High-thermal-conductivity low-expansion carbon ceramic material and preparation method thereof

Abstract

The application discloses a kind of high-thermal-conductivity low-expansion carbon ceramic materials and preparation method thereof, its preparation method includes the following steps: depositing pyrolytic carbon on carbon fiber preform, then heat treatment is carried out, and the preform with interface layer is prepared;Then first impregnation in slurry A that organic silicone resin, curing agent, catalyst and inorganic filler are composed, after solidification, pyrolysis, again impregnation in slurry B that resin, curing agent and solvent are composed, after solidification, pyrolysis, carbon carbon composite material is prepared;Finally, after ceramming treatment, it is prepared.The high-thermal-conductivity low-expansion carbon ceramic material prepared by the application on the one hand effectively improves the thermal conductivity, is favorable to the heat dissipation when component high temperature, on the other hand, the thermal stress damage in preparation process is reduced, and the mechanical properties of material are improved, and can be applicable to the preparation of brake disc, brake pad and other flat plate components.

Description

Technical Field

[0001] This invention relates to the field of carbon ceramic material preparation technology, specifically to a high thermal conductivity, low expansion carbon ceramic material and its preparation method. Background Technology

[0002] Carbon-ceramic materials are widely used in aerospace, rail transportation, and automotive fields due to their advantages such as low density, high specific strength, high temperature resistance, corrosion resistance, and weather resistance. Common methods for preparing carbon-ceramic materials include chemical vapor infiltration (CVI), precursor infiltration pyrolysis (PIP), and reactive melt infiltration (RMI).

[0003] Among them, the CVI method for preparing the interface layer and matrix has high mechanical properties and is more suitable for irregularly shaped components, but it is costly and prone to density gradients. The PIP method for preparing the interface layer and matrix has the advantages of good uniformity and low cost, but it has the problem of long preparation cycle. At present, the CVI method is usually used in engineering applications. For thicker preforms, there is a problem of internal density inhomogeneity. At the same time, due to the poor thermal conductivity of carbon ceramic materials, the temperature resistance requirements of adjacent components in the component are high. Taking brake discs as an example, the cast iron discs currently used have fast thermal conductivity and have little thermal impact on auxiliary components such as calipers and oil pipes during use. However, carbon ceramic discs prepared by normal processes have poor thermal conductivity, and the thermal diffusivity is generally 10 mm. 2 Below 0.5 rpm, it is insufficient to meet the braking safety and long service life requirements of carbon ceramic discs. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide a high thermal conductivity, low expansion carbon ceramic material and its preparation method, thereby solving the problems of uneven internal density and poor thermal conductivity in existing carbon ceramic materials.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows:

[0006] A method for preparing a high thermal conductivity, low expansion carbon ceramic material includes the following steps:

[0007] (1) Pyrolytic carbon is deposited on a carbon fiber preform and then heat-treated to obtain a preform with an interface layer.

[0008] (2) Mix the silicone resin, curing agent, catalyst and inorganic filler evenly to obtain slurry A; then vacuum impregnate the preform with interface layer obtained in step (1) in slurry A, and then cure and pyrolyze it to obtain a semi-finished carbon-carbon composite material.

[0009] (3) mixing the thermosetting resin, the curing agent and the solvent uniformly to prepare slurry B; then performing pressure impregnation on the semi-finished carbon-carbon composite material obtained in step (2) in slurry B, and then performing curing and pyrolysis until the material density reaches 1.2-1.5 g / cm 3 , to prepare the carbon-carbon composite material;

[0010] (4) performing high-temperature ceramicization treatment on the carbon-carbon composite material prepared in step (3) to prepare the high-thermal-conductivity low-expansion carbon ceramic material.

