An organic nanofiber modified carbon nanotube fiber as a ceramic matrix composite for heat dissipation passage and a preparation method thereof

Abstract

The application relates to a ceramic matrix composite with organic nanofiber modified carbon nanotube fibers as a heat dissipation channel and a preparation method thereof. The method comprises the following steps: placing carbon nanotube fibers in a strong acid to swell; preparing an organic nanofiber solution; soaking the swollen carbon nanotube fibers in the organic nanofiber solution and circulating and stretching, then performing a coagulation bath treatment, water washing and drying to obtain organic nanofiber modified carbon nanotube fibers; weaving the organic nanofiber modified carbon nanotube fibers into a fiber preform; depositing a carbon interface layer on the fiber surface of the fiber preform through a chemical vapor deposition method; and performing microwave instantaneous high-temperature treatment to obtain a high-thermal-conductivity preform skeleton; and reacting a ceramic precursor with the high-thermal-conductivity preform skeleton through an impregnation pyrolysis method to obtain the ceramic matrix composite with the organic nanofiber modified carbon nanotube fibers as the heat dissipation channel. The ceramic matrix composite prepared by the application has high thermal conductivity and high mechanical strength, and can meet the requirements of long-time oxidation resistance and service reliability.

Description

Technical Field

[0001] This invention belongs to the field of ceramic matrix composite material preparation technology, and particularly relates to a ceramic matrix composite material with organic nanofiber modified carbon nanotube fiber as a heat conduction pathway and its preparation method. Background Technology

[0002] In recent years, with the rapid development of various new types of spacecraft, the nose cone and wing leading edge of the spacecraft will face extreme service conditions under high-speed flight, placing extremely stringent requirements on the thermophysical properties of related materials. Materials with high thermal conductivity can rapidly transfer localized high heat loads to low-temperature regions, quickly reducing thermal damage to local structures and extending the service life of materials. Ceramic matrix composites, with fibers as reinforcement and ceramic materials as the matrix, are an important component of ultra-high temperature structural composites. They combine the advantages of efficient heat transfer and high-temperature heat resistance, possessing not only the excellent properties of ceramic materials but also the lightweight and high-strength advantages of the reinforcing fiber phase. Traditional fiber-reinforced materials, such as silicon carbide fibers and carbon fibers, suffer from limitations due to their low degree of graphitization, small graphite crystallite size, and low thermal conductivity, making it difficult to form effective thermal conduction pathways. High thermal conductivity mesophase pitch-based carbon fibers, on the other hand, exhibit problems such as high modulus, brittle texture after graphitization, the need for auxiliary processes in the thickness direction for piercing and weaving, inability to form three-dimensional continuous preforms, weak bonding between carbon fibers and the matrix, and in-plane thermal conductivity approximately 10 to 100 times that along thickness, as well as anisotropic thermal conductivity. These fiber-based ceramic matrix composites cannot meet the requirements for thermal conductivity, high-temperature dimensional stability, and oxidation resistance under extreme environments. By using high-strength, high-thermal-conductivity continuous fibers to form effective thermal conduction pathways, and ultra-high-temperature ceramics as the main anti-oxidation and anti-ablation material, a thermally conductive ceramic matrix composite material can achieve high thermal conductivity while meeting the requirements for long-term oxidation resistance and service reliability. Among them, fibers, as toughening phase and main thermally conductive phase, must simultaneously meet the requirements of high strength, high toughness and high thermal conductivity.

[0003] As a typical representative of novel high-performance fibers, carbon nanotube fibers (CNTFs), one-dimensional macroscopic materials composed of oriented carbon nanotubes, exhibit excellent properties such as lightweight, high strength, high toughness, and high thermal conductivity. The main methods for preparing carbon nanotube fibers include floating catalyst chemical vapor deposition (FCCVD), array spinning, and wet spinning. Currently, FCCVD can obtain stable and continuous carbon nanotube fibers; however, due to the uneven arrangement of carbon nanotubes within the fiber, there are many internal defects and a large porosity, which limits the transfer of the excellent mechanical and thermal properties of carbon nanotubes from the microscopic to the macroscopic level.

[0004] Therefore, improving the orientation of carbon nanotubes, reducing internal defects, lowering porosity, and effectively enhancing their mechanical strength and thermal conductivity are key to achieving the superior performance of high thermal conductivity ceramic matrix composites prepared from carbon nanotube fibers.

[0005] In summary, it is essential to provide a ceramic matrix composite material in which organic nanofibers modify carbon nanotube fibers as thermal conduction pathways, and a method for its preparation. Summary of the Invention

[0006] To address one or more technical problems in the prior art, this invention provides a ceramic matrix composite material with organic nanofiber-modified carbon nanotube fibers as thermal conductivity pathways and its preparation method. The method of this invention reduces internal defects and porosity of carbon nanotube fibers by improving their orientation, thereby obtaining an organic nanofiber-modified carbon nanotube fiber. This effectively improves the mechanical strength and thermal conductivity of the carbon nanotube fiber, resulting in a thermally conductive ceramic matrix composite material that simultaneously possesses high thermal conductivity, high mechanical strength, and meets the requirements of long-term oxidation resistance and service reliability.

[0007] The present invention provides, in a first aspect, a method for preparing a ceramic matrix composite material in which organic nanofibers modified carbon nanotube fibers serve as thermal conduction pathways, the method comprising the following steps:

[0008] (1) Carbon nanotube fibers are placed in a strong acid for swelling treatment to obtain swollen carbon nanotube fibers;

[0009] (2) Prepare an organic nanofiber solution by using a strong acid;

[0010] (3) The swollen carbon nanotube fibers are immersed in an organic nanofiber solution and the swollen carbon nanotube fibers are cyclically stretched. Then, after coagulation bath treatment, water washing and drying, organic nanofiber modified carbon nanotube fibers are obtained.

[0011] (4) Organic nanofiber modified carbon nanotube fibers are woven into fiber preforms, and then a carbon interface layer is deposited on the fiber surface of the fiber preforms by chemical vapor deposition. Then, the preforms are subjected to microwave instantaneous high temperature treatment to obtain a high thermal conductivity preform skeleton.

[0012] (5) A ceramic matrix composite material with organic nanofiber modified carbon nanotube fibers as thermal conduction pathways was prepared by reacting the ceramic precursor with the high thermal conductivity preform skeleton through impregnation pyrolysis method.

[0013] Preferably, in step (1): the carbon nanotube fiber is a continuous carbon nanotube fiber prepared by floating catalyst chemical vapor deposition; and / or the carbon nanotube fiber has a tensile strength of 1.8–3.2 GPa, an elongation at break of 6%–8%, and a density of 1.1–1.2 g / cm³.3 The fiber porosity is 40%–60%.

[0014] Preferably, in step (1): the swelling treatment time is 1 to 10 minutes; the strong acid is concentrated sulfuric acid and / or chlorosulfonic acid; and / or the carbon nanotube fibers are placed in a strong acid under a certain tension for swelling treatment.

[0015] Preferably, in step (2): the strong acid is concentrated sulfuric acid and / or chlorosulfonic acid; the organic nanofiber is one or more of poly(p-benzimidazole-terephthalamide) nanofiber, poly(p-phenylene terephthalamide) nanofiber, and poly(p-phenylene benzodioxazole) nanofiber; the concentration of the organic nanofiber solution is 0.01-1 wt%; and / or the diameter of the organic nanofiber is 10-50 nm and the length is 500-1000 nm.

[0016] Preferably, in step (3): the total number of cyclic stretching cycles is 50 to 100 times; each cyclic stretching cycle is to stretch the swollen carbon nanotube fiber for 3 to 20 seconds and then reduce it for 3 to 20 seconds under a stretching ratio of 1 to 1.5; and / or the coagulation bath is acetone.

