High-strength high-thermal-conductivity reaction-sintered SiC ceramic material and preparation method thereof

Abstract

The invention provides a high-strength high-thermal-conductivity reaction-sintered SiC ceramic material and a preparation method thereof.The preparation method comprises the following steps that silicon carbide powder and carbon source powder are mixed and then subjected to ball milling treatment, and mixed powder is obtained; mixing the mixed powder with a binder, a plasticizer and a lubricant, and carrying out high-speed centrifugal stirring and rolling homogenization treatment to obtain a silicon carbide mud blank for injection molding; putting the silicon carbide mud blank for injection molding into a mold, carrying out hot-press injection molding, demolding to obtain a silicon carbide prefabricated body, and carrying out glue removal treatment to obtain a silicon carbide biscuit; and paving silicon particles on the silicon carbide biscuit, carrying out vacuum high-temperature infiltration, and cooling. According to the preparation method, the plastic deformation capacity of the silicon carbide mud blank is optimized by regulating and controlling the component proportion, in the preparation process, the movement rearrangement effect among particles is enhanced by applying reinforced shearing centrifugal stirring and rolling treatment to a mixed system, the density of a biscuit is effectively improved, residual silicon is promoted to be uniformly distributed, and the content and size of the residual silicon are reduced; and the overall performance of the material is improved.

Description

Technical Field

[0001] This invention relates to the field of ceramic technology, specifically to a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material and its preparation method. Background Technology

[0002] Silicon carbide ceramics possess advantages such as high hardness, high elastic modulus, high thermal conductivity, low coefficient of thermal expansion, and excellent high-temperature resistance, corrosion resistance, and wear resistance, making them widely used in aerospace, semiconductor manufacturing, and automotive industries. Reaction-bonded silicon carbide (RBSC) ceramics utilize capillary force to infiltrate liquid silicon into a porous carbon-containing silicon carbide preform, achieving sintering and densification through a carbon-silicon reaction. Compared to hot-pressing and pressureless sintering of silicon carbide, this method has a lower sintering temperature, shorter production cycle, and lower cost. It can achieve net-size molding of large-sized, complex-shaped silicon carbide products, offering significant advantages for large-scale industrial applications.

[0003] In the preparation process of RBSC ceramics, incomplete carbon-silicon reaction often results in residual silicon phase in the sintered body. Excessive residual silicon, acting as a brittle phase with low strength and low thermal conductivity, significantly reduces the mechanical and thermal properties of the ceramic. Therefore, based on the complex shape forming process of RBSC ceramic green bodies, the preparation of low-residual-silicon, high-performance RBSC ceramic materials is of great significance for expanding their applications. Currently, the main complex shape forming processes for RBSC ceramics include gel casting, injection molding, slip casting, and 3D printing. These processes primarily involve preparing water-based or polymer-based slurries with good flowability for green body forming. However, these slurries experience solid particle sedimentation during casting, making it difficult to control the content and distribution of residual silicon in the sintered body. Furthermore, due to the low solid content of the slurry, the drying shrinkage rate is high, leading to easy cracking of the green body (e.g., patents CN117550898A and CN114956852A). To reduce the residual silicon content and control the residual silicon distribution, some studies have used repeated impregnation-curing-pyrolysis processes to improve the compaction of the green body and obtain high-performance RBSC ceramics. However, this method has the problems of complex process and high preparation cost.

[0004] Therefore, there is an urgent need to develop a new method for preparing reactive sintered silicon carbide that can simplify the process and reduce costs while taking into account both the thermal conductivity and mechanical properties of the material. Summary of the Invention

[0005] In view of the technical problems existing in the background art, the present invention provides a high-strength and high-thermal-conductivity reactive sintered SiC ceramic material and its preparation method, aiming to solve the technical problems of high residual silicon content, poor performance and complex and costly preparation process in the existing RBSC preparation technology.

