiber is preferred. Natural plant extract antioxidants can be plant extracts containing flavonoids (such as ginkgo leaf extract) as antioxidants. Flavonoids have multiple phenolic hydroxyl groups, which can provide hydrogen atoms to combine with free radicals, thereby terminating the free radical chain reaction. In the two-stage high-temperature heat treatment process, when the temperature rises, ginkgo leaf extract can form an antioxidant protective layer on the surface and inside of the material, preventing the carbon / carbon composite material from being over-oxidized in a high-temperature environment and protecting the structure and properties of the material. Of course, natural plant extract antioxidants can also be rosemary extract antioxidants, etc.

[0041] In a preferred embodiment, the carbon / carbon composite material of the present invention further comprises 3%-6% rare earth oxides, more preferably, the rare earth oxides comprising 2%-4% cerium oxide and 1%-2% yttrium oxide. In the carbon / carbon composite material, cerium oxide and yttrium oxide, as rare earth oxides, share some excellent properties. They can react with oxygen at high temperatures to form a dense protective film on the material surface. Specifically, cerium oxide can be reacted with cerium oxide... 4+ / Ce 3+ The redox cycle captures and releases oxygen atoms, and this protective film can prevent oxygen from further diffusing into the material, thereby effectively improving the material's oxidation resistance. At the same time, rare earth oxides can also refine the grains. During the material preparation process, especially in the high-temperature heat treatment stage, cerium oxide and yttrium oxide can inhibit grain growth, improve the microstructure of the material, and make the material's performance more stable. During high-temperature oxidation, the refined grain structure can reduce oxidation channels, reduce the oxidation rate, and further improve the material's oxidation resistance.

[0042] As shown in Figure 1, the preparation method of the carbon / carbon composite material of the present invention includes:

[0043] S1: Polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are woven in multiple layers according to an internal and external gradient structure to obtain a preform.

[0044] In a preferred embodiment, the multi-layer weaving process involves inner layer weaving, middle layer weaving, and outer layer weaving in sequence.

[0045] Specifically, the inner layer weaving is performed first: the length of T1000 grade high-strength, high-modulus polyacrylonitrile-based carbon fibers is controlled at 3-6 mm. The selected carbon fibers are pre-stretched, with the pre-stretch stress set at 5%-10% of their breaking strength. This pre-stretch state is maintained for 10-15 minutes to eliminate residual stress inside the fibers and improve their stability and mechanical property consistency during the weaving process. The pre-treated high-strength, high-modulus polyacrylonitrile-based carbon fibers are then conveyed to the weaving area via an automated feeding device. Following alternating weaving angles of 0° and 90°, and with a fiber density of approximately 100-150 fibers / cm², the fibers are guided by a fiber guiding device and woven by a mechanical weaving device. The inner layer is woven at a speed controlled at 10-20 mm / s. During the weaving process, a constant tension is applied to each fiber using a tension sensor, with the tension value set at 5-10 grams. The error range is controlled within ±1° for the weaving angle and ±5 fibers / cm² for the fiber density. Then, the middle layer is woven: after the inner layer reaches the predetermined thickness (preferably 30%-40% of the total thickness of the preform), high thermal conductivity pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are gradually introduced into the middle layer weaving. The length of the high thermal conductivity pitch-based carbon fiber is 2-5 mm, the length of the nano-silica grafted carbon fiber is 1-4 mm, and the length of the graphitized carbon fiber is 0 mm.5-2 mm. First, high-strength, high-modulus polyacrylonitrile-based carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-silica grafted carbon fiber: graphitized carbon fiber = 7:1:1:1 are mixed evenly in an automated fiber mixing device. The mixing device is equipped with a stirring device at a speed of 50-100 rpm for 10-15 minutes, supplemented by ultrasonic vibration at a power of 200-300 watts for 5-10 minutes to ensure thorough mixing and prevent entanglement. The mixed fibers are then transferred to the intermediate layer weaving mold via an automated conveying system. Weaving is performed according to the requirement of ±30° / ±60° weaving angle. The intermediate layer weaving mold inherits some of the structure and function of the inner layer weaving mold, but the fiber guiding device has been redesigned. The fiber density gradually decreases to 80-120 fibers / cm². During the weaving process, the weaving speed is 8-15 mm / s. Finally, the outer layer weaving is performed: when the intermediate layer... After the pre-fabricated structure reaches the predetermined thickness (preferably 50%-60% of the total preform thickness), the ratio of the four types of carbon fibers is further adjusted to a ratio of high-strength, high-modulus polyacrylonitrile-based carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-silica grafted carbon fiber: graphitized carbon fiber = 5:2:2:1. The fibers are then remixed in an automated fiber mixing container according to the new ratio, with the stirring and ultrasonic treatment parameters remaining the same as during the intermediate layer mixing, ensuring uniform fiber mixing. The mixed fibers are then conveyed to the outer layer weaving mold via an automated conveying pipeline and woven at weaving angles of ±30° / ±60°, with a weaving speed controlled at 6-12 mm / s. After weaving, the preform undergoes overall post-processing, including removing surface impurities and loose fibers using an automated cleaning device, followed by automated pre-compaction. The pre-compaction force is 0.5-1 MPa, and the pre-compaction time is 10-15 minutes to improve the overall stability and structural integrity of the preform, ultimately forming a preform structure with gradually changing mechanical and thermal properties.

[0046] S2: Place the woven preform into a plasma treatment device for plasma treatment.

[0047] Preferably, in step S2 above, the plasma power of the plasma treatment device is 100-300 watts, the treatment time is 10-30 minutes, the gas is a mixture of oxygen and argon, the oxygen content is 10%-30%, active particles are used to etch impurities and weak bonding layers on the carbon fiber surface, and argon ion bombardment generates active sites to enhance the bonding force with the carbon matrix precursor.

[0048] S3: Prepare a precursor solution containing bio-asphalt and nano-graphene modified phenolic resin. Add silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles and natural plant extract antioxidants to the precursor solution. Then, sequentially or simultaneously subject the mixed solution to ultrasonic treatment and stirring treatment.

[0049] Preferably, in step S3 above, the ultrasonic treatment time is 30-60 minutes, and the stirring treatment is carried out at 200-300℃ and 1000-2000 rpm for 60-120 minutes to ensure that the additives are uniformly dispersed.

[0050] S4: Place the preform into the impregnation container, inject the mixed solution and seal it, then fill the impregnation container with supercritical carbon dioxide.

[0051] Preferably, in step S4 above, supercritical carbon dioxide is introduced at a set pressure of 8-15 MPa, a temperature of 40-60°C, and an immersion treatment time of 2-4 hours, after which the pressure is slowly released to allow excess solution to flow out.

[0052] S5: Place the impregnated preform into a microwave curing device for curing.

[0053] Preferably, in step S5 above, the curing power is 500-1000 watts, the time is 10-20 minutes, and the temperature is 150-200℃. Microwave heating cures the phenolic resin to form a preliminary carbon matrix. During curing, vacuum can be used to remove volatiles and improve density.