[0017] Preferably, in step (4): organic nanofiber modified carbon nanotube fibers are woven into fiber preforms using 2.5D weaving or triaxial orthogonal weaving; the fiber volume content in the fiber preform is 40-50%; and / or the organic nanofiber modified carbon nanotube fiber content in the fiber preform is 10-50%.

[0018] Preferably, in step (4): the deposition temperature of the chemical vapor deposition method is 900-1100℃, the deposition time is 50-150h, and the deposition pressure is 10-150Pa.

[0019] Preferably, in step (4): the microwave instantaneous high temperature treatment is performed at a temperature of 1800–3200°C for a time of 60–300 s; and / or the microwave instantaneous high temperature treatment is performed in a nitrogen atmosphere.

[0020] Preferably, in step (5): the ceramic precursor is one or more of zirconium-silicon precursor, silicon carbide precursor, zirconium carbide precursor, and hafnium carbide precursor; and / or the density of the ceramic matrix composite material in which the organic nanofiber modified carbon nanotube fiber serves as a thermal conduction pathway is 2.0–2.5 g / cm³. 3 .

[0021] In a second aspect, the present invention provides a ceramic matrix composite material in which organic nanofibers modified carbon nanotube fibers, prepared by the preparation method described in the first aspect of the present invention, serve as thermal conduction pathways.

[0022] Compared with the prior art, the present invention has at least the following beneficial effects:

[0023] (1) This invention uses strong acid swelling combined with cyclic stretching to introduce organic nanofibers into the internal pores of carbon nanotube fibers, reducing internal defects of carbon nanotube fibers, lowering porosity, and improving the orientation and density of carbon nanotube fibers, thus obtaining an organic nanofiber modified carbon nanotube fiber, thereby improving the mechanical properties and spinnability of carbon nanotube fibers; at the same time, this invention uses a 2.5D or triaxial orthogonal weaving method to weave the organic nanofiber modified carbon nanotube fibers (also referred to as carbon nanotube / organic nanofiber composite fibers) into a preform, which can control the path and distribution of carbon nanotube / organic nanofiber composite fibers through combined structural design and weaving parameters, thereby obtaining fiber preforms with adjustable thermal conductivity in different directions, and thus obtaining ceramic matrix composite materials with adjustable thermal conductivity in different directions.

[0024] (2) The present invention uses microwave instantaneous high temperature treatment to rapidly carbonize the organic nanofibers in organic nanofiber modified carbon nanotube fibers (carbon nanotube / organic nanofiber composite fibers). The carbonized organic nanofibers (also referred to as organic nanofibers) bridge the carbon nanotubes inside the fiber to obtain a highly efficient heat conduction path. At the same time, the microwave instantaneous high temperature treatment method used in the present invention has a very short treatment time, which can effectively avoid damage to the structure and performance of the fiber caused by long-term high temperature.

[0025] (3) The present invention adopts a strategy of first weaving the preform and then carbonizing, which can maintain good toughness and weavability of the fiber during the weaving process and avoid broken fibers and defects in the fiber preform; in addition, the carbonization of the organic nanofiber (organic fiber nanofiber) in the present invention increases the internal thermal conductivity pathway and density of the carbon nanotube fiber, which can effectively improve the strength and thermal conductivity of the ceramic matrix composite material. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0027] The present invention provides, in a first aspect, a method for preparing a ceramic matrix composite material in which organic nanofibers modified carbon nanotube fibers serve as thermal conduction pathways, the method comprising the following steps:

[0028] (1) Carbon nanotube fibers are swollen in a strong acid to obtain swollen carbon nanotube fibers; specifically, for example, carbon nanotube fibers continuously prepared by floating catalyst chemical vapor deposition (floating catalyst CVD) are swollen in a strong acid environment such as concentrated sulfuric acid or chlorosulfonic acid; the present invention does not specify the amount of strong acid used for swelling treatment, as long as the carbon nanotube fibers are completely immersed in the strong acid;

[0029] (2) Prepare an organic nanofiber solution by using a strong acid to prepare organic nanofiber solution;

[0030] (3) The swollen carbon nanotube fibers are immersed in an organic nanofiber solution and cyclically stretched. Then, after coagulation bath treatment, water washing and drying, organic nanofiber modified carbon nanotube fibers (also referred to as carbon nanotube / organic nanofiber composite fibers) are obtained. In this invention, the coagulation bath treatment is to remove excess strong acid from the fibers through a double diffusion process, so that the material solidifies and forms a shape. In this invention, acetone is used as the coagulation bath. This invention does not make specific limitations on the operation of the coagulation bath treatment, and those skilled in the art can choose conventionally. In this invention, specifically, during the cyclic stretching process, organic nanofibers are introduced into the interior of the swollen carbon nanotube fibers. After coagulation bath treatment, water washing and drying, carbon nanotube / organic nanofiber composite fibers are obtained. This invention does not make specific limitations on the amount of organic nanofiber solution used, as long as the swollen carbon nanotube fibers are completely immersed in the organic nanofiber solution.

[0031] (4) Organic nanofibers modified with carbon nanotubes are woven into a fiber preform, and then a carbon interface layer is deposited on the fiber surface of the fiber preform by chemical vapor deposition. Then, the preform is subjected to microwave instantaneous high temperature treatment to obtain a high thermal conductivity preform skeleton. In this invention, the carbon interface layer deposited on the fiber surface in the fiber preform can serve as a transition layer between the fiber and the ceramic matrix. In this invention, the microwave instantaneous high temperature treatment method can rapidly carbonize the organic nanofibers in the fiber preform. The carbonized organic nanofibers can bridge the carbon nanotubes inside the fiber to obtain a highly efficient thermal conductivity pathway.

[0032] (5) A ceramic matrix composite material (abbreviated as ceramic matrix composite material) is prepared by reacting a ceramic precursor with a high thermal conductivity preform framework through an impregnation-pyrolysis method (impregnation / curing / pyrolysis PIP process). In other words, in this invention, a ceramic matrix composite material with organic nanofiber modified carbon nanotube fibers as thermal conduction pathways is prepared by using a ceramic precursor as a reactant through a precursor impregnation-pyrolysis method. In this invention, the ceramic precursor is, for example, one or more of zirconium-silicon precursor, silicon carbide precursor, zirconium carbide precursor, and hafnium carbide precursor, preferably zirconium-silicon precursor. In this invention, the zirconium-silicon precursor is a polymer mainly composed of zirconium and silicon. This polymer can be converted into ZrC / SiC ceramics after high-temperature pyrolysis treatment. It is a known product in the prior art, for example, it can be purchased from the Institute of Chemistry, Chinese Academy of Sciences, or it can be synthesized by referring to existing methods. In the PIP process, a zirconium-silicon precursor solution is used as the impregnation liquid. The zirconium-silicon precursor solution uses the zirconium-silicon precursor as the solute and xylene as the solvent. The solid content of the zirconium-silicon precursor solution can be, for example, 50-70 wt%. Preferably, in the impregnation / curing / pyrolysis PIP process, the impregnation is first performed under vacuum pressure (e.g., 20-200 Pa), followed by pressure impregnation at 1-2 MPa. Each vacuum impregnation lasts 1-2 hours, and each pressure impregnation lasts 1-2 hours. The curing temperature is 200-300°C, and each curing time is 1-3 hours, performed in an argon atmosphere. The pyrolysis temperature is 1400-1600°C, and each pyrolysis holding time is 1-4 hours, also performed in an argon atmosphere. This invention does not specify the number of repetitions of impregnation, curing, and pyrolysis until the density of the ceramic matrix composite reaches 2.0-2.5 g / cm³. 3 That is all; in this invention, all pressures refer to absolute pressure.

