A three-dimensional synergistic high thermal conductivity carbon / carbon composite material and its preparation method and application

Abstract

The present invention discloses a three-dimensional synergistic high thermal conductivity carbon / carbon composite material and its preparation method and application, which relate to the technical field of carbon / carbon composite materials. The method comprises a non-woven fabric woven from mesophase pitch-based carbon fibers and a web woven from chopped mesophase pitch-based carbon fibers, alternately stacking the heat-treated non-woven fabric and the web, and needle-punching the carbon fibers perpendicular to the stacking direction to fix them to form a needle-punched carbon felt preform; the needle-punched carbon felt preform is densified using a chemical vapor infiltration process, and then treated at 2800-3000°C in an inert atmosphere for 2-4 hours to obtain a three-dimensional synergistic high thermal conductivity carbon / carbon composite material. The present invention designs the preform structure by changing the fiber type and adjusting the ply distance, thereby regulating the layered structure of the high-texture pyrolytic carbon, coordinating the high-thermal conductivity carbon fibers and constructing a long-range heat transfer channel to improve the overall thermal conductivity of the C / C composite material.

Description

Technical Field

[0001] The present invention relates to the technical field of carbon / carbon composite materials, and in particular to a three-dimensional synergistic high thermal conductivity carbon / carbon composite material and a preparation method and application thereof. Background Art

[0002] Carbon / carbon (C / C) composites are carbon-based composites reinforced with carbon fibers. They are considered the preferred high-temperature thermal protection material in the aerospace industry due to their low density, high specific strength, excellent high-temperature mechanical properties, and designability. The development and manufacture of new-generation hypersonic vehicles are placing ever-more stringent demands on the structure and performance of C / C composites. The structure of the preform and the arrangement and orientation of the carbon fibers directly determine the thermophysical and mechanical properties of the thermally structured C / C composite. Designing preforms with different structures to meet the service requirements of different aircraft components to fully utilize the composite's thermal conductivity and load-bearing properties is crucial.

[0003] At present, researchers have carried out a lot of research and development and exploration in the design and preparation of preform structures of C / C composite materials, and successfully prepared preforms with unidirectional, two-dimensional lamination, needle punching, carbon cloth puncture and orthogonal three-dimensional structures, and obtained C / C composite materials after densification. Among them, the C / C composite material with needle punching structure is widely used because of its advantages such as easy densification and enhanced interlayer connection strength. However, due to the anisotropy of the composite material itself, there are obvious differences in the thermal physical properties in the X, Y and Z directions, that is, the thermal conductivity in the X and Y directions is high, but its thermal conductivity along the thickness direction (Z direction) is low, and the excellent performance of the three-dimensional synergistic high thermal conductivity is not fully utilized. Therefore, the optimization and design of the preform structure, while improving its interlayer thermal conductivity without damaging its in-plane thermal conductivity, so that it has the ability to have high thermal conductivity as a whole is a problem that needs to be solved urgently. Summary of the Invention

[0004] To address the shortcomings of the aforementioned background technology, the present invention provides a three-dimensional synergistic high-thermal-conductivity carbon / carbon composite material, its preparation method, and its application. This method designs the preform structure by varying the fiber type and adjusting the ply spacing. This method then modulates the layered structure of the high-texture pyrolytic carbon, synergizing the high-thermal-conductivity carbon fibers and constructing long-range heat transfer channels to enhance the overall thermal conductivity of the C / C composite material.

[0005] The first object of the present invention is to provide a method for preparing a three-dimensional synergistic high thermal conductivity carbon / carbon composite material, comprising the following steps:

[0006] A non-woven fabric woven with mesophase pitch-based carbon fibers and a mat woven with chopped mesophase pitch-based carbon fibers are heat-treated at 1500-1600° C., the heat-treated non-woven fabric and the mat are alternately stacked, and the carbon fibers are needle-punched perpendicularly to the stacking direction to fix them to form a needle-punched carbon felt preform;

[0007] After the needle-punched carbon felt preform is densified, it is treated at 2800-3000° C. for 2-4 hours in an inert atmosphere to obtain a three-dimensional synergistic high thermal conductivity carbon / carbon composite material.

