A preparation process for high thermal conductivity carbon fiber-ceramic composite material

Abstract

The present invention provides a preparation process for a high thermal conductivity carbon fiber-ceramic composite material, which belongs to the field of ceramic-based composite materials. The preparation process comprises the following steps: polyboron carbosilazane is dispersed in xylene to obtain a precursor mixture, high thermal conductivity carbon fiber is impregnated in the precursor mixture, and then cured and pyrolyzed to obtain the high thermal conductivity carbon fiber-ceramic composite material; the high thermal conductivity carbon fiber of the present invention serves as a reinforcing phase, and can form a continuous heat conduction path in the high thermal conductivity carbon fiber-ceramic composite material. The high thermal conductivity of copper further improves the thermal conductivity of the high thermal conductivity carbon fiber-ceramic composite material; in addition, by introducing boron and nitrogen to synergize with the high thermal conductivity carbon fiber, the surface temperature of the ablation zone is reduced by rapid heat conduction, ablation damage is reduced, and high temperature ablation resistance is improved.

Description

Technical Field

[0001] The present invention relates to the field of ceramic-based composite materials, and in particular to a preparation process of a high thermal conductivity carbon fiber-ceramic composite material. Background Art

[0002] In many key areas of modern industry, the success or failure of a material's application depends on its thermal conductivity and ablation resistance. Industries like aerospace and electronic packaging place particularly stringent demands on materials, requiring them to efficiently conduct heat to ensure proper equipment operation and performance, while also exhibiting excellent ablation resistance to withstand thermal erosion in high-temperature environments. However, existing technologies face significant challenges in developing materials that combine these two properties.

[0003] During the preparation process of traditional carbon fiber-ceramic composites, it is often difficult to simultaneously take into account thermal conductivity and ablation resistance. On the one hand, when the thermal conductivity is improved by increasing the content of carbon fibers or optimizing their arrangement, the ablation resistance of the material may be affected. For example, in carbon fiber reinforced polymer composites, although thermal conductivity can be improved by surface modification, directional treatment and other methods, these methods may cause the stability of the material to decrease in high temperature environments. On the other hand, modifications to the material to improve ablation resistance, such as adding an antioxidant coating or using a special preparation process, may reduce the thermal conductivity of the material. For example, in carbon fiber reinforced carbon-based-ultra-high temperature ceramic-based composites, although the ablation resistance can be improved by introducing ultra-high temperature ceramic modifications, it may also have an adverse effect on thermal conductivity.

[0004] Chinese invention patent CN10216930B discloses a high-strength ceramic resin composite material and a preparation method thereof. The preparation method is simple and the composite material has good temperature resistance. However, its production process makes it difficult to ensure the uniformity of the ceramic in the matrix, and the mechanical properties of the composite material are relatively low. Chinese invention patent CN109320278B discloses a heat-conducting ceramic-based composite material and a preparation method thereof. The preparation method is process-controllable and easy to operate. The heat-conducting ceramic-based composite material in this patent application can achieve good ablation resistance, but still has problems such as low thermal conductivity and low mechanical properties.

[0005] Therefore, providing a high thermal conductivity carbon fiber-ceramic composite material that can simultaneously take into account thermal conductivity and ablation resistance is an important issue that needs to be solved in this field. Summary of the Invention

[0006] To solve the problems existing in the prior art, the present invention provides a preparation process for a high thermal conductivity carbon fiber-ceramic composite material. Specifically, the technical solution of the present invention includes the following contents:

[0007] A preparation process of a high thermal conductivity carbon fiber-ceramic composite material, the preparation process comprising the following steps:

[0008] Polyboronocarbosilazane is dispersed in xylene to obtain a precursor mixture, and high thermal conductivity carbon fiber is impregnated in the precursor mixture, followed by sequential curing and high-temperature cracking to obtain the high thermal conductivity carbon fiber-ceramic composite material.

[0009] Furthermore, the preparation method of the polyboronocarbosilazane comprises the following steps:

[0010] Diaminomaleonitrile, pinacol borane and triethylaluminum are subjected to a first stirring reaction to obtain an intermediate product, and the intermediate product, methylhydrodichlorosilane and a catalyst are subjected to a second stirring reaction to obtain the polyboronocarbosilazane.