[0033] The method of this invention uses strong acid swelling combined with cyclic stretching to fill the pores of carbon nanotube fibers with organic nanofibers, thereby improving the fiber orientation and density. After being woven into a fiber preform, a carbon interface layer is deposited, followed by microwave rapid carbonization treatment. The carbonized organic nanofibers bridge the carbon nanotubes inside the fibers, obtaining a highly efficient thermal conductivity pathway. By controlling the content of carbon nanotube fibers modified by organic nanofibers in different directions, this invention can achieve controllable thermal conductivity of ceramic matrix composites in different directions. Specifically, this invention employs strong acid swelling combined with cyclic stretching to introduce organic nanofibers into the internal pores of carbon nanotube fibers. This reduces internal defects in the carbon nanotube fibers, lowers porosity, increases the orientation degree of the carbon nanotube fibers, densifies the fibers, and improves fiber strength, resulting in an organic nanofiber-modified carbon nanotube fiber that improves the mechanical properties and spinnability of the carbon nanotube fibers. Simultaneously, this invention utilizes a 2.5D or triaxial orthogonal weaving method to weave the organic nanofiber-modified carbon nanotube fibers (also referred to as carbon nanotube / organic nanofiber composite fibers) into preforms. The path and distribution of the carbon nanotube / organic nanofiber composite fibers can be controlled through combined structural design and weaving parameters to obtain fiber preforms with adjustable thermal conductivity in different directions, thereby obtaining ceramic matrix composite materials with adjustable thermal conductivity in different directions. This invention also employs microwave instantaneous high-temperature treatment... The method described in this invention enables the rapid carbonization of organic nanofibers in organic nanofiber-modified carbon nanotube fibers (carbon nanotube / organic nanofiber composite fibers). The carbonized organic nanofibers (also referred to as organic nanofibers) bridge the carbon nanotubes within the fibers, obtaining highly efficient thermal conductivity pathways and a preform skeleton with high-quality thermal conductivity pathways. Simultaneously, the microwave instantaneous high-temperature treatment method used in this invention has an extremely short processing time, effectively avoiding damage to the fiber structure and properties caused by prolonged high temperatures. The strategy of first weaving the preform and then carbonizing allows the fibers to maintain good toughness and weavability during the weaving process, avoiding fiber breakage and defects within the fiber preform. Furthermore, the carbonization of the organic nanofibers (organic nanofibers) in this invention increases the internal thermal conductivity pathways and density of the carbon nanotube fibers, effectively improving both the strength and thermal conductivity of the ceramic matrix composite material.

[0034] According to some preferred embodiments, in step (1): the carbon nanotube fiber is a continuous carbon nanotube fiber prepared by floating catalyst chemical vapor deposition; and / or the carbon nanotube fiber has a tensile strength of 1.8–3.2 GPa, an elongation at break of 6%–8%, and a density of 1.1–1.2 g / cm³. 3 The fiber porosity is 40% to 60%. In this invention, the preparation of continuous carbon nanotube fibers by floating catalyst chemical vapor deposition is a conventional technique in the field, which can be conventionally selected by those skilled in the art.

[0035] According to some preferred embodiments, in step (1): the swelling treatment time is 1 to 10 minutes (e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, or 10 minutes), preferably 1 to 3 minutes; the strong acid is concentrated sulfuric acid and / or chlorosulfonic acid, and in this invention, the mass fraction of the concentrated sulfuric acid is not less than 70%; and / or the carbon nanotube fibers are placed in a strong acid under a certain tension for swelling treatment. This invention does not specifically limit the magnitude of this tension, as long as the carbon nanotube fibers maintain their original length under a certain tension. For example, carbon nanotube fibers can be kept at their original length and subjected to swelling treatment in a strong acid under a stretching condition with a stretching ratio of 1. In this invention, it is preferred that the carbon nanotube fibers be subjected to swelling treatment in a strong acid for 1 to 10 minutes under a stretching condition with a stretching ratio of 1. This allows the carbon nanotube fibers to swell under protonation, and the spacing between the carbon nanotubes increases uniformly, making the carbon nanotube fibers exhibit a certain degree of elasticity. By stretching, the orientation of the carbon nanotubes is improved, which is beneficial to improving the mechanical strength and thermal conductivity of the final ceramic matrix composite material.

[0036] According to some preferred embodiments, in step (2): the strong acid is concentrated sulfuric acid and / or chlorosulfonic acid, wherein the mass fraction of the concentrated sulfuric acid is not less than 70%; the organic nanofibers are one or more of poly(p-benzimidazole-terephthalamide) nanofibers (i.e., PBIA nanofibers), poly(p-phenylene terephthalamide) nanofibers (i.e., PPTA nanofibers), and poly(p-phenylenebenzodioxazole) nanofibers (i.e., PBO nanofibers); the concentration of the organic nanofiber solution is 0.01–1 wt% (e.g., 0.01 wt%, 0.03 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.15 ...08 wt%, 0.05 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.08 wt%, 0.0 The concentration of the organic nanofiber solution refers to the mass fraction of organic nanofibers contained in the organic nanofiber solution; and / or the diameter (average diameter) of the organic nanofibers is 10-50 nm, and the length (average length) is 500-1000 nm. (The concentrations are 2 wt%, 0.25 wt%, 0.3 wt%, 0.35 wt%, 0.4 wt%, 0.45 wt%, 0.5 wt%, 0.55 wt%, 0.6 wt%, 0.65 wt%, 0.7 wt%, 0.75 wt%, 0.8 wt%, 0.85 wt%, 0.9 wt%, 0.95 wt%, or 1 wt%).

[0037] This invention does not specifically limit the source of the organic nanofibers; they can be directly purchased products or products synthesized by existing methods. For example, organic nanofibers can be prepared using either a top-down or bottom-up method. The bottom-up method involves adding a certain amount of unsuitable solvent (e.g., deionized water) to a polymer solution (e.g., PBIA polymer solution, PPTA polymer solution, and / or PBO polymer solution) and directly preparing organic nanofibers under mechanical stirring assistance. The top-down method involves dissolving fiber-forming agents (e.g., PBIA fiber-forming agents, PPTA fiber-forming agents, and / or PBO fiber-forming agents) with strong acids and / or strong bases to produce organic nanofibers.

[0038] According to some preferred embodiments, in step (3): the total number of cyclic stretching cycles is 50 to 100 times (e.g., 50, 60, 70, 80, 90 or 100 times); one cyclic stretching cycle is stretching the swollen carbon nanotube fiber for 3 to 20 seconds and then reducing (relaxing) it for 3 to 20 seconds under a stretching ratio of 1 to 1.5; in the cyclic stretching process of the present invention, the cyclic stretching can be carried out under a certain fixed stretching ratio, or the stretching ratio can be gradually increased; in the present invention, it is preferred that the organic nanofiber is introduced into the interior of the swollen carbon nanotube fiber during the 50-100 cyclic stretching cycles, and the stretching ratio of the cyclic stretching is 1 to 1.5. Compared with direct stretching treatment, the cyclic stretching described in the present invention is more conducive to the organic nanofiber entering the pores inside the carbon nanotube fiber and oriented synchronously with the carbon nanotube under a certain tension, which is conducive to improving the fiber orientation degree, reducing porosity, densifying the fiber and improving the fiber strength, thereby improving the mechanical strength and thermal conductivity of the final ceramic matrix composite material.

[0039] According to some preferred embodiments, in step (3), the coagulation bath is acetone; in this invention, it is preferred to remove strong acid by coagulation bath and water washing, and then dry to obtain organic nanofiber modified carbon nanotube fiber (carbon nanotube / organic nanofiber composite fiber).

[0040] According to some preferred embodiments, in step (4): organic nanofiber modified carbon nanotube fibers are woven into fiber preforms using 2.5D weaving or triaxial orthogonal weaving; the fiber volume content in the fiber preform is 40-50%; and / or the organic nanofiber modified carbon nanotube fiber content (volume content) in the fiber preform is 10-50%.

