A method for preparing a carbon-based composite material, a carbon-based composite material and applications thereof

Abstract

The application belongs to the technical field of carbon-based composite material preparation, and specifically discloses a carbon-based composite material preparation method, a carbon-based composite material and application thereof. The method of the application takes a carbon fiber preform as a raw material, adopts an ultrafast high-temperature joule heat heating technology to sequentially perform pretreatment, graphitization treatment after rough layer pyrolytic carbon deposition, impregnation-crosslinking solidification-pyrolysis treatment, coating preparation and heat treatment, and matches corresponding ultrafast high-temperature joule heat heating specific technical methods according to the structure state and reaction characteristics of different preparation stages, and simultaneously combines temperature-resistance double feedback control treatment end points. The application cooperatively couples joule heat treatment with pretreatment, pyrolysis into carbon, in-situ reaction of ceramic phases, coating preparation and residual elemental phase consumption process, can shorten the preparation period, reduce interface thermal damage, and improve the ceramic phase distribution and friction interface stability. The obtained carbon-based composite material can be used for high-speed braking materials, aerospace thermal protection materials, wear-resistant structural parts and high-temperature components.

Description

Technical Field

[0001] This invention relates to the field of carbon-based composite material preparation technology, and in particular to a method for preparing carbon-based composite materials, carbon-based composite materials and their applications. Background Technology

[0002] Carbon-based composite materials possess characteristics such as high temperature resistance, low density, wear resistance, smooth braking, strong environmental adaptability, and long service life, making them promising for applications in high-speed braking systems and aerospace thermal protection. Their preparation typically begins with carbon fiber preforms, followed by pretreatment, chemical vapor infiltration pyrolysis for carbon densification, and graphitization to obtain porous C / C composite materials. These processes generally need to be completed separately in different specialized equipment, resulting in long production cycles, high energy consumption, and demanding equipment requirements.

[0003] To further achieve densification, porous C / C composites typically require processes such as chemical vapor infiltration (CVI), polymer impregnation pyrolysis (PIP), reactive melt infiltration (RMI), or slurry impregnation (SI) to fill the pores. Among these, CVI has a slow deposition rate and a long preparation cycle; PIP requires multiple impregnation-crosslinking curing-pyrolysis cycles, and the slow heating of traditional carbon tube furnaces easily leads to interface debonding, pore and crack accumulation; SI processes suffer from poor powder dispersion, uneven slurry penetration and coating, easily resulting in uneven ceramic phase distribution; while RMI can achieve rapid densification, it easily causes fiber damage, residual stress, and segregation of residual elemental and ceramic phases. These problems reduce the material's mechanical and tribological properties, and cause vibration, screeching, thermal degradation, fluctuations in the coefficient of friction, and accelerated wear during high-speed braking.

[0004] Regarding polymer impregnation and pyrolysis, Chinese patent CN116606158B discloses a method for rapidly preparing high-density C / C composite materials based on polyaryl acetylene resin. This method involves repeating the process of "vacuum impregnation-isostatic pressing-curing pyrolysis-graphitization" to produce high-density C / C composite materials. This method is energy-intensive, time-consuming, and requires various specialized equipment to produce high-density C / C composite materials. Regarding slurry impregnation processes, Chinese patent CN118495976B discloses a method for preparing carbon fiber reinforced multiphase ceramic matrix composite materials. This method involves impregnating a C / C preform in a resin slurry containing Ti powder, followed by crosslinking curing, pyrolysis carbonization, and heat treatment. Then, a silicon-zirconium mixed powder is used for reactive melting and infiltration to obtain a C / C-TiC-SiC-ZrC composite material. However, this method uses traditional equipment for all heat treatment steps, resulting in a slow heating rate, an overall preparation cycle of hundreds of hours, and the use of various specialized equipment, consuming a large amount of energy.

[0005] In recent years, ultrafast high-temperature Joule heating technology has attracted widespread attention due to its ultrafast heating rate and high energy efficiency. Chinese patent publication CN119874398A discloses a method for rapidly reactant infiltration to prepare ceramic matrix composites, applying Joule heating technology to the single RMI (Reactive Motion Infiltration) stage; Chinese patent publication CN121426582A discloses an ultrafast impregnation pyrolysis method for preparing ceramic matrix composites, applying Joule heating technology to the single PIP (Plasma Infiltration Infiltration) pyrolysis stage. However, neither of these methods involves key processes such as pretreatment, graphitization, heat treatment, and coating preparation, and the overall process chain is not integrated and accelerated.

[0006] Therefore, developing a rapid preparation process for carbon-based composite materials that can significantly shorten the preparation cycle while ensuring material properties has important engineering application value. Summary of the Invention

[0007] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention provides a method for preparing carbon-based composite materials. This invention establishes a staged, matched ultrafast high-temperature Joule heat treatment process targeting the structural state and reaction characteristics of carbon-based composite materials at different stages, including pre-treatment of the preform, graphitization treatment, impregnation pyrolysis, heat treatment, coating preparation, and post-heat treatment. Simultaneously, it combines temperature-resistance dual feedback control of the treatment endpoint and synergistically couples this process with the impregnation of resin slurry or resin-based slurry containing ceramic phase precursor powder, the formation of the ceramic phase, and the consumption of residual elemental phases. Therefore, this invention can, on the one hand, rapidly prepare high-density C / C composite materials with protective coatings; on the other hand, it can pre-construct uniform ceramic phase nucleation sites in porous C / C composite materials, and, combined with reactive melting and post-heat treatment, obtain carbon-based composite materials with uniform structure, low residual elemental phase, and stable tribological properties.

[0008] This invention deeply considers the significant differences in pore structure, thermal expansion behavior, and volatile component release behavior among carbon fiber preforms, porous C / C composites, C / C-resin preforms, C / C-ceramic resin preforms, and carbon-based composite preforms after reaction melting and infiltration. A staged, matched ultrafast high-temperature Joule heat treatment process is established, applying ultrafast high-temperature Joule heating technology to the entire integrated preparation process of carbon-based composites, rather than simply replacing the heating method or using Joule heating in a single step. Directly using a single rapid heating regime can easily lead to problems such as localized overheating, instantaneous release of resin decomposition gases, pore blockage, preform cracking, migration and agglomeration of ceramic phase precursor powders, uneven distribution of the ceramic phase, and incomplete reaction with residual elemental phases. This invention, through a staged, matched ultrafast high-temperature Joule heat treatment process, overcomes the technical concerns of rapidly treating porous preforms containing resin or slurry at high temperatures, achieving a balance between rapid preparation and structural stability control.

[0009] The present invention also provides a carbon-based composite material.

[0010] This invention also proposes the application of carbon-based composite materials.

[0011] A first aspect of the present invention provides a method for preparing a carbon-based composite material, comprising the following steps:

[0012] S1. The carbon fiber preform is pretreated by depositing a rough layer of pyrolytic carbon on the surface of the carbon fiber using chemical vapor infiltration, followed by graphitization treatment to obtain a porous C / C composite material.

[0013] S2. The porous C / C composite material is impregnated in resin slurry or resin-based slurry containing ceramic phase precursor powder, and impregnation, cross-linking curing and pyrolysis treatment are performed in sequence, followed by a first heat treatment to obtain C / C-resin preform or C / C-ceramic resin preform.

[0014] S3. Prepare a surface coating on the C / C-resin preform to obtain a carbon-based composite material; or,

[0015] The carbon-based composite material is obtained by introducing the melt-infiltrating powder into the C / C-ceramic resin preform using a reactive melt-infiltrating method, followed by a second heat treatment.

[0016] The pretreatment, graphitization treatment, pyrolysis treatment, first heat treatment, coating preparation and second heat treatment all adopt ultrafast high temperature Joule heating technology, combined with temperature-resistance dual feedback control.