[0011] The present application has the advantages that: the present application adopts CVI+PIP process for densification processing, and the preparation period is short; on the one hand, the pyrolytic carbon interface layer guarantees the performance of the material, and on the other hand, the components of the slurry in the PIP process have the characteristics of strong designability, and the densification efficiency of the component can be greatly improved by adding high-density fillers in slurry A, thereby further shortening the preparation period of the carbon-carbon stage; the high-thermal-conductivity low-expansion carbon ceramic material prepared by the present application effectively improves the thermal diffusivity and mechanical properties of the material through impregnation processing in slurry A and other processes.

[0012] Further, the preparation method of the carbon fiber preform in step (1) is: alternately stacking the no-woven cloth and the mesh tire layer to the designed thickness, and sewing in the needle punching manner in the Z direction to prepare the carbon fiber preform.

[0013] Further, the no-woven cloth and the mesh tire layer are both T300 carbon fiber or T700 carbon fiber; each layer is stacked in the clockwise or counterclockwise rotation of 45° during the alternate stacking.

[0014] Further, the temperature for depositing the pyrolytic carbon in step (1) is 600-1200℃, and the time is 40-100h; the temperature for heat treatment is 2000-2500℃, and the time is 1-5h.

[0015] Preferably, the temperature for depositing the pyrolytic carbon in step (1) is 900℃, and the time is 60h; the temperature for heat treatment is 2300℃, and the time is 4h.

[0016] Further, the mass ratio of the organic silicon resin, the curing agent, the catalyst and the inorganic filler in step (2) is 80-120:40-60:1-5:20-50.

[0017] Preferably, the mass ratio of the organic silicon resin, the curing agent, the catalyst and the inorganic filler in step (2) is 100:50:3:40.

[0018] Further, the organic silicon resin comprises polydimethylsiloxane or polymethylphenylsiloxane; the curing agent is divinylbenzene or vinylsiloxane; the catalyst is chloroplatinic acid alcohol solution with a mass fraction of 0.8-1.2%; and the inorganic filler comprises at least one of iron powder, aluminum powder, copper-iron alloy powder, aluminum oxide, silicon oxide, aluminum nitride, silicon nitride, silicon carbide, carbon black, graphite and zirconium tungstate, and has a particle size of 0.5-5 μm.

[0019] The beneficial effects of the above further technical solutions are: when the carbon matrix is prepared by the PIP process, the damage to the carbon fiber in the first cycle is the largest, far exceeding the sum of the subsequent cycles, and the main damage form is thermal stress physical damage. Because the structure of the low-density preform is unstable, when impregnated directly with a thermosetting resin (phenolic resin, etc.), the volume shrinks after curing, which affects the structure of the preform. The organic silicon resin in slurry A is addition type, and there is no low-molecular by-product during curing, so there is basically no volume shrinkage, which can maximize the integrity of the microstructure. At the same time, the addition of high-thermal-conductivity fillers can improve the thermal conductivity of the product and effectively improve the thermal diffusivity. The addition of negative expansion fillers such as zirconium tungstate can balance the thermal expansion coefficient of the matrix, reduce the crack defects generated during preparation, and improve the mechanical properties of the product.

[0020] Further, the vacuum degree of the vacuum impregnation in step (2) is -0.1-0 MPa, and the time is 1-2 h; the curing temperature is 100-150℃, and the time is 4-8 h; and the pyrolysis temperature is 800-1200℃, and the time is 1-5 h.

[0021] Preferably, the vacuum degree of the vacuum impregnation in step (2) is -0.1 MPa, and the time is 1 h; the curing temperature is 150℃, and the time is 6 h; and the pyrolysis temperature is 1000℃, and the time is 4 h.

[0022] Further, the mass ratio of the thermosetting resin, the curing agent and the solvent in step (3) is 50-150:5-20:80-120.

[0023] Preferably, the mass ratio of the thermosetting resin, the curing agent and the solvent in step (3) is 120:15:80.