[0041] In this invention, 2.5D or triaxial orthogonal weaving technology is used to achieve a preform volume content of 40%-50% and an organic nanofiber modified carbon nanotube fiber volume content of 10%-50%. The weaving direction of the organic nanofiber modified carbon nanotube fiber can be any of the X, Y, and Z directions. This invention controls the path and distribution of the organic nanofiber modified carbon nanotube fiber through combined structural design and weaving parameters. In this invention, 2.5D weaving can adopt two normal high thermal conductivity weaving methods: 2.5D+normal weaving method, where the weft yarn is arranged along the thickness direction, and after completing a full weft, the normal yarn passes through the preform along the thickness direction; 2.5D+double normal weaving method, where one weft yarn is introduced twice, and a normal yarn passes through between the two weft yarns, thereby increasing the organic nanofiber modified carbon nanotube fiber content in the normal direction. In this invention, directions that do not require thermal conductivity can be woven with carbon fiber or woven with carbon fiber doping.

[0042] According to some preferred embodiments, in step (4): the deposition temperature of the chemical vapor deposition method is 900–1100°C (e.g., 900°C, 950°C, 1000°C, 1050°C, or 1100°C), the deposition time is 50–150 h (e.g., 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, or 150 h), and the deposition pressure is 10–150 Pa (e.g., 10, 20, 30, 40, 5 Pa). (Pa values ​​of 0, 60, 70, 80, 90, 100, 110, 120, 130, 140 or 150); In this invention, the fiber preform is placed in a chemical vapor deposition furnace, and by controlling the heating temperature, a carbon interface layer with a thickness of 500 nm to 1.5 μm is formed on the surface of the organic nanofiber modified carbon nanotube fiber after a certain deposition time under vacuum high temperature conditions; In this invention, preferably, the thickness of the carbon interface layer is 500 nm to 1.5 μm.

[0043] According to some preferred embodiments, in step (4): the temperature of the microwave instantaneous high-temperature treatment is 1800-3200℃ (e.g., 1800℃, 1900℃, 2000℃, 2100℃, 2200℃, 2300℃, 2400℃, 2500℃, 2600℃, 2700℃, 2800℃, 2900℃, 3000℃, 3100℃ or 3200℃), and the time is 60-300s (e.g., 60, 90, 120, 150, 180, 210, 240, 270 or 300s); the microwave instantaneous high-temperature treatment is carried out in a nitrogen atmosphere; and / or during the microwave instantaneous high-temperature treatment, the fiber preform after the carbon interface layer is deposited is fixed in each direction (four corners), so that the length of the fiber preform in each direction is fixed to the original length accordingly.

[0044] In this invention, for example, the four corners of the fiber preform after the carbon interface layer is deposited are fixed so that the fiber preform maintains a certain tension during the microwave process. It is then placed in a microwave processing device, protected with nitrogen gas, and the instantaneous microwave processing temperature is 1800–3200°C for 60–300 seconds. This invention does not have specific requirements for the tension maintained by the fiber preform during the microwave process; it only requires that the length of the fiber preform in each direction be fixed to its original length to avoid high-temperature shrinkage. In this invention, the instantaneous high-temperature microwave treatment causes the organic matter in the fiber preform to... Rapid carbonization of nanofibers allows them to maintain good toughness and weavability during the weaving process, preventing fiber breakage and defects within the fiber preform. Furthermore, carbonization of organic nanofibers increases the internal thermal conductivity pathways and density of carbon nanotube fibers, resulting in highly efficient thermal conduction channels. This effectively improves both the strength and thermal conductivity of ceramic matrix composites. This invention does not have specific power requirements for the microwave processing device; it only needs to reach the preset microwave instantaneous high-temperature treatment temperature. In this invention, the microwave power of the microwave processing device can be, for example, 200–400 W.

[0045] According to some preferred embodiments, in step (5): the ceramic precursor is one or more of zirconium-silicon precursor, silicon carbide precursor, zirconium carbide precursor, and hafnium carbide precursor; and / or the density of the ceramic matrix composite material in which the organic nanofiber modified carbon nanotube fiber serves as a thermal conduction pathway is 2.0–2.5 g / cm³. 3 .

[0046] In a second aspect, the present invention provides a ceramic matrix composite material with organic nanofiber modified carbon nanotube fibers as thermal conduction pathways, prepared by the preparation method described in the first aspect of the present invention. The ceramic matrix composite material with organic nanofiber modified carbon nanotube fibers as thermal conduction pathways prepared by the method of the present invention not only has high thermal conductivity, but also significantly improved mechanical and antioxidant properties.

[0047] The present invention will be further described below by way of examples, but the scope of protection of the present invention is not limited to these embodiments. The present invention may have many other embodiments, and those skilled in the art can make various corresponding changes and modifications based on the present invention without departing from its spirit and essence. However, all such corresponding changes and modifications should fall within the scope of protection of the appended claims. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods. Unless otherwise specified, the materials, reagents, etc., used in the following embodiments can be obtained commercially or prepared by existing methods.

[0048] Example 1

[0049] ① Continuous carbon nanotube fibers prepared by a floating catalytic CVD method are provided. The carbon nanotube fibers are immersed in chlorosulfonic acid for swelling treatment for 1 min under a draw ratio of 1 to obtain swollen carbon nanotube fibers. The continuous carbon nanotube fibers prepared by the floating catalytic CVD method have a tensile strength of 1.8 GPa, a continuous length of 15 m, an elongation at break of 6%, and a density of 1.1 g / cm³. 3 The fiber porosity is 40%.

[0050] ② A 0.1% (w / w) poly(p-benzimidazole-terephthalamide) polymer solution (PBIA polymer solution) was slowly mixed with deionized water (the amount of deionized water added was 2.5% of the mass of the poly(p-benzimidazole-terephthalamide) polymer solution) under high-speed stirring at 5000 r / min. After all the deionized water was added, the mixture was stirred at 5000 r / min for another 30 min. The mixture was then freeze-dried at -20℃ for 72 h to obtain poly(p-benzimidazole-terephthalamide) nanofibers (PBIA). The nanofibers, specifically poly(p-benzimidazole)-terephthalamide (PBIA) nanofibers, have an average diameter of 20 nm and an average length of 500 nm. The PBIA polymerization solution uses an N,N-dimethylacetamide / lithium chloride (DMAC / LiCl) system as a solvent, with the N,N-dimethylacetamide / lithium chloride system containing 2 wt% LiCl. The PBIA nanofibers are dissolved in chlorosulfonic acid to obtain an organic nanofiber solution with a concentration of 0.01 wt%.

[0051] ③ The swollen carbon nanotube fibers obtained in step ① are immersed in the organic nanofiber solution obtained in step ② and subjected to 50 cycles of stretching using a multi-roller stretching machine. During the cyclic stretching process, the organic nanofibers are introduced into the interior of the swollen carbon nanotube fibers. Then, the fibers are treated with an acetone coagulation bath and washed with water to remove chlorosulfonic acid. Finally, they are dried by a drying roller to obtain organic nanofiber modified carbon nanotube fibers. Each cycle of stretching involves stretching the swollen carbon nanotube fibers for 5 seconds and then reducing them for 5 seconds under a stretching ratio of 1.3.

[0052] ④ A fiber preform is woven using 2.5D+ normal weaving technology. The fiber volume content in the fiber preform is 40%, of which the Z-direction uses organic nanofiber modified carbon nanotube fibers obtained in step ③, with the Z-direction content of organic nanofiber modified carbon nanotube fibers being 15%. The remaining directions are woven using T300 carbon fiber. Then, the fiber preform is placed in a chemical vapor deposition furnace, and a carbon interface layer with a thickness of 0.8 μm is deposited on the fiber surface of the fiber preform by chemical vapor deposition. The deposition temperature of the chemical vapor deposition method is 900℃, the deposition time is 75h, and the deposition pressure is 100Pa. The four corners of the fiber preform with the deposited carbon interface layer are then fixed, so that the length of the fiber preform in each direction is correspondingly fixed to the original length. It is then placed in a microwave processing device (microwave power of 300W), protected by nitrogen gas, and subjected to microwave instantaneous high-temperature treatment at 2400℃ for 60s to obtain a high thermal conductivity preform skeleton.