[0008] Preferably, the densification treatment includes:

[0009] The needle-punched carbon felt preform is placed in a pyrolytic carbon deposition furnace with a deposition temperature of 1000-1100° C., a pressure of 2-10 kP, a natural gas flow rate of 15-18 L / min, and a deposition time of 130-150 h.

[0010] Preferably, the density of the needle-punched carbon felt preform after densification treatment is 1.84-1.86 g / cm 3 The texture type of the carbon matrix is ​​high texture, and the extinction angle is 23°≤Ae≤28°.

[0011] Preferably, the density of the needle-punched carbon felt preform is 0.61-0.68 g / cm 3 .

[0012] Preferably, the warp density of the non-woven fabric woven with mesophase pitch-based carbon fibers is 40-60 yarns / 10 mm and the surface density is 185-190 g / m 2 ; The diameter of the mesophase asphalt-based carbon fiber is 10-11 μm, and the brand is TC20.

[0013] Preferably, the surface density of the chopped mesophase pitch-based carbon fiber woven mat is 50-60 g / m 2 ; The length of the chopped mesophase pitch-based carbon fiber is 50-80mm.

[0014] Preferably, during the alternating lamination process, the angle between two adjacent layers of the non-woven fabric is 90°.

[0015] The second object of the present invention is to provide a three-dimensional synergistic high thermal conductivity carbon / carbon composite material.

[0016] The third object of the present invention is to provide a three-dimensional synergistic high thermal conductivity carbon / carbon composite material for use in high-temperature thermal protection.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The present invention provides a three-dimensional synergistic high thermal conductivity carbon / carbon composite material and its preparation method and application. The present invention forms a needle-punched carbon felt preform by needle-punching carbon fibers perpendicular to the stacking direction to fix them. The density of the needle-punched carbon felt preform is 0.61-0.68 g / cm 3 The volume fraction of the fiber is regulated by controlling the density of the preform. The main factor affecting the thermal conductivity of the C / C composite in the X and Y directions is the volume fraction of the fiber. At a high volume fraction, heat can be efficiently conducted along the axial direction of the mesophase pitch (MP)-based carbon fiber. However, when the volume fraction of the fiber is too high, the densification efficiency of the preform is affected, resulting in a large number of pores and defects in the composite material. At the same time, the interlayer distance is reduced, which reduces the deposition of pyrolytic carbon.

[0019] The present invention regulates the density to constrain the interlayer distance. Since the high-texture pyrolytic carbon grows in a layered structure around the fiber, when the interlayer distance is too close, the volume of pyrolytic carbon deposited between the fibers in the radial direction is very small, and no overlapping structure is formed between the pyrolytic carbon and the pyrolytic carbon, showing a state where the annularly grown pyrolytic carbon is "tangential" to each other. At this time, heat is still conducted through the interlayer, and the interfacial thermal resistance is very large, which affects the heat transfer efficiency. Figure 3 As shown in (b); when the interlayer distance increases, the volume of pyrolytic carbon deposited between fibers in the radial direction increases, and the annularly grown pyrolytic carbons show an "intersection" state, thereby forming a clear overlapping structure, thereby constructing a long-range heat transfer channel. Heat is transferred along the surface of the pyrolytic carbon, greatly improving the efficiency of heat conduction, see Figure 3 As shown in (a); when the interlayer distance is further increased, although the thermal conductivity is further improved, the interlayer bonding becomes weaker, which greatly reduces its mechanical properties. Therefore, the appropriate interlayer distance enables it to have excellent thermal conductivity and bending strength, and its bending strength can reach 80MPa.

[0020] The present invention uses a non-dimensional cloth made of MP-based carbon fibers with "radial" structural characteristics instead of a non-dimensional cloth made of PAN-based carbon fibers with a turbostratic graphite structure, so that heat can be radially conducted between layers through the large lamellar structure of the MP-based carbon fibers, thereby accelerating the efficiency of heat conduction.