[0024] Further, the thermosetting resin comprises furan resin or phenolic resin; the curing agent comprises dimethylbenzene sulfonic acid or urotropine; and the solvent comprises any one of ethanol, acetone and dimethylbenzene.

[0025] The beneficial effects of the further technical scheme are: the carbon matrix is prepared by the PIP process, slurry A with addition type silicone resin as the main body is selected in the first cycle, and slurry B with thermosetting resin (phenolic resin, etc.) as the main body is used in the subsequent densification process, which can effectively avoid the volume shrinkage caused by directly using thermosetting resin for impregnation in the first cycle, and affect the structure of the preform; on the other hand, slurry B is used for densification after the first cycle, which guarantees the efficiency of the densification process and shortens the preparation cycle of the carbon-carbon stage.

[0026] Further, the pressure impregnation in step (3) is performed at a pressure of 1-3 MPa for 1-4 h, the curing is performed at a temperature of 100-150℃ for 2-4 h, and the pyrolysis is performed at a temperature of 800-1200℃ for 1-5 h.

[0027] Preferably, the pressure impregnation in step (3) is performed at a pressure of 2 MPa for 2 h, the curing is performed at a temperature of 120℃ for 4 h, and the pyrolysis is performed at a temperature of 1200℃ for 3 h.

[0028] Further, the ceramic treatment in step (4) is performed at a temperature of 1200-1600℃ for 1-4 h, and the raw material for the ceramic treatment is at least one of silicon powder, iron powder, copper powder, iron-silicon powder and copper-silicon powder.

[0029] Preferably, the ceramic treatment in step (4) is performed at a temperature of 1400℃ for 3 h.

[0030] A high-thermal-conductivity and low-expansion carbon ceramic material is prepared by the above preparation method.

[0031] The present application has the following beneficial effects:

[0032] (1) The high-thermal-conductivity filler and metal powder are added to the slurry A, which can be matched according to the particle size, and can effectively improve the thermal conductivity of the prepared high-thermal-conductivity and low-expansion carbon ceramic material, effectively improve the densification degree of the carbon ceramic material, and form heat conduction between the internal electrons of the carbon ceramic material through the introduced metal atoms, thereby further improving the thermal conductivity of the carbon ceramic material.

[0033] (2) Carbon carbon composite material processing technology generally adopts CVI process, which needs at least 30-45 days from the preform densification process to the ceramic state, which needs higher time cost and labor cost. The present application adopts CVI+PIP combined process for densification processing, and the whole preparation cycle is only 15-20 days. On the one hand, the present application ensures the performance of the material by processing the pyrolytic carbon interface layer, and on the other hand, the slurry composition part in PIP process has strong designability, which can greatly improve the densification efficiency by adding high-density filler in slurry A, and further shorten the preparation cycle of carbon carbon stage.

[0034] (3) When using PIP process to prepare carbon matrix, the damage to carbon fiber in the first cycle is the largest, far more than the sum of the subsequent cycles, and the main damage form is thermal stress physical damage. Because the low-density preform structure is unstable, when directly impregnated with thermosetting resin (phenolic resin, etc.), the volume shrinkage after curing will affect the preform structure. In the present application, the silicone resin in slurry A is addition type, and there is no low molecular by-product during curing, and the volume shrinkage is basically zero, which can maximize the integrity of the microstructure; at the same time, the addition of high thermal conductivity filler can improve the thermal conductivity of the product, and effectively improve the thermal diffusivity; the addition of tungsten acid zirconium and other negative expansion fillers can balance the thermal expansion coefficient of the matrix, reduce the crack defects generated during preparation, and improve the mechanical properties of the product. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 SEM image of the cross section of the carbon ceramic brake disc prepared in Example 1;

[0036] Figure 2 SEM image of the surface of the carbon ceramic brake disc prepared in Example 1 and Comparative Example 1, wherein (a) is Example 1, and (b) is Comparative Example 1;

[0037] Figure 3 SEM image of the surface of the carbon carbon composite material prepared in Example 1 and Comparative Example 1, wherein (a) is Example 1, and (b) is Comparative Example 1. DETAILED DESCRIPTION

[0038] The principles and characteristics of the present application are described below in conjunction with the drawings, and the examples are only used to explain the present application, and are not used to limit the scope of the present application. If the specific conditions are not specified in the examples, the conventional conditions or the conditions recommended by the manufacturer are used. If the reagents or instruments used are not specified by the manufacturer, they are all conventional products that can be purchased on the market.