[0054] S6: Place the preform in a chemical vapor deposition reaction chamber for thermal gradient chemical vapor deposition.

[0055] Preferably, in step S6 above, during the thermal gradient chemical vapor deposition of the preform, methane and hydrogen are used as gas sources, with a methane flow rate of 50-100 mL / min and a hydrogen flow rate of 200-400 mL / min. The center temperature of the thermal gradient is 800-1000°C, the edge temperature is 600-800°C, and the deposition time is 2-5 hours. Simultaneously, the precursors of cerium oxide and yttrium oxide are dissolved in a solvent and introduced into the reaction chamber in the form of atomization, so that cerium oxide, yttrium oxide and carbon are deposited together on the surface and pores of the preform.

[0056] S7: Place the preform after chemical vapor deposition in a pressure impregnation device, and inject the mixed solution into the pressure impregnation device to permeate the preform to densify the carbon matrix.

[0057] Preferably, in step S7 above, the pressure of the pressure impregnation equipment is 2-5 MPa, the temperature is 80-120°C, and the permeation treatment time is 1-3 hours, so that the liquid phase precursor and the carbon deposited by chemical vapor deposition can be combined to densify the carbon matrix.

[0058] S8: The composite material that has undergone infiltration treatment is placed in a high-temperature heat treatment furnace for high-temperature heat treatment.

[0059] Preferably, step S8 specifically includes:

[0060] S81: The composite material is placed in a high-temperature heat treatment furnace, argon gas is introduced, and it is heated to 1500-1800℃ at a heating rate of 3-8℃ / min and held for 1.5-3.5 hours. During this process, carbon atoms in the carbon matrix rearrange and the structure becomes regularized. Some amorphous carbon is converted into graphitic carbon, and cerium oxide and yttrium oxide begin to play an antioxidant role, protecting the material structure.

[0061] S82: Continue heating at a rate of 2-4℃ / min to 2000-2500℃ and hold for 2.5-4.5 hours. At this time, the graphitization of the carbon matrix deepens, the crystal structure is perfected, and cerium oxide and yttrium oxide are further integrated into the material structure to form a stable anti-oxidation layer, which improves the high-temperature anti-oxidation and comprehensive performance of the material. After the treatment is completed, cool the furnace to room temperature to obtain the final carbon / carbon composite material.

[0062] The technical solution of the present invention will be further illustrated below through multiple embodiments and comparative examples.

[0063] Example 1

[0064] The carbon / carbon composite material, measured by mass percentage, includes: 45% polyacrylonitrile-based carbon fiber, 10% pitch-based carbon fiber, 10% nano-silica grafted carbon fiber, 10% bio-asphalt, 10% nano-graphene modified phenolic resin, 4% silicon carbide whiskers, 3% zirconium boride nanoparticles, 3% graphitized carbon fiber, 2% ginkgo leaf extract antioxidant, 2% cerium oxide, and 1% yttrium oxide.

[0065] Methods for preparing carbon / carbon composite materials include:

[0066] The length of T1000 grade high-strength, high-modulus polyacrylonitrile-based carbon fibers is controlled at 3-6 mm. The selected carbon fibers undergo pre-stretching treatment, with the pre-stretch stress set at 10% of their breaking strength. This pre-stretch state is maintained for 15 minutes. The pre-treated high-strength, high-modulus polyacrylonitrile-based carbon fibers are then conveyed to the weaving area via an automated feeding device. Weaving is performed by a mechanical weaving device under the guidance of a fiber guiding device, with an alternating weaving angle of 0° / 90° and a fiber density of approximately 150 fibers / cm². The weaving speed is controlled at 20 mm / s. During the weaving process, tension sensors monitor each fiber. A constant tension is applied, set at 10 grams, with the error range controlled within ±1° for the weaving angle and ±5 fibers / cm² for the fiber density. Then, the intermediate layer is woven: once the inner layer weaving reaches 35% of the total preform thickness, high thermal conductivity pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are gradually introduced for the intermediate layer weaving. The high thermal conductivity pitch-based carbon fiber is 2-5 mm long, the nano-silica grafted carbon fiber is 1-4 mm long, and the graphitized carbon fiber is 0.5-2 mm long. Initially, the weaving sequence is: high-strength, high-modulus polyacrylonitrile-based carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-... Silica-grafted carbon fiber and graphitized carbon fiber were mixed in an automated fiber mixing device at a ratio of 7:1:1:1 to achieve uniform mixing. The mixing speed was 100 rpm for 15 minutes, supplemented by ultrasonic vibration at a power of 300 watts for 10 minutes. Weaving was then performed according to the requirements of ±30° / ±60° weaving angle, gradually reducing the fiber density to 120 fibers / cm². During the weaving process, the weaving speed was 15 mm / s. Finally, the outer layer was woven. After the middle layer weaving reached 60% of the total thickness of the preform, high-strength, high-modulus polyacrylonitrile was applied. The ratio of base carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-silica grafted carbon fiber: graphitized carbon fiber = 5:2:2:1 is used to remix the fibers in an automated fiber mixing container according to the new ratio. The stirring and ultrasonic treatment parameters are the same as those used when mixing the intermediate layer. The mixed fibers are then sent to the outer layer weaving mold through an automated conveying pipeline and woven at a weaving angle of ±30° / ±60°. The weaving speed is controlled at 12 mm / s. After weaving, an automated cleaning device is used to remove surface impurities and loose fibers. Then, an automated pre-compaction treatment is performed with a pre-compaction force of 1 MPa and a pre-compaction time of 15 minutes.

[0067] The woven preform is placed in a plasma treatment device for plasma treatment. The plasma power of the plasma treatment device is 100 watts, the treatment time is 10 minutes, and the gas is a mixture of oxygen and argon with an oxygen content of 10%.

[0068] A precursor solution containing bio-asphalt and nano-graphene modified phenolic resin was prepared. Silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles, and natural plant extract antioxidants were added to the precursor solution. The mixed solution was then subjected to ultrasonic treatment and stirring treatment in sequence. The ultrasonic treatment time was 30 minutes, and the stirring treatment was carried out at 200°C and 1000 rpm for 60 minutes.

[0069] The preform is placed in an impregnation container, the mixed solution is injected and then sealed. Supercritical carbon dioxide is then introduced into the impregnation container, and the pressure is set at 8 MPa, the temperature at 40°C, and the impregnation time is 2 hours.

[0070] The impregnated preform is placed in a microwave curing device for curing. The curing power is 500 watts, the time is 10 minutes, and the temperature is 150℃.

[0071] The preform was placed in a chemical vapor deposition reaction chamber for thermal gradient chemical vapor deposition. During the thermal gradient chemical vapor deposition of the preform, methane and hydrogen were used as gas sources, with a methane flow rate of 50 mL / min and a hydrogen flow rate of 200 mL / min. The center temperature of the thermal gradient was 800 °C and the edge temperature was 600 °C. The deposition time was 2 hours.