[0021] The present invention adds a mat layer composed of chopped MP-based carbon fibers between the non-dimensional fabric layers. On the one hand, it is beneficial to the deposition of pyrolytic carbon, achieving overall densification and reducing the overall porosity of the composite material. On the other hand, it regulates the distance between the non-dimensional fabric layers, thereby adjusting and controlling the volume of high-texture pyrolytic carbon between the non-dimensional fabric layers to achieve improved thermal conductivity along the thickness Z direction. The density of the prepared needle-punched high thermal conductivity composite material is 1.84-1.86g / cm 3The porosity is only 12-15%, the thermal conductivity along the X and Y directions is 300W / (m·K), and the thermal conductivity along the thickness Z direction at room temperature can reach 128W / (m·K).

[0022] The present invention performs heat treatment at 2800-3000°C, so that the graphite microcrystals of the composite material have a perfect crystal structure, few defects, and thus high thermal conductivity; the heat treatment time is controlled to be 1-2 hours, which not only reduces the defects of the composite material, but also avoids the weakening of interlayer bonding and serious reduction of its mechanical properties due to long-term high-temperature heat treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A scanning electron microscope image of the mesophase pitch-based carbon fiber provided by the present invention;

[0024] Figure 2 This is a macroscopic photograph of the three-dimensional synergistic high thermal conductivity carbon / carbon composite material provided by the present invention;

[0025] Figure 3 Schematic diagram of the heat conduction path of high-texture pyrolytic carbon after regulating the interlayer distance provided by the present invention.

[0026] Figure 4 Schematic diagram of the layup method of needle-punched carbon felt preform. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand and implement the technical solution of the present invention, the present invention is further described below with reference to specific embodiments and drawings, but the embodiments are not intended to limit the present invention.

[0028] The present invention is mainly based on mesophase pitch (MP) based carbon fibers with radial structure, see Figure 1 As shown in the figure, the directional and perfect graphite crystal structure makes it have higher thermal conductivity in both axial and radial directions compared with randomly oriented polyacrylonitrile (PAN)-based carbon fibers. At the same time, the in-plane thermal conductivity of high-texture pyrolytic carbon with a layered structure reaches 1000W / (m·K). Therefore, by changing the fiber type, adjusting the ply distance and designing the layered structure of high-texture pyrolytic carbon to construct a long-range heat transfer channel, the goal of ultimately achieving three-dimensional synergistic high thermal conductivity of the composite material can be achieved.

[0029] The three directions mentioned in the present invention refer to the X direction, Y direction and Z direction in the three-dimensional structure.

[0030] A first aspect of the present invention provides a method for preparing a three-dimensional synergistic high thermal conductivity carbon / carbon composite material, comprising the following steps:

[0031] A non-woven fabric woven with mesophase pitch-based carbon fibers and a mat woven with chopped mesophase pitch-based carbon fibers are heat-treated at 1500-1600° C., the heat-treated non-woven fabric and the mat are alternately stacked, and the carbon fibers are needle-punched perpendicularly to the stacking direction to fix them to form a needle-punched carbon felt preform;

[0032] The needle-punched carbon felt preform is densified by chemical vapor infiltration process, and then treated at 2800-3000° C. for 2-4 hours in an inert atmosphere to obtain a three-dimensional synergistic high thermal conductivity carbon / carbon composite material.

[0033] See also Figure 2 As shown, a macroscopic photograph of a three-dimensional synergistic high thermal conductivity carbon / carbon composite material is shown, showing three directions, namely X, Y and Z directions.

[0034] The present invention proposes a design concept and preparation method for a carbon / carbon composite material with synergistic high thermal conductivity in the X-, Y-, and Z-directions. The aim is to design the preform structure by changing the fiber type and adjusting the ply distance, thereby regulating the layered structure of high-texture pyrolytic carbon, and synergizing high-thermal conductivity carbon fibers and constructing long-range heat transfer channels to improve the overall thermal conductivity of the C / C composite material, providing an important solution for the structural design of thermal protection materials for aerospace vehicles.