[0011] Furthermore, the method for preparing the high thermal conductivity carbon fiber comprises the following steps:

[0012] The chopped carbon fibers are sequentially subjected to degumming reaction and desizing reaction to obtain desized carbon fibers, and the desized carbon fibers are mixed with silver nanoparticles to obtain activated carbon fibers. Copper sulfate pentahydrate, disodium ethylenediaminetetraacetic acid, glyoxylic acid, 2,2'-bipyridine and potassium ferrocyanide are dispersed in deionized water to obtain a copper plating solution, and the activated carbon fibers are subjected to a plating reaction in the copper plating solution to obtain the high thermal conductivity carbon fibers.

[0013] Furthermore, the weight ratio of the diaminomaleonitrile, pinacol borane and triethylaluminum is 1:1.2-1.5:0.09-0.11.

[0014] Furthermore, the weight ratio of the intermediate product to the catalyst is 1:0.3-0.5.

[0015] Furthermore, the weight ratio of the intermediate product to methylhydrogendichlorosilane is 4.5-5.5:2.5-3.

[0016] Furthermore, the catalyst is triethylamine.

[0017] Furthermore, the reaction temperature of the first stirring reaction is 98-105° C., and the reaction time is 20-24 h.

[0018] Furthermore, the reaction temperature of the second stirring reaction is 8-12° C., and the reaction time is 36-40 h.

[0019] Furthermore, the reaction temperature of the degumming reaction is 50-55° C., and the reaction time is 120-150 min.

[0020] Furthermore, the reaction temperature of the desizing reaction is 23-25° C., and the reaction time is 60-80 min.

[0021] Furthermore, the weight ratio of the desized carbon fibers to the silver nanoparticles is 1:0.01-0.02.

[0022] Furthermore, the reaction temperature of the mixed reaction is 23-25° C., and the reaction time is 30-60 min.

[0023] Furthermore, the weight ratio of the copper sulfate pentahydrate, disodium ethylenediaminetetraacetic acid, glyoxylic acid, 2,2'-bipyridine, potassium ferrocyanide and deionized water is 2.5-3.5:5-5.2:0.8-0.95:0.001-0.0015:0.001-0.0015:100.

[0024] Furthermore, the reaction temperature of the plating reaction is 50-55° C., and the reaction time is 2.5-3.5 hours.

[0025] Furthermore, the weight ratio of the polyborocarbosilazane to xylene is 50-60:100.

[0026] Furthermore, the immersion treatment is performed at a temperature of 50-60° C. and for a time of 8-10 hours.

[0027] Furthermore, the curing treatment temperature is 150-200° C., and the treatment time is 2-4 hours.

[0028] Furthermore, the pyrolysis temperature of the high-temperature pyrolysis is 1800-2200° C., and the pyrolysis time is 2-3 hours.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) In the present invention, diaminomaleic acid dinitrile and pinacol borane are subjected to a hydroboration reaction to obtain an intermediate product, and the intermediate product undergoes an aminolysis reaction with methylhydrodichlorosilane to obtain polyboronocarbosilazane; short-cut carbon fibers are subjected to a degumming reaction and a desizing reaction to obtain desized carbon fibers; silver nanoparticles on the surface of the desized carbon fibers are catalyzed by glyoxylic acid oxidation to provide electrons for the reduction of Cu(II) coordination ions, thereby achieving copper plating on the surface of the desized carbon fibers to obtain high thermal conductivity carbon fibers; the high thermal conductivity carbon fibers are impregnated in a xylene solution of polyboronocarbosilazane, cured, and subjected to high-temperature pyrolysis to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0031] (2) The dense protective layer formed by the polyboronocarbon silazane at high temperature in the present invention can isolate oxygen and prevent the combustion reaction from proceeding; the high thermal conductivity carbon fiber can quickly conduct heat from the ablation surface to the interior of the material, avoiding the ablation caused by local excessive temperature. This thermal management capability makes the high thermal conductivity carbon fiber-ceramic composite material have good ablation resistance; by introducing boron and nitrogen to work synergistically with the high thermal conductivity carbon fiber, the surface temperature of the ablation area is reduced by rapid heat conduction, reducing ablation damage and improving high temperature ablation resistance.

[0032] (3) The high thermal conductivity carbon fiber of the present invention serves as a reinforcing phase and can form a continuous heat conduction path in the high thermal conductivity carbon fiber-ceramic composite material. The high thermal conductivity of copper further improves the thermal conductivity of the high thermal conductivity carbon fiber-ceramic composite material.