[0017] According to specific embodiments of the present invention, unlike conventional Joule heating which is simply used for a single process, the carbon-based composite material preparation method provided by the present invention designs each heat treatment step and the material structure evolution process as a continuous process chain; the pretreatment stage is used to remove the sizing agent on the fiber surface and activate the interface; the graphitization stage is used to enhance the graphitization degree of the carbon matrix and reduce interface damage caused by long-term high-temperature treatment; the impregnation and pyrolysis stage forms a uniform microporous structure through short-term controlled heating; the first heat treatment stage promotes the in-situ reaction between the ceramic phase precursor powder and the resin carbon to form fine ceramic phase nucleation sites; the coating preparation stage allows the coating raw materials to enter the surface and near-surface pores of the C / C-resin preform through gas phase migration, surface diffusion or infiltration deposition under short-term high temperature, forming a continuous, dense, stable protective coating with gradient transition characteristics; the second heat treatment stage further consumes the residual elemental phase, releases residual stress and stabilizes the ceramic phase structure; the present invention utilizes the connection between each step to jointly achieve rapid preparation, uniform microstructure and reduction of residual elemental phase.

[0018] According to some embodiments of the present invention, the ultrafast high-temperature Joule heating technology includes continuous Joule heat treatment, segmented rate-limited pulse Joule heat treatment, or finite temperature difference pulse Joule heat treatment.

[0019] Based on the pore structure, volatile component release behavior, reaction characteristics, and thermal stress sensitivity of the material to be treated in different processing stages, this invention allows for the selection of appropriate Joule heat treatment methods. Preferably, continuous Joule heat treatment is used in the pretreatment and graphitization stages to achieve functions such as degumming activation of the carbon fiber surface and ordered carbonization through pyrolysis; segmented rate-limited pulsed Joule heat treatment is used in the pyrolysis stage to achieve functions such as staged devolatification of the resin precursor, carbonization shrinkage control, and high-temperature carbonization stabilization; and limited temperature difference pulsed Joule heat treatment is used in the first heat treatment, coating preparation, and second heat treatment stages to promote in-situ reaction of the ceramic phase precursor powder, near-surface deposition reaction of the coating, and further consumption of residual elemental phases after reaction melting and infiltration.

[0020] According to some embodiments of the present invention, the continuous Joule heat treatment refers to a Joule heat treatment method in which the temperature is first raised to the target processing temperature, held at that temperature, and then cooled down when the resistance change rate during the continuous heating process is less than 0.5% to 5%. This method is suitable for stages such as pretreatment and graphitization, where continuous heating and stable high-temperature processing are the main processes.

[0021] According to some embodiments of the present invention, the segmented rate-limited pulsed Joule heat treatment refers to a treatment method in which the temperature is first increased in stages and then held for a short time according to different temperature ranges, and then the temperature is increased to the target treatment temperature and multiple Joule heat pulses are introduced. When the resistance change rate of two or more consecutive Joule heat pulses is less than 0.5% to 5%, the temperature is reduced to room temperature. Each Joule heat pulse includes a rapid heating stage, a short holding stage, and an intermediate cooling stage. This treatment method is mainly aimed at the pyrolysis process of porous green bodies containing resin or slurry. The staged heating and short holding are used to control the gradual release of solvents, low-molecular-weight volatiles, and pyrolysis gases in the resin precursor, reducing the risk of green body cracking, pore blockage, and migration of ceramic phase precursor powder. The subsequent Joule heat pulses are used to further promote the conversion of pyrolysis products and stabilize the carbon structure of the resin. Thus, the segmented rate-limited pulsed Joule heat treatment forms a treatment mechanism of "staged gas release and controlled compression - high-temperature pulse stabilization".

[0022] According to some embodiments of the present invention, the finite temperature difference pulsed Joule heat treatment refers to a treatment method in which the temperature is first raised to the target processing temperature at a set heating rate, and then subjected to multiple Joule heat pulses. When the resistance change rate of two or more consecutive Joule heat pulses is less than 0.5% to 5%, the temperature is lowered to room temperature. Each Joule heat pulse includes a rapid heating stage, a short-term holding stage, and an intermediate cooling stage. This treatment method is mainly aimed at ceramic phase formation, coating preparation, and post-reaction melting and infiltration processes. It allows the material to enter the short-term high-temperature reaction window multiple times, promoting in-situ reaction of the ceramic phase, coating penetration and deposition, and the consumption and transformation of residual elemental phases, while reducing grain coarsening, interfacial thermal damage, and local overheating caused by prolonged continuous high-temperature holding. Thus, the finite temperature difference pulsed Joule heat treatment forms a treatment mechanism of "short-term high-temperature reaction - finite temperature difference buffer - repeated activation".

[0023] According to some embodiments of the present invention, the temperature-resistance dual feedback control refers to the real-time acquisition of voltage, current, and material surface temperature at both ends of the blank, graphite crucible, graphite fixture, or conductive carrier during ultrafast high-temperature Joule heating, and the calculation of resistance value or resistance change rate based on voltage and current. The material surface temperature is used to determine whether the external heat treatment conditions have reached the preset treatment temperature, and the resistance value or resistance change rate reflects changes in the overall conductive network, carbon structure adjustment, ceramic phase formation, residual elemental phase reaction, or coating formation process of the blank. When the material surface temperature reaches the preset treatment temperature, and the resistance change rate during continuous heating is lower than a preset threshold of 0.5% to 5%, or the resistance change rate after two or more consecutive finite temperature difference Joule heat pulses is lower than the preset threshold, it is determined that the internal reaction process of the material in this stage tends to stabilize, and the holding time is ended, the heating power is reduced, the next Joule heat pulse is initiated, or the Joule heat treatment of this stage is terminated. This control method can reduce insufficient or excessive heat treatment caused by judging the treatment endpoint solely based on material surface temperature or fixed holding time, and improve the stability and repeatability of the processing of porous blanks in different batches.

[0024] According to some embodiments of the present invention, in step S1, the pretreatment and the graphitization treatment are carried out by continuous Joule heat treatment at a heating rate of 30~80 ℃ / s, heating to 1800~2200 ℃ and holding for 15~60 min. When the resistance change rate during the continuous heating process is less than 0.5%~5%, the temperature is reduced to room temperature at a cooling rate of 5~20 ℃ / s.

[0025] This invention employs continuous Joule heat treatment to perform high-temperature degumming and surface activation treatment on carbon fiber preforms. Through the above treatment, sizing agents and volatile impurities on the carbon fiber surface can be removed in a short time, resulting in a clean and highly active fiber surface, and reducing the thermal damage to the fiber and interface caused by traditional long-term high-temperature treatment. The controlled cooling process also helps to reduce the thermal stress generated after rapid heat treatment, providing a stable interface basis for subsequent pyrolytic carbon deposition of the roughening layer.

[0026] Then, a roughened pyrolytic carbon layer is deposited on the surface of the pretreated carbon fiber preform. The formed roughened pyrolytic carbon layer increases the contact area between the subsequent resin or resin-based slurry containing ceramic phase precursor powder and the fiber surface, improving the wetting uniformity and interfacial bonding effect. On the other hand, when further reaction and melting are required, the roughened pyrolytic carbon layer can serve as a preferential reaction carbon source to generate a ceramic phase, reducing the direct erosion of the carbon fiber body. It also improves the mechanical interlocking, crack deflection ability and frictional stability between the ceramic phase and the carbon matrix through the roughened interface.

[0027] After deposition, graphitization is performed again using continuous Joule heat treatment. Through ultrafast high-temperature graphitization, the pyrolytic carbon in the deposited rough layer can enhance the graphitization degree and thermal conductivity in a very short time, and reduce the risk of thermal shock damage in subsequent high-temperature treatment. At the same time, it avoids fiber / matrix interface debonding and microcrack propagation caused by long-term heat preservation and reduces thermal damage, resulting in porous C / C composite material.