[0072] The preform after chemical vapor deposition was placed in a pressure impregnation device, and a mixed solution was injected into the pressure impregnation device to permeate the preform to densify the carbon matrix. The pressure of the pressure impregnation device was 2 MPa, the temperature was 80°C, and the permeation time was 1 hour.

[0073] The infiltration-treated composite material was placed in a high-temperature heat treatment furnace, argon gas was introduced, and the temperature was increased to 1500°C at a rate of 3°C / min and held for 1.5 hours. The temperature was then increased to 2000°C at a rate of 2°C / min and held for 2.5 hours. After the treatment was completed, the furnace was cooled to room temperature to obtain the final carbon / carbon composite material.

[0074] Example 2

[0075] The carbon / carbon composite material, measured by mass percentage, includes: 45% polyacrylonitrile-based carbon fiber, 10% pitch-based carbon fiber, 10% nano-silica grafted carbon fiber, 10% bio-asphalt, 10% nano-graphene modified phenolic resin, 4% silicon carbide whiskers, 3% zirconium boride nanoparticles, 3% graphitized carbon fiber, 2% ginkgo leaf extract antioxidant, 2% cerium oxide, and 1% yttrium oxide.

[0076] Methods for preparing carbon / carbon composite materials include:

[0077] The length of T1000 grade high-strength, high-modulus polyacrylonitrile-based carbon fibers is controlled at 3-6 mm. The selected carbon fibers undergo pre-stretching treatment, with the pre-stretch stress set at 10% of their breaking strength. This pre-stretch state is maintained for 15 minutes. The pre-treated high-strength, high-modulus polyacrylonitrile-based carbon fibers are then conveyed to the weaving area via an automated feeding device. Weaving is performed by a mechanical weaving device under the guidance of a fiber guiding device, with an alternating weaving angle of 0° / 90° and a fiber density of approximately 150 fibers / cm². The weaving speed is controlled at 20 mm / s. During the weaving process, tension sensors monitor each fiber. A constant tension is applied, set at 10 grams, with the error range controlled within ±1° for the weaving angle and ±5 fibers / cm² for the fiber density. Then, the intermediate layer is woven: once the inner layer weaving reaches 35% of the total preform thickness, high thermal conductivity pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are gradually introduced for the intermediate layer weaving. The high thermal conductivity pitch-based carbon fiber is 2-5 mm long, the nano-silica grafted carbon fiber is 1-4 mm long, and the graphitized carbon fiber is 0.5-2 mm long. Initially, the weaving sequence is: high-strength, high-modulus polyacrylonitrile-based carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-... Silica-grafted carbon fiber and graphitized carbon fiber were mixed in an automated fiber mixing device at a ratio of 7:1:1:1 to achieve uniform mixing. The mixing speed was 100 rpm for 15 minutes, supplemented by ultrasonic vibration at a power of 300 watts for 10 minutes. Weaving was then performed according to the requirements of ±30° / ±60° weaving angle, gradually reducing the fiber density to 120 fibers / cm². During the weaving process, the weaving speed was 15 mm / s. Finally, the outer layer was woven. After the middle layer weaving reached 60% of the total thickness of the preform, high-strength, high-modulus polyacrylonitrile was applied. The ratio of base carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-silica grafted carbon fiber: graphitized carbon fiber = 5:2:2:1 is used to remix the fibers in an automated fiber mixing container according to the new ratio. The stirring and ultrasonic treatment parameters are the same as those used when mixing the intermediate layer. The mixed fibers are then sent to the outer layer weaving mold through an automated conveying pipeline and woven at a weaving angle of ±30° / ±60°. The weaving speed is controlled at 12 mm / s. After weaving, an automated cleaning device is used to remove surface impurities and loose fibers. Then, an automated pre-compaction treatment is performed with a pre-compaction force of 1 MPa and a pre-compaction time of 15 minutes.

[0078] The woven preform is placed in a plasma treatment device for plasma treatment. The plasma power of the plasma treatment device is 200 watts, the treatment time is 20 minutes, and the gas is a mixture of oxygen and argon with an oxygen content of 20%.

[0079] A precursor solution containing bio-asphalt and nano-graphene modified phenolic resin was prepared. Silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles, and natural plant extract antioxidants were added to the precursor solution. The mixed solution was then subjected to ultrasonic treatment and stirring treatment in sequence. The ultrasonic treatment time was 45 minutes, and the stirring treatment was carried out at 250°C and 1500 rpm for 90 minutes.

[0080] The preform is placed in an impregnation container, the mixed solution is injected and then sealed. Supercritical carbon dioxide is then introduced into the impregnation container, and the pressure is set at 12 MPa, the temperature at 50°C, and the impregnation time is 3 hours.

[0081] The impregnated preform is placed in a microwave curing device for curing. The curing power is 750 watts, the time is 15 minutes, and the temperature is 175℃.

[0082] The preform was placed in a chemical vapor deposition reaction chamber for thermal gradient chemical vapor deposition. During the thermal gradient chemical vapor deposition of the preform, methane and hydrogen were used as gas sources, with a methane flow rate of 75 mL / min and a hydrogen flow rate of 300 mL / min. The center temperature of the thermal gradient was 900 °C and the edge temperature was 700 °C. The deposition time was 3.5 hours.

[0083] The preform after chemical vapor deposition was placed in a pressure impregnation device, and a mixed solution was injected into the pressure impregnation device to permeate the preform to densify the carbon matrix. The pressure of the pressure impregnation device was 3.5 MPa, the temperature was 100°C, and the permeation time was 2 hours.

[0084] The infiltration-treated composite material was placed in a high-temperature heat treatment furnace, argon gas was introduced, and the temperature was increased to 1650°C at a rate of 5°C / min and held for 2.5 hours. The temperature was then increased to 2250°C at a rate of 3°C / min and held for 3.5 hours. After the treatment was completed, the furnace was cooled to room temperature to obtain the final carbon / carbon composite material.

[0085] Example 3

[0086] The carbon / carbon composite material, measured by mass percentage, includes: 45% polyacrylonitrile-based carbon fiber, 10% pitch-based carbon fiber, 10% nano-silica grafted carbon fiber, 10% bio-asphalt, 10% nano-graphene modified phenolic resin, 4% silicon carbide whiskers, 3% zirconium boride nanoparticles, 3% graphitized carbon fiber, 2% ginkgo leaf extract antioxidant, 2% cerium oxide, and 1% yttrium oxide.