[0035] Wherein, the densification treatment includes:

[0036] The needle-punched carbon felt preform is placed in a pyrolytic carbon deposition furnace with a deposition temperature of 1000-1100° C., a pressure of 2-10 kP, a natural gas flow rate of 15-18 L / min, and a deposition time of 130-150 h.

[0037] The density of the needle-punched carbon felt preform after densification treatment is 1.84-1.86 g / cm 3 The texture type of the carbon matrix is ​​high texture, and the extinction angle is 23°≤Ae≤28°.

[0038] According to the present invention, a needle-punched carbon felt preform is formed by needle-punching carbon fibers perpendicular to the stacking direction to fix the carbon fibers. The density of the needle-punched carbon felt preform is 0.61 to 0.68 g / cm 3 .

[0039] In the present invention, the warp density of the non-woven fabric woven with mesophase pitch-based carbon fibers is 40-60 yarns / 10 mm and the surface density is 185-190 g / m 2 ; The diameter of the mesophase asphalt-based carbon fiber is 10-11 μm, and the brand is TC20.

[0040] The surface density of the chopped mesophase pitch-based carbon fiber woven mat is 50-60g / m 2; The length of the chopped mesophase pitch-based carbon fiber is 50-80mm.

[0041] See also Figure 4 As shown, during the alternating layering process, the angle between two adjacent layers of the flat fabric is 90°. Specifically, the flat fabric and the mat layer are alternately laid in a pattern of 0° / mat / 90° / mat / 0° / mat / 90° / ... It should be noted that during the actual laying process, the preform thickness should be adjusted based on the required thickness for the application. For a thicker thickness, more alternating layers should be used; for a thinner thickness, fewer alternating layers should be used.

[0042] A second aspect of the present invention provides a three-dimensional synergistic high thermal conductivity carbon / carbon composite material.

[0043] A third aspect of the present invention provides an application of a three-dimensional synergistic high thermal conductivity carbon / carbon composite material in high-temperature thermal protection.

[0044] In one embodiment, a method for preparing a three-dimensional synergistic high thermal conductivity carbon / carbon composite material comprises the following steps:

[0045] Step 1: Design and preparation of a preform of a needle-punched high thermal conductivity C / C composite material: a non-woven fabric woven with mesophase pitch-based carbon fibers and a mat woven with chopped mesophase pitch-based carbon fibers are heat-treated at 1500-1600°C. Subsequently, the non-woven fabric and the mat are alternately stacked, with the angle between the non-woven fabric layers being 90°. The carbon fibers are needle-punched perpendicular to the stacking direction to fix them to form a needle-punched carbon felt preform with a density of 0.61-0.68 g / cm 3 By regulating the density to constrain the interlayer distance, the deposition amount of pyrolytic carbon and the heat transfer channel can be regulated.

[0046] Step 2: Preparation of needle-punched high thermal conductivity C / C composite material: Place the preform obtained in step 1 into a pyrolytic carbon deposition furnace and densify it using the ICVI process. The deposition temperature is 1000-1100°C, the pressure is 2-10kP, the natural gas flow rate is 15-18L / min, and the deposition time is 130-150h. The specific characteristics of the composite material after deposition are as follows: the density of the composite material is 1.84-1.86g / cm 3 The texture type of the carbon matrix is ​​high texture, and the extinction angle is 23°≤Ae≤28°.

[0047] Step 3: heat-treating the C / C composite material obtained in step 2 at a temperature of 2800-3000° C. for 2-4 hours in an argon atmosphere.