[0028] According to some embodiments of the present invention, in step S1, the pretreatment process is carried out under a vacuum or inert atmosphere;

[0029] The chemical vapor infiltration method uses a mixed gas with propylene as the carbon source and nitrogen as the diluent to deposit carbon in the rough layer through pyrolysis. The flow ratio of propylene to nitrogen is (1~4):1, the deposition temperature is 900~1200 ℃, the furnace pressure is 0.5~1.0 kPa, and the time is 60~120 h.

[0030] According to some embodiments of the present invention, in step S2, the pyrolysis process employs segmented rate-limited pulsed Joule heat treatment; the segmented rate-limited pulsed Joule heat treatment includes a low-temperature devolatification stage, a medium-temperature carbonization shrinkage control stage, and a high-temperature carbonization pulse stabilization stage; wherein, in the low-temperature devolatification stage, the temperature is increased to 250-400°C at a rate of 1-3°C / s and held for 1-3 minutes; in the medium-temperature carbonization shrinkage control stage, the temperature is increased to 600-800°C at a rate of 0.5-1.5°C / s and held for 1-3 minutes; then, 2-6 Joule heat pulses are introduced as the high-temperature carbonization pulse stabilization stage; when the resistivity change rate of two or more consecutive Joule heat pulses is less than 0.5%-5%, the temperature is reduced to room temperature at a rate of 5-10°C / s; each Joule heat pulse includes a rapid heating stage, a short-term holding stage, and an intermediate cooling stage; wherein, in the rapid heating stage, the temperature is increased to the target temperature of 900-1200°C at a rate of 5-10°C / s. The temperature is set at ℃, with a short holding time of 1~5 min. During the intermediate cooling phase, the temperature drops to 75%~90% of the target temperature before entering the next Joule thermal pulse.

[0031] This invention employs segmented, rate-limited pulsed Joule heat treatment in the pyrolysis process. First, a low-temperature devolatification stage and a medium-temperature carbonization shrinkage control stage gradually release solvents, low-molecular-weight volatiles, and pyrolysis gases from the resin precursor, reducing the risk of green body cracking, pore blockage, and ceramic phase precursor powder migration caused by rapid heating. Subsequently, a high-temperature carbonization pulsed stabilization stage promotes further transformation of pyrolysis products and stabilizes the resin's carbon structure. This treatment method can shorten the pyrolysis cycle while improving the stability of the pore structure after pyrolysis, providing stable channels and interfacial foundations for subsequent impregnation, heat treatment, and reactive melting.

[0032] According to some embodiments of the present invention, in step S2, in the first heat treatment, a finite temperature difference pulsed Joule heat treatment is used to raise the temperature to the target temperature of 1600-2800 ℃ at a rate of 5-15 ℃ / s, and then subject it to 4-8 Joule heat pulses. When the resistivity change rate is less than 0.5%-5% after two or more consecutive Joule heat pulses, the temperature is lowered to room temperature at a rate of 3-8 ℃ / s. Specifically, the rapid heating phase of the Joule heat pulse raises the temperature to the target treatment temperature of 1600-2800 ℃ at a rate of 10-20 ℃ / s, with a short holding time of 3-5 min. The intermediate cooling phase lowers the temperature to 65%-85% of the target temperature before the next Joule heat pulse begins.

[0033] According to some embodiments of the present invention, in step S2, the resin slurry comprises a resin precursor I and a solvent, wherein the resin precursor I comprises at least one of furan resin, phenolic resin, benzoxazine resin or polyarylacetylene resin;

[0034] The resin-based slurry containing ceramic phase precursor powder comprises ceramic phase precursor powder, resin precursor II, silane coupling agent, cellulose acetate butyrate, surfactant, and solvent. The ceramic phase precursor powder includes at least one element or alloy of Si, Ti, Zr, Hf, Ta, and W. The resin precursor II includes at least one of furan resin, phenolic resin, polyimide resin, benzoxazine resin, or polyarylacetylene resin.

[0035] According to some embodiments of the present invention, the mass ratio of the ceramic phase precursor powder, resin precursor II, silane coupling agent, cellulose acetate butyrate, surfactant and solvent is (20~40):(30~65):(3~8):(4~9):(4~9):(10~20).

[0036] The above-mentioned proportions in this invention are not arbitrarily selected, but are used to adapt to the subsequent ultrafast high-temperature Joule thermal decomposition and heat treatment process: when the content of ceramic phase precursor powder is too low, there are insufficient nucleation sites for ceramic phase in the green body, and coarse ceramic grains and residual elemental phases are easily formed during the subsequent reaction melting process; when the content of ceramic phase precursor powder is too high, the powder is prone to sedimentation and the viscosity of the slurry increases, making it difficult to enter the internal pores of the C / C composite material, and powder migration, agglomeration and pore blockage are easily generated during the rapid decomposition process.

[0037] According to some embodiments of the present invention, the solvent includes at least one of acetone, anhydrous ethanol, or ethylene glycol.

[0038] This invention uses a resin precursor as a carrier and carbon source for ceramic phase precursor powder; a silane coupling agent is used to establish an interfacial connection between the ceramic phase precursor powder surface and the resin precursor, reducing the risk of interfacial debonding between the ceramic phase precursor powder and the resin carbon during rapid pyrolysis; cellulose acetate butyrate is used to improve the uniformity of slurry coating and penetration, reducing pore blockage caused by local enrichment; and a surfactant is used to improve the dispersion stability of the ceramic phase precursor powder in the resin system, reducing sedimentation during standing and impregnation.

[0039] According to some embodiments of the present invention, in step S2, the impregnation, cross-linking curing and pyrolysis treatments are repeated 2 to 8 times in sequence, and after each 2 repetitions, a first heat treatment is performed.

[0040] According to some embodiments of the present invention, the impregnation employs a combination of vacuum impregnation and pressure impregnation to ensure that the resin precursor fully penetrates the internal pores of the porous C / C composite material. The vacuum impregnation is performed at a vacuum level of -0.1 MPa, an impregnation temperature of 40–45 °C, and an impregnation time of 1–2 h. Subsequently, pressure impregnation is performed using nitrogen gas as the pressure source, at a pressure of 3–6 MPa, for an impregnation time of 2–3 h, and at an impregnation temperature of 50–60 °C. The crosslinking and curing pressure is 3–6 MPa, the temperature is 80–180 °C, and the holding time is 2–10 h.

[0041] The use of the above-mentioned additives, together with vacuum impregnation, pressure impregnation, and Joule thermal rapid pyrolysis, allows the ceramic phase precursor powder to enter the interior of the porous C / C composite material along with the resin precursor, and forms a uniformly distributed microporous structure and ceramic phase nucleation sites after pyrolysis.

[0042] Traditional multi-stage pyrolysis processes involve long heating, holding, and cooling times, and repeated thermal cycling can easily lead to uneven resin carbon shrinkage, accumulation of pore cracks, and debonding at the fiber / matrix interface. This invention employs segmented, rate-limited pulsed Joule heat treatment during the pyrolysis stage, allowing for the gradual release of solvents, low-molecular-weight volatiles, and pyrolysis gases, reducing the risk of green body cracking, pore blockage, and migration of ceramic phase precursor powders. Simultaneously, short-duration controlled high-temperature carbonization stabilizes the resin carbon structure. The microporous structure formed by pyrolysis provides infiltration channels and ceramic phase nucleation sites for subsequent reaction melting and infiltration, which helps improve microstructure uniformity and reduce residual elemental phases.

[0043] This invention, by placing the first heat treatment between multiple impregnation-pyrolysis cycles, can remove residual volatile components, stabilize the pore structure formed after pyrolysis, reduce the risk of pore blockage and green body cracking during subsequent rapid heating processes, and improve the penetration uniformity and densification efficiency of the next round of resin or slurry impregnation. For C / C-resin green bodies, the first heat treatment can further promote the stability of the resin carbon structure and improve the thermal stability of the green body; for C / C-ceramic resin green bodies, the first heat treatment can promote the in-situ reaction between ceramic phase precursor powder and resin carbon, forming dispersed ceramic phase nucleation sites, providing a basis for the uniform generation of ceramic phase and grain refinement during subsequent reaction melting and infiltration processes.