[0039] Example 1:

[0040] A preparation method of a high-thermal-conductivity and low-expansion carbon ceramic brake disc, comprising the following steps:

[0041] (1) Preparation of the preform

[0042] The non-woven fabric and the net tire layer are alternately stacked, each layer is laid in a clockwise rotation of 45°, the thickness is stacked to 30mm, and the Z direction is stitched in a needling manner to obtain a preform, wherein the non-woven fabric and the net tire layer are both selected from T300 carbon fibers.

[0043] (2) Preparation of the interface layer

[0044] A. The preform plate prepared in step (1) is placed in a gas deposition furnace, natural gas is used as the carbon source gas, and pyrolytic carbon is deposited at 900℃ for 60h;

[0045] B. Then the preform plate after deposition is placed in a high temperature furnace for heat treatment, the heat treatment temperature is 2300℃, and the time is 4h, to obtain a preform plate with an interface layer;

[0046] (3) Preparation of carbon-carbon composite material

[0047] A. Polydimethylsiloxane, divinylbenzene, 1% mass fraction of chloroplatinic acid alcohol solution and inorganic filler are weighed and mixed uniformly according to the mass ratio of 100:50:3:40 to obtain slurry A; wherein the inorganic filler is copper powder, aluminum nitride, silicon carbide, carbon black and zirconium tungstate, and the mass ratio is 30:5:10:5:20, the particle size of silicon carbide in the inorganic filler is 2μm, and the rest is 0.5μm;

[0048] B. Then the preform plate with an interface layer prepared in step (2) is soaked in slurry A for vacuum impregnation, the vacuum degree is-0.1MPa, and the time is 1h, and then it is taken out and solidified at 150℃ for 6h;

[0049] C. The preform plate with an interface layer after solidification is placed in a high temperature furnace for pyrolysis, the pyrolysis temperature is 1000℃, and the time is 4h, to obtain a semi-finished carbon-carbon composite material;

[0050] D. Phenol formaldehyde resin, urotropine and acetone are mixed uniformly according to the mass ratio of 120:15:80 to obtain slurry B;

[0051] E. Then the semi-finished carbon-carbon composite material is soaked in slurry B for pressure impregnation, the pressure is 2MPa, and the time is 2h, and then it is taken out and solidified at 120℃ for 4h;

[0052] F. Finally, the semi-finished carbon-carbon composite material after solidification is placed in a high temperature furnace for pyrolysis, the pyrolysis temperature is 1200℃, and the time is 3h;

[0053] G. Repeat steps E and F until the density of the semi-finished carbon-carbon composite material reaches 1.5g / cm 3 , to obtain a carbon-carbon composite material.

[0054] (4) Machining

[0055] The carbon-carbon composite material prepared in step (3) is machined according to the design size of the brake disc to prepare a carbon-carbon brake disc.

[0056] (5) Ceramization treatment

[0057] The carbon-carbon brake disc prepared in step (4) is placed in a high-temperature furnace for ceramization treatment, the treatment temperature is 1400℃, and the time is 3h, to prepare a carbon ceramic brake disc with a density of 2.5g / cm 3 The raw material for ceramization treatment is selected from copper-silicon alloy powder.