[0087] Methods for preparing carbon / carbon composite materials include:

[0088] The length of T1000 grade high-strength, high-modulus polyacrylonitrile-based carbon fibers is controlled at 3-6 mm. The selected carbon fibers undergo pre-stretching treatment, with the pre-stretch stress set at 10% of their breaking strength. This pre-stretch state is maintained for 15 minutes. The pre-treated high-strength, high-modulus polyacrylonitrile-based carbon fibers are then conveyed to the weaving area via an automated feeding device. Weaving is performed by a mechanical weaving device under the guidance of a fiber guiding device, with an alternating weaving angle of 0° / 90° and a fiber density of approximately 150 fibers / cm². The weaving speed is controlled at 20 mm / s. During the weaving process, tension sensors monitor each fiber. A constant tension is applied, set at 10 grams, with the error range controlled within ±1° for the weaving angle and ±5 fibers / cm² for the fiber density. Then, the intermediate layer is woven: once the inner layer weaving reaches 35% of the total preform thickness, high thermal conductivity pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are gradually introduced for the intermediate layer weaving. The high thermal conductivity pitch-based carbon fiber is 2-5 mm long, the nano-silica grafted carbon fiber is 1-4 mm long, and the graphitized carbon fiber is 0.5-2 mm long. Initially, the weaving sequence is: high-strength, high-modulus polyacrylonitrile-based carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-... Silica-grafted carbon fiber and graphitized carbon fiber were mixed in an automated fiber mixing device at a ratio of 7:1:1:1 to achieve uniform mixing. The mixing speed was 100 rpm for 15 minutes, supplemented by ultrasonic vibration at a power of 300 watts for 10 minutes. Weaving was then performed according to the requirements of ±30° / ±60° weaving angle, gradually reducing the fiber density to 120 fibers / cm². During the weaving process, the weaving speed was 15 mm / s. Finally, the outer layer was woven. After the middle layer weaving reached 60% of the total thickness of the preform, high-strength, high-modulus polyacrylonitrile was applied. The ratio of base carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-silica grafted carbon fiber: graphitized carbon fiber = 5:2:2:1 is used to remix the fibers in an automated fiber mixing container according to the new ratio. The stirring and ultrasonic treatment parameters are the same as those used when mixing the intermediate layer. The mixed fibers are then sent to the outer layer weaving mold through an automated conveying pipeline and woven at a weaving angle of ±30° / ±60°. The weaving speed is controlled at 12 mm / s. After weaving, an automated cleaning device is used to remove surface impurities and loose fibers. Then, an automated pre-compaction treatment is performed with a pre-compaction force of 1 MPa and a pre-compaction time of 15 minutes.

[0089] The woven preform is placed in a plasma treatment device for plasma treatment. The plasma power of the plasma treatment device is 300 watts, the treatment time is 30 minutes, and the gas is a mixture of oxygen and argon with an oxygen content of 30%.

[0090] A precursor solution containing bio-asphalt and nano-graphene modified phenolic resin was prepared. Silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles, and natural plant extract antioxidants were added to the precursor solution. The mixed solution was then subjected to ultrasonic treatment and stirring treatment in sequence. The ultrasonic treatment time was 60 minutes, and the stirring treatment was carried out at 300℃ and 2000 rpm for 120 minutes.

[0091] The preform is placed in an impregnation container, the mixed solution is injected and then sealed. Supercritical carbon dioxide is then introduced into the impregnation container, and the pressure is set at 15 MPa, the temperature at 60°C, and the impregnation time is 4 hours.

[0092] The impregnated preform is placed in a microwave curing device for curing. The curing power is 1000 watts, the time is 20 minutes, and the temperature is 200℃.

[0093] The preform was placed in a chemical vapor deposition reaction chamber for thermal gradient chemical vapor deposition. During the thermal gradient chemical vapor deposition of the preform, methane and hydrogen were used as gas sources, with a methane flow rate of 100 mL / min and a hydrogen flow rate of 400 mL / min. The center temperature of the thermal gradient was 1000 °C and the edge temperature was 800 °C. The deposition time was 5 hours.

[0094] The preform after chemical vapor deposition was placed in a pressure impregnation device, and a mixed solution was injected into the pressure impregnation device to permeate the preform to densify the carbon matrix. The pressure of the pressure impregnation device was 5 MPa, the temperature was 120°C, and the permeation time was 3 hours.

[0095] The infiltration-treated composite material was placed in a high-temperature heat treatment furnace, argon gas was introduced, and the temperature was increased to 1800°C at a rate of 8°C / min and held for 3.5 hours. The temperature was then increased to 2500°C at a rate of 4°C / min and held for 4.5 hours. After the treatment was completed, the furnace was cooled to room temperature to obtain the final carbon / carbon composite material.

[0096] Example 4

[0097] The carbon / carbon composite material, measured by mass percentage, includes: 42% polyacrylonitrile-based carbon fiber, 12% pitch-based carbon fiber, 11% nano-silica grafted carbon fiber, 10% bio-asphalt, 10% nano-graphene modified phenolic resin, 4% silicon carbide whiskers, 3% zirconium boride nanoparticles, 3% graphitized carbon fiber, 2% ginkgo leaf extract antioxidant, 2% cerium oxide, and 1% yttrium oxide.

[0098] Methods for preparing carbon / carbon composite materials include:

[0099] The length of T1000 grade high-strength, high-modulus polyacrylonitrile-based carbon fibers is controlled at 3-6 mm. The selected carbon fibers undergo pre-stretching treatment, with the pre-stretch stress set at 10% of their breaking strength. This pre-stretch state is maintained for 15 minutes. The pre-treated high-strength, high-modulus polyacrylonitrile-based carbon fibers are then conveyed to the weaving area via an automated feeding device. Weaving is performed by a mechanical weaving device under the guidance of a fiber guiding device, with an alternating weaving angle of 0° / 90° and a fiber density of approximately 150 fibers / cm². The weaving speed is controlled at 20 mm / s. During the weaving process, tension sensors monitor each fiber. A constant tension is applied, set at 10 grams, with the error range controlled within ±1° for the weaving angle and ±5 fibers / cm² for the fiber density. Then, the intermediate layer is woven: once the inner layer weaving reaches 35% of the total preform thickness, high thermal conductivity pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are gradually introduced for the intermediate layer weaving. The high thermal conductivity pitch-based carbon fiber is 2-5 mm long, the nano-silica grafted carbon fiber is 1-4 mm long, and the graphitized carbon fiber is 0.5-2 mm long. Initially, the weaving sequence is: high-strength, high-modulus polyacrylonitrile-based carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-... Silica-grafted carbon fiber and graphitized carbon fiber were mixed in an automated fiber mixing device at a ratio of 7:1:1:1 to achieve uniform mixing. The mixing speed was 100 rpm for 15 minutes, supplemented by ultrasonic vibration at a power of 300 watts for 10 minutes. Weaving was then performed according to the requirements of ±30° / ±60° weaving angle, gradually reducing the fiber density to 120 fibers / cm². During the weaving process, the weaving speed was 15 mm / s. Finally, the outer layer was woven. After the middle layer weaving reached 60% of the total thickness of the preform, high-strength, high-modulus polyacrylonitrile was applied. The ratio of base carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-silica grafted carbon fiber: graphitized carbon fiber = 5:2:2:1 is used to remix the fibers in an automated fiber mixing container according to the new ratio. The stirring and ultrasonic treatment parameters are the same as those used when mixing the intermediate layer. The mixed fibers are then sent to the outer layer weaving mold through an automated conveying pipeline and woven at a weaving angle of ±30° / ±60°. The weaving speed is controlled at 12 mm / s. After weaving, an automated cleaning device is used to remove surface impurities and loose fibers. Then, an automated pre-compaction treatment is performed with a pre-compaction force of 1 MPa and a pre-compaction time of 15 minutes.