[0044] According to some embodiments of the present invention, in step S3, during the coating preparation, a finite temperature difference pulsed Joule heat treatment is used to raise the temperature to the target treatment temperature of 1800-2400 °C at a rate of 50-60 °C / s, followed by 3-8 Joule heat pulses. When the resistivity change rate is less than 0.5%-5% after two or more consecutive Joule heat pulses, the temperature is lowered to room temperature at a rate of 3-8 °C / s. Specifically, the rapid heating phase of the Joule heat pulse raises the temperature to the target treatment temperature of 1800-2400 °C at a rate of 80-90 °C / s, with a short holding time of 3-5 min. The intermediate cooling phase lowers the temperature to 65%-85% of the target temperature before the next Joule heat pulse.

[0045] According to some embodiments of the present invention, in step S3, the second heat treatment employs a finite temperature difference pulsed Joule heat treatment, heating to a target temperature of 1700-2200 °C at a rate of 5-15 °C / s, followed by 4-8 Joule heat pulses. When the resistivity change rate is less than 0.5%-5% after two or more consecutive Joule heat pulses, the temperature is reduced to room temperature at a rate of 3-8 °C / s. Specifically, the rapid heating phase of the Joule heat pulse reaches the target temperature of 1700-2200 °C at a rate of 10-20 °C / s, with a short holding time of 2-3 minutes. The intermediate cooling phase reduces the temperature to 65%-85% of the target temperature before the next Joule heat pulse begins.

[0046] In this invention, the first heat treatment, coating preparation, and second heat treatment all employ finite-difference pulsed Joule heat treatment, but each stage serves a different purpose. The first heat treatment stabilizes the pore structure and resin carbon structure after pyrolysis and promotes the in-situ reaction between the precursor powder and resin carbon in the system containing ceramic phase precursor powder, forming dispersed ceramic phase nucleation sites. The coating preparation allows the coating raw materials to undergo gas phase migration, surface diffusion, infiltration deposition, and interfacial reaction at short-term high temperatures, entering the surface and near-surface pores of the C / C-resin preform to form a stable protective coating. The second heat treatment promotes further reaction of the residual elemental phase after reaction melting and infiltration, releases residual stress, and stabilizes the ceramic phase structure. This treatment method, through multiple short-term high-temperature reactions and intermediate cooling buffers, balances reaction activation and thermal shock control, which is beneficial for reducing interfacial thermal damage, inhibiting ceramic phase coarsening, and improving the structural stability of the material.

[0047] According to some embodiments of the present invention, in step S3, the raw material for the coating preparation includes at least one of elemental powder or alloy powder of Si, Ti, Zr, Hf, and Ta.

[0048] The reaction melting infiltration method involves heating to 1600~2100 ℃ under vacuum or inert gas atmosphere and holding at that temperature for 60~150 min; the melting infiltration powder includes at least one of elemental or alloyed Si, Ti, Zr, Hf, and Ta.

[0049] According to some embodiments of the present invention, the melt-infiltrating powder is preferably a Si-based, Si-Ti-based, Si-Zr-based, Si-Hf-based, or Si-Ta-based melt-infiltrating system that can form a liquid phase at 1600~2100 °C.

[0050] This invention utilizes finite-difference pulsed Joule heating technology. Each Joule heating pulse allows the coating raw material to reach a highly reactive state within a short time. It then enters the surface and near-surface pores of the C / C-resin preform through gas-phase migration, surface diffusion, and surface deposition. During short-term holding and intermediate cooling, it undergoes deposition, diffusion, or in-situ reaction with resin carbon or pyrolytic carbon. Repeated pulse treatment facilitates the formation of a dense, continuous, and well-bonded protective coating. Because the temperature only drops to an intermediate range between adjacent pulses rather than room temperature, thermal shock at the coating / substrate interface is reduced while maintaining a certain level of diffusion activity. Compared to traditional furnace heat treatment, embedding methods, or slurry sintering coatings, this method features rapid heating, short holding times, and minimal thermal damage to the substrate. This helps suppress coating grain coarsening and forms reactive bonds or gradient transition structures near the material surface, improving the bonding stability between the coating and the substrate and enhancing high-temperature protection.

[0051] During the reaction melting process, the liquid melting agent enters the pores of the green body under the action of capillary force, and reacts with the carbon matrix, resin carbon and pre-placed ceramic phase precursor powder in situ, interface, or solid solution, thereby promoting the uniform generation of ceramic phase inside the green body and reducing local ceramic phase segregation, pore closure and enrichment of residual elemental phase.

[0052] After the carbon-based composite material is prepared, high-temperature heat treatment can promote the release of residual stress, the improvement of ceramic phase crystallization, and the further reaction of residual elemental phases, while avoiding excessive growth of ceramic grains, thereby improving the material's thermal shock resistance, mechanical properties, and tribological stability. Compared with traditional furnace heat treatment, finite-difference Joule heating technology has the characteristics of rapid heating, short holding time, and minimal thermal damage. It allows the carbon-based composite material to enter the short-term high-temperature window of 1700~2200 ℃ multiple times, which can promote the further reaction between the residual elemental phase and the carbon matrix, reduce the residual elemental phase, and inhibit the coarsening of ceramic phase grains. Therefore, the Joule heat treatment in this invention is not a simple replacement for traditional furnace heat treatment, but rather achieves synergistic regulation of residual phase consumption, grain refinement, interface stability, and performance improvement through short-term high-temperature and rapid heating and cooling processes. It is particularly suitable for the rapid post-treatment of C / C-SiC and multi-component carbide-modified C / C-SiC composite materials after RMI.

[0053] This invention systematically applies ultrafast high-temperature Joule heating technology to pretreatment, graphitization, pyrolysis, first heat treatment, coating preparation and / or heat treatment after reaction melting and infiltration. However, its technical effect does not come from a simple replacement of the heating method, but from the matching between different stages of Joule heat treatment methods, heating rate, treatment temperature, holding time, intermediate cooling range, number of pulses and temperature-resistance feedback endpoint control. The pretreatment and graphitization stages employ high heating rates and short-duration high-temperature treatments to activate the fiber surface and order the pyrolytic carbon. The pyrolysis stage uses relatively low heating rates and short-duration holding times to avoid instantaneous release of resin pyrolysis gases that could cause cracking of the green body or blockage of pores. The first heat treatment stage uses high-temperature short-duration treatment to induce in-situ reaction between the ceramic phase precursor powder and the resin carbon, inhibiting ceramic grain growth and forming dispersed ceramic phase nucleation sites. The coating preparation stage uses short-duration high-temperature pulse treatment to promote the penetration, deposition, and reaction of coating raw materials on the substrate surface and near-surface pores, forming a stable protective coating. The second heat treatment stage is carried out after reaction melting and infiltration to promote further reaction between residual elemental or alloy phases such as Si, Ti, Zr, Hf, and Ta and the carbon matrix or pre-placed ceramic phase. Thus, this invention can achieve ceramic phase refinement, reduction of residual elemental phases, and stabilization of the friction interface while shortening the cycle time.

[0054] In a second aspect, the present invention provides a carbon-based composite material, which is prepared by the preparation method described in the first aspect of the present invention.

[0055] A third aspect of the invention provides the application of the carbon-based composite material as described in the second aspect of the invention, the application including the use of the carbon-based composite material in the preparation of high-speed braking materials, aerospace thermal protection materials, wear-resistant structural parts or high-temperature components.