[0048] The present invention regulates the density to constrain the interlayer distance. Since the high-texture pyrolytic carbon grows in a layered structure around the fiber, when the interlayer distance is too close, the volume of pyrolytic carbon deposited between the fibers in the radial direction is very small, and no overlapping structure is formed between the pyrolytic carbon and the pyrolytic carbon, showing a state where the annularly grown pyrolytic carbon is "tangential" to each other. At this time, heat is still conducted through the interlayer, and the interfacial thermal resistance is very large, which affects the heat transfer efficiency. Figure 3 As shown in (b); when the interlayer distance increases, the volume of pyrolytic carbon deposited between fibers in the radial direction increases, and the annularly grown pyrolytic carbons show an "intersection" state, thereby forming a clear overlapping structure, thereby constructing a long-range heat transfer channel. Heat is transferred along the surface of the pyrolytic carbon, greatly improving the efficiency of heat conduction, see Figure 3 As shown in (a); when the interlayer distance is further increased, although the thermal conductivity is further improved, the interlayer bonding becomes weaker, which greatly reduces its mechanical properties. Therefore, the appropriate interlayer distance enables it to have excellent thermal conductivity and bending strength, and its bending strength can reach 80MPa.

[0049] It should be noted that the experimental methods used in the present invention are all conventional methods unless otherwise specified; the reagents and materials used are all commercially available unless otherwise specified.

[0050] Example 1

[0051] 1. The non-woven fabric woven with mesophase pitch-based carbon fiber and the mat woven with short-cut mesophase pitch-based carbon fiber were heat-treated at 1600°C. Subsequently, the non-woven fabric and the mat were alternately stacked. The angle between the non-woven fabric layers was 90°. The carbon fibers were needle-punched perpendicular to the stacking direction to form a needle-punched carbon felt preform with a density of 0.63g / cm 3 .

[0052] 2. Densification was performed using the ICVI process with a deposition temperature of 1000°C, a pressure of 8kP, a natural gas flow rate of 15L / min, and a deposition time of 130h. The density of the obtained C / C composite material was 1.84g / cm 3 , the porosity is 15%.

[0053] 3. The prepared C / C composite material was heat treated at 2800°C in an argon atmosphere for 2 hours. The thermal conductivity of the composite material along the X and Y directions was 260 W / (m·K), the thermal conductivity along the thickness Z direction was 120 W / (m·K), and the flexural strength was 75 MPa.

[0054] Example 2

[0055] 1. The non-woven fabric woven with mesophase pitch-based carbon fiber and the mat woven with short-cut mesophase pitch-based carbon fiber were heat-treated at 1600°C. Subsequently, the non-woven fabric and the mat were alternately stacked. The angle between the non-woven fabric layers was 90°. The carbon fibers were needle-punched perpendicular to the stacking direction to form a needle-punched carbon felt preform with a density of 0.65g / cm 3 .

[0056] 2. The densification was carried out using the ICVI process. The deposition temperature was 1050°C, the pressure was 10kP, the flow rate of natural gas was 15L / min, and the deposition time was 140h. The density of the obtained C / C composite material was 1.86g / cm 3 , the porosity is 12.0%.

[0057] 3. The prepared C / C composite material was heat treated at 3000℃ in an argon atmosphere for 2 hours. The thermal conductivity of the composite material along the X and Y directions was 300W / (m·K), the thermal conductivity along the thickness Z direction was 128W / (m·K), and the flexural strength was 80MPa.

[0058] Example 3

[0059] 1. The non-woven fabric woven with mesophase pitch-based carbon fiber and the mat woven with chopped mesophase pitch-based carbon fiber were heat-treated at 1500°C. Subsequently, the non-woven fabric and the mat were alternately stacked. The angle between the non-woven fabric layers was 90°. The carbon fibers were needle-punched perpendicular to the stacking direction to form a needle-punched carbon felt preform with a density of 0.68g / cm 3 .

[0060] 2. Densification was performed using the ICVI process with a deposition temperature of 1100°C, a pressure of 2 kPa, a natural gas flow rate of 18 L / min, and a deposition time of 150 h. The density of the obtained C / C composite material was 1.85 g / cm 3 , the porosity is 14.0%.