[0053] ⑤ The zirconium silicon precursor solution was reacted with the high thermal conductivity preform framework obtained in step ④ using an impregnation-pyrolysis method (impregnation / curing / pyrolysis PIP process) to prepare a preform with a density of 2.1 g / cm³. 3 Organic nanofibers modified with carbon nanotubes are used as the thermal conduction pathway in a ceramic matrix composite material. The zirconium-silicon precursor solution uses zirconium-silicon precursor as solute and xylene as solvent, and the solid content of the zirconium-silicon precursor solution is 60 wt%. In each impregnation / curing / pyrolysis cycle, the impregnation is first performed by vacuum impregnation at a pressure of 200 Pa, followed by pressure impregnation at a pressure of 1.5 MPa. The duration of each vacuum impregnation is 1.5 h, and the duration of each pressure impregnation is 1.5 h. The curing temperature is 200 °C, and the curing time is 1 h. The curing is carried out in an argon atmosphere. The pyrolysis temperature is 1400 °C, and the pyrolysis time is 2 h. The pyrolysis is carried out in an argon atmosphere.

[0054] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material with organic nanofiber modified carbon nanotube fiber as thermal conduction pathway prepared in this embodiment was tested to have a tensile strength of 240 MPa and a Z-axis room temperature thermal conductivity of 350 W / (m·K) in an air environment at 1500℃.

[0055] Example 2

[0056] ① Continuous carbon nanotube fibers prepared by a floating catalytic CVD method are provided. The carbon nanotube fibers are immersed in chlorosulfonic acid for swelling treatment for 2 minutes under a draw ratio of 1 to obtain swollen carbon nanotube fibers. The continuous carbon nanotube fibers prepared by the floating catalytic CVD method have a tensile strength of 2.4 GPa, a continuous length of 15 m, an elongation at break of 7%, and a density of 1.2 g / cm³. 3 The fiber porosity is 40%.

[0057] ② Potassium hydroxide (KOH) was dissolved in dimethyl sulfoxide (DMSO), and then poly(p-phenylene terephthalamide) fibers (PPTA fibers) were added and stirred magnetically for one week to obtain a PPTA nanofiber dispersion with a concentration of 2 mg / mL. The ratio of KOH, DMSO, and PPTA fibers was 1.5 g: 500 mL: 1 g. The solvent was then removed by centrifugation and ultrasonic cleaning, and the nanofibers were freeze-dried at -20°C for 72 h to obtain PPTA nanofibers with an average diameter of 50 nm and an average length of 900 nm. The PPTA nanofibers were then dissolved in chlorosulfonic acid to obtain an organic nanofiber solution with a concentration of 0.03 wt%.

[0058] ③ The swollen carbon nanotube fibers obtained in step ① are immersed in the organic nanofiber solution obtained in step ② and subjected to 60 cycles of stretching using a multi-roller stretching machine. During the cyclic stretching process, the organic nanofibers are introduced into the interior of the swollen carbon nanotube fibers. Then, the fibers are treated with an acetone coagulation bath and washed with water to remove chlorosulfonic acid. Finally, they are dried with a drying roller to obtain organic nanofiber modified carbon nanotube fibers. Each cycle of stretching involves stretching the swollen carbon nanotube fibers for 5 seconds and then reducing them for 5 seconds at a stretching ratio of 1.3.

[0059] ④ A fiber preform is woven using 2.5D+ dual-normal weaving technology. The fiber volume content in the fiber preform is 50%. The Z-axis uses organic nanofiber modified carbon nanotube fibers obtained in step ③, with the Z-axis content of organic nanofiber modified carbon nanotube fibers being 20%. The remaining directions are woven using T300 carbon fiber. Then, the fiber preform is placed in a chemical vapor deposition furnace, and a carbon interface layer with a thickness of 1 μm is deposited on the fiber surface of the fiber preform by chemical vapor deposition. The deposition temperature of the chemical vapor deposition method is 1000℃, the deposition time is 75h, and the deposition pressure is 100Pa. The four corners of the fiber preform with the deposited carbon interface layer are then fixed so that the length of the fiber preform in each direction is correspondingly fixed to the original length. The preform is then placed in a microwave processing device (microwave power of 350W), protected by nitrogen gas, and subjected to microwave instantaneous high-temperature treatment at 2800℃ for 90s to obtain a high thermal conductivity preform skeleton.

[0060] ⑤ The zirconium silicon precursor solution was reacted with the high thermal conductivity preform framework obtained in step ④ using an impregnation-pyrolysis method (impregnation / curing / pyrolysis PIP process) to prepare a preform with a density of 2.3 g / cm³. 3Organic nanofibers modified with carbon nanotubes are used as the thermal conduction pathway in a ceramic matrix composite material. The zirconium-silicon precursor solution uses zirconium-silicon precursor as solute and xylene as solvent, and the solid content of the zirconium-silicon precursor solution is 60 wt%. In each impregnation / curing / pyrolysis cycle, the impregnation is first performed by vacuum impregnation at a pressure of 200 Pa, followed by pressure impregnation at a pressure of 1.5 MPa. The duration of each vacuum impregnation is 1.5 h, and the duration of each pressure impregnation is 1.5 h. The curing temperature is 200 °C, and the curing time is 1 h. The curing is carried out in an argon atmosphere. The pyrolysis temperature is 1400 °C, and the pyrolysis time is 2 h. The pyrolysis is carried out in an argon atmosphere.

[0061] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material with organic nanofiber modified carbon nanotube fiber as thermal conduction pathway prepared in this embodiment was tested to have a tensile strength of 260 MPa and a Z-axis room temperature thermal conductivity of 420 W / (m·K) in an air environment at 1500℃.

[0062] Example 3

[0063] ① Continuous carbon nanotube fibers prepared by a floating catalytic CVD method are provided. The carbon nanotube fibers are immersed in chlorosulfonic acid for swelling treatment for 3 minutes under a draw ratio of 1 to obtain swollen carbon nanotube fibers. The continuous carbon nanotube fibers prepared by the floating catalytic CVD method have a tensile strength of 3.0 GPa, a continuous length of 15 m, an elongation at break of 8%, and a density of 1.2 g / cm³. 3 The fiber porosity is 40%.

[0064] ② Poly(p-phenylene benzodioxazole) fibers (PBO fibers) were placed in chlorosulfonic acid and stirred magnetically for 2 hours to obtain a 1 wt% poly(p-phenylene benzodioxazole) nanofiber dispersion. Then, chlorosulfonic acid was added to dilute it to a 0.05 wt% poly(p-phenylene benzodioxazole) nanofiber (PBO nanofiber) dispersion, which is the organic nanofiber solution. The PBO nanofibers have an average diameter of 20 nm and an average length of 500 nm.

[0065] ③ The swollen carbon nanotube fibers obtained in step ① are immersed in the organic nanofiber solution obtained in step ② and subjected to 80 cycles of cyclic stretching using a multi-roller stretching machine. During the cyclic stretching process, the organic nanofibers are introduced into the interior of the swollen carbon nanotube fibers. Then, the fibers are treated with an acetone coagulation bath and washed with water to remove chlorosulfonic acid. Finally, they are dried by a drying roller to obtain organic nanofiber modified carbon nanotube fibers. Each cycle of stretching involves stretching the swollen carbon nanotube fibers for 5 seconds and then reducing them for 5 seconds under a stretching ratio of 1.3.