[0056] The beneficial effects of this invention are:

[0057] 1) This invention matches ultrafast high-temperature Joule heating technology with the structural evolution process of different preparation stages of carbon-based composite materials, rather than simply replacing traditional furnace heating. By employing continuous Joule heating, segmented rate-limited pulse Joule heating, and finite temperature difference pulse Joule heating in the pretreatment, graphitization, pyrolysis, first heat treatment, coating preparation, and / or second heat treatment stages, respectively, and combining temperature-resistance dual feedback control, the stability of the process can be determined based on temperature and resistance changes, allowing rapid heating, short-term holding, and end-point control to work together. This reduces the preparation cycle of the traditional route (over 400 hours) to approximately 140-160 hours, while reducing the risks of local overheating, insufficient reaction, or excessive heat treatment, achieving a rapid and controlled preparation process.

[0058] 2) This invention addresses the problems of rapid cracking, pore blockage, and powder migration in porous preforms containing resin or slurry. It employs segmented, rate-limited pulsed Joule heat treatment to gradually release solvents, low-molecular-weight volatiles, and pyrolysis gases, while stabilizing the resin carbon structure through high-temperature, short-duration pulses. Simultaneously, the first heat treatment is placed between multiple impregnation-pyrolysis cycles to remove residual volatile components, stabilize the pyrolysis pore structure, and improve the penetration uniformity and densification efficiency of subsequent resin or slurry impregnation. This design creates a continuous connection between the pyrolysis, pore formation, carbonization, and re-impregnation processes, which is beneficial for obtaining C / C-resin preforms or C / C-ceramic resin preforms with more stable structures and higher densification.

[0059] 3) This invention utilizes the synergistic effects of resin-based slurry impregnation containing ceramic phase precursor powder, pre-nucleation through a first heat treatment, reactive melting and infiltration, and post-heat treatment to allow the ceramic phase precursor powder to penetrate into the porous C / C composite material and form dispersed nucleation sites. This promotes the uniform formation of ceramic phases such as SiC and ZrC, and reduces residual elemental phases and intermediate compounds. Simultaneously, the finite-difference pulsed Joule heat treatment can also be used for coating preparation, promoting the deposition, diffusion, and reaction of coating raw materials on the substrate surface and near-surface pores. Therefore, this invention can simultaneously improve microstructure uniformity, interface stability, coating adhesion, and tribological properties, making it suitable for high-speed braking materials, aerospace thermal protection materials, wear-resistant structural components, and high-temperature components.

[0060] 4) This invention still possesses the advantages of low energy consumption, high equipment integration, and good process compatibility. Since Joule heat treatment only involves rapid heating of the conductive blank or graphite crucible system during key heat treatment stages, eliminating the need for prolonged heating of the entire furnace, it reduces the energy consumption per unit product. Simultaneously, pretreatment, graphitization, pyrolysis, heat treatment, and coating preparation steps can be completed on a similar Joule heat treatment equipment platform, facilitating subsequent industrial scale-up. This effect, as an auxiliary advantage of this invention, together with the aforementioned structural control and performance improvement, constitutes the comprehensive technical effect of this invention.

[0061] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0062] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0063] Figure 1 The images shown are SEM images of the high-density C / C-resin preform of Embodiment 1 of the present invention. Image a is a SEM image magnified 1000 times, and image b is a SEM image magnified 5000 times.

[0064] Figure 2These are SEM images of SiC-coated C / C-resin preforms from Embodiment 1(a) and Comparative Example 2(b) of the present invention;

[0065] Figure 3 This is a SEM image of the C / C-ceramic resin preform of Example 2 of the present invention;

[0066] Figure 4 This is a comparison of the friction curves of the C / C-SiC-ZrC composite materials of Example 2 and Comparative Example 4 of the present invention;

[0067] Figure 5 The images show a comparison of XRD analyses of the C / C-SiC-ZrC composite materials from Example 2 and Comparative Example 4 of this invention. Detailed Implementation

[0068] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0069] In the specific implementation method, unless otherwise specified, the standard conditions or the manufacturer's recommended conditions shall be followed. Reagents or instruments whose manufacturers are not specified are all commercially available products.

[0070] In a specific implementation, ultrafast high-temperature Joule heating technology refers to a heating treatment technology that uses an electric current to generate Joule heat through a conductive blank, graphite crucible, graphite fixture or other conductive carrier to rapidly raise the temperature of the material body or the area near the sample. The heating rate can be adjusted according to the material state and the processing stage, and the maximum operating temperature can reach about 3000 ℃.

[0071] In the specific implementation method, the bulk density and apparent porosity of the material are measured with reference to the QB / T-1642-2012 standard; the bending performance is tested with reference to the GB / T 6569-2006 standard; a reciprocating friction and wear tester is used, with SiC balls as the grinding balls, a friction load of 80 N, a friction stroke of 10 mm, a speed of 100 mm / s, and a test at room temperature for 30 min. The average value of the last 10 min of the friction curve is taken as the average friction coefficient, and the wear resistance of the material is evaluated using the specific wear rate.

[0072] Example 1

[0073] This embodiment provides a method for preparing high-density carbon-based composite materials with SiC coating using ultrafast high-temperature Joule heating technology. The specific steps are as follows:

[0074] 1) Pretreatment and graphitization of carbon fiber preforms:

[0075] Take a bulk density of 0.55 g / cm³ 3 The T300 needle-punched carbon fiber preform was clamped between the electrodes of the Joule heating device; the furnace pressure was evacuated to ≤10 Pa, and then argon gas was introduced; continuous Joule heat treatment was adopted, heating to 1900 ℃ at a heating rate of 60 ℃ / s and holding for 30 min, and when the resistance change rate during the continuous heating process was 2%, cooling to room temperature at a cooling rate of 15 ℃ / s to complete the pretreatment.

[0076] The pretreated carbon fiber preform was placed in a chemical vapor infiltration furnace and deposited using propylene as the carbon source and nitrogen as the diluent gas. The process parameters were: propylene flow rate 3 L / min, nitrogen flow rate 1 L / min, furnace pressure 0.95 kPa, deposition temperature 1100 ℃, and deposition time 90 h, yielding a density of approximately 0.88 g / cm³. 3 Porous C / C composite materials with a rough layer of pyrolytic carbon;

[0077] The porous C / C composite material with a rough layer of pyrolytic carbon deposited is then clamped between the electrodes of the Joule heating device, and the furnace pressure is evacuated to ≤10 Pa. Argon gas is then introduced. The temperature is increased to 2100 ℃ at a heating rate of 60 ℃ / s and held for 30 min. When the resistance change rate during the continuous heating process is 2%, the temperature is then cooled to room temperature at a cooling rate of 10 ℃ / s to complete the graphitization process.

[0078] 2) Impregnation-crosslinking curing-pyrolysis treatment and first heat treatment:

[0079] The graphitized porous C / C composite material was impregnated in polyaryl acetylene resin with acetone as the solvent. First, it was vacuum impregnated for 2 h at a vacuum degree of -0.1 MPa and an impregnation temperature of 45 ℃. Then, it was subjected to pressure impregnation and cross-linking curing at a pressure of 3.5 MPa, an impregnation temperature of 60 ℃, an impregnation time of 3 h, and cross-linking curing for 10 h at a curing temperature of 140 ℃.

[0080] The pyrolysis was carried out using segmented rate-limited pulsed Joule heat treatment. First, in the low-temperature devolatification stage, the temperature was increased to 300 ℃ at 2 ℃ / s and held for 3 min. In the medium-temperature carbonization shrinkage control stage, the temperature was increased to 700 ℃ at 1 ℃ / s and held for 2 min. Then, in the high-temperature carbonization pulse stabilization stage, the temperature was rapidly increased to the target temperature of 1200 ℃ at 8 ℃ / s and held for 3 min. In the intermediate cooling stage, the temperature was reduced to 90% of the target temperature before the next Joule heat pulse. Subsequently, four Joule heat pulses were performed. When the resistance change rate of the last two Joule heat pulses was less than 1%, the temperature was reduced to room temperature at 8 ℃ / s.