[0100] The woven preform is placed in a plasma treatment device for plasma treatment. The plasma power of the plasma treatment device is 100 watts, the treatment time is 10 minutes, and the gas is a mixture of oxygen and argon with an oxygen content of 10%.

[0101] A precursor solution containing bio-asphalt and nano-graphene modified phenolic resin was prepared. Silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles, and natural plant extract antioxidants were added to the precursor solution. The mixed solution was then subjected to ultrasonic treatment and stirring treatment in sequence. The ultrasonic treatment time was 30 minutes, and the stirring treatment was carried out at 200°C and 1000 rpm for 60 minutes.

[0102] The preform is placed in an impregnation container, the mixed solution is injected and then sealed. Supercritical carbon dioxide is then introduced into the impregnation container, and the pressure is set at 8 MPa, the temperature at 40°C, and the impregnation time is 2 hours.

[0103] The impregnated preform is placed in a microwave curing device for curing. The curing power is 500 watts, the time is 10 minutes, and the temperature is 150℃.

[0104] The preform was placed in a chemical vapor deposition reaction chamber for thermal gradient chemical vapor deposition. During the thermal gradient chemical vapor deposition of the preform, methane and hydrogen were used as gas sources, with a methane flow rate of 50 mL / min and a hydrogen flow rate of 200 mL / min. The center temperature of the thermal gradient was 800 °C and the edge temperature was 600 °C. The deposition time was 2 hours.

[0105] The preform after chemical vapor deposition was placed in a pressure impregnation device, and a mixed solution was injected into the pressure impregnation device to permeate the preform to densify the carbon matrix. The pressure of the pressure impregnation device was 2 MPa, the temperature was 80°C, and the permeation time was 1 hour.

[0106] The infiltration-treated composite material was placed in a high-temperature heat treatment furnace, argon gas was introduced, and the temperature was increased to 1500°C at a rate of 3°C / min and held for 1.5 hours. The temperature was then increased to 2000°C at a rate of 2°C / min and held for 2.5 hours. After the treatment was completed, the furnace was cooled to room temperature to obtain the final carbon / carbon composite material.

[0107] Example 5

[0108] The carbon / carbon composite material, measured by mass percentage, includes: 42% polyacrylonitrile-based carbon fiber, 12% pitch-based carbon fiber, 11% nano-silica grafted carbon fiber, 10% bio-asphalt, 10% nano-graphene modified phenolic resin, 4% silicon carbide whiskers, 3% zirconium boride nanoparticles, 3% graphitized carbon fiber, 2% ginkgo leaf extract antioxidant, 2% cerium oxide, and 1% yttrium oxide.

[0109] Methods for preparing carbon / carbon composite materials include:

[0110] The length of T1000 grade high-strength, high-modulus polyacrylonitrile-based carbon fibers is controlled at 3-6 mm. The selected carbon fibers undergo pre-stretching treatment, with the pre-stretch stress set at 10% of their breaking strength. This pre-stretch state is maintained for 15 minutes. The pre-treated high-strength, high-modulus polyacrylonitrile-based carbon fibers are then conveyed to the weaving area via an automated feeding device. Weaving is performed by a mechanical weaving device under the guidance of a fiber guiding device, with an alternating weaving angle of 0° / 90° and a fiber density of approximately 150 fibers / cm². The weaving speed is controlled at 20 mm / s. During the weaving process, tension sensors monitor each fiber. A constant tension is applied, set at 10 grams, with the error range controlled within ±1° for the weaving angle and ±5 fibers / cm² for the fiber density. Then, the intermediate layer is woven: once the inner layer weaving reaches 35% of the total preform thickness, high thermal conductivity pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are gradually introduced for the intermediate layer weaving. The high thermal conductivity pitch-based carbon fiber is 2-5 mm long, the nano-silica grafted carbon fiber is 1-4 mm long, and the graphitized carbon fiber is 0.5-2 mm long. Initially, the weaving sequence is: high-strength, high-modulus polyacrylonitrile-based carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-... Silica-grafted carbon fiber and graphitized carbon fiber were mixed in an automated fiber mixing device at a ratio of 7:1:1:1 to achieve uniform mixing. The mixing speed was 100 rpm for 15 minutes, supplemented by ultrasonic vibration at a power of 300 watts for 10 minutes. Weaving was then performed according to the requirements of ±30° / ±60° weaving angle, gradually reducing the fiber density to 120 fibers / cm². During the weaving process, the weaving speed was 15 mm / s. Finally, the outer layer was woven. After the middle layer weaving reached 60% of the total thickness of the preform, high-strength, high-modulus polyacrylonitrile was applied. The ratio of base carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-silica grafted carbon fiber: graphitized carbon fiber = 5:2:2:1 is used to remix the fibers in an automated fiber mixing container according to the new ratio. The stirring and ultrasonic treatment parameters are the same as those used when mixing the intermediate layer. The mixed fibers are then sent to the outer layer weaving mold through an automated conveying pipeline and woven at a weaving angle of ±30° / ±60°. The weaving speed is controlled at 12 mm / s. After weaving, an automated cleaning device is used to remove surface impurities and loose fibers. Then, an automated pre-compaction treatment is performed with a pre-compaction force of 1 MPa and a pre-compaction time of 15 minutes.

[0111] The woven preform is placed in a plasma treatment device for plasma treatment. The plasma power of the plasma treatment device is 200 watts, the treatment time is 20 minutes, and the gas is a mixture of oxygen and argon with an oxygen content of 20%.

[0112] A precursor solution containing bio-asphalt and nano-graphene modified phenolic resin was prepared. Silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles, and natural plant extract antioxidants were added to the precursor solution. The mixed solution was then subjected to ultrasonic treatment and stirring treatment in sequence. The ultrasonic treatment time was 45 minutes, and the stirring treatment was carried out at 250°C and 1500 rpm for 90 minutes.

[0113] The preform is placed in an impregnation container, the mixed solution is injected and then sealed. Supercritical carbon dioxide is then introduced into the impregnation container, and the pressure is set at 12 MPa, the temperature at 50°C, and the impregnation time is 3 hours.

[0114] The impregnated preform is placed in a microwave curing device for curing. The curing power is 750 watts, the time is 15 minutes, and the temperature is 175℃.

[0115] The preform was placed in a chemical vapor deposition reaction chamber for thermal gradient chemical vapor deposition. During the thermal gradient chemical vapor deposition of the preform, methane and hydrogen were used as gas sources, with a methane flow rate of 75 mL / min and a hydrogen flow rate of 300 mL / min. The center temperature of the thermal gradient was 900 °C and the edge temperature was 700 °C. The deposition time was 3.5 hours.