[0006] In a first aspect, the present invention provides a method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material, comprising the following steps: S1. After mixing silicon carbide powder and carbon source powder, the mixture is ball-milled to obtain a mixed powder. S2. The mixed powder is mixed with binder, plasticizer, and lubricant, and then subjected to high-speed centrifugal stirring and roller pressing homogenization to obtain silicon carbide slurry blanks for injection molding; the solid content of the mixed powder in the silicon carbide slurry blanks for injection molding is 70~85wt%; S3. Place the silicon carbide blank for injection molding into the mold, perform hot-press injection molding, demold to obtain the silicon carbide preform, and perform debinding treatment to obtain the silicon carbide blank. S4. Silicon particles are laid flat on top of the silicon carbide blank, and vacuum high-temperature melting and infiltration are carried out. After cooling, high-strength and high-thermal-conductivity reactive sintered SiC ceramic material is obtained.

[0007] In a second aspect, the present invention provides a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material, which is prepared by the preparation method described in the first aspect.

[0008] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) This invention provides a method for preparing high-strength, high-thermal-conductivity reactive sintered SiC ceramic materials. SiC powder is used as raw material, graphite / carbon black as carbon source, phenolic resin solution as binder, and glycerol and liquid paraffin are added as plasticizer and lubricant to prepare a high-solids-content silicon carbide blank with good plastic deformation ability. Through the strong shearing effect of centrifugal stirring and rolling process, the movement and rearrangement of silicon carbide particles and carbon source powder in the blank are promoted. On the one hand, the powder packing density is increased, which helps to form a continuous silicon carbide phase in the sintered body. On the other hand, it helps to form a continuous porous carbon network in the unbound blank, promotes the uniform distribution of residual silicon and reduces the residual silicon content and size. Therefore, the thermal conductivity and mechanical properties of the material are synergistically improved.

[0009] (2) The reaction sintered silicon carbide ceramic prepared by the present invention has a thermal conductivity of 218 W / mK and a bending strength of 500 MPa. It has both high strength and high thermal conductivity, and has good application potential in the fields of heat exchange devices, space optical devices and semiconductor equipment parts manufacturing.

[0010] (3) The present invention produces a high solid content silicon carbide blank with good plastic deformation ability, which can be combined with calendering, injection molding and other molding methods to realize the complex shape of reaction sintered silicon carbide ceramics. The blank has uniform composition and no sedimentation problem. In addition, the preparation process of the present invention is simple and suitable for industrial production. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the process flow for preparing the high-strength, high-thermal-conductivity reactive sintered SiC ceramic material of the present invention. Figure 2 SEM images of the RBSC green blanks prepared in Example 1 and Comparative Example 1 of this invention; Figure 3 SEM images of RBSC ceramics prepared in Example 1 and Comparative Example 1 of this invention; Figure 4 The complex-shaped SiC ceramic reaction-sintered structural component prepared in Example 1 of this invention. Detailed Implementation

[0012] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. These embodiments are merely illustrative of the technical solution of the present invention and are therefore intended to limit the scope of protection of the present invention.

[0013] To address the technical problems of high residual silicon content, poor performance, and complex and costly preparation processes in existing RBSC preparation technologies, this invention provides a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material and its preparation method. The method optimizes the plastic deformation capacity of the silicon carbide blank by adjusting the component ratio. During the preparation process, strong shearing centrifugal stirring and rolling treatment of the mixed system further enhances the particle rearrangement effect, thereby effectively improving the density of the green blank, promoting uniform distribution of residual silicon, reducing residual silicon content and size, and ultimately improving the overall performance of the material.

[0014] In a first aspect, embodiments of the present invention provide a method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material, comprising the following steps: S1. After mixing silicon carbide powder and carbon source powder, the mixture is ball-milled to obtain a mixed powder. S2. The mixed powder is mixed with binder, plasticizer, and lubricant, and then subjected to high-speed centrifugal stirring and roller pressing homogenization to obtain silicon carbide slurry blanks for injection molding; the solid content of the mixed powder in the silicon carbide slurry blanks for injection molding is 70~85wt%; S3. Place the silicon carbide blank for injection molding into the mold, perform hot-press injection molding, demold to obtain the silicon carbide preform, and perform debinding treatment to obtain the silicon carbide blank. S4. Silicon particles are laid flat on top of the silicon carbide blank, and vacuum high-temperature melting and infiltration are carried out. After cooling, high-strength and high-thermal-conductivity reactive sintered SiC ceramic material is obtained.

