Preparation method of high-thermal-conductivity graphene film-carbon-carbon composite material

Abstract

The invention relates to a preparation method of a high-thermal-conductivity graphene film-carbon-carbon composite material, which comprises the following steps: S1, dispersing carbon precursor powder in isopropyl-ketone to obtain matrix slurry; s2, carbon unidirectional fiber cloth is directionally arranged in a laminated mode, and the space between the two layers is evenly smeared with the base body slurry; s3, performing hot pressing on the unidirectional cloth laminated blank, taking out the unidirectional cloth laminated blank after cooling, and then cutting the unidirectional cloth laminated blank along the direction parallel to fibers to obtain a low-density one-dimensional composite material strip-shaped sample; s4, uniformly brushing a graphene film with the matrix slurry, enabling the matrix slurry to pass through the low-density one-dimensional composite material strip-shaped samples which are arranged side by side according to an S shape, and performing heating and heat preservation; and S5, sequentially densifying and carbonizing the graphene film / low-density carbon-carbon composite material in the step S5, and then carrying out high-temperature graphitization treatment to obtain the high-thermal-conductivity graphene film-carbon-carbon composite material. Compared with the prior art, the method has the advantage that the overall heat-conducting property of the one-dimensional composite material can be improved under the condition that the mechanical property is not influenced.

Description

Technical Field

[0001] The present invention belongs to the technical field of composite material preparation, and relates to a preparation process of a high thermal conductivity graphene film - carbon / carbon composite material. Background Art

[0002] With the rapid development of fields such as national defense technology, aerospace technology, semiconductor technology, new energy vehicles, etc., higher and higher requirements are put forward for the thermal conductivity of key components. Traditional high - thermal - conductivity metal materials, such as copper, aluminum, etc., are difficult to meet the increasingly stringent heat dissipation requirements due to their limited thermal conductivity, large density, and high coefficient of thermal expansion. Therefore, it is necessary to develop a material with light weight, high strength, and excellent thermal conductivity.

[0003] Mesophase pitch fiber has extremely high thermal conductivity (up to more than 1000 W / (m*K)), and the C / C composite material with it as the reinforcement is a very promising new thermal - conductive material. However, due to the orientation of fiber heat conduction, usually only some directions of the pitch - based C / C composite material can reach extremely high thermal conductivity, and the thermal conductivity in other directions is very poor. Taking one - dimensional pitch - based C / C composite material as an example, its thermal conductivity along the fiber direction can reach 800 W / (m*K), while the thermal conductivity perpendicular to the fiber direction is only 10 - 20 W / (m*K), which undoubtedly restricts the popularization and application of pitch - based C / C composite materials.

[0004] Patent CN116283332A discloses a preparation method of a pitch - based carbon / carbon composite material with high thermal conductivity in the thickness direction. First, a one - dimensional composite material embryo is prepared, then thermal - conductive channels are constructed along the direction perpendicular to the fiber direction by laser drilling, and finally impregnation carbonization and graphitization are carried out. The composite material prepared by this method improves the thermal conductivity in the thickness direction, but during the laser - drilling process, the continuous fibers are damaged, which will have an adverse impact on the overall mechanical properties of the composite material.

[0005] In order to solve the problem of the thermal - conductivity orientation of one - dimensional pitch - based C / C composite materials under the condition of minimizing the influence on the mechanical properties of the material, the present invention is specifically proposed. Summary of the Invention

[0006] The purpose of the present invention is to provide a preparation method of a high thermal conductivity graphene film - carbon / carbon composite material, so as to solve the problem of the thermal - conductivity orientation of one - dimensional pitch - based C / C composite materials under the condition of minimizing the influence on the mechanical properties of the material, etc.

[0007] The purpose of the present invention can be achieved by the following technical solutions:

[0008] A preparation method of a high thermal conductivity graphene film - carbon / carbon composite material, comprising the following steps:

[0009] S1. Grind the carbon precursor particles into powder, and then disperse them in isopropanol solution to obtain a matrix slurry;

[0010] S2. Orient and stack the carbonaceous unidirectional fiber cloth, and evenly apply the matrix slurry between two layers of carbonaceous unidirectional fiber cloth to obtain a unidirectional cloth laminated blank;

[0011] S3. Hot press the unidirectional cloth laminated blank, take it out after cooling to obtain a low-density one-dimensional composite material, and then cut it along the direction parallel to the fiber to obtain a low-density one-dimensional composite material strip sample;

[0012] S4. Take the matrix slurry in S1 and evenly brush it on the graphene film, then pass the graphene film through the low-density one-dimensional composite material strip samples arranged side by side in an S shape, and then place it in a mold for heating and heat preservation to obtain a graphene film / low-density carbon-carbon composite material;

[0013] S5. Subject the graphene film / low-density carbon-carbon composite material in S5 to densification and carbonization in sequence, and then perform high-temperature graphitization treatment on the sample after the densification and carbonization are completed to obtain a high-thermal-conductivity graphene film-carbon-carbon composite material, which is the target product.