[0061] 3. The prepared C / C composite material was heat treated at 3000℃ in an argon atmosphere for 4 hours. The thermal conductivity along the X and Y directions was 285W / (m·K), the thermal conductivity along the thickness Z direction of the composite material was 123W / (m·K), and the flexural strength was 65MPa.

[0062] Comparative Example 1

[0063] 1. The non-woven fabric woven with mesophase pitch-based carbon fiber and the mat woven with short-cut mesophase pitch-based carbon fiber were heat-treated at 1600°C. Subsequently, the non-woven fabric and the mat were alternately stacked. The angle between the non-woven fabric layers was 90°. The carbon fibers were needle-punched perpendicular to the stacking direction to form a needle-punched carbon felt preform with a density of 0.65g / cm 3.

[0064] 2. The densification was carried out using the ICVI process. The deposition temperature was 1050°C, the pressure was 10 kPa, the flow rate of natural gas was 15 L / min, and the deposition time was 140 h. The density of the obtained C / C composite material was 1.86 g / cm 3 , the porosity is 12.0%.

[0065] 3. The prepared C / C composite material was heat treated at 2300°C in an argon atmosphere for 2 hours. The thermal conductivity of the composite material along the X and Y directions was 170W / (m·K), the thermal conductivity along the thickness Z direction was 85W / (m·K), and the bending strength was 82MPa. The lower heat treatment temperature cannot maximize the thermal conductivity of the mesophase pitch-based carbon fiber.

[0066] Comparative Example 2

[0067] 1. The non-woven fabric layer prepared with PAN-based long carbon fiber and the PAN-based carbon fiber mesh layer were heat-treated at 1600°C. Subsequently, the non-woven fabric and the mesh layer were alternately stacked. The angle between the non-woven fabric layers was 90°. The carbon fibers were needle-punched perpendicular to the stacking direction to form a needle-punched carbon felt preform with a density of 0.65g / cm 3 .

[0068] 2. The densification was carried out using the ICVI process. The deposition temperature was 1050°C, the pressure was 10 kPa, the flow rate of natural gas was 15 L / min, and the deposition time was 140 h. The density of the obtained C / C composite material was 1.80 g / cm 3 , the porosity is 13.0%.

[0069] 3. The prepared C / C composite material was heat treated at 3000°C in an argon atmosphere for 2 hours. The thermal conductivity of the composite material along the X and Y directions was 140W / (m·K), the thermal conductivity along the thickness Z direction was 58W / (m·K), and the bending strength was 78MPa. Since the thermal conductivity of PAN-based carbon fiber itself is low, the thermal conductivity of the composite material prepared with PAN-based long carbon fiber as reinforcement is low.

[0070] Comparative Example 3

[0071] 1. Heat treatment of a non-woven fabric woven with mesophase pitch-based carbon fiber and a mat woven with chopped mesophase pitch-based carbon fiber at 1600°C was performed. Subsequently, the non-woven fabric and the mat were alternately stacked. The angle between the non-woven fabric layers was 90°. The carbon fibers were needle-punched perpendicular to the stacking direction to form a needle-punched carbon felt preform with a density of 0.45g / cm 3 .

[0072] 2. The densification was carried out using the ICVI process. The deposition temperature was 1050°C, the pressure was 10 kPa, the flow rate of natural gas was 15 L / min, and the deposition time was 140 h. The density of the obtained C / C composite material was 1.84 g / cm 3 , the porosity is 11.0%.

[0073] 3. The prepared C / C composite material was heat treated at 3000℃ in an argon atmosphere for 2h. The thermal conductivity along the X and Y directions was 250W / (m·K), the thermal conductivity along the thickness Z direction of the composite material was 131W / (m·K), and the flexural strength was 64MPa. Due to the low density of the preform, low fiber volume fraction, and large interlayer distance, a large number of pyrolytic carbons in annular growth are in an "intersecting" state, which constructs a long-range heat transfer channel. Therefore, the thermal conductivity along the thickness Z direction is improved. However, the thermal conductivity and mechanical properties in the X and Y directions are significantly reduced due to the low fiber volume fraction.