[0058] Example 2:

[0059] A method for preparing a high-thermal-conductivity and low-expansion carbon ceramic brake disc, comprising the following steps:

[0060] (1) Preparation of a preform

[0061] The layers of the non-woven fabric and the net tire layer are alternately stacked, each layer is laid in a clockwise rotation of 45°, and after the thickness is stacked to 40mm, the Z-direction is sewn in a needling manner to prepare a preform, wherein the non-woven fabric and the net tire layer are both selected from T700 carbon fibers.

[0062] (2) Preparation of an interface layer

[0063] A. The preform plate prepared in step (1) is placed in a gas deposition furnace, natural gas is used as the carbon source gas, and pyrolytic carbon is deposited at 800℃ for 80h;

[0064] B. Then the preform plate after deposition is placed in a high-temperature furnace for heat treatment, the heat treatment temperature is 2500℃, and the time is 4h, to prepare a preform plate with an interface layer;

[0065] (3) Preparation of a carbon-carbon composite material

[0066] A. Polyphenylmethylsiloxane, vinylsiloxane, 1% mass fraction of chloroplatinic acid alcohol solution, and inorganic fillers are weighed and mixed uniformly according to a mass ratio of 80:60:4:50 to prepare slurry A; wherein the inorganic fillers are iron powder, aluminum oxide, silicon nitride, graphite, and zirconium tungstate, and the mass ratio is 30:5:10:5:20, the particle size of the silicon nitride in the inorganic fillers is 2μm, and the particle sizes of the rest are all 0.5μm;

[0067] B. Then the preform plate with an interface layer prepared in step (2) is soaked in slurry A for vacuum impregnation, the vacuum degree is -0.1MPa, and the time is 1h, and then it is taken out and cured at 150℃ for 6h;

[0068] C. The cured preform with interface layer is placed in a high temperature furnace for pyrolysis, the pyrolysis temperature is 1000℃, and the time is 4h, to obtain a semi-finished carbon-carbon composite material;

[0069] D. Furan resin, dimethyl benzene sulfonic acid and dimethylbenzene are mixed uniformly according to the mass ratio of 130:10:100 to obtain slurry B;

[0070] E. Then the semi-finished carbon-carbon composite material is soaked in slurry B for pressure impregnation, the pressure is 2MPa, and the time is 2h, and then it is taken out and cured at 120℃ for 4h;

[0071] F. Finally, the cured semi-finished carbon-carbon composite material is placed in a high temperature furnace for pyrolysis, the pyrolysis temperature is 1200℃, and the time is 3h;

[0072] G. Repeat steps E and F until the density of the semi-finished carbon-carbon composite material reaches 1.4g / cm 3 , to obtain a carbon-carbon composite material.

[0073] (4) Machining

[0074] The carbon-carbon composite material prepared in step (3) is machined according to the design size of the brake disc to obtain a carbon-carbon brake disc.

[0075] (5) Ceramization treatment

[0076] The carbon-carbon brake disc prepared in step (4) is placed in a high temperature furnace for ceramization treatment, the treatment temperature is 1400℃, and the time is 3h, to obtain a carbon ceramic brake disc with a density of 2.6g / cm 3 . The raw material for ceramization treatment is selected from iron-silicon alloy powder.

[0077] Example 3:

[0078] A method for preparing a high-thermal-conductivity and low-expansion carbon ceramic brake disc, comprising the following steps:

[0079] (1) Preform preparation

[0080] The non-woven fabric and the net tire layer are alternately stacked, each layer is laid in a clockwise rotation of 45°, and after the thickness is stacked to 32mm, it is sewn in a needling manner in the Z direction to obtain a preform, wherein the non-woven fabric and the net tire layer are selected from T300 carbon fibers.