[0033] (4) The present invention disperses high thermal conductivity carbon fibers in the precursor mixture and impregnates them so that the components are evenly distributed in the composite material, thereby improving the high thermal conductivity and ablation resistance of the high thermal conductivity carbon fiber-ceramic composite material while maintaining good mechanical properties. DETAILED DESCRIPTION

[0034] The following will clearly and completely describe the technical solutions of the present invention through the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0035] Unless otherwise specified, the raw materials and reagents used in the present invention are commercially available or can be prepared by known methods.

[0036] Preparation Example 1:

[0037] The preparation of polyborocarbosilazane comprises the following steps:

[0038] In a nitrogen protection environment, 10 parts by weight of diaminomaleic dinitrile, 12 parts by weight of pinacol borane and 0.9 parts by weight of triethylaluminum are dispersed in 100 parts by weight of toluene, and stirred at 98° C. for 20 hours to perform a first stirring reaction. After the reaction is completed, the intermediate product is concentrated and purified to obtain a product. In a nitrogen protection environment, 45 parts by weight of the intermediate product and 13.5 parts by weight of triethylamine are dispersed in 150 parts by weight of n-hexane, stirred and mixed at 8° C. for 5 minutes, and then 25 parts by weight of methylhydrodichlorosilane are added and stirred for 36 hours to perform a second stirring reaction. After the reaction is completed, the polyborocarbosilazane is obtained by washing and drying.

[0039] Preparation Example 2:

[0040] The preparation of polyborocarbosilazane comprises the following steps:

[0041] In a nitrogen protection environment, 10 parts by weight of diaminomaleic dinitrile, 13 parts by weight of pinacol borane and 0.95 parts by weight of triethylaluminum are dispersed in 100 parts by weight of toluene, and stirred at 100° C. for 21 hours to perform a first stirring reaction. After the reaction is completed, the intermediate product is concentrated and purified to obtain a product. In a nitrogen protection environment, 48 parts by weight of the intermediate product and 19.2 parts by weight of triethylamine are dispersed in 160 parts by weight of n-hexane, stirred and mixed at 10° C. for 7 minutes, and then 26 parts by weight of methylhydrodichlorosilane are added and stirred for 37 hours to perform a second stirring reaction. After the reaction is completed, the polyborocarbosilazane is prepared by washing and drying.

[0042] Preparation Example 3:

[0043] The preparation of polyborocarbosilazane comprises the following steps:

[0044] In a nitrogen protection environment, 10 parts by weight of diaminomaleic dinitrile, 14 parts by weight of pinacol borane and 1 part by weight of triethylaluminum are dispersed in 100 parts by weight of toluene, and stirred at 101° C. for 22 hours to perform a first stirring reaction. After the reaction is completed, the intermediate product is concentrated and purified to obtain a product. In a nitrogen protection environment, 50 parts by weight of the intermediate product and 20 parts by weight of triethylamine are dispersed in 180 parts by weight of n-hexane, stirred and mixed at 10° C. for 8 minutes, and then 28 parts by weight of methylhydrodichlorosilane are added and stirred for 38 hours to perform a second stirring reaction. After the reaction is completed, the polyborocarbosilazane is prepared by washing and drying.

[0045] Preparation Example 4:

[0046] The preparation of polyborocarbosilazane comprises the following steps:

[0047] In a nitrogen protection environment, 10 parts by weight of diaminomaleonitrile, 15 parts by weight of pinacol borane and 1.1 parts by weight of triethylaluminum are dispersed in 100 parts by weight of toluene, and stirred at 105° C. for 24 hours to perform a first stirring reaction. After the reaction is completed, the intermediate product is concentrated and purified to obtain a product. In a nitrogen protection environment, 55 parts by weight of the intermediate product and 27.5 parts by weight of triethylamine are dispersed in 200 parts by weight of n-hexane, stirred and mixed at 12° C. for 10 minutes, and then 30 parts by weight of methylhydrodichlorosilane are added and stirred for 40 hours to perform a second stirring reaction. After the reaction is completed, the polyborocarbosilazane is prepared by washing and drying.