[0014] Further, in S1, the carbon precursor particles are mesophase pitch particles or phenolic resin particles.

[0015] Further, in S1, the particle size of the powder is 350-450 mesh, and the addition ratio of the carbon precursor particles to the isopropanol solution is 0.5-1.5 g:1 mL, preferably 1 g:1 mL.

[0016] Further, in S2, the carbonaceous unidirectional fiber cloth is a mesophase pitch unidirectional fiber cloth or a polyacrylonitrile-based carbon fiber cloth.

[0017] Further, in S2, the mass ratio of the carbonaceous unidirectional fiber cloth to the coated matrix slurry is 1:1-1:2.

[0018] Further, in S3, the temperature of the hot press is 300-500 °C, the pressure is 2-5 Mpa, and the time is 1-5 h;

[0019] The width of the low-density one-dimensional composite material strip sample is 1-5 mm.

[0020] Further, in S4, the matrix slurry is evenly coated on both surfaces of the graphene film, the temperature of the heating and heat preservation is 300-500 °C, the time is 1-3 h, and the thickness of the graphene film is 100-200 μm.

[0021] It should be noted here that the graphene film passes through adjacent strip-shaped samples of low-density one-dimensional composite materials in a manner similar to the interweaving of warp and weft lines in a "one-up-one-down" pattern, and during the heating and heat preservation process in the mold, the corresponding surfaces of the graphene film are ensured to be in good contact with the strip-shaped samples of low-density one-dimensional composite materials as much as possible. In this way, during subsequent processes such as heating and heat preservation, and carbonization, good interfacial contact can be achieved between the graphene film and the strip-shaped samples of low-density one-dimensional composite materials, thereby further optimizing the thermal conductivity and so on.

[0022] Furthermore, in S4, the densification method is pressure impregnation densification or chemical vapor infiltration densification, where

[0023] The process of pressure impregnation is as follows: The powder ground from the carbon precursor particles in S1 is selected as the impregnating agent. First, the pressure impregnation equipment is evacuated to a negative pressure, and then it is impregnated by heating and increasing pressure. The impregnation temperature is 300 - 450 °C, the impregnation pressure is 2 - 4 Mpa, and the time is 1 - 4 h;

[0024] The process conditions for chemical vapor infiltration densification are as follows: Methane is used as the carbon source, nitrogen is used as the diluting gas, the methane flow rate is 2 - 10 L / min, the nitrogen flow rate is 2 - 10 L / min, the chemical vapor infiltration temperature is 900 - 1200 °C, and the deposition time is 50 - 100 h;

[0025] In S4, the carbonization temperature is 900 - 1200 °C, and the time is 2 - 5 h.

[0026] Furthermore, in S4, the densification and carbonization are carried out once respectively according to the densification effect, or cycled several times until the density reaches 1.7 g / cm 3 above.

[0027] Furthermore, in S5, the temperature for high-temperature graphitization treatment is 3000 °C, and the heat preservation time is 2 - 4 h.

[0028] Compared with the prior art, the present invention improves the overall thermal conductivity of one-dimensional composite materials by adding a highly thermally conductive graphene film as a thermal conduction channel in the direction perpendicular to the fiber. Since the integrity of the fiber is not damaged, the axial mechanical properties of the composite material are retained, and thus the problem of thermal conductivity orientation of one-dimensional pitch-based C / C composite materials can be solved without affecting the mechanical properties of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the composite of the graphene film and the strip-shaped sample of low-density one-dimensional composite material;

[0030] Explanation of the marks in the figure:

[0031] 1 - graphene film, 2 - strip-shaped sample of low-density one-dimensional composite material. Detailed Embodiments

[0032] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. This embodiment is implemented on the premise of the technical solution of the present invention, and gives detailed implementation manners and specific operation processes, but the protection scope of the present invention is not limited to the following embodiments.

[0033] In the following embodiments, the mesophase pitch carbon fiber used is the K13X2U type mesophase pitch carbon fiber produced by Mitsubishi Chemical of Japan; the mesophase pitch particles used are purchased from Shanghai Baowu Carbon Industry;

[0034] For the remaining raw materials or processing technologies without special instructions, it means that they are all conventional commercially available raw materials or conventional processing technologies in this field.