[0081] (2) Interface layer preparation

[0082] A. The preform plate prepared in step (1) is placed in a gas deposition furnace, and natural gas is used as carbon source gas to deposit pyrolytic carbon at 950℃ for 50h;

[0083] B. Then the deposited preform flat plate is placed in a high temperature furnace for heat treatment, the heat treatment temperature is 2300℃, and the time is 4h, to obtain a preform flat plate with an interface layer;

[0084] (3) Carbon-carbon composite material preparation

[0085] A. Polydimethylsiloxane, vinylsiloxane, 1% mass fraction chloroplatinic acid alcohol solution and inorganic filler are weighed and mixed uniformly according to the mass ratio of 120:40:2:30 to obtain slurry A; wherein the inorganic filler is aluminum powder, aluminum oxide, silicon carbide, carbon black and zirconium tungstate, and the mass ratio is 30:5:10:5:20, the particle size of silicon carbide in the inorganic filler is 2μm, and the rest is 0.5μm;

[0086] B. Then the preform flat plate with an interface layer prepared in step (2) is soaked in slurry A for vacuum impregnation, the vacuum degree is-0.1MPa, and the time is 1h, and then it is taken out and solidified at 150℃ for 6h;

[0087] C. The solidified preform flat plate with an interface layer is placed in a high temperature furnace for pyrolysis, the pyrolysis temperature is 1000℃, and the time is 4h, to obtain a semi-finished carbon-carbon composite material;

[0088] D. Phenolic resin, urotropine and ethanol are mixed uniformly according to the mass ratio of 150:5:120 to obtain slurry B;

[0089] E. Then the semi-finished carbon-carbon composite material is soaked in slurry B for pressure impregnation, the pressure is 2MPa, and the time is 2h, and then it is taken out and solidified at 120℃ for 4h;

[0090] F. Finally, the solidified semi-finished carbon-carbon composite material is placed in a high temperature furnace for pyrolysis, the pyrolysis temperature is 1200℃, and the time is 3h;

[0091] G. Repeat steps E and F until the density of the semi-finished carbon-carbon composite material reaches 1.5g / cm 3 , to obtain a carbon-carbon composite material.

[0092] (4) Machining

[0093] The carbon-carbon composite material prepared in step (3) is machined according to the design size of the brake disc to obtain a carbon-carbon brake disc.

[0094] (5) Ceramization treatment

[0095] The carbon-carbon brake disc prepared in step (4) is placed in a high temperature furnace for ceramization treatment, the treatment temperature is 1500℃, and the time is 2h, to obtain a carbon-carbon brake disc with a density of 2.4g / cm 3A carbon ceramic brake disc, wherein the raw material for the ceramization treatment is selected from silicon powder and copper powder in a weight ratio of 1:1.

[0096] Comparative Example 1

[0097] A method for preparing a high-thermal-conductivity and low-expansion carbon ceramic brake disc, comprising the following steps:

[0098] (1) Preform preparation

[0099] The non-woven fabric and the mesh tire layer are alternately stacked, and each layer is laid in a clockwise rotation of 45°. After stacking to the designed thickness, the Z-direction is sewn in the form of needling to obtain a preform. The non-woven fabric and the mesh tire layer are both selected from T300 carbon fibers.

[0100] (2) Interface layer preparation

[0101] A. The preform plate prepared in step (1) is placed in a gas deposition furnace, and natural gas is used as the carbon source gas to deposit pyrolytic carbon at 900°C for 50h;

[0102] B. Then the preform plate after deposition is placed in a high-temperature furnace for heat treatment, and the heat treatment temperature is 2300°C and the time is 4h, to obtain a preform plate with an interface layer;

[0103] (3) Carbon-carbon composite material preparation

[0104] A. Phenolic resin, urotropine and acetone are mixed uniformly according to a mass ratio of 120:15:80 to obtain slurry A;

[0105] B. Then the semi-finished carbon-carbon composite material is soaked in slurry B for pressure impregnation, the pressure is 2MPa, and the time is 2h, and then it is taken out and solidified at 120°C for 4h;

[0106] C. Finally, the solidified semi-finished carbon-carbon composite material is placed in a high-temperature furnace for pyrolysis, the pyrolysis temperature is 1200°C, and the time is 3h;

[0107] D. Repeat steps B and C until the density of the semi-finished carbon-carbon composite material reaches 1.5g / cm 3 , to obtain a carbon-carbon composite material.