[0081] The impregnation-crosslinking curing-pyrolysis cycle was repeated 6 times, with a first heat treatment performed after every 2 cycles. The first heat treatment employed finite-difference pulsed Joule heating, with a temperature increase of 10 °C / s to the target temperature of 2800 °C, followed by 5 finite-difference Joule heat pulses. After the last two Joule heat pulses, when the resistivity change was less than 1%, the temperature was reduced to room temperature at 5 °C / s. The rapid heating phase of the Joule heat pulse involved a temperature increase to 2800 °C at 15 °C / s, a short holding time of 5 min, and an intermediate cooling phase where the temperature was reduced to 85% of the target temperature before the next Joule heat pulse.

[0082] A C / C-resin preform was obtained, and its density was measured to be 1.86 g / cm³. 3 The open area ratio is 5.41%, as observed under a scanning electron microscope. Figure 1 As shown.

[0083] 3) Coating preparation:

[0084] A C / C resin preform was placed in a Joule heating apparatus, with silicon powder placed near the surface of the preform. The apparatus was evacuated to ≤10 Pa and argon gas was introduced. A finite-difference pulsed Joule heating process was then employed, raising the temperature to the target processing temperature of 2000 °C at a rate of 60 °C / s. This was followed by five finite-difference Joule heating pulses. After the last two Joule heating pulses, when the resistivity change rate was less than 1%, the temperature was lowered to room temperature at a rate of 5 °C / s. The rapid heating phase of the Joule heating pulse involved raising the temperature to 2000 °C at 85 °C / s with a short holding time of 3 min. The intermediate cooling phase reduced the temperature to 80% of the target temperature before the next Joule heating pulse. At the high temperature of 2000 °C, the silicon powder formed a gaseous state and diffused, deposited, and reacted with the carbon matrix on the surface and near-surface pores of the C / C resin preform to form a SiC coating.

[0085] A smooth, continuous, dense, and stable protective coating with gradient transition characteristics is formed on the C / C-resin preform. The coating thickness is approximately 150 μm. Scanning electron microscopy observation shows... Figure 2 As shown in Figure a.

[0086] Comparative Example 1

[0087] This comparative example provides a method for creating a SiC-coated carbon-based composite material, the specific steps of which are as follows:

[0088] This comparative example is used to illustrate the effects of segmented rate-limited pulse pyrolysis treatment and limited temperature difference pulse first heat treatment on gas release, micropore construction, pore structure stability and subsequent impregnation densification effect of C / C-resin preform. Except for the pyrolysis treatment and first heat treatment process in step 2) impregnation-crosslinking curing-pyrolysis treatment and the first heat treatment stage, the other steps and processes are the same as in Example 1.

[0089] Specifically, porous C / C composite materials were prepared according to the method in Example 1, followed by impregnation-crosslinking curing-pyrolysis treatment and heat treatment stages. However, the pyrolysis treatment involved heating to the target temperature of 1200 °C at a rate of 30 °C / s, holding at that temperature for 30 min, and then cooling to room temperature at a rate of 5 °C / s; the first heat treatment involved heating to the target temperature of 2800 °C at a rate of 20 °C / s, holding at that temperature for 30 min, and then cooling to room temperature at a rate of 5 °C / s. Finally, a coating was prepared to form a carbon-based composite material with a SiC coating.

[0090] A C / C-resin preform was obtained, and its density was measured to be 1.78 g / cm³. 3 The open area ratio is 8.64%.

[0091] Comparative Example 2

[0092] This comparative example provides a method for preparing SiC-coated carbon-based composite materials using a conventional carbon tube furnace, with the specific steps as follows:

[0093] 1) Pretreatment and graphitization of carbon fiber preforms:

[0094] The same T300 carbon fiber needled preform as in Example 1 was selected and placed in a large carbon tube furnace. After evacuating to ≤10Pa, argon gas was introduced and heated to 1900 ℃ at a heating rate of 5 ℃ / min. The temperature was held for 2 h and then naturally cooled to room temperature with the furnace to complete the pretreatment.

[0095] The CVI deposition process was the same as in Example 1, yielding a density of approximately 0.88 g / cm³. 3 Porous C / C composite material; The deposited porous C / C composite material was placed in a large graphitization furnace, and after being evacuated to ≤10 Pa, argon gas was introduced and heated to 2100 ℃ at a heating rate of 5 ℃ / min, held for 2 h, and then naturally cooled to room temperature with the furnace to complete the graphitization process.

[0096] 2) Impregnation-crosslinking curing-pyrolysis treatment and first heat treatment:

[0097] The resin formulation and impregnation and curing process are the same as in Example 1;

[0098] The cured material was placed in a carbon tube furnace, evacuated, and argon gas was introduced. The temperature was increased to 1100 ℃ at a heating rate of 2 ℃ / min, held for 2 h, and then cooled in the furnace to complete the pyrolysis process.

[0099] The above impregnation-crosslinking curing-pyrolysis cycle was repeated 6 times. After every two impregnation-crosslinking curing-pyrolysis cycles, a heat treatment was performed. The heat treatment involved heating to 2000 °C at a rate of 10 °C / min, holding at that temperature for 2 h, and then cooling down in the furnace. After the final pyrolysis, the sample was placed in a graphitization heat treatment furnace and heated to 2700 °C at a rate of 5 °C / min, holding at that temperature for 2 h, and then cooling down in the furnace to obtain a C / C-resin preform with a measured density of approximately 1.69 g / cm³. 3 The open area ratio is 18.36%.

[0100] 3) Coating preparation:

[0101] The C / C-resin preform was placed on a graphite grid above the coating powder, and the vacuum was drawn to ≤10 Pa. Argon gas was introduced, and the temperature was raised to 1800 ℃ at 5 ℃ / min and held for 30 min.

[0102] The coating debonded from the interface between itself and the C / C-resin preform; the coating was uneven and cracked, with a thickness of approximately 95 μm. Scanning electron microscopy revealed the following: Figure 2 As shown in Figure b.

[0103] Example 2

[0104] This embodiment provides a method for preparing C / C-SiC-ZrC composite materials using ultrafast high-temperature Joule heating technology. The specific steps are as follows:

[0105] 1) Pretreatment and graphitization of carbon fiber preforms:

[0106] The raw materials, carbon fiber preform pretreatment, chemical vapor infiltration, and graphitization treatment are the same as in Example 1;

[0107] 2) Impregnation-crosslinking curing-pyrolysis treatment and first heat treatment:

[0108] Resin-based slurry containing ceramic phase precursor powder: By mass, 15 parts of Si powder with an average particle size of 200 nm, 15 parts of Zr powder with an average particle size of 200 nm, 40 parts of phenolic resin, 4 parts of silane coupling agent KH-550, 5 parts of cellulose acetate butyrate, and 5 parts of Tween were added to 15 parts of anhydrous ethanol; the resin-based slurry containing ceramic phase precursor powder was placed in a planetary mixer at a speed of 200 r / min for 10 h to obtain a uniform and stable resin-based slurry containing ceramic phase precursor powder.

[0109] The porous C / C composite material was immersed in a resin-based slurry containing ceramic phase precursor powder, and the vacuum and pressure impregnation process and pyrolysis process were the same as in Example 1.

[0110] The process involved two cycles of impregnation-crosslinking curing-pyrolysis, followed by a first heat treatment. This first heat treatment employed a finite-difference pulsed Joule heating process, with a heating rate of 5 °C / s to the target temperature of 1600 °C. This was followed by four finite-difference Joule heat pulses. After the last two Joule heat pulses, when the resistivity change was less than 1%, the temperature was lowered to room temperature at 3 °C / s. The rapid heating phase of the Joule heat pulse involved a heating rate of 10 °C / s to the target temperature of 1600 °C, followed by a short holding time of 3 min. The intermediate cooling phase reduced the temperature to 85% of the target temperature before the next Joule heat pulse. This yielded a C / C-ceramic resin preform with a measured density of approximately 1.31 g / cm³. 3 Scanning electron microscope image as follows Figure 3 As shown.