[0035] Example 1

[0036] This example is to prepare a carbon-carbon fin for space heat pipe reactor heat dissipation. The carbon-carbon fin structure is a one-dimensional composite material, using mesophase pitch carbon fiber as the reinforcement and mesophase pitch as the matrix. The fin is about 200 - 300 mm long, about 200 - 300 mm wide, and 2 - 3 mm thick.

[0037] This embodiment includes the following steps:

[0038] (1) Preparation of raw materials

[0039] The mesophase pitch carbon fiber is woven into a unidirectional fiber cloth by hot melting and cutting to the required size of the fin; the mesophase pitch particles are ground and sieved, and the fineness is required to be 400 mesh; the ground mesophase pitch powder is fully dispersed in isopropone solution at a ratio of 1 g:1 mL to prepare a matrix slurry; the high thermal conductivity graphene film is cut to the required size.

[0040] (2) Preparation of low-density specimens

[0041] The mesophase pitch unidirectional fiber cloth is arranged directionally, and the matrix slurry is evenly applied between two layers of fiber cloth. The mass ratio of the fiber cloth to the matrix slurry is 1:1.5; after the unidirectional fiber cloth is laminated, it is placed in a stainless steel mold and hot pressed. The hot pressing temperature is 500 °C, the pressure is 2 MPa, and the hot pressing time is 2 h. After the green body is hot pressed, it is taken out with the mold cooled to obtain a low-density one-dimensional composite material plate. The plate is cut into splines at intervals of 2 mm along the direction parallel to the fiber.

[0042] (3) Composite of graphene film and carbon-carbon composite

[0043] The matrix slurry is evenly coated on the high thermal conductivity graphene film, and then the graphene film is sandwiched in an S shape between the low-density one-dimensional composite material strip samples (such as Figure 1), the obtained graphene film / strip sample material is placed in a stainless steel mold, heated to about 400 °C, kept warm for 2 h, and then cooled to obtain a graphene film-low density carbon-carbon composite material.

[0044] (4) Densification of the composite material

[0045] The graphene film-low density carbon-carbon composite material is placed in a pressure impregnation device for impregnation densification. Mesophase pitch powder is used as the impregnating agent. First, it is evacuated to a negative pressure, and then the temperature and pressure are increased for impregnation. The impregnation temperature is 350 °C, the impregnation pressure is 3 MPa, and the impregnation time is 1 - 4 h.

[0046] (5) Carbonization and graphitization of the composite material

[0047] The impregnated sample is carbonized at a carbonization temperature of 1000 °C for a holding time of 2 h. According to the densification effect, impregnation and carbonization are cycled multiple times until the density reaches 1.7 g / cm 3 or more.

[0048] The carbonized sample is subjected to high-temperature graphitization treatment, and the specimen is processed to the required size to obtain the target material.

[0049] Example 2

[0050] A method for preparing a high thermal conductivity carbon-carbon composite material, except that the mesophase pitch-based carbon fiber in step 1 of Example 1 is changed to a polyacrylonitrile-based carbon fiber, and the remaining steps are the same as those in Example 1.

[0051] Example 3

[0052] A method for preparing a high thermal conductivity carbon-carbon composite material, except that the mesophase pitch matrix in step 1 of Example 1 is changed to phenolic resin, and the hot pressing temperature in step 2 is changed to 150 °C, and the remaining steps are the same as those in Example 1.

[0053] Example 4

[0054] A method for preparing a high thermal conductivity carbon-carbon composite material, except that the impregnation densification in step 4 of Example 1 is changed to chemical vapor infiltration (CVI) densification. Methane is used as the carbon source and nitrogen is used as the dilution gas in the chemical vapor infiltration process. The methane flow rate is about 8 L / min, the nitrogen flow rate is 8 L / min, the CVI temperature is 1100 °C, and the deposition time is 60 h. The remaining steps are the same as those in Example 1.

[0055] Comparative Example 1

[0056] Compared with Example 1, most of them are the same, except that no graphene film is used, and a one-dimensional carbon-carbon composite material is directly prepared.

[0057] Table 1 below shows the performance data of the graphene film-carbon carbon composite material prepared in Example 1. Comparing it with the one-dimensional carbon carbon composite material in Comparative Example 1 with a similar density, it can be seen that its thermal conductivity and tensile properties along the fiber direction are comparable to those of the one-dimensional composite material, but its properties perpendicular to the fiber direction are significantly better than those of the one-dimensional composite material, indicating the superiority of the present invention.