[0116] The preform after chemical vapor deposition was placed in a pressure impregnation device, and a mixed solution was injected into the pressure impregnation device to permeate the preform to densify the carbon matrix. The pressure of the pressure impregnation device was 3.5 MPa, the temperature was 100°C, and the permeation time was 2 hours.

[0117] The infiltration-treated composite material was placed in a high-temperature heat treatment furnace, argon gas was introduced, and the temperature was increased to 1650°C at a rate of 5°C / min and held for 2.5 hours. The temperature was then increased to 2250°C at a rate of 3°C / min and held for 3.5 hours. After the treatment was completed, the furnace was cooled to room temperature to obtain the final carbon / carbon composite material.

[0118] Example 6

[0119] The carbon / carbon composite material, measured by mass percentage, includes: 42% polyacrylonitrile-based carbon fiber, 12% pitch-based carbon fiber, 11% nano-silica grafted carbon fiber, 10% bio-asphalt, 10% nano-graphene modified phenolic resin, 4% silicon carbide whiskers, 3% zirconium boride nanoparticles, 3% graphitized carbon fiber, 2% ginkgo leaf extract antioxidant, 2% cerium oxide, and 1% yttrium oxide.

[0120] Methods for preparing carbon / carbon composite materials include:

[0121] The length of T1000 grade high-strength, high-modulus polyacrylonitrile-based carbon fibers is controlled at 3-6 mm. The selected carbon fibers undergo pre-stretching treatment, with the pre-stretch stress set at 10% of their breaking strength. This pre-stretch state is maintained for 15 minutes. The pre-treated high-strength, high-modulus polyacrylonitrile-based carbon fibers are then conveyed to the weaving area via an automated feeding device. Weaving is performed by a mechanical weaving device under the guidance of a fiber guiding device, with an alternating weaving angle of 0° / 90° and a fiber density of approximately 150 fibers / cm². The weaving speed is controlled at 20 mm / s. During the weaving process, tension sensors monitor each fiber. A constant tension is applied, set at 10 grams, with the error range controlled within ±1° for the weaving angle and ±5 fibers / cm² for the fiber density. Then, the intermediate layer is woven: once the inner layer weaving reaches 35% of the total preform thickness, high thermal conductivity pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are gradually introduced for the intermediate layer weaving. The high thermal conductivity pitch-based carbon fiber is 2-5 mm long, the nano-silica grafted carbon fiber is 1-4 mm long, and the graphitized carbon fiber is 0.5-2 mm long. Initially, the weaving sequence is: high-strength, high-modulus polyacrylonitrile-based carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-... Silica-grafted carbon fiber and graphitized carbon fiber were mixed in an automated fiber mixing device at a ratio of 7:1:1:1 to achieve uniform mixing. The mixing speed was 100 rpm for 15 minutes, supplemented by ultrasonic vibration at a power of 300 watts for 10 minutes. Weaving was then performed according to the requirements of ±30° / ±60° weaving angle, gradually reducing the fiber density to 120 fibers / cm². During the weaving process, the weaving speed was 15 mm / s. Finally, the outer layer was woven. After the middle layer weaving reached 60% of the total thickness of the preform, high-strength, high-modulus polyacrylonitrile was applied. The ratio of base carbon fiber: high thermal conductivity pitch-based carbon fiber: nano-silica grafted carbon fiber: graphitized carbon fiber = 5:2:2:1 is used to remix the fibers in an automated fiber mixing container according to the new ratio. The stirring and ultrasonic treatment parameters are the same as those used when mixing the intermediate layer. The mixed fibers are then sent to the outer layer weaving mold through an automated conveying pipeline and woven at a weaving angle of ±30° / ±60°. The weaving speed is controlled at 12 mm / s. After weaving, an automated cleaning device is used to remove surface impurities and loose fibers. Then, an automated pre-compaction treatment is performed with a pre-compaction force of 1 MPa and a pre-compaction time of 15 minutes.

[0122] The woven preform is placed in a plasma treatment device for plasma treatment. The plasma power of the plasma treatment device is 300 watts, the treatment time is 30 minutes, and the gas is a mixture of oxygen and argon with an oxygen content of 30%.

[0123] A precursor solution containing bio-asphalt and nano-graphene modified phenolic resin was prepared. Silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles, and natural plant extract antioxidants were added to the precursor solution. The mixed solution was then subjected to ultrasonic treatment and stirring treatment in sequence. The ultrasonic treatment time was 60 minutes, and the stirring treatment was carried out at 300℃ and 2000 rpm for 120 minutes.

[0124] The preform is placed in an impregnation container, the mixed solution is injected and then sealed. Supercritical carbon dioxide is then introduced into the impregnation container, and the pressure is set at 15 MPa, the temperature at 60°C, and the impregnation time is 4 hours.

[0125] The impregnated preform is placed in a microwave curing device for curing. The curing power is 1000 watts, the time is 20 minutes, and the temperature is 200℃.

[0126] The preform was placed in a chemical vapor deposition reaction chamber for thermal gradient chemical vapor deposition. During the thermal gradient chemical vapor deposition of the preform, methane and hydrogen were used as gas sources, with a methane flow rate of 100 mL / min and a hydrogen flow rate of 400 mL / min. The center temperature of the thermal gradient was 1000 °C and the edge temperature was 800 °C. The deposition time was 5 hours.

[0127] The preform after chemical vapor deposition was placed in a pressure impregnation device, and a mixed solution was injected into the pressure impregnation device to permeate the preform to densify the carbon matrix. The pressure of the pressure impregnation device was 5 MPa, the temperature was 120°C, and the permeation time was 3 hours.

[0128] The infiltration-treated composite material was placed in a high-temperature heat treatment furnace, argon gas was introduced, and the temperature was increased to 1800°C at a rate of 8°C / min and held for 3.5 hours. The temperature was then increased to 2500°C at a rate of 4°C / min and held for 4.5 hours. After the treatment was completed, the furnace was cooled to room temperature to obtain the final carbon / carbon composite material.

[0129] Comparative Example 1

[0130] The carbon / carbon composite material, measured by mass percentage, comprises: 40% polyacrylonitrile-based carbon fiber, 15% viscose-based carbon fiber, 10% pitch-based carbon fiber, 20% phenolic resin, 10% furan resin, 3% silicon carbide particles, and 2% potassium titanate whiskers.

[0131] Methods for preparing carbon / carbon composite materials include:

[0132] Polyacrylonitrile-based carbon fibers with a length of 3-6 mm, viscose-based carbon fibers with a length of 2-5 mm, and pitch-based carbon fibers with a length of 4-7 mm were selected respectively. The three types of carbon fibers were first mixed in a three-dimensional mixer for 45 minutes to ensure uniform mixing. Then, the mixed carbon fibers were placed into a preform mold and a multi-directional weaving process was adopted, with weaving angles of 0° / 90° and ±45° combinations. The fiber density was controlled at 110 fibers / cm². After weaving, hot pressing was performed under a pressure of 0.5 MPa at a temperature of 165°C for 25 minutes to obtain the carbon fiber preform.