[0066] ④ A three-dimensional orthogonal weaving technique is used to weave a fiber preform. The fiber volume content in the fiber preform is 45%, of which the Z-axis uses organic nanofiber modified carbon nanotube fibers obtained in step ③, with the Z-axis content of organic nanofiber modified carbon nanotube fibers being 25%. The remaining directions are woven with T300 carbon fiber. Then, the fiber preform is placed in a chemical vapor deposition furnace, and a carbon interface layer with a thickness of 1.2 μm is deposited on the fiber surface of the fiber preform by chemical vapor deposition. The deposition temperature of the chemical vapor deposition method is 950℃, the deposition time is 150h, and the deposition pressure is 100Pa. Then, the four corners of the fiber preform with the deposited carbon interface layer are fixed so that the length of the fiber preform in each direction is fixed to the original length. It is then placed in a microwave processing device (microwave power of 400W), protected by nitrogen, and subjected to microwave instantaneous high temperature treatment at 3000℃ for 60s to obtain a high thermal conductivity preform skeleton.

[0067] ⑤ The zirconium silicon precursor solution was reacted with the high thermal conductivity preform framework obtained in step ④ using an impregnation-pyrolysis method (impregnation / curing / pyrolysis PIP process) to prepare a preform with a density of 2.2 g / cm³. 3 Organic nanofibers modified with carbon nanotubes are used as the thermal conduction pathway in a ceramic matrix composite material. The zirconium-silicon precursor solution uses zirconium-silicon precursor as solute and xylene as solvent, and the solid content of the zirconium-silicon precursor solution is 60 wt%. In each impregnation / curing / pyrolysis cycle, the impregnation is first performed by vacuum impregnation at a pressure of 200 Pa, followed by pressure impregnation at a pressure of 1.5 MPa. The duration of each vacuum impregnation is 1.5 h, and the duration of each pressure impregnation is 1.5 h. The curing temperature is 200 °C, and the curing time is 1 h. The curing is carried out in an argon atmosphere. The pyrolysis temperature is 1400 °C, and the pyrolysis time is 2 h. The pyrolysis is carried out in an argon atmosphere.

[0068] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material with organic nanofiber modified carbon nanotube fiber as thermal conduction pathway prepared in this embodiment was tested to have a tensile strength of 265 MPa and a Z-axis room temperature thermal conductivity of 480 W / (m·K) in an air environment at 1500℃.

[0069] Example 4

[0070] ① Continuous carbon nanotube fibers prepared by a floating catalytic CVD method are provided. The carbon nanotube fibers are immersed in chlorosulfonic acid for swelling treatment for 3 minutes under a draw ratio of 1 to obtain swollen carbon nanotube fibers. The continuous carbon nanotube fibers prepared by the floating catalytic CVD method have a tensile strength of 3.2 GPa, a continuous length of 15 m, an elongation at break of 8%, and a density of 1.2 g / cm³. 3 The fiber porosity is 50%.

[0071] ② Dissolve potassium hydroxide (KOH) in dimethyl sulfoxide (DMSO), then add poly(p-benzimidazole-terephthalamide) fiber (PBIA fiber) and stir magnetically for one week to obtain a PBIA nanofiber dispersion with a concentration of 2 mg / mL. The ratio of KOH, DMSO, and PBIA fiber is 1.5 g: 500 mL: 1 g. The solvent is then removed by centrifugation and ultrasonic cleaning, and the nanofiber is freeze-dried at -20℃ for 72 h to obtain PBIA nanofibers with an average diameter of 50 nm and an average length of 1000 nm. The PBIA nanofibers are then dissolved in chlorosulfonic acid to obtain an organic nanofiber solution with a concentration of 0.1 wt%.

[0072] ③ The swollen carbon nanotube fibers obtained in step ① are immersed in the organic nanofiber solution obtained in step ② and subjected to 100 cycles of stretching using a multi-roller stretching machine. During the cyclic stretching process, the organic nanofibers are introduced into the interior of the swollen carbon nanotube fibers. Then, the fibers are treated with an acetone coagulation bath and washed with water to remove chlorosulfonic acid. Finally, they are dried by a drying roller to obtain organic nanofiber modified carbon nanotube fibers. Each cycle of stretching involves stretching the swollen carbon nanotube fibers for 5 seconds and then reducing them for 5 seconds at a stretching ratio of 1.3.

[0073] ④ A three-dimensional orthogonal weaving technique is used to weave a fiber preform. The fiber volume content in the fiber preform is 50%. The X and Y directions are made of organic nanofiber modified carbon nanotube fibers obtained in step ③, with the X and Y directions each containing 15%. The Z direction is woven with T300 carbon fiber. Then, the fiber preform is placed in a chemical vapor deposition furnace, and a carbon interface layer with a thickness of 1.2 μm is deposited on the fiber surface of the fiber preform by chemical vapor deposition. The deposition temperature of the chemical vapor deposition method is 950℃, the deposition time is 150h, and the deposition pressure is 100Pa. The four corners of the fiber preform with the deposited carbon interface layer are then fixed so that the length of the fiber preform in each direction is fixed to the original length. The preform is then placed in a microwave processing device (microwave power of 400W), protected by nitrogen, and subjected to microwave instantaneous high-temperature treatment at 3000℃ for 60s to obtain a high thermal conductivity preform skeleton.

[0074] ⑤ The zirconium silicon precursor solution was reacted with the high thermal conductivity preform framework obtained in step ④ using an impregnation-pyrolysis method (impregnation / curing / pyrolysis PIP process) to prepare a preform with a density of 2.3 g / cm³. 3Organic nanofibers modified with carbon nanotubes are used as the thermal conduction pathway in a ceramic matrix composite material. The zirconium-silicon precursor solution uses zirconium-silicon precursor as solute and xylene as solvent, and the solid content of the zirconium-silicon precursor solution is 60 wt%. In each impregnation / curing / pyrolysis cycle, the impregnation is first performed by vacuum impregnation at a pressure of 200 Pa, followed by pressure impregnation at a pressure of 1.5 MPa. The duration of each vacuum impregnation is 1.5 h, and the duration of each pressure impregnation is 1.5 h. The curing temperature is 200 °C, and the curing time is 1 h. The curing is carried out in an argon atmosphere. The pyrolysis temperature is 1400 °C, and the pyrolysis time is 2 h. The pyrolysis is carried out in an argon atmosphere.

[0075] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material with organic nanofiber modified carbon nanotube fiber as thermal conduction pathway prepared in this embodiment was tested to have a tensile strength of 278 MPa and a room temperature thermal conductivity of 360 W / (m·K) in the X / Y direction under air environment of 1500℃.

[0076] Example 5

[0077] ① Continuous carbon nanotube fibers prepared by a floating catalytic CVD method are provided. The carbon nanotube fibers are immersed in chlorosulfonic acid for swelling treatment for 3 minutes under a draw ratio of 1 to obtain swollen carbon nanotube fibers. The continuous carbon nanotube fibers prepared by the floating catalytic CVD method have a tensile strength of 3.2 GPa, a continuous length of 15 m, an elongation at break of 8%, and a density of 1.2 g / cm³. 3 The fiber porosity is 50%.

[0078] ② Dissolve potassium hydroxide (KOH) in dimethyl sulfoxide (DMSO), then add poly(p-benzimidazole-terephthalamide) fiber (PBIA fiber) and stir magnetically for one week to obtain a PBIA nanofiber dispersion with a concentration of 2 mg / mL. The ratio of KOH, DMSO, and PBIA fiber is 1.5 g: 500 mL: 1 g. The solvent is then removed by centrifugation and ultrasonic cleaning, and the nanofiber is freeze-dried at -20℃ for 72 h to obtain PBIA nanofibers with an average diameter of 50 nm and an average length of 1000 nm. The PBIA nanofibers are then dissolved in chlorosulfonic acid to obtain an organic nanofiber solution with a concentration of 0.1 wt%.

