Preparation Method and Application of Carbon Particles and Silicon Carbide Powder

Abstract

The present application relates to a method for preparing carbon particles and silicon carbide powder and their application. The method for preparing carbon particles comprises the following steps: mixing carbon powder, a binder, a dispersant, and an organic solvent to obtain a prefabricated carbon mixed solution; the binder has a crosslinking temperature T1 less than 100°C; placing the prefabricated carbon mixed solution in water to obtain a suspension; heating the suspension to the binder's crosslinking temperature T1, performing solid-liquid separation, and obtaining a carbon particle precursor; and carbonizing the carbon particle precursor to obtain carbon particles. The above-mentioned method for preparing carbon particles uses commercially available high-purity nano- or micron-sized carbon powder as raw material to prepare high-purity millimeter-sized carbon particles, which can be further synthesized into high-purity millimeter-sized silicon carbide powder.

Description

Technical Field

[0001] The present application relates to the field of materials, and in particular to a preparation method and application of carbon particles and silicon carbide powder. Background Art

[0002] Silicon carbide (SiC) is a representative material of the third generation of wide bandgap semiconductor materials. Compared with the first generation semiconductor materials represented by Si and the second generation semiconductor materials represented by GaAs, it has a large bandgap, high critical breakdown electric field strength, high carrier saturation migration velocity, high thermal conductivity, and good chemical stability. It has a wide range of applications in the fields of microelectronics and optoelectronics. At present, silicon carbide single crystal substrates are generally divided into two categories: semi-insulating silicon carbide substrates and low-resistance silicon carbide substrates. Among them, transistors made of semi-insulating silicon carbide can generate power with a power density that is five times higher than that of GaAs microwave devices at frequencies up to 10 GHz. They are often used in microwave power devices and are also widely used in 5G communications, radars and other fields. Low-resistance silicon carbide substrates are often used in power electronic devices. The main advantages are improving the efficiency of electric energy utilization and realizing the miniaturization of power electronic devices, as well as being able to operate in harsh environments above 200°C.

[0003] The commonly used preparation method for silicon carbide crystals is physical vapor transport (PVT). Silicon carbide powder is placed in a sealed graphite crucible, and a silicon carbide seed crystal is placed on the top of the crucible. The thermal field distribution of the single crystal furnace is reasonably designed to make the temperature of the powder source area higher than the temperature of the seed crystal area, and the powder source area reaches the sublimation temperature point of the silicon carbide powder source. The Si, C, Si2C, SiC2, SiC and other molecules generated by the sublimation of the silicon carbide powder source are transported to the vicinity of the seed crystal area through diffusion or convection effects. Due to the low temperature of the seed crystal area, the above atmosphere forms a certain degree of supercooling and crystallizes as silicon carbide crystals on the surface of the seed crystal. As crystal growth progresses, the silicon carbide powder near the crucible wall evaporates first, leaving a certain proportion of carbon particles. Small-sized silicon carbide powder, corresponding to the residual carbon particles, is also smaller in size, and easily forms a "sponge"-like insulation layer, affecting the heat transfer from the crucible to the center of the crucible, thereby affecting the subsequent volatilization rate of the powder. Small-particle silicon carbide powder easily sinters to form a dense ceramic body, blocking the volatilization channel and inhibiting the volatilization rate of the powder. Furthermore, the small carbon particles remaining in the small-sized silicon carbide powder are easily disturbed by the atmosphere flow field and fall to the crystal growth surface, forming carbon inclusions and affecting the crystal quality. Therefore, compared with small-sized silicon carbide powder on the order of tens to hundreds of microns, large-sized silicon carbide powder sources on the millimeter scale are more suitable for growing high-quality silicon carbide crystals.

[0004] Traditional methods for preparing millimeter-sized silicon carbide powder include synthesizing large-particle silicon carbide powder by crystallizing small-particle silicon carbide powder, a method that requires high-temperature treatment above 2000°C and takes a long time; or directly purchasing large-particle carbon powder to synthesize millimeter-sized silicon carbide powder. However, commercially available large-particle carbon powder, whether natural graphite or graphite synthesized from petroleum and coal-based chemicals, has a high impurity content. The high density of carbon powder makes it difficult for halogen gas to penetrate the interior of the carbon powder, making it difficult to improve the purity of the carbon powder. As a result, the resulting silicon carbide powder cannot meet the purity requirements of silicon carbide single crystal materials, especially the purity requirements of high-purity semi-insulating silicon carbide substrates.

[0005] Therefore, it is of great significance to provide a method for preparing carbon particles with high purity and large particle size. Summary of the Invention

[0006] Based on this, the present application provides a method for preparing carbon particles with high purity and large particle size and silicon carbide powder, as well as the application of silicon carbide powder.

[0007] The technical solution of this application to solve the above technical problems is as follows.

[0008] A method for preparing carbon particles comprises the following steps:

[0009] Mixing carbon powder, a binder, a dispersant and an organic solvent to obtain a prefabricated carbon mixed solution; the crosslinking temperature T1 of the binder is less than 100° C.;

[0010] placing the prefabricated carbon mixed solution in water to obtain a suspension;

[0011] Heating the suspension to the cross-linking temperature T1 of the binder, performing solid-liquid separation, and obtaining a carbon particle precursor;

[0012] The carbon particle precursor is carbonized to obtain carbon particles.