[0015] In the technical solution of this invention, silicon carbide and carbon source are uniformly mixed by ball milling. Phenolic resin binder, plasticizer, and lubricant are added for synergistic effects. High-speed centrifugation and roller pressing homogenize the mixture to achieve homogenization and flowability control of a 70-85 wt% high-solids blank. This blank is then formed into a complex, irregularly shaped preform under hot-press injection molding. After debinding, the residual carbon from resin pyrolysis and graphite together form a continuous carbon skeleton. Under vacuum, the silicon particle melt penetrates the pores and reacts in situ with carbon to generate secondary silicon carbide, achieving shrinkage-free densification. This approach utilizes high packing density to reduce melt infiltration channels, effectively reducing residual silicon content and ensuring its uniform distribution, mitigating thermal expansion mismatch, and ultimately achieving a synergistic effect of high strength and high thermal conductivity. In particular, the strong shearing effect of high-speed centrifugation and rolling process promotes the movement and rearrangement of silicon carbide particles and carbon source powder in the blank, increases the powder packing density and forms a continuous porous carbon network in the sintered blank, so that a continuous silicon carbide phase is formed in the sintered body, promotes the uniform distribution of residual silicon and reduces the residual silicon content and size, so that the thermal conductivity and mechanical properties of the material are synergistically improved.

[0016] Furthermore, in some embodiments, the mass ratio of silicon carbide powder, carbon source powder, binder, plasticizer, and lubricant is (63~73):(7~12):(9~28):(1~3):(1~3).

[0017] Furthermore, in some embodiments, the carbon source powder includes graphite and / or carbon black; the average particle size of the carbon source powder is 0.5~5μm.

[0018] Furthermore, in some embodiments, the carbon source powder is a mixture of graphite and carbon black, wherein the graphite content in the mixture is 50wt% to 80wt%.

[0019] Furthermore, in some embodiments, silicon carbide powder is graded by mass ratio, with the mass ratio of powder with an average particle size of 0.5~5μm to powder with an average particle size of 20~100μm being (0~4):(6~10).

[0020] In the technical solution of this invention, a particle size distribution strategy for SiC powder is utilized to achieve precise optimization of particle arrangement at the microscale. Coarse particles form the main skeleton, while fine particles permeate the spaces between them, fully filling the gaps. This reduces porosity and significantly increases packing density, resulting in a denser preform structure, enhanced mechanical strength, and restricted penetration channels of the molten silicon during the melting and infiltration stage, thereby effectively reducing residual silicon content. Since silicon and silicon carbide have significantly different coefficients of thermal expansion, reducing residual silicon can significantly alleviate interfacial stress caused by temperature changes, achieving a comprehensive improvement in the overall performance of the material.

[0021] Furthermore, in some embodiments, in step S1, the ball milling process specifically involves mixing silicon carbide powder and carbon source powder, then adding anhydrous ethanol for wet ball milling, with a ball-to-material ratio of (5~10):1, a ball milling speed of 150~200 rpm / min, and a ball milling time of 4~8 h.

[0022] In the technical solution of this invention embodiment, ball milling fully mixes silicon carbide powder and carbon source at the nano / micro scale to ensure uniform carbon distribution during subsequent reaction sintering and avoid incomplete local reaction or excessive residual silicon accumulation.

[0023] Furthermore, in some embodiments, the binder comprises a phenolic resin solution; the phenolic resin solution is obtained by mixing phenolic resin powder with ethylene glycol.

[0024] Furthermore, in some embodiments, the mass ratio of phenolic resin powder to ethylene glycol is (0.8~1.2):1.

[0025] Furthermore, in some embodiments, the mass ratio of plasticizer to lubricant is (0.8~1.2):1.