[0079] ③ The swollen carbon nanotube fibers obtained in step ① are immersed in the organic nanofiber solution obtained in step ② and subjected to 100 cycles of stretching using a multi-roller stretching machine. During the cyclic stretching process, the organic nanofibers are introduced into the interior of the swollen carbon nanotube fibers. Then, the fibers are treated with an acetone coagulation bath and washed with water to remove chlorosulfonic acid. Finally, they are dried by a drying roller to obtain organic nanofiber modified carbon nanotube fibers. Each cycle of stretching involves stretching the swollen carbon nanotube fibers for 5 seconds and then reducing them for 5 seconds at a stretching ratio of 1.3.

[0080] ④ A three-dimensional orthogonal weaving technique is used to weave a fiber preform. The fiber volume content in the fiber preform is 50%. The X, Y, and Z directions are woven using a mixture of organic nanofiber modified carbon nanotube fibers and T300 carbon fibers from step ③. The content of organic nanofiber modified carbon nanotube fibers in the X, Y, and Z directions is 15% each. Then, the fiber preform is placed in a chemical vapor deposition furnace, and a carbon interface layer with a thickness of 1.2 μm is deposited on the fiber surface of the fiber preform by chemical vapor deposition. The deposition temperature of the chemical vapor deposition method is 950℃, the deposition time is 150h, and the deposition pressure is 100Pa. The four corners of the fiber preform with the deposited carbon interface layer are then fixed so that the length of the fiber preform in each direction is fixed to the original length. The preform is then placed in a microwave processing device (microwave power of 400W), protected by nitrogen, and subjected to microwave instantaneous high-temperature treatment at 3000℃ for 60s to obtain a high thermal conductivity preform skeleton.

[0081] ⑤ The zirconium silicon precursor solution was reacted with the high thermal conductivity preform framework obtained in step ④ using an impregnation-pyrolysis method (impregnation / curing / pyrolysis PIP process) to prepare a preform with a density of 2.3 g / cm³. 3 Organic nanofibers modified with carbon nanotubes are used as the thermal conduction pathway in a ceramic matrix composite material. The zirconium-silicon precursor solution uses zirconium-silicon precursor as solute and xylene as solvent, and the solid content of the zirconium-silicon precursor solution is 60 wt%. In each impregnation / curing / pyrolysis cycle, the impregnation is first performed by vacuum impregnation at a pressure of 200 Pa, followed by pressure impregnation at a pressure of 1.5 MPa. The duration of each vacuum impregnation is 1.5 h, and the duration of each pressure impregnation is 1.5 h. The curing temperature is 200 °C, and the curing time is 1 h. The curing is carried out in an argon atmosphere. The pyrolysis temperature is 1400 °C, and the pyrolysis time is 2 h. The pyrolysis is carried out in an argon atmosphere.

[0082] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material with organic nanofiber modified carbon nanotube fiber as thermal conduction pathway prepared in this embodiment was tested to have a tensile strength of 280 MPa and a room temperature thermal conductivity of 360 W / (m·K) in the X / Y / Z directions under air environment of 1500℃.

[0083] Example 6

[0084] Example 6 is basically the same as Example 3, except that:

[0085] ① Continuous carbon nanotube fibers prepared by a floating catalytic CVD method are provided. The carbon nanotube fibers are immersed in chlorosulfonic acid for swelling treatment for 15 min under a draw ratio of 1 to obtain swollen carbon nanotube fibers. The continuous carbon nanotube fibers prepared by the floating catalytic CVD method have a tensile strength of 3.0 GPa, a continuous length of 15 m, an elongation at break of 8%, and a density of 1.2 g / cm³. 3 The fiber porosity is 40%.

[0086] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material prepared in this embodiment was tested to have a tensile strength of 220 MPa and a Z-axis room temperature thermal conductivity of 350 W / (m·K) in an air environment at 1500℃.

[0087] Example 7

[0088] Example 7 is basically the same as Example 3, except that:

[0089] ④ A three-dimensional orthogonal weaving technique is used to weave a fiber preform. The fiber volume content in the fiber preform is 45%, of which the Z-axis uses organic nanofiber modified carbon nanotube fibers obtained in step ③, with the Z-axis content of organic nanofiber modified carbon nanotube fibers being 25%. The remaining directions are woven with T300 carbon fiber. Then, the fiber preform is placed in a chemical vapor deposition furnace, and a carbon interface layer with a thickness of 1.2 μm is deposited on the fiber surface of the fiber preform by chemical vapor deposition. The deposition temperature of the chemical vapor deposition method is 950℃, the deposition time is 150h, and the deposition pressure is 100Pa. Then, the four corners of the fiber preform with the deposited carbon interface layer are fixed so that the length of the fiber preform in each direction is fixed to the original length. It is then placed in a microwave processing device, protected by nitrogen, and subjected to microwave instantaneous high-temperature treatment at 3500℃ for 420s to obtain a high thermal conductivity preform skeleton.

[0090] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material prepared in this embodiment was tested to have a tensile strength of 215 MPa and a Z-axis room temperature thermal conductivity of 380 W / (m·K) in an air environment at 1500℃.

[0091] Comparative Example 1

[0092] ① Provides continuous carbon nanotube fibers prepared by floating catalytic CVD method; the continuous carbon nanotube fibers prepared by floating catalytic CVD method have a tensile strength of 3.0 GPa, a continuous length of 15 m, an elongation at break of 8%, and a density of 1.2 g / cm³. 3 The fiber porosity is 40%.

[0093] ② is the same as step ② in Example 3.

[0094] ③ The continuous carbon nanotube fibers from step ① are immersed in the organic nanofiber solution obtained in step ② and subjected to 80 cycles of cyclic stretching using a multi-roller stretching machine. Then, the fibers are treated with an acetone coagulation bath and washed with water to remove chlorosulfonic acid. Finally, they are dried with a drying roller to obtain organic nanofiber modified carbon nanotube fibers. In the cyclic stretching, the stretching ratio is gradually increased from 1 to 1.3 and then maintained at this stretching ratio. Each stretching lasts 5 seconds, followed by a 5-second reduction.

[0095] ④ is the same as step ④ in Example 3.

[0096] ⑤ is the same as step ⑤ in Example 3.

[0097] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material prepared in this comparative example was tested to have a tensile strength of 200 MPa and a Z-axis room temperature thermal conductivity of 280 W / (m·K) in an air environment at 1500℃.

[0098] Comparative Example 2

[0099] Comparative Example 2 is basically the same as Example 3, except that:

[0100] ③ The swollen carbon nanotube fibers obtained in step ① are immersed in the organic nanofiber solution obtained in step ② and the swollen carbon nanotube fibers are stretched. Then, they are treated with an acetone coagulation bath and washed with water to remove chlorosulfonic acid. Finally, they are dried by a drying roller to obtain organic nanofiber modified carbon nanotube fibers. The stretching is performed by stretching the swollen carbon nanotube fibers for 800s at a stretching ratio of 1.3.

[0101] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material prepared in this comparative example was tested to have a tensile strength of 180 MPa and a Z-axis room temperature thermal conductivity of 230 W / (m·K) in an air environment at 1500℃.

[0102] Comparative Example 3

[0103] Comparative Example 3 is basically the same as Example 3, except that:

[0104] ④ A fiber preform is woven using a three-dimensional orthogonal weaving technique. The fiber volume content in the fiber preform is 45%. The Z-axis uses organic nanofiber-modified carbon nanotube fibers obtained in step ③, with the Z-axis content of the organic nanofiber-modified carbon nanotube fibers being 25%. The remaining directions are woven using T300 carbon fiber. Then, the fiber preform is placed in a chemical vapor deposition furnace, and a carbon interface layer with a thickness of 1.2 μm is deposited on the fiber surface of the fiber preform by chemical vapor deposition. The deposition temperature of the chemical vapor deposition method is 950℃, the deposition time is 150 h, and the deposition pressure is 100 Pa, resulting in a fiber preform with a deposited carbon interface layer.