[0108] (4) Mechanical processing

[0109] The carbon-carbon composite material prepared in step (3) is processed according to the design size of the brake disc to obtain a carbon-carbon brake disc.

[0110] (5) Ceramization treatment

[0111] The carbon-carbon brake disc prepared in step (4) is placed in a high-temperature furnace for ceramization treatment, the treatment temperature is 1400℃, and the treatment time is 3h, thereby obtaining a carbon ceramic brake disc with a density of 2.5g / cm 3 The raw material for ceramization treatment is selected from copper-silicon alloy powder.

[0112] Test example:

[0113] The carbon-carbon composite material and the carbon ceramic brake disc prepared in Example 1 and Comparative Example 1 are subjected to performance characterization, and the characterization methods include bending property test, thermal diffusivity determination, and scanning electron microscope observation. The bending property of the carbon ceramic brake disc is determined by an INSTRON3369 universal tensile testing machine, the sample size is 60x8x6mm, and the test conditions are: 25℃, and the loading speed is 0.5mm / min. The thermal diffusivity is determined by a netzsch LFA457 laser method thermal conductivity instrument, the sample size is 12.5x2.5mm, and the test conditions are: vacuum degree 1Pa, and the test temperature point is 50℃.

[0114] The bending property and thermal diffusivity experimental results are shown in Table 1 below.

[0115] Table 1: Bending property and thermal diffusivity test results

[0116] Bending performance (MPa) Thermal diffusivity (mm 2 / s) Example 1 180 8.2 Comparative Example 1 150 15.8

[0117] According to the test results in the above table, compared with the carbon ceramic brake disc prepared in Comparative Example 1, the carbon ceramic brake disc prepared in Example 1 has significant improvement in both bending property and thermal diffusivity.

[0118] Figures 1-3 The scanning electron microscope test results are shown in the following table, wherein, Figure 1 is the cross-sectional SEM picture of the carbon ceramic brake disc prepared in Example 1, which shows the three-dimensional network heat conduction channel structure formed by inorganic fillers with different particle sizes in the composite material, and this structure can effectively improve the thermal conductivity of the composite material; Figure 2 shows the surface microstructure of the carbon ceramic brake discs prepared in Example 1 and Comparative Example 1, and according to the content in the figure, the carbon ceramic brake disc prepared in Comparative Example 1 has obvious crack structure; Figure 3 ​The surface microstructure of the impregnated slurry of Example 1 and Comparative Example 1 after curing is shown, and according to the content of the figure, the surface of the carbon-carbon composite material prepared in Comparative Example 1 has obvious pore structure. The reason for the crack structure and pore structure in the SEM result of Comparative Example 1 is that the structure of the low-density preform is unstable, and when directly impregnated with a thermosetting resin (phenolic resin, etc.), the structure of the preform will be affected due to volume shrinkage after curing, leading to obvious crack defects due to thermal stress during preparation. In the present application, the slurry A prepared by using the addition-type silicone resin in the first cycle is used for impregnation, and there is no low-molecular by-product during curing, and there is basically no volume shrinkage, which ensures the integrity of the fiber structure. Combined with the addition of negative expansion fillers such as zirconium tungstate, it can balance the thermal expansion coefficient of the matrix, effectively avoiding crack defects due to thermal stress during preparation.