[0026] Furthermore, in some embodiments, the plasticizer includes glycerin; the lubricant includes paraffin wax.

[0027] In the technical solutions of this invention, plasticizers include, but are not limited to, glycerin listed in the embodiments of this invention, and other plasticizers in the art can also be conventionally selected, such as polyethylene glycol, phthalates, etc.; lubricants can also be selected according to actual needs, such as stearic acid, oleic acid, or other commonly used lubricants. The selection of these additives needs to comprehensively consider their compatibility with the silicon carbide blank system, thermal stability, and impact on the final material properties.

[0028] Furthermore, in some embodiments, in step S2, the high-speed centrifugation speed is 1000~2000 rpm / min, and the centrifugation time is 2~10 min.

[0029] Furthermore, in some embodiments, the conditions for the roll homogenization process in step S2 are: roll temperature 20~80℃, roll speed 2~20m / min, and roll time 0.5~4h.

[0030] In the technical solution of this invention embodiment, the strong shearing effect of high-speed centrifugation and rolling process promotes the movement and rearrangement of silicon carbide particles and carbon source powder in the clay blank, increases the powder packing density and forms a continuous porous carbon network in the glue-removed blank, which helps to form a continuous silicon carbide phase in the sintered body, promotes the uniform distribution of residual silicon and reduces the residual silicon content and size, so that the thermal conductivity and mechanical properties of the material are synergistically improved.

[0031] Furthermore, in some embodiments, in step S3, the conditions for hot-press injection molding are: injection pressure of 0.1-5 MPa, gelation temperature of 140-180°C, and holding time of 1-10 h.

[0032] Furthermore, in some embodiments, in step S3, the conditions for the adhesive removal process are as follows: the adhesive removal atmosphere is argon or nitrogen, the adhesive removal temperature is 900~1100℃, the heating rate is 1~5℃ / min, and the holding time is 1~4h.

[0033] Furthermore, in some embodiments, in step S4, the particle size of the silicon particles is 0.5~5mm, and the amount of silicon particles added is 1~1.5 times the mass of the silicon carbide preform.

[0034] Furthermore, in some embodiments, the conditions for vacuum high-temperature melting and infiltration in step S4 are: ambient vacuum degree ≤50Pa, heating rate of 2~10℃ / min, reaction temperature of 1500~1800℃, and holding time of 1~6h.

[0035] Secondly, embodiments of the present invention provide a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material, which is prepared by the preparation method described in the first aspect.

[0036] In the technical solution of the present invention, the reaction-sintered silicon carbide ceramic material prepared by the present invention has α-SiC particles that are interlocked and tightly packed together. Combined with the β-SiC generated by the reaction, the gaps between the α-SiC particles are filled, ensuring good continuity of the silicon carbide phase. At the same time, this structure promotes the uniformity of Si phase distribution, reduces residual silicon content and size, and thus synergistically enhances the thermal conductivity and mechanical properties of the ceramic.

[0037] The following are some specific embodiments. It should be noted that the embodiments described below are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention. Where specific techniques or conditions are not specified in the embodiments, they shall be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0038] In the following embodiments of the present invention, the phenolic resin powder is type 2132 phenolic resin and contains 10% hexamethylenetetramine (curing agent).

[0039] Example 1 A high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is prepared by means of the following raw materials by mass percentage: 65.9% SiC powder, 7.3% carbon source powder, 12.2% phenolic resin (containing 10% hexamethylenetetramine), 12.2% ethylene glycol, 1.2% glycerol, and 1.2% paraffin wax; wherein the silicon carbide powder has a particle size distribution of 45μm:5μm=6:4; the carbon source powder is graphite powder with a particle size of 5μm, accounting for 10% of the solid powder content.