[0133] Phenolic resin and furan resin were mixed in proportion, and an appropriate amount of acetone was added and stirred to dissolve them, so as to prepare an impregnation solution with a solid content of about 55%. The preform was placed in the impregnation solution and impregnated for 2 hours under vacuum with an impregnation pressure of -0.07 MPa. Then it was taken out and cured in an oven at 100°C for 4 hours. The cured preform was placed in a carbonization furnace and heated to 900°C at a heating rate of 4°C / min under nitrogen protection for 2 hours. The impregnation-curing-carbonization process was repeated 5 times.

[0134] Using acetylene as the gas source and hydrogen as the carrier gas, the acetylene flow rate was controlled at 50 ml / min and the hydrogen flow rate at 150 ml / min. The preform that had undergone multiple impregnation-curing-carbonization processes was placed in the chemical vapor deposition reaction chamber. The deposition temperature was set at 1100℃, the deposition pressure at 8 kPa, and the deposition time at 2 hours.

[0135] The prepared composite material was placed in a high-temperature heat treatment furnace, argon gas was introduced, and the temperature was increased to 1900℃ at a heating rate of 7℃ / min. The temperature was held for 2.5 hours, and after cooling, carbon / carbon composite material was obtained.

[0136] Comparative Example 2

[0137] The carbon / carbon composite material, measured by mass percentage, comprises: 30% high-strength polyacrylonitrile-based carbon fiber, 20% high-modulus polyacrylonitrile-based carbon fiber, 10% graphite fiber, 25% coal tar pitch, 10% modified phenolic resin, 2% boron oxide, and 3% titanium diboride.

[0138] Methods for preparing carbon / carbon composite materials include:

[0139] The high-strength polyacrylonitrile-based carbon fiber is selected with a length of 4-7 mm, the high-modulus polyacrylonitrile-based carbon fiber with a length of 3-6 mm, and the graphite fiber with a length of 2-5 mm. The three types of carbon fibers are mixed in a high-speed mixer for 55 minutes. A small amount of dispersant is added during mixing to prevent fiber agglomeration. Then, a preform is prepared by needle punching. First, a layer of fiber web is laid, and then needle punched with a needle punching machine at a needle punching density of 250 needles / cm². The laying and needle punching process is repeated for 6 layers. Finally, a preform with a certain thickness and strength is obtained, with a fiber density of about 125 fibers / cm².

[0140] Coal tar pitch was heated to 220℃ and melted, then mixed evenly with modified phenolic resin to obtain a matrix precursor mixture. The preform was immersed in the precursor mixture for 50 minutes at an immersion temperature of 210℃. After immersion, it was removed and pyrolyzed in a vacuum environment at an immersion temperature of 800℃, a pyrolysis pressure of -0.04 MPa, and a pyrolysis time of 2 hours. The immersion-pyrolysis process was repeated 4 times.

[0141] Using ethylene as the gas source and argon as the dilution gas, with an ethylene flow rate of 40 ml / min and an argon flow rate of 110 ml / min, the preform that has undergone impregnation-pyrolysis treatment was placed in a chemical vapor permeation reaction chamber. The reaction temperature was set at 900℃, the reaction pressure at 4 kPa, and the permeation time at 3 hours.

[0142] The composite material was placed in a high-temperature furnace, argon gas was introduced, and the temperature was raised to 2100℃ at a rate of 5℃ / min, and held for 3 hours.

[0143] The performance of the carbon / carbon composite materials obtained in Examples 1 to 6 and Comparative Examples 1 and 2 were measured respectively, and the comparison table is as follows:

[0144] By comparison, the embodiments employ various special-function carbon fibers, such as polyacrylonitrile-based carbon fibers providing a high strength base, pitch-based carbon fibers aiding in heat conduction, nano-silica-grafted carbon fibers enhancing interfacial bonding, and graphitized carbon fibers improving self-lubrication and conductivity. Furthermore, each carbon fiber is distributed in a gradient across different layers in a specific ratio. This synergistic effect of multiple carbon fiber types allows the material to effectively disperse stress under different stress modes (tension, compression, bending, and shear). In contrast, Comparative Example 1 uses a simple mixture of conventional polyacrylonitrile-based, viscose-based, and pitch-based carbon fibers, while Comparative Example 2 uses a combination of high-strength, high-modulus polyacrylonitrile-based and graphite fibers. These methods are less diverse and synergistic in terms of fiber functionality, resulting in significantly lower tensile, compressive, bending, and shear strengths compared to the embodiments. For example, the tensile strength in the embodiments is generally above 800-900 MPa, while in Comparative Example 1 it is only around 650-700 MPa. The examples used bio-asphalt and nano-graphene-modified phenolic resin as matrix precursors, and added silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide, yttrium oxide, and natural plant extract antioxidants. The combination of bio-asphalt and modified phenolic resin can form a more stable and high-quality carbon matrix during carbonization, improving the overall structural stability of the material. Silicon carbide whiskers and zirconium boride nanoparticles enhance the hardness and wear resistance of the material, and make a positive contribution to compressive and shear strength. Cerium oxide and yttrium oxide, together with antioxidants, significantly improve the antioxidant performance. Comparative Example 1 used ordinary phenolic resin and furan resin as matrix precursors. The additives in Comparative Example 1 are only silicon carbide particles and potassium titanate whiskers, which have limited strengthening and antioxidant effects on the matrix. The matrix precursors in Comparative Example 2 are coal tar pitch and modified phenolic resin. The additives boron oxide and titanium diboride mainly focus on antioxidant and high-temperature performance improvement, but they are not as good as the examples in terms of overall performance synergy. This makes the examples perform better in terms of high temperature resistance and antioxidant properties. For example, the high temperature resistance of the examples can generally reach above 2000℃, and the antioxidant property (oxidative weight loss rate) can be controlled at around 3% or even lower under the condition of 1500℃ / 10h. In contrast, the high temperature resistance of Comparative Example 1 is only around 1600℃, and the oxidation weight loss rate is as high as 7% or more.