[0111] 3) Reactive infiltration and second heat treatment:

[0112] The C / C-ceramic resin preform obtained in step 2) was placed in a graphite crucible and completely embedded with Si powder with an average particle size of 50 μm and Zr powder with an average particle size of 50 μm (mass ratio, Si:Zr=75:25). The graphite crucible was placed in a carbon tube furnace and evacuated to ≤10 Pa. The furnace was heated to 1850 ℃ at a heating rate of 10 ℃ / min and held for 120 min to allow molten Si-Zr to penetrate into the preform and react with the carbon matrix to form a SiC-ZrC ceramic phase. The preform was then cooled to room temperature in the furnace to obtain the C / C-SiC-ZrC composite material preform.

[0113] Residual infiltrator adhering to the material surface was removed, and the material was then placed in a graphite crucible. The electrodes of the Joule heating device were clamped to the graphite crucible, and the vacuum was evacuated to ≤10 Pa before being filled with argon gas. Finite-difference pulsed Joule heat treatment was then performed, with the temperature increased to the target temperature of 1800 ℃ at a rate of 10 ℃ / s. Five finite-difference Joule heat pulses were then applied, and the resistance change rate was reduced to less than 1% after the last two Joule heat pulses. The temperature was then reduced to room temperature at a rate of 3 ℃ / s. During the rapid heating phase of the Joule heat pulse, the temperature was increased to the target temperature of 1800 ℃ at a rate of 10 ℃ / s, with a short holding time of 2 min. The intermediate cooling phase reduced the temperature to 75% of the target temperature before the next Joule heat pulse, resulting in the C / C-SiC-ZrC composite material.

[0114] The C / C-SiC-ZrC composite material prepared in this embodiment had a final measured density of 2.79 g / cm³. 3 The open area ratio is 5.3%; the flexural strength reaches 295 MPa; such as Figure 4As shown, the friction coefficient curve is stable, with an average friction coefficient of 0.4373 and a wear rate of 1.034 × 10⁻⁶. ⁻5 mm 3 ·N -1 ·m -1 The C / C-SiC-ZrC composite material was cut along the Z-axis, and the XRD values ​​were measured as follows: Figure 5 As shown, XRD analysis revealed that the material is mainly composed of SiC, ZrC, and C, with no residual Si, Zr elemental, or ZrSi2 compound diffraction peaks observed.

[0115] Comparative Example 3

[0116] This comparative example provides a method for preparing C / C-SiC-ZrC composite materials, the specific steps of which are as follows:

[0117] This comparative example illustrates the effect of the second heat treatment after reactive melting on the consumption of residual elemental phase, the stabilization of the ceramic phase structure, and the improvement of tribological properties. Except for step 3), which does not involve heat treatment after reactive melting, the remaining steps and processes are the same as in Example 2.

[0118] Specifically, a C / C-ceramic resin preform was prepared according to the method of Example 2, and a reaction infiltration treatment was performed using the same Si-Zr mixed infiltration powder as in Example 2. After the reaction infiltration was completed, the preform was cooled to room temperature in the furnace, and the residual infiltration agent on the material surface was removed to obtain the C / C-SiC-ZrC composite material.

[0119] The C / C-SiC-ZrC composite material prepared in this comparative example has the following properties: density 2.70 g / cm³. 3 The open area ratio is 6.8%; the flexural strength is only 257 MPa; the friction coefficient curve fluctuates wildly, with an average friction coefficient of 0.374 and a wear rate of 5.41 × 10⁻⁶. ⁻5 mm 3 ·N -1 ·m -1 .

[0120] Comparative Example 4

[0121] This comparative example provides a method for preparing C / C-SiC-ZrC composite materials using a conventional carbon tube furnace, with the specific steps as follows:

[0122] 1) Pretreatment and graphitization of carbon fiber preforms:

[0123] The raw materials, carbon fiber preform pretreatment, chemical vapor infiltration, and graphitization treatment were the same as those in Comparative Example 2.

[0124] 2) Impregnation-crosslinking curing-pyrolysis treatment and first heat treatment:

[0125] The slurry formulation and impregnation and curing process are the same as in Example 2;

[0126] The cured material was placed in a carbon tube furnace, evacuated, and then purged with argon gas. It was heated to 1100 °C at a heating rate of 2 °C / min and held for 2 h. The furnace was then cooled to complete the pyrolysis treatment. This impregnation-crosslinking curing-pyrolysis cycle was repeated twice. After the final pyrolysis, the sample was placed in a heat treatment furnace and heated to 2000 °C at a heating rate of 5 °C / min, held for 2 h, and then cooled to obtain a C / C-ceramic resin preform with a measured density of approximately 1.39 g / cm³. 3 .

[0127] 3) Reactive infiltration and second heat treatment:

[0128] The reactive melting process is the same as in Example 2 to ensure consistency in the RMI process;

[0129] The residual infiltrator adhering to the surface of the material was removed, and the material was placed in a graphite crucible and then placed in a carbon tube furnace for heat treatment. The vacuum was evacuated to ≤10 Pa and then filled with argon. The material was heated to 1650 °C at 5 °C / min, held for 30 min, and then cooled to room temperature in the furnace to obtain the C / C-SiC-ZrC composite material.

[0130] The density of the C / C-SiC-ZrC composite material obtained in this comparative example was measured to be 2.54 g / cm³. 3 The open area ratio is 7.5%. The flexural strength is only 219 MPa; the friction coefficient curve is not stable, showing abrupt changes, with an average friction coefficient of only 0.3095 (e.g., ...). Figure 4 As shown), the wear rate is as high as 4.358 × 10⁻⁶. ⁻4 mm 3 ·N -1 ·m -1 XRD analysis, such as Figure 5 As shown, there are obvious residual Si elemental diffraction peaks and ZrSi2 compound diffraction peaks.

[0131] Comparative analysis of various embodiments and comparative examples:

[0132] As can be seen from Example 1 and Comparative Example 1, under the condition that the raw material system and coating preparation process are basically the same, after adopting segmented rate-limited pulse pyrolysis and finite temperature difference pulse first heat treatment, the density of C / C- resin preform is reduced from 1.78 g / cm³. 3 Increased to 1.85 g / cm³ 3 The porosity decreased from 8.46% to 5.41%. This indicates that the treatment method is beneficial for controlling the release of pyrolysis gases, stabilizing the pore structure, and improving the subsequent impregnation and densification effect.

[0133] As can be seen from Example 1 and Comparative Example 2, compared with Example 1, Comparative Example 2 used conventional equipment for heating, with a preparation cycle exceeding 400 hours, while Example 1 took approximately 140-160 hours. Furthermore, the C / C-resin preform obtained by the conventional carbon tube furnace process had lower density and higher porosity. In addition, the interface between the prepared coating and the C / C-resin preform was uneven and cracked, and the coating thickness was only 95 μm, lower than the 150 μm prepared in Example 1. This demonstrates that the present invention matches different Joule heat treatment methods to the pretreatment, graphitization, pyrolysis, first heat treatment, and coating preparation stages, which not only shortens the preparation time but also improves the densification degree of the C / C-resin preform and the coating quality.

[0134] A comparison of Example 2 and Comparative Example 3 shows that Comparative Example 3 did not undergo a second heat treatment after reaction melting and infiltration, resulting in a material density that was 2.79 g / cm³. 3 It decreased to 2.70 g / cm³ 3 The bending strength decreased from 295 MPa to 257 MPa, the average friction coefficient decreased from 0.4373 to 0.374, and the wear rate decreased from 1.034 × 10⁻⁶. ⁻5 mm 3 ·N ⁻1 ·m ⁻1 Increased to 5.41 × 10 ⁻5 mm 3 ·N ⁻1 ·m ⁻1 This indicates that the main function of the second heat treatment is to promote further reaction of the residual elemental phase and stabilize the interface between the ceramic phase and the carbon matrix, as well as to release internal stress in the material, rather than simply increasing density.