[0040] The specific steps for preparing this high-strength, high-thermal-conductivity reactive sintered SiC ceramic material are as follows: S1. Mix silicon carbide powder and carbon source powder in a certain proportion, add anhydrous ethanol and mix, then perform wet ball milling with a ball-to-material ratio of 5:1, a speed of 150 rpm / min, and a ball milling time of 4 h. After ball milling, the powder is vacuum dried at 80℃ for 24 h and then sieved for later use. S2. Phenolic resin powder and ethylene glycol are mixed evenly to form a phenolic resin solution. Glycerin and paraffin are then added and mixed evenly. The mixed powder of silicon carbide and graphite is added to the phenolic resin solution and centrifuged at a speed of 1500 rpm / min for 10 min to obtain the initial clay blank. S3. The clay blank is subjected to roller pressing homogenization treatment. The roller pressing temperature is 60℃, the roller pressing speed is 10m / min, and the roller pressing time is 2h to obtain silicon carbide clay blank for injection molding. S4. Place the silicon carbide blank for injection molding into the mold and perform pressure injection molding. The heating gelation temperature is 150℃, the injection pressure is 2MPa, the holding time is 2h, and the silicon carbide preform is obtained by demolding. S5. The silicon carbide preform is subjected to debinding treatment. The debinding atmosphere is argon, the debinding temperature is 1000℃, the heating rate is 1℃ / min, and the holding time is 1h to obtain the silicon carbide blank. S6. Place the silicon carbide blank into a graphite crucible, spread 1mm-sized Si particles on top of the blank, and add 1.2 times the mass of the blank. Perform high-temperature silicon infiltration sintering with an ambient vacuum of 5Pa, a heating rate of 5℃ / min, a reaction temperature of 1550℃, and a holding time of 2h. S7. Polish the cooled sintered body to remove the residual silicon layer on the surface and obtain reaction sintered SiC ceramic.

[0041] Example 2 A high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is prepared by means of the following raw materials by mass percentage: 65.9% SiC powder, 7.3% carbon source powder, 12.2% phenolic resin (containing 10% hexamethylenetetramine), 12.2% ethylene glycol, 1.2% glycerol, and 1.2% paraffin wax; wherein the silicon carbide powder has a particle size distribution of 45μm:5μm=8:2; the carbon source powder is graphite powder with a particle size of 5μm, accounting for 10% of the solid powder content.

[0042] The preparation method of this high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is the same as that in Example 1.

[0043] Example 3 A high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is prepared by means of the following raw materials by mass percentage: 65.9% SiC powder, 7.3% carbon source powder, 12.2% phenolic resin (containing 10% hexamethylenetetramine), 12.2% ethylene glycol, 1.2% glycerol, and 1.2% paraffin wax; wherein the silicon carbide powder has a particle size distribution of 45μm:5μm=6:4; the ratio of graphite powder (5μm) to carbon black powder (5μm) in the carbon source powder is 2:1, and the carbon source powder accounts for 10% of the solid powder content.

[0044] The preparation method of this high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is the same as that in Example 1.

[0045] Example 4 A high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is prepared by means of the following raw materials by mass percentage: 65.9% SiC powder, 7.3% carbon source powder, 12.2% phenolic resin (containing 10% hexamethylenetetramine), 12.2% ethylene glycol, 1.2% glycerol, and 1.2% paraffin wax; wherein the silicon carbide powder has a particle size of 45 μm; the carbon source powder is graphite powder with a particle size of 5 μm, accounting for 10% of the solid powder content.

[0046] The preparation method of this high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is the same as that in Example 1.

[0047] Example 5 A high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is prepared by means of the following raw materials by mass percentage: 68% SiC powder, 12% carbon source powder, 8% phenolic resin (containing 10% hexamethylenetetramine), 8% ethylene glycol, 2% glycerol, and 2% paraffin wax; wherein the silicon carbide powder has a particle size of 45 μm; the carbon source powder is graphite powder with a particle size of 5 μm, accounting for 15% of the solid powder content.

[0048] The preparation method of this high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is the same as that in Example 1.

[0049] Comparative Example 1 Compared with Example 1, the raw materials for preparing reaction-sintered SiC ceramic materials are the same in this comparative example. The difference is that in the preparation method, step S3, which involves rolling and homogenizing the clay blank, is omitted, and the clay blank obtained in step S2 is directly placed into the mold for pressure injection molding.