[0048] Preparation Example 5:

[0049] The preparation of polycarbosilazane comprises the following steps:

[0050] In a nitrogen atmosphere, 55 parts by weight of diaminomaleonitrile and 27.5 parts by weight of triethylamine were dispersed in 200 parts by weight of n-hexane, stirred and mixed at 12° C. for 10 minutes, and then 30 parts by weight of methylhydrodichlorosilane were added and stirred for 40 hours to perform a second stirring reaction. After the reaction was completed, polyborocarbosilazane was obtained by washing and drying.

[0051] Preparation Example 6:

[0052] The preparation of high thermal conductivity carbon fiber includes the following steps:

[0053] The chopped carbon fibers were dispersed in acetone and immersed at 50°C for 120 minutes for degumming reaction. After the reaction, the chopped carbon fibers were dispersed in 65% concentrated nitric acid and immersed at 23°C for 60 minutes for desizing reaction. After the reaction, the chopped carbon fibers were neutralized, washed and dried to obtain desized carbon fibers. 100 parts by weight of desized carbon fibers and 1 part by weight of silver nanoparticles were dispersed in deionized water and ultrasonicated for 5 minutes, followed by mixing and reacting at 23°C for 30 minutes to obtain activated carbon fibers. 25 parts by weight of copper sulfate pentahydrate, 50 parts by weight of disodium ethylenediaminetetraacetate, 8.5 parts by weight of glyoxylic acid, 0.01 parts by weight of 2,2'-bipyridine and 0.01 parts by weight of potassium ferrocyanide were dispersed in 1000 parts by weight of deionized water, and the pH value was adjusted to 11 to obtain a copper plating solution. The activated carbon fibers obtained above were dispersed in the copper plating solution and treated at 50°C for 2.5 hours for plating reaction to obtain high thermal conductivity carbon fibers.

[0054] Preparation Example 7:

[0055] The preparation of high thermal conductivity carbon fiber includes the following steps:

[0056] The chopped carbon fibers were dispersed in acetone and immersed at 52° C. for 130 min for a degumming reaction. After the reaction, the fibers were dispersed in 65% concentrated nitric acid and immersed at 24° C. for 65 min for a desizing reaction. After the reaction, the fibers were neutralized, washed, and dried to obtain desized carbon fibers. 100 parts by weight of desized carbon fibers and 1.3 parts by weight of silver nanoparticles were dispersed in deionized water and ultrasonicated for 7 min, followed by a mixing reaction at 24° C. for 40 min to obtain activated carbon fibers. 28 parts by weight of copper sulfate pentahydrate, 51 parts by weight of disodium ethylenediaminetetraacetate, 8.8 parts by weight of glyoxylic acid, 0.012 parts by weight of 2,2'-bipyridine, and 0.012 parts by weight of potassium ferrocyanide were dispersed in 1000 parts by weight of deionized water, and the pH value was adjusted to 11.5 to obtain a copper plating solution. The activated carbon fibers obtained above were dispersed in the copper plating solution and treated at 52° C. for 2.8 h for a plating reaction to obtain high thermal conductivity carbon fibers.

[0057] Preparation Example 8:

[0058] The preparation of high thermal conductivity carbon fiber includes the following steps:

[0059] The chopped carbon fibers were dispersed in acetone and immersed at 53°C for 140 minutes for degumming reaction. After the reaction, the fibers were dispersed in 65% concentrated nitric acid and immersed at 24°C for 75 minutes for desizing reaction. After the reaction, the fibers were neutralized, washed and dried to obtain desized carbon fibers. 100 parts by weight of desized carbon fibers and 1.7 parts by weight of silver nanoparticles were dispersed in deionized water and ultrasonicated for 8 minutes, followed by mixing and reacting at 24°C for 50 minutes to obtain activated carbon fibers. 32 parts by weight of copper sulfate pentahydrate, 51 parts by weight of disodium ethylenediaminetetraacetate, 9.2 parts by weight of glyoxylic acid, 0.013 parts by weight of 2,2'-bipyridine and 0.013 parts by weight of potassium ferrocyanide were dispersed in 1000 parts by weight of deionized water, and the pH value was adjusted to 11.5 to obtain a copper plating solution. The activated carbon fibers obtained above were dispersed in the copper plating solution and treated at 503°C for 3.2 hours for plating reaction to obtain high thermal conductivity carbon fibers.