[0074] Comparative Example 4

[0075] 1. The non-woven fabric woven with mesophase pitch-based carbon fiber and the mat woven with short-cut mesophase pitch-based carbon fiber were heat-treated at 1600°C. Subsequently, the non-woven fabric and the mat were alternately stacked. The angle between the non-woven fabric layers was 90°. The carbon fibers were needle-punched perpendicular to the stacking direction to form a needle-punched carbon felt preform with a density of 0.7g / cm 3 .

[0076] 2. The densification was carried out using the ICVI process. The deposition temperature was 1050°C, the pressure was 10 kPa, the flow rate of natural gas was 15 L / min, and the deposition time was 140 h. The density of the obtained C / C composite material was 1.86 g / cm 3 , the porosity is 17.0%.

[0077] 3. The prepared C / C composite was heat treated at 3000°C for 2 hours in an argon atmosphere. The thermal conductivity of the composite along the X and Y directions was 285 W / (m·K), the thermal conductivity along the thickness Z direction was 118 W / (m·K), and the flexural strength was 75 MPa. Due to the high density of the preform, the volume fraction of the fibers was too high, making densification difficult. This increased the porosity within the composite. Furthermore, the interlayer spacing was too small, resulting in an increase in the number of tangential pyrolytic carbons growing in an annular manner, preventing the formation of long-range heat transfer channels and thus affecting the thermal conductivity along the thickness Z direction. The slight decrease in thermal conductivity along the X and Y directions is due to the increased internal porosity, which inhibits efficient heat transfer.

[0078] The present invention describes preferred embodiments and their effects. However, those skilled in the art, once informed of the basic inventive concept, may make additional changes and modifications to these embodiments. Therefore, it is intended that the appended claims be interpreted to include the preferred embodiments as well as all changes and modifications that fall within the scope of the invention.

[0079] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a three-dimensional synergistic high thermal conductivity carbon / carbon composite material, characterized in that: The following steps are involved: A non-woven fabric woven with mesophase pitch-based carbon fibers and a mat woven with chopped mesophase pitch-based carbon fibers are heat-treated at 1500-1600°C, the non-woven fabric and the mat are alternately stacked, and the carbon fibers are needle-punched perpendicularly to the stacking direction to fix them to form a needle-punched carbon felt preform; After densification treatment of the needle-punched carbon felt preform, it is treated at 2800-3000℃ for 2-4 hours in an inert atmosphere to obtain a three-dimensional synergistic high thermal conductivity carbon / carbon composite material; The densification treatment comprises: The needle-punched carbon felt preform is placed in a pyrolytic carbon deposition furnace at a deposition temperature of 1000-1100°C, a pressure of 2-10 kP, a natural gas flow rate of 15-18 L / min, and a deposition time of 130-150 h. The density of the needle-punched carbon felt preform is 0.61-0.68 g / cm 3 ; The warp density of the non-woven fabric woven with mesophase pitch-based carbon fibers is 40-60 yarns / 10 mm and the surface density is 185-190 g / m 2 ; The diameter of the mesophase pitch-based carbon fiber is 10-11 μm; The surface density of the chopped mesophase pitch-based carbon fiber woven mat is 50-60 g / m 2 ; The length of the chopped mesophase pitch-based carbon fiber is 50-80 mm; During the alternating lamination process, the angle between two adjacent layers of the non-wefted fabric is 90°.

2. The method for preparing a three-dimensional synergistic high thermal conductivity carbon / carbon composite material according to claim 1, characterized in that: The density of the needle-punched carbon felt preform after densification treatment is 1.84~1.86 g / cm 3 The texture type of the carbon matrix is ​​high texture, and the extinction angle is 23°≤Ae≤28°.

3. A three-dimensional synergistic high thermal conductivity carbon / carbon composite material prepared by the method according to claim 1 or 2.

4. Application of the three-dimensional synergistic high thermal conductivity carbon / carbon composite material according to claim 3 in high-temperature thermal protection.

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