[0135] As shown in Example 2 and Comparative Example 4, the C / C-SiC-ZrC composite material obtained by the conventional carbon tube furnace route has a lower density, higher porosity, significantly reduced flexural strength and tribological properties, and exhibits residual elemental Si and ZrSi2 compound diffraction peaks in XRD. In contrast, the material obtained in Example 2 has a density of 2.79 g / cm³. 3 The open area ratio is 5.3%, the flexural strength is 295 MPa, the average friction coefficient is 0.4373, and the wear rate is 1.034 × 10⁻⁶. ⁻5 mm 3 ·N ⁻1 ·m ⁻1 Furthermore, no residual Si, Zr elemental phases, or ZrSi2 diffraction peaks were observed. This indicates that there is a synergistic effect between resin-based slurry impregnation containing ceramic phase precursor powder, pre-nucleation during the first heat treatment, reactive melting and infiltration, and the second heat treatment. This can promote the uniform formation of the SiC-ZrC ceramic phase, reduce residual elemental phases and intermediate compounds, and improve the mechanical and tribological properties of the material.

[0136] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for preparing a carbon-based composite material, characterized in that, Includes the following steps: S1. The carbon fiber preform is pretreated by depositing a rough layer of pyrolytic carbon on the surface of the carbon fiber using chemical vapor infiltration, followed by graphitization treatment to obtain a porous C / C composite material. S2. The porous C / C composite material is impregnated in resin slurry or resin-based slurry containing ceramic phase precursor powder, and impregnation, cross-linking curing and pyrolysis treatment are performed in sequence, followed by a first heat treatment to obtain C / C-resin preform or C / C-ceramic resin preform. S3. A surface coating is applied to the C / C-resin preform to obtain a carbon-based composite material. or, The carbon-based composite material is obtained by introducing the melt-infiltrating powder into the C / C-ceramic resin preform using a reactive melt-infiltrating method, followed by a second heat treatment. The pretreatment, graphitization treatment, pyrolysis treatment, first heat treatment, coating preparation and second heat treatment all adopt ultrafast high temperature Joule heating technology, combined with temperature-resistance dual feedback control.

2. The method for preparing carbon-based composite materials according to claim 1, characterized in that, In step S1, the pretreatment and graphitization treatment employ continuous Joule heat treatment at a heating rate of 30-80 ℃ / s, heating to 1800-2200 ℃ and holding for 15-60 min. When the resistance change rate during the continuous heating process is less than 0.5%-5%, the temperature is reduced to room temperature at a cooling rate of 5-20 ℃ / s.

3. The method for preparing carbon-based composite materials according to claim 1, characterized in that, In step S2, the pyrolysis process employs segmented rate-limited pulsed Joule heat treatment, including a low-temperature devolatification stage, a medium-temperature carbonization shrinkage control stage, and a high-temperature carbonization pulse stabilization stage. In the low-temperature devolatification stage, the temperature is increased to 250-400°C at a rate of 1-3°C / s and held for 1-3 minutes. In the medium-temperature carbonization shrinkage control stage, the temperature is increased to 600-800°C at a rate of 0.5-1.5°C / s and held for 1-3 minutes. Then, 2-6 Joule heat pulses are introduced as the high-temperature carbonization pulse stabilization stage. When the resistivity change rate of two or more consecutive Joule heat pulses is less than 0.5%-5%, the temperature is reduced to room temperature at a rate of 5-10°C / s. Each Joule heat pulse includes a rapid heating stage, a short-term holding stage, and an intermediate cooling stage. In the rapid heating stage, the temperature is increased to the target temperature of 900-1200°C at a rate of 5-10°C / s, and the short-term holding time is 1-5 minutes. After the intermediate cooling phase reaches 75%~90% of the target temperature, the next Joule thermal pulse begins. In the first heat treatment, a finite temperature difference pulse Joule heat treatment is adopted, which raises the temperature to the target temperature of 1600~2800 ℃ at a rate of 5~15 ℃ / s, and then undergoes 4~8 Joule heat pulses. When the resistance change rate is less than 0.5%~5% after two or more consecutive Joule heat pulses, the temperature is lowered to room temperature at a rate of 3~8 ℃ / s. In the rapid heating phase of the Joule heat pulse, the temperature is raised to the target treatment temperature of 1600~2800 ℃ at a rate of 10~20 ℃ / s, and the short holding time is 3~5 min. In the intermediate cooling phase, the temperature is lowered to 65%~85% of the target temperature before the next Joule heat pulse begins.

4. The method for preparing carbon-based composite materials according to claim 1, characterized in that, In step S3, during the coating preparation, a finite temperature difference pulsed Joule heat treatment is used to raise the temperature to the target treatment temperature of 1800-2400 ℃ at a rate of 50-60 ℃ / s, followed by 3-8 Joule heat pulses. When the resistivity change rate is less than 0.5%-5% after two or more consecutive Joule heat pulses, the temperature is lowered to room temperature at a rate of 3-8 ℃ / s. The rapid heating phase of the Joule heat pulse raises the temperature to the target treatment temperature of 1800-2400 ℃ at a rate of 80-90 ℃ / s, with a short holding time of 3-5 min. The intermediate cooling phase lowers the temperature to 65%-85% of the target temperature before entering the next Joule heat pulse. In the second heat treatment, a finite temperature difference pulse Joule heat treatment is used to raise the temperature to the target temperature of 1700-2200 ℃ at a rate of 5-15 ℃ / s, and then subject it to 4-8 Joule heat pulses. When the resistance change rate is less than 0.5%-5% after two or more consecutive Joule heat pulses, the temperature is lowered to room temperature at a rate of 3-8 ℃ / s. In the rapid heating phase of the Joule heat pulse, the temperature is raised to the target temperature of 1700-2200 ℃ at a rate of 10-20 ℃ / s, and the short holding time is 2-3 min. In the intermediate cooling phase, the temperature is lowered to 65%-85% of the target temperature before the next Joule heat pulse begins.

5. The method for preparing carbon-based composite materials according to claim 1, characterized in that, In step S2, the resin slurry comprises resin precursor I and solvent, wherein the resin precursor I comprises at least one of furan resin, phenolic resin, benzoxazine resin or polyarylacetylene resin. The resin-based slurry containing ceramic phase precursor powder comprises ceramic phase precursor powder, resin precursor II, silane coupling agent, cellulose acetate butyrate, surfactant, and solvent.

6. The method for preparing carbon-based composite materials according to claim 5, characterized in that, The mass ratio of the ceramic phase precursor powder, resin precursor II, silane coupling agent, cellulose acetate butyrate, surfactant, and solvent is (20~40):(30~65):(3~8):(4~9):(4~9):(10~20); the ceramic phase precursor powder includes at least one of elemental or alloyed Si, Ti, Zr, Hf, Ta, and W; and the resin precursor II includes at least one of furan resin, phenolic resin, polyimide resin, benzoxazine resin, or polyarylacetylene resin.

7. The method for preparing carbon-based composite materials according to claim 1, characterized in that, In step S2, the impregnation, cross-linking curing and pyrolysis treatments are repeated 2 to 8 times in sequence, and after each 2 repetitions, a first heat treatment is performed.

8. The method for preparing carbon-based composite materials according to claim 1, characterized in that, In step S3, the raw materials for the coating preparation include at least one of elemental powders or alloy powders of Si, Ti, Zr, Hf, and Ta. The reaction melting infiltration method involves heating to 1600~2100 ℃ under vacuum or inert gas atmosphere and holding at that temperature for 60~150 min; the melting infiltration powder includes at least one of elemental or alloyed Si, Ti, Zr, Hf, and Ta.

9. A carbon-based composite material, characterized in that, The carbon-based composite material is prepared by the preparation method according to any one of claims 1 to 8.

10. The application of the carbon-based composite material as described in claim 9, characterized in that, The applications include the use of the carbon-based composite material in the preparation of high-speed braking materials, aerospace thermal protection materials, wear-resistant structural parts, or high-temperature components.

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