[0060] Preparation Example 9:

[0061] The preparation of high thermal conductivity carbon fiber includes the following steps:

[0062] The chopped carbon fibers were dispersed in acetone and immersed at 55° C. for 150 min for degumming reaction. After the reaction, the chopped carbon fibers were dispersed in 65% concentrated nitric acid and immersed at 25° C. for 80 min for desizing reaction. After the reaction, the chopped carbon fibers were neutralized, washed, and dried to obtain desized carbon fibers. 100 parts by weight of desized carbon fibers and 2 parts by weight of silver nanoparticles were dispersed in deionized water and ultrasonicated for 10 min, followed by mixing and reacting at 25° C. for 60 min to obtain activated carbon fibers. 35 parts by weight of copper sulfate pentahydrate, 52 parts by weight of disodium ethylenediaminetetraacetate, 9.5 parts by weight of glyoxylic acid, 0.015 parts by weight of 2,2'-bipyridine, and 0.015 parts by weight of potassium ferrocyanide were dispersed in 1000 parts by weight of deionized water, and the pH value was adjusted to 12 to obtain a copper plating solution. The activated carbon fibers obtained above were dispersed in the copper plating solution and treated at 55° C. for 3.5 h for plating reaction to obtain high thermal conductivity carbon fibers.

[0063] Preparation Example 10:

[0064] The preparation of modified carbon fiber comprises the following steps:

[0065] The chopped carbon fibers were dispersed in acetone and immersed at 55°C for 150 min for degumming reaction. After the reaction, they were dispersed in 65% concentrated nitric acid and immersed at 25°C for 80 min for desizing reaction. After the reaction, the modified carbon fibers were neutralized, washed, and dried to obtain the modified carbon fibers.

[0066] Preparation Example 11:

[0067] The preparation of high thermal conductivity carbon fiber includes the following steps:

[0068] The chopped carbon fibers were dispersed in acetone and immersed at 55°C for 150 minutes for degumming reaction. After the reaction, they were dispersed in concentrated nitric acid with a concentration of 65% and immersed at 25°C for 80 minutes for desizing reaction. After the reaction, they were neutralized, washed, and dried to obtain desized carbon fibers. 100 parts by weight of desized carbon fibers were dispersed in 500 parts by weight of deionized water, and the pH was adjusted to 4. 35 parts by weight of copper sulfate pentahydrate were added and stirred for reaction for 5 hours. 8 parts by weight of 2,2'-bipyridine were added and stirred for reaction for 3 hours. After the reaction, the carbon fibers were washed and dried to obtain high thermal conductivity carbon fibers.

[0069] Example 1:

[0070] The preparation of a high thermal conductivity carbon fiber-ceramic composite material comprises the following steps:

[0071] 50 parts by weight of the polyborocarbosilazane prepared in Preparation Example 1 are dispersed in 100 parts by weight of a xylene solution to obtain a precursor mixture, and the high thermal conductivity carbon fiber prepared in Preparation Example 6 is dispersed in the above-mentioned precursor mixture. After being immersed at 50°C for 8 hours, it is cured at 150°C for 2 hours in a nitrogen protection environment, and then heated to 1800°C and kept warm for 2 hours for high-temperature cracking to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0072] Example 2:

[0073] The preparation of a high thermal conductivity carbon fiber-ceramic composite material comprises the following steps:

[0074] 53 parts by weight of the polyborocarbosilazane prepared in Preparation Example 2 were dispersed in 100 parts by weight of a xylene solution to obtain a precursor mixture, and the high thermal conductivity carbon fiber prepared in Preparation Example 7 was dispersed in the above-mentioned precursor mixture. After being immersed at 52°C for 8.2 hours, it was cured at 160°C for 2.4 hours in a nitrogen protection environment, and then heated to 1900°C and kept warm for 2.2 hours for high-temperature cracking to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0075] Example 3:

[0076] The preparation of a high thermal conductivity carbon fiber-ceramic composite material comprises the following steps:

[0077] 57 parts by weight of the polyborocarbosilazane prepared in Preparation Example 3 were dispersed in 100 parts by weight of a xylene solution to obtain a precursor mixture, and the high thermal conductivity carbon fiber prepared in Preparation Example 8 was dispersed in the above-mentioned precursor mixture. After being immersed at 56°C for 9 hours, it was cured at 180°C for 3 hours in a nitrogen protection environment, and then heated to 2000°C and kept warm for 2.8 hours for high-temperature cracking to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0078] Example 4:

[0079] The preparation of a high thermal conductivity carbon fiber-ceramic composite material comprises the following steps:

[0080] 60 parts by weight of the polyborocarbosilazane prepared in Preparation Example 4 were dispersed in 100 parts by weight of a xylene solution to obtain a precursor mixture, and the high thermal conductivity carbon fiber prepared in Preparation Example 9 was dispersed in the above-mentioned precursor mixture. After being immersed at 60°C for 10 hours, it was cured at 200°C for 4 hours in a nitrogen protection environment, and then heated to 2200°C and kept warm for 3 hours for high-temperature cracking to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0081] Comparative Example 1:

[0082] The preparation of a high thermal conductivity carbon fiber-ceramic composite material comprises the following steps:

[0083] 60 parts by weight of the polycarbosilazane prepared in Preparation Example 5 are dispersed in 100 parts by weight of a xylene solution to obtain a precursor mixture, and the high thermal conductivity carbon fiber prepared in Preparation Example 9 is dispersed in the above-mentioned precursor mixture. After being immersed at 60°C for 10 hours, it is cured at 200°C for 4 hours in a nitrogen protection environment, and then heated to 2200°C and kept warm for 3 hours for high-temperature cracking to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0084] Comparative Example 2:

[0085] The preparation of a high thermal conductivity carbon fiber-ceramic composite material comprises the following steps:

[0086] 60 parts by weight of dimethylpolysilane are dispersed in 100 parts by weight of xylene solution to obtain a precursor mixture. The high thermal conductivity carbon fiber obtained in Preparation Example 9 is dispersed in the above-mentioned precursor mixture. After being immersed at 60°C for 10 hours, it is cured at 200°C for 4 hours in a nitrogen protection environment, and then heated to 2200°C and kept warm for 3 hours for high-temperature cracking to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0087] Comparative Example 3:

[0088] The preparation of a high thermal conductivity carbon fiber-ceramic composite material comprises the following steps:

[0089] 60 parts by weight of the polyborocarbosilazane prepared in Preparation Example 4 were dispersed in 100 parts by weight of a xylene solution to obtain a precursor mixture, and the modified carbon fiber prepared in Preparation Example 10 was dispersed in the above-mentioned precursor mixture. After being immersed at 60°C for 10 hours, it was cured at 200°C for 4 hours in a nitrogen protection environment, and then heated to 2200°C and kept warm for 3 hours for high-temperature cracking to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0090] Comparative Example 4:

[0091] The preparation of a high thermal conductivity carbon fiber-ceramic composite material comprises the following steps:

[0092] 60 parts by weight of the polyborocarbosilazane prepared in Preparation Example 4 were dispersed in 100 parts by weight of a xylene solution to obtain a precursor mixture, and the high thermal conductivity carbon fiber prepared in Preparation Example 11 was dispersed in the above-mentioned precursor mixture. After being immersed at 60°C for 10 hours, it was cured at 200°C for 4 hours in a nitrogen protection environment, and then heated to 2200°C and kept warm for 3 hours for high-temperature cracking to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0093] Comparative Example 5:

[0094] The preparation of a high thermal conductivity carbon fiber-ceramic composite material comprises the following steps:

[0095] 60 parts by weight of dimethylpolysilane are dispersed in 100 parts by weight of xylene solution to obtain a precursor mixture, and short carbon fibers are dispersed in the above-mentioned precursor mixture. After being immersed at 60°C for 10 hours, the mixture is cured at 200°C for 4 hours in a nitrogen protection environment, and then heated to 2200°C and kept warm for 3 hours for high-temperature cracking to obtain a high thermal conductivity carbon fiber-ceramic composite material.

[0096] Performance testing:

[0097] The high thermal conductivity carbon fiber-ceramic composite materials prepared in Examples 1 to 4 of the present invention and Comparative Examples 1 to 5 were subjected to thermal conductivity tests, 2800K / 1000s linear ablation rate tests, and mechanical property tests. The test results are shown in Table 1.