[0105] ⑤ The zirconium silicon precursor solution was reacted with the fiber preform with the deposited carbon interface layer obtained in step ④ using an impregnation-pyrolysis method (impregnation / curing / pyrolysis PIP process) to prepare a fiber preform with a density of 2.2 g / cm³. 3 The ceramic matrix composite material; the zirconium silicon precursor solution uses zirconium silicon precursor as solute and xylene as solvent, and the solid content of the zirconium silicon precursor solution is 60 wt%; in each impregnation / curing / pyrolysis cycle, the impregnation is first vacuum impregnation at a pressure of 200 Pa, followed by pressure impregnation at a pressure of 1.5 MPa, the vacuum impregnation time is 1.5 h, the pressure impregnation time is 1.5 h, the curing temperature is 200 °C, the curing time is 1 h, the curing is carried out in an argon atmosphere, the pyrolysis temperature is 1400 °C, the pyrolysis time is 2 h, and the pyrolysis is carried out in an argon atmosphere.

[0106] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material prepared in this comparative example was tested to have a tensile strength of 250 MPa and a Z-axis room temperature thermal conductivity of 130 W / (m·K) in an air environment at 1500℃.

[0107] Comparative Example 4

[0108] ① Preparation of carbon nanotube fibers: Carbon nanotube fibers are grown by floating catalyst chemical vapor deposition. The grown carbon nanotube fibers are shrunk and densified in a water tank. The shrunk and densified fibers are then passed through a 50μm diameter drawing die in a wetted state to obtain wetted fibers with a cylindrical cross-section. The obtained fibers are dried with hot air at 110℃, with the hot air flow direction along the axial direction of the fiber.

[0109] ② Add poly(p-phenylenebenzodioxazole) fiber (PBO fiber) to methanesulfonic acid and stir at 25°C for 1 hour to prepare a PBO methanesulfonic acid solution with a PBO concentration of 0.1 g / L.

[0110] ③ The carbon nanotube fibers obtained in step ① are introduced into the PBO methanesulfonic acid solution prepared in step ②, and are immersed in the solution and continuously moved at a certain rate, so that the residence time in the solution is 10s, to obtain intermediate fibers; the intermediate fibers are continuously and persistently subjected to a load tension of 5g, and then dried at 100℃ for 60min, thereby obtaining continuous carbon nanotube / PBO composite fibers.

[0111] ④ A three-dimensional orthogonal weaving technique is used to weave a fiber preform. The fiber volume content in the fiber preform is 45%. The Z-axis uses continuous carbon nanotube / PBO composite fibers obtained in step ③, with a Z-axis content of 25%. The remaining directions are woven with T300 carbon fiber. Then, the fiber preform is placed in a chemical vapor deposition furnace, and a carbon interface layer with a thickness of 1.2 μm is deposited on the fiber surface of the fiber preform by chemical vapor deposition. The deposition temperature of the chemical vapor deposition method is 950℃, the deposition time is 150h, and the deposition pressure is 100Pa. The four corners of the fiber preform with the deposited carbon interface layer are then fixed so that the length of the fiber preform in each direction is fixed to the original length. The preform is then placed in a microwave processing device (microwave power of 400W), protected by nitrogen, and subjected to microwave instantaneous high-temperature treatment at 3000℃ for 60s to obtain a high thermal conductivity preform skeleton.

[0112] ⑤ is the same as step ⑤ in Example 3.

[0113] Mechanical properties test under high temperature and oxygen environment: The ceramic matrix composite material prepared in this comparative example was tested to have a tensile strength of 170 MPa and a Z-axis room temperature thermal conductivity of 120 W / (m·K) in an air environment at 1500℃.

[0114] The parts of this invention not described in detail are techniques known to those skilled in the art.

[0115] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing a ceramic matrix composite material with organic nanofiber-modified carbon nanotube fibers as thermal conduction pathways, characterized in that, The method includes the following steps: (1) Carbon nanotube fibers are placed in a strong acid for swelling treatment to obtain swollen carbon nanotube fibers; (2) Prepare an organic nanofiber solution by using a strong acid; in step (2): the strong acid is concentrated sulfuric acid and / or chlorosulfonic acid; the organic nanofiber is one or more of poly(p-benzimidazole-terephthalamide) nanofiber, poly(p-phenylene terephthalamide) nanofiber, and poly(p-phenylene benzodioxazole) nanofiber; the concentration of the organic nanofiber solution is 0.01~1wt%; the diameter of the organic nanofiber is 10~50nm and the length is 500~1000nm; (3) The swollen carbon nanotube fibers are immersed in an organic nanofiber solution and the swollen carbon nanotube fibers are cyclically stretched. Then, after coagulation bath treatment, water washing and drying, organic nanofiber modified carbon nanotube fibers are obtained. (4) Organic nanofiber modified carbon nanotube fibers are woven into fiber preforms, and then a carbon interface layer is deposited on the fiber surface of the fiber preforms by chemical vapor deposition. Then, the preforms are subjected to microwave instantaneous high temperature treatment to obtain a high thermal conductivity preform skeleton. In step (4): the temperature of the microwave instantaneous high temperature treatment is 1800~3200℃ and the time is 60~300s. The microwave instantaneous high temperature treatment is carried out in a nitrogen atmosphere. (5) The ceramic precursor was reacted with the high thermal conductivity preform skeleton by impregnation pyrolysis method to obtain a ceramic matrix composite material with organic nanofiber modified carbon nanotube fiber as thermal conduction pathway.

2. The preparation method according to claim 1, characterized in that, In step (1): The carbon nanotube fibers are continuous carbon nanotube fibers prepared by floating catalyst chemical vapor deposition; and / or The carbon nanotube fibers have a tensile strength of 1.8–3.2 GPa, an elongation at break of 6%–8%, and a density of 1.1–1.2 g / cm³. 3 The fiber porosity is 40%~60%.

3. The preparation method according to claim 1, characterized in that, In step (1): The swelling treatment time is 1~10 min; The strong acid is concentrated sulfuric acid and / or chlorosulfonic acid; and / or The carbon nanotube fibers were subjected to swelling treatment in a strong acid under a certain tension.

4. The preparation method according to claim 1, characterized in that, In step (3): The total number of cyclic stretching cycles is 50 to 100. One cycle of drawing is described as drawing the swollen carbon nanotube fibers for 3-20 seconds and then reducing them for 3-20 seconds under a draw ratio of 1-1.5; and / or The coagulation bath is acetone.

5. The preparation method according to claim 1, characterized in that, In step (4): Organic nanofibers modified with carbon nanotubes are woven into fiber preforms using 2.5D weaving or triaxial orthogonal weaving. The fiber volume content in the fiber preform is 40-50%; and / or The content of organic nanofiber modified carbon nanotube fibers in the fiber preform is 10-50%.

6. The preparation method according to claim 1, characterized in that, In step (4): The chemical vapor deposition method has a deposition temperature of 900~1100℃, a deposition time of 50~150h, and a deposition pressure of 10~150Pa.

7. The preparation method according to claim 1, characterized in that, In step (5): The ceramic precursor is one or more of zirconium-silicon precursor, silicon carbide precursor, zirconium carbide precursor, and hafnium carbide precursor; and / or The density of the ceramic matrix composite material in which the organic nanofiber-modified carbon nanotube fiber serves as a thermal conduction pathway is 2.0~2.5 g / cm³. 3 .

8. A ceramic matrix composite material in which organic nanofiber-modified carbon nanotube fibers, prepared by any one of claims 1 to 7, serve as a thermal conduction pathway.