[0145] The preform weaving in this embodiment employs a meticulously designed gradient structure and precise weaving parameter control. It initially uses a high-strength, high-modulus polyacrylonitrile-based carbon fiber inner layer, alternating between 0° and 90° weaving angles with high fiber density. Then, as it transitions to the outer layer, the fiber type and weaving angle are adjusted, and the fiber density is reduced, forming a preform structure with gradually changing mechanical and thermal properties. This weaving method allows the material to better adapt to stress and heat transfer requirements in different parts, effectively improving the material's overall performance. In contrast, the multi-directional weaving process in Comparative Example 1 and the needle-punching process in Comparative Example 2 are relatively simple and lack this performance-optimized gradient structure design, leading to internal… The stress distribution was not ideal, affecting the mechanical properties. In this embodiment, the woven preform underwent plasma treatment. The plasma power, treatment time, and a specific oxygen-argon mixture were used to etch and activate the carbon fiber surface, enhancing the bonding force between the carbon fiber and the subsequent matrix precursor. This step was not used in the comparative example, resulting in relatively weak interfacial bonding, making it prone to interfacial separation under stress and affecting the overall strength of the material, especially tensile and flexural strength. This embodiment used supercritical carbon dioxide-assisted impregnation, allowing the precursor solution to penetrate more fully into the pores of the preform. Combined with microwave curing, rapid and uniform curing was achieved. By reducing porosity and improving the density and uniformity of the matrix, the strength and stability of the material are enhanced. Comparative Example 1 uses conventional vacuum impregnation and oven curing, while Comparative Example 2 uses an impregnation-pyrolysis process. Both methods are inferior to the examples in terms of impregnation effect and curing uniformity, resulting in limited mechanical properties and high-temperature resistance. The examples utilize a thermal gradient chemical vapor deposition combined with pressure impregnation and infiltration process. By controlling parameters such as gas flow rate, temperature gradient, and pressure, carbon is directionally grown on the surface and in the pores of the preform and combines with the impregnated matrix, further densifying the carbon matrix, optimizing the material's microstructure, and improving its mechanical properties and high-temperature resistance. In terms of temperature performance, the chemical vapor deposition or chemical vapor infiltration process parameters in Comparative Examples 1 and 2 are relatively simple and lack this multi-step synergistic optimization process design, resulting in limited improvement in material performance. The embodiment uses a two-stage high-temperature heat treatment, first performing preliminary graphitization treatment at 1500-1800℃, and then performing deep graphitization treatment at 2000-2500℃, which gradually improves the carbon matrix structure and makes the crystal structure more regular, comprehensively improving the mechanical, thermal, and electrical properties of the material. The high-temperature heat treatment process in the comparative examples is relatively simple and lacks this precise temperature control and multi-stage treatment, resulting in limited improvement in material performance.

[0146] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0147] The various embodiments in this invention are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0148] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this disclosure is limited to these examples; within the framework of this disclosure, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of different aspects of one or more embodiments of the present invention as described above, which are not provided in detail for the sake of brevity.

[0149] Although this disclosure has been described in conjunction with specific embodiments thereof, many substitutions, modifications and variations of these embodiments will be apparent to those skilled in the art from the foregoing description.

[0150] One or more embodiments of the present invention are intended to cover all such substitutions, modifications, and variations that fall within the scope of protection of the present invention. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of one or more embodiments of the present invention should be included within the scope of protection of this disclosure.

Claims

1. A carbon / carbon composite material, characterized in that, The carbon / carbon composite material comprises, by weight percentage: 40%-55% polyacrylonitrile-based carbon fiber, 10%-25% pitch-based carbon fiber, 8%-20% nano-silica grafted carbon fiber, 8%-20% bio-asphalt, 8%-15% nano-graphene modified phenolic resin, 3%-6% silicon carbide whiskers, 2%-4% zirconium boride nanoparticles, 2%-4% graphitized carbon fiber, and 1%-3% natural plant extract antioxidants.

2. The carbon / carbon composite material according to claim 1, characterized in that, The carbon / carbon composite material comprises, by weight percentage: 42%-47% polyacrylonitrile-based carbon fiber, 10%-16% pitch-based carbon fiber, 10%-16% nano-silica grafted carbon fiber, 10% bio-asphalt, 10% nano-graphene modified phenolic resin, 4% silicon carbide whiskers, 3% zirconium boride nanoparticles, 3% graphitized carbon fiber, and 2% natural plant extract antioxidant.

3. The carbon / carbon composite material according to claim 1, characterized in that, The carbon / carbon composite material also includes 3%-6% rare earth oxides.

4. The carbon / carbon composite material according to claim 3, characterized in that, The rare earth oxides include 2%-4% cerium oxide and 1%-2% yttrium oxide.

5. A method for preparing a carbon / carbon composite material according to any one of claims 1-4, characterized in that, The preparation method includes: S1: Polyacrylonitrile-based carbon fiber, pitch-based carbon fiber, nano-silica grafted carbon fiber, and graphitized carbon fiber are woven in multiple layers according to an internal and external gradient structure to obtain a preform. S2: Place the woven preform into a plasma treatment device for plasma treatment; S3: Prepare a precursor solution containing bio-asphalt and nano-graphene modified phenolic resin. Add silicon carbide whiskers, zirconium boride nanoparticles, cerium oxide nanoparticles, yttrium oxide nanoparticles and natural plant extract antioxidants to the precursor solution. Then, sequentially or simultaneously subject the mixed solution to ultrasonic treatment and stirring treatment. S4: Place the preform into the impregnation container, inject the mixed solution and seal it, then fill the impregnation container with supercritical carbon dioxide; S5: Place the impregnated preform into a microwave curing device for curing. S6: Place the preform in a chemical vapor deposition reaction chamber for thermal gradient chemical vapor deposition; S7: The preform after chemical vapor deposition is placed in a pressure impregnation device, and the mixed solution is injected into the pressure impregnation device to permeate the preform to densify the carbon matrix. S8: The composite material that has undergone infiltration treatment is placed in a high-temperature heat treatment furnace for high-temperature heat treatment.

6. The method for preparing carbon / carbon composite materials according to claim 5, characterized in that, In step S2, the plasma power of the plasma processing device is 100-300 watts, the processing time is 10-30 minutes, and the gas is a mixture of oxygen and argon with an oxygen content of 10%-30%.

7. The method for preparing carbon / carbon composite materials according to claim 5, characterized in that, In step S3, the ultrasonic treatment time is 30-60 minutes, and the stirring treatment is carried out at 200-300℃ and 1000-2000 rpm for 60-120 minutes.

8. The method for preparing carbon / carbon composite materials according to claim 5, characterized in that, In step S4, supercritical carbon dioxide is introduced at a set pressure of 8-15 MPa, a temperature of 40-60°C, and an impregnation time of 2-4 hours. In step S5, the curing power is 500-1000 watts, the time is 10-20 minutes, and the temperature is 150-200℃.

9. The method for preparing carbon / carbon composite materials according to claim 5, characterized in that, In step S6, during the thermal gradient chemical vapor deposition of the preform, methane and hydrogen are used as gas sources, with a methane flow rate of 50-100 mL / min and a hydrogen flow rate of 200-400 mL / min. The center temperature of the thermal gradient is 800-1000℃, the edge temperature is 600-800℃, and the deposition time is 2-5 hours. In step S7, the pressure of the pressure impregnation equipment is 2-5 MPa, the temperature is 80-120°C, and the permeation treatment time is 1-3 hours.

10. The method for preparing carbon / carbon composite materials according to claim 5, characterized in that, Step S8 specifically includes: S81: Place the composite material in a high-temperature heat treatment furnace, introduce argon gas, heat to 1500-1800℃ at a heating rate of 3-8℃ / min, and hold for 1.5-3.5 hours; S82: Continue heating at a rate of 2-4℃ / minute to 2000-2500℃, and hold for 2.5-4.5 hours.

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