[0050] Comparative Example 2 Compared with Example 1, the raw materials for preparing the reaction-sintered SiC ceramic material in this comparative example are the same. The difference is that the centrifugal stirring speed of the slurry in step S2 of the preparation method is 500 rpm / min.

[0051] Comparative Example 3 A reaction-sintered SiC ceramic material is prepared by means of the following raw materials by mass percentage: 45% SiC powder, 5% carbon source powder, 23% phenolic resin (containing 10% hexamethylenetetramine), 23% ethylene glycol, 2% glycerol, and 2% paraffin wax. The silicon carbide powder has a particle size distribution of 45μm:5μm = 6:4; the carbon source powder is graphite powder with a particle size of 5μm, accounting for 10% of the solid powder content.

[0052] The preparation method of this high-strength, high-thermal-conductivity reactive sintered SiC ceramic material is the same as that in Example 1.

[0053] Performance testing: The performance of the reaction-sintered silicon carbide ceramic materials prepared in Examples 1-5 and Comparative Examples 1-3 was tested, and the test results are shown in Table 1 below.

[0054] Table 1

[0055] Table 1 shows that the reaction-sintered silicon carbide ceramic materials prepared in the embodiments of the present invention exhibit excellent performance. In particular, Example 3, by optimizing the silicon carbide powder gradation and carbon source powder type, further reduced the residual silicon content while improving the mechanical properties and thermal conductivity of the material. Data from Comparative Examples 1 and 2 show that roller pressing homogenization and high-speed centrifugal stirring have a significant impact on material properties. Comparative Example 1, lacking roller pressing homogenization, has a lower bulk density, significantly increased porosity and residual silicon content, leading to a substantial decrease in flexural strength and thermal conductivity. Similarly, Comparative Example 2, with reduced centrifugal stirring speed, also exhibits similar performance degradation, indicating the importance of strong shearing in promoting particle rearrangement and increasing packing density. The lower solid content in the clay blank of Comparative Example 3 resulted in insufficient density of the final sintered body, a significant increase in porosity, and a substantial rise in residual silicon content, thus severely affecting the mechanical and thermal conductivity of the material.

[0056] Figure 2 The images show SEM images of the RBSC blanks prepared in Example 1 and Comparative Example 1 of this invention. As can be seen from the images, the blank in Example 1 has a higher density than the blank in Comparative Example 1. The silicon carbide particles are uniformly coated with graphite powder and porous carbon, and the silica-diffused pores formed by the graphite powder and porous carbon are smaller in size and more uniformly distributed.

[0057] Figure 3The images show SEM images of RBSC ceramics prepared in Example 1 and Comparative Example 1 of this invention. As can be seen from the images, the residual silicon content in Example 1 is significantly lower than that in Comparative Example 1. The SiC particles contact each other and merge to grow. Free silicon is distributed between the SiC particles. The initial Si phase between the SiC particles is almost entirely converted into the precipitated β-SiC phase. The residual silicon is in a diffuse distribution state.

[0058] Figure 4 This invention relates to the preparation of complex-shaped SiC ceramic structural parts using the reaction-sintered process of this invention. As shown in the figure, the ceramic blank prepared by this invention possesses excellent shaping ability, and combined with injection molding gelation, it can be used to prepare preforms of complex shapes. These preforms exhibit good machinability, allowing for cutting, grinding, and polishing. After sintering, they can be used to prepare net-shape structural parts, demonstrating promising prospects for industrial applications.

[0059] In summary, this invention uses SiC powder as raw material, graphite / carbon black as carbon source, phenolic resin solution as binder, and adds glycerol and liquid paraffin as plasticizer and lubricant to prepare a high-solids-content silicon carbide blank with good plastic deformation ability. Through the strong shearing effect of centrifugal stirring and rolling, the movement and rearrangement of silicon carbide particles and carbon source powder in the blank are promoted. On the one hand, this increases the powder packing density, which helps to form a continuous silicon carbide phase in the sintered body. On the other hand, it helps to form a continuous porous carbon network in the unbound blank, promoting uniform distribution of residual silicon and reducing its content and size. Ultimately, this results in a synergistic improvement in the material's thermal conductivity and mechanical properties.