[0119] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing a high thermal conductive and low expansion carbon ceramic material, characterized in that, The method comprises the following steps: (1) depositing pyrolytic carbon on a carbon fiber preform, and then performing heat treatment to obtain a preform with an interface layer; (2) uniformly mixing silicone resin, curing agent, catalyst and inorganic filler to obtain slurry A; then performing vacuum impregnation of the preform with the interface layer obtained in step (1) in the slurry A, and then curing and pyrolyzing to obtain a semi-finished carbon-carbon composite material; (3) mixing the thermosetting resin, the curing agent and the solvent uniformly to obtain slurry B; then pressure impregnating the semi-finished carbon-carbon composite material obtained in step (2) in slurry B, and then curing and pyrolyzing until the material density reaches 1.2-1.5 g / cm 3 , to obtain a carbon-carbon composite material; (4) mixing the thermosetting resin, the curing agent and the solvent uniformly to obtain slurry B; then pressure impregnating the semi-finished carbon-carbon composite material obtained in step (2) in slurry B, and then curing and pyrolyzing until the material density reaches 1.2-1.5 g / cm 3 , to obtain a carbon-carbon composite material; (4) performing high-temperature ceramicization treatment on the carbon-carbon composite material obtained in step (3) to obtain a carbon-carbon composite material with a ceramic interface layer. In step (2), the mass ratio of the silicone resin, the curing agent, the catalyst and the inorganic filler is 80-120:40-60:1-5:20-50; the silicone resin comprises polydimethylsiloxane or polymethylphenylsiloxane; the curing agent is divinylbenzene or vinylsiloxane; the catalyst is an alcohol solution of chloroplatinic acid with a mass fraction of 0.8-1.2%; and the inorganic filler comprises at least one of iron powder, aluminum powder, copper-iron alloy powder, aluminum oxide, silicon oxide, aluminum nitride, silicon nitride, silicon carbide, carbon black, graphite and zirconium tungstate, and has a particle size of 0.5-5 μm. In step (3), the mass ratio of the thermosetting resin, the curing agent and the solvent is 50-150:5-20:80-120; the thermosetting resin comprises furan resin or phenolic resin; the curing agent comprises dimethylbenzene sulfonic acid or urotropine; and the solvent comprises any one of ethanol, acetone and dimethylbenzene.

2. The method of claim 1, wherein the high thermal conductive and low expansion carbon ceramic material is prepared by the steps of: mixing a carbon material and a ceramic material to form a mixture; and sintering the mixture at a temperature of 1,000°C to 2,000°C in a vacuum or an inert gas atmosphere. In step (1), the temperature for depositing pyrolytic carbon is 600-1200 ℃, and the time is 40-100 h; and the temperature for heat treatment is 2000-2500 ℃, and the time is 1-5 h.

3. The method of claim 1, wherein the high thermal conductive and low expansion carbon ceramic material is prepared by the steps of: mixing a carbon material and a ceramic material; and sintering the mixed material. In step (2), the vacuum degree for vacuum impregnation is -0.1~0 MPa, and the time is 1-2 h; the temperature for curing is 100-150 ℃, and the time is 4-8 h; and the temperature for pyrolysis is 800-1200 ℃, and the time is 1-5 h.

4. The method of claim 1, wherein the high thermal conductive and low expansion carbon ceramic material is prepared by the steps of: mixing a carbon material and a ceramic material; and sintering the mixed material. In step (3), the pressure for pressure impregnation is 1-3 MPa, and the time is 1-4 h; the temperature for curing is 100-150 ℃, and the time is 2-4 h; and the temperature for pyrolysis is 800-1200 ℃, and the time is 1-5 h.

5. The method of claim 1, wherein the high thermal conductive and low expansion carbon ceramic material is prepared by the steps of: mixing a carbon material and a ceramic material; and sintering the mixed carbon material and ceramic material. In step (4), the temperature for ceramicization treatment is 1200-1600 ℃, and the time is 1-4 h; and the raw material for ceramicization treatment is at least one of silicon powder, iron powder, copper powder, iron-silicon powder and copper-silicon powder.

6. A high thermal conductive low expansion carbon ceramic material, characterized by, The carbon-carbon composite material with a ceramic interface layer is prepared by the method in any one of claims 1-5.

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