[0058] Performance comparison of two structural carbon carbon composite materials in Table 1

[0059]

[0060] The above description of the embodiments is for the convenience of those of ordinary skill in the art to understand and use the invention. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative efforts. Therefore, the present invention is not limited to the above embodiments, and all improvements and modifications made by those skilled in the art without departing from the scope of the present invention according to the disclosure of the present invention should be within the protection scope of the present invention.

Claims

1. A preparation method of a high thermal conductivity graphene film-carbon carbon composite material, characterized in that, The following steps are involved: S1, grinding carbon precursor particles into powder, and then dispersing the powder in an isopropyl ketone solution to obtain a matrix slurry; S2, arranging the carbon unidirectional fiber cloth in a directional stacked manner, and evenly applying the matrix slurry between two layers of the carbon unidirectional fiber cloth to obtain a unidirectional cloth stacked embryo; S3, hot pressing the unidirectional fabric laminated embryo, taking it out after cooling, to obtain a low-density one-dimensional composite material, and then cutting it along a direction parallel to the fiber direction to obtain a low-density one-dimensional composite material strip sample; S4, taking the matrix slurry in S1 and evenly brushing it on the graphene film, then passing the graphene film through the low-density one-dimensional composite material strip samples arranged side by side in an S shape, and then placing it in a mold for heating and heat preservation to obtain a graphene film / low-density carbon-carbon composite material; S5. Densify and carbonize the graphene film / low-density carbon-carbon composite material in S5 in sequence, and then perform high-temperature graphitization on the densified and carbonized sample to obtain a high thermal conductivity graphene film-carbon-carbon composite material, which is the target product.

2. The preparation method of a high thermal conductivity graphene film-carbon-carbon composite material according to claim 1, characterized in that, In S1, the carbon precursor particles are mesophase pitch particles or phenolic resin particles.

3. The preparation method of a high thermal conductivity graphene film-carbon carbon composite material according to claim 1, characterized in that, In S1, the particle size of the powder is 350-450 mesh, and the ratio of the added amount of the carbon precursor particles to the isopropyl ketone solution is (0.5-1.5) g:1 mL.

4. The preparation method of a high thermal conductivity graphene film-carbon carbon composite material according to claim 1, characterized in that, In S2, the carbonaceous unidirectional fiber cloth is a mesophase pitch unidirectional fiber cloth or a polyacrylonitrile-based carbon fiber cloth.

5. The preparation method of a high thermal conductivity graphene film-carbon-carbon composite material according to claim 1, characterized in that, In S2, the mass ratio of the carbonaceous unidirectional fiber cloth to the coated substrate slurry is 1:1 to 1:

2.

6. The preparation method of a high thermal conductivity graphene film-carbon-carbon composite material according to claim 1, wherein In S3, the hot pressing temperature is 300-500°C, the pressure is 2-5 MPa, and the time is 1-5 h; The width of the low-density one-dimensional composite material strip sample is 1 to 5 mm.

7. The preparation method of a high thermal conductivity graphene film-carbon carbon composite material according to claim 1, characterized in that, In S4, the matrix slurry is evenly coated on both sides of the graphene film, and the heating and insulation temperature is 300-500° C. for 1 to 3 hours.

8. The preparation method of a high thermal conductivity graphene film-carbon-carbon composite material according to claim 1, characterized in that, In S4, the densification method is pressure impregnation densification or chemical vapor infiltration densification, wherein: The process of pressure impregnation is as follows: the powder ground from the carbon precursor particles in S1 is selected as the impregnating agent, the pressure impregnation equipment is first evacuated to negative pressure, and then the temperature and pressure are increased for impregnation, the impregnation temperature is 300-450°C, the impregnation pressure is 2-4Mpa, and the time is 1-4h; The process conditions of chemical vapor infiltration densification are: methane is used as the carbon source, nitrogen is used as the diluent gas, the methane flow rate is 2-10L / min, the nitrogen flow rate is 2-10L / min, the chemical vapor infiltration temperature is 900-1200°C, and the deposition time is 50-100h; In S4, the carbonization temperature is 900-1200°C and the time is 2-5 hours.

9. The preparation method of a high thermal conductivity graphene film-carbon-carbon composite material according to claim 1, characterized in that, In S4, the densification and carbonization are each carried out once or cycled several times according to the densification effect until the density reaches 1.7 g / cm 3 or more.

10. The preparation method of a high thermal conductivity graphene film-carbon-carbon composite material according to claim 1, characterized in that, In S5, the temperature of high temperature graphitization treatment is 3000°C, and the temperature is kept for 2-4 hours.

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