[0098] Table 1. Performance indicators of Examples 1 to 4 and Comparative Examples 1 to 5

[0099]

[0100] It can be seen from the above results that compared with the high thermal conductivity carbon fiber-ceramic composite materials obtained in Comparative Examples 1 to 5, Examples 1 to 4 of the present invention have good thermal conductivity, ablation resistance and mechanical properties; high thermal conductivity carbon fiber as a reinforcing phase can form a continuous heat conduction path in the high thermal conductivity carbon fiber-ceramic composite material. In addition, the high thermal conductivity of copper further improves the thermal conductivity of the high thermal conductivity carbon fiber-ceramic composite material; nitrogen forms stable nitrides with carbon, silicon and other elements during the high temperature cracking process. These nitrides have extremely high thermal stability and oxidation resistance, and can be used at high temperature. It effectively resists thermal decomposition and oxidative corrosion in an ablation environment. Boron forms borides with carbon, silicon and other elements at high temperatures. These borides have extremely high melting points and thermal stability and can maintain structural integrity in extremely high-temperature ablation environments. By introducing boron and nitrogen to work synergistically with high thermal conductivity carbon fibers, the surface temperature of the ablation zone is lowered by rapid heat conduction, reducing ablation damage. The high thermal conductivity carbon fibers are dispersed and impregnated in the precursor mixture, so that the components are evenly distributed in the composite material, thereby improving the high thermal conductivity and ablation resistance of the high thermal conductivity carbon fiber-ceramic composite material while maintaining good mechanical properties.

[0101] The embodiments described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A process for preparing a high thermal conductivity carbon fiber-ceramic composite material, characterized in that: The preparation process comprises the following steps: Polyboron carbosilazane is dispersed in xylene to obtain a precursor solution, high thermal conductivity carbon fiber is immersed in the precursor solution, and then cured and pyrolyzed to obtain the high thermal conductivity carbon fiber-ceramic composite material; The preparation method of the polyboronocarbosilazane comprises the following steps: Diaminomaleonitrile, HBpin and triethylaluminum are subjected to a first stirring reaction to obtain an intermediate product, and the intermediate product, methylhydrodichlorosilane and a catalyst are dispersed in n-hexane and subjected to a second stirring reaction to obtain the polyborocarbosilazane; The method for preparing the high thermal conductivity carbon fiber comprises the following steps: The chopped carbon fibers are subjected to degumming and desizing reactions to obtain desized carbon fibers, and the desized carbon fibers are mixed with silver nanoparticles to obtain activated carbon fibers; copper sulfate pentahydrate, disodium ethylenediaminetetraacetic acid, glyoxylic acid, 2,2'-bipyridine, and potassium ferrocyanide are dispersed in deionized water to obtain a copper plating solution, and the activated carbon fibers are plated in the copper plating solution to obtain the high thermal conductivity carbon fibers; The temperature of the high-temperature cracking is 1800~2200℃.

2. A process for preparing a high thermal conductivity carbon fiber-ceramic composite material according to claim 1, characterized in that: The weight ratio of the diaminomaleonitrile, HBpin and triethylaluminum is 1:1.2-1.5:0.09-0.

11.

3. A process for preparing a high thermal conductivity carbon fiber-ceramic composite material according to claim 1, characterized in that: The weight ratio of the intermediate product to the catalyst is 1:0.3-0.

5.

4. A process for preparing a high thermal conductivity carbon fiber-ceramic composite material according to claim 1, characterized in that: The weight ratio of the intermediate product to methylhydrogendichlorosilane is 4.5-5.5:2.5-3.

5. A process for preparing a high thermal conductivity carbon fiber-ceramic composite material according to claim 1, characterized in that: The catalyst is triethylamine.

6. A process for preparing a high thermal conductivity carbon fiber-ceramic composite material according to claim 1, characterized in that: The weight ratio of the desized carbon fibers to the silver nanoparticles is 1:0.01-0.

02.

7. A process for preparing a high thermal conductivity carbon fiber-ceramic composite material according to claim 1, characterized in that: The weight ratio of the copper sulfate pentahydrate, disodium ethylenediaminetetraacetic acid, glyoxylic acid, 2,2'-bipyridine, potassium ferrocyanide and deionized water is 2.5-3.5:5-5.2:0.8-0.95:0.001-0.0015:0.001-0.0015:

100.

8. A process for preparing a high thermal conductivity carbon fiber-ceramic composite material according to claim 1, characterized in that: The weight ratio of the polyborocarbosilazane to xylene is 50-60:100.

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