[0060] It should be noted that the present invention is not limited to the above-described embodiments. The above embodiments are merely examples, and any embodiments that have the same structure and perform the same effects as the technical concept within the scope of the present invention are included within the scope of the present invention. Furthermore, various modifications that can be conceived by those skilled in the art to the embodiments, and other ways of constructing by combining some of the constituent elements of the embodiments, without departing from the spirit of the present invention, are also included within the scope of the present invention.

Claims

1. A method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material, characterized in that, Includes the following steps: S1. After mixing silicon carbide powder and carbon source powder, the mixture is ball-milled to obtain a mixed powder. S2. The mixed powder is mixed with binder, plasticizer, and lubricant, and then subjected to high-speed centrifugal stirring and roller pressing homogenization to obtain silicon carbide slurry blank for injection molding; the solid content of the mixed powder in the silicon carbide slurry blank for injection molding is 70~85wt%; S3. Place the silicon carbide blank for injection molding into the mold, perform hot-press injection molding, demold to obtain silicon carbide preform, and perform degumming treatment to obtain silicon carbide blank. S4. Silicon particles are laid flat on the silicon carbide blank, and vacuum high-temperature melting and infiltration are performed. After cooling, the high-strength and high-thermal-conductivity reactive sintered SiC ceramic material is obtained.

2. The method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material according to claim 1, characterized in that, The mass ratio of silicon carbide powder, carbon source powder, binder, plasticizer and lubricant is (63~73):(7~12):(9~28):(1~3):(1~3).

3. The method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material according to claim 1, characterized in that, The carbon source powder includes graphite and / or carbon black; the average particle size of the carbon source powder is 0.5~5μm.

4. The method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material according to claim 3, characterized in that, The carbon source powder is a mixture of graphite and carbon black, wherein the graphite content in the mixture is 50wt% to 80wt%.

5. The method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material according to claim 1, characterized in that, The silicon carbide powder is graded by mass ratio, with the mass ratio of powder with an average particle size of 0.5~5μm to powder with an average particle size of 20~100μm being (0~4):(6~10).

6. The method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material according to claim 1, characterized in that, The adhesive comprises a phenolic resin solution; the phenolic resin solution is obtained by mixing phenolic resin powder with ethylene glycol; the mass ratio of the phenolic resin powder to ethylene glycol is (0.8~1.2):

1.

7. The method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material according to claim 1, characterized in that, In step S2, the high-speed centrifugation speed is 1000~2000 rpm / min, and the centrifugation time is 2~10 min; And / or, the conditions for the roller pressing homogenization treatment are: roller pressing temperature 20~80℃, roller pressing speed 2~20m / min, and roller pressing time 0.5~4h.

8. The method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material according to claim 1, characterized in that, In step S3, the conditions for the glue removal process are as follows: the glue removal atmosphere is argon or nitrogen, the glue removal temperature is 900~1100℃, the heating rate is 1~5℃ / min, and the holding time is 1~4h.

9. The method for preparing a high-strength, high-thermal-conductivity reactive sintered SiC ceramic material according to claim 1, characterized in that, In step S4, the particle size of the silicon particles is 0.5~5mm, and the amount of silicon particles added is 1~1.5 times the mass of the silicon carbide preform. The conditions for vacuum high-temperature melting and infiltration are: ambient vacuum degree ≤50Pa, heating rate 2~10℃ / min, reaction temperature 1500~1800℃, and holding time 1~6h.

10. A high-strength, high-thermal-conductivity reactive sintered SiC ceramic material, characterized in that, It is prepared by the preparation method of high-strength, high-thermal-conductivity reactive sintered SiC ceramic material according to any one of claims 1 to 9.

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