[0013] In some embodiments, in the method for preparing carbon particles, the purity of the carbon powder is ≥99.99%, and the purity of the binder is ≥99.99%.

[0014] In some embodiments, in the method for preparing carbon particles, the binder is selected from at least one of epoxy resin, asphalt and phenolic resin.

[0015] In some embodiments, in the method for preparing carbon particles, the dispersant is selected from at least one of acrylic resin, coconut monoethanolamide and polyacrylamide.

[0016] In some embodiments, in the method for preparing carbon particles, the mass ratio of the dispersant to the carbon powder is (0.05-0.2):1.

[0017] In some embodiments, in the method for preparing carbon particles, the organic solvent is selected from at least one of ethanol, acetone and ethyl acetate.

[0018] In some embodiments, in the method for preparing carbon particles, the carbonization temperature is 500°C to 800°C.

[0019] In some embodiments, in the method for preparing carbon particles, the carbon particles have a particle size of 1 mm to 3 mm.

[0020] The present application provides a carbon particle prepared by the above-mentioned carbon particle preparation method.

[0021] The present application provides a method for preparing silicon carbide powder, comprising the following steps:

[0022] The carbon particles and silicon powder are mixed and reacted at 1800°C to 2000°C.

[0023] The present application provides the use of silicon carbide powder prepared by the above-mentioned method for preparing silicon carbide powder in the preparation of semiconductor materials.

[0024] Compared with the prior art, the method for preparing carbon particles of the present application has the following beneficial effects:

[0025] The preparation method of the above-mentioned carbon particles is to mix carbon powder, adhesive, dispersant and organic solvent, and when the obtained prefabricated carbon mixed solution is placed in water, under the action of the dispersant, the carbon powder in the prefabricated carbon mixed solution forms millimeter-sized carbon powder clusters in the aqueous environment; further heating the suspension containing the carbon powder clusters to the cross-linking temperature T1 of the adhesive to complete the solidification of the carbon powder clusters, and controlling the cross-linking temperature T1 of the adhesive to be lower than the boiling point of water to ensure that the solidified carbon particle precursor sinks to the bottom of the aqueous environment, and obtaining a millimeter-sized carbon particle precursor through solid-liquid separation; carbonizing the carbon particle precursor, and carbonizing the adhesive in the carbon particle precursor, which can further increase the size of the carbon particles; small-sized carbon powder on the market can have a higher purity, and by adopting the above-mentioned specific preparation method, the purity of the obtained millimeter-sized large-sized carbon particles can be higher. DETAILED DESCRIPTION

[0026] The technical solutions of the present application are further described in detail below with reference to specific embodiments. The present application can be implemented in many different forms and is not limited to the embodiments described herein. It should be understood that the purpose of providing these embodiments is to provide a more thorough and comprehensive understanding of the disclosure of the present application.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this application pertains. The terms used herein in the specification of this application are for the purpose of describing specific embodiments only and are not intended to limit this application. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0028] In the description of this application, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, "plurality" means two or more, unless otherwise specifically defined.

[0029] The weights of the relevant components mentioned in the examples of this application may not only refer to the specific content of each component, but also represent the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the examples of this application, it is within the scope disclosed in the examples of this application. Specifically, the weights described in the examples of this application may be mass units known in the chemical industry, such as μg, mg, g, and kg.

[0030] One embodiment of the present application provides a method for preparing carbon particles, comprising steps S10 to S50:

[0031] Step S10: mixing carbon powder, a binder, a dispersant and an organic solvent to obtain a prefabricated carbon mixed solution; the cross-linking temperature T1 of the binder is less than 100°C.

[0032] In some examples, in step S10 , the purity of the carbon powder is ≥99.99%, and the purity of the adhesive is ≥99.99%.

[0033] It can be understood that by controlling the purity of the carbon powder and the binder and adopting a specific preparation method, the purity of the obtained millimeter-sized carbon particles can be made higher.

[0034] Optionally, in step S10, the purity of the carbon powder is ≥99.999%, and the purity of the adhesive is ≥99.999%.

[0035] In some examples, in step S10 , the adhesive is selected from at least one of epoxy resin, asphalt, and phenolic resin.

[0036] Furthermore, the epoxy resin is a water-based epoxy resin.

[0037] Optionally, the epoxy resin is selected from at least one of low molecular weight liquid bisphenol A epoxy resin, high molecular weight cured bisphenol A epoxy resin and low molecular weight liquid epoxy resin emulsion.

[0038] It can be understood that the cross-linking temperature T1 of epoxy resin, asphalt and phenolic resin is less than 100°C; by controlling the cross-linking temperature T1 of the adhesive to be lower than the boiling point of water, the boiling of the aqueous solution to form local cavitation and strong convection is avoided, thereby ensuring that the solidified carbon particle precursor sinks to the bottom of the aqueous environment.

[0039] In some examples, in step S10, the dispersant is selected from at least one of acrylic resin, coconut monoethanolamide, and polyacrylamide.

[0040] The size of the agglomerates can be further increased by using specific types of dispersants.

[0041] In some examples, in step S10, the mass ratio of the dispersant to the carbon powder is (0.05-0.2):1.

[0042] It can be understood that the mass ratio of dispersant to carbon powder includes but is not limited to 0.05:1, 0.1:1, 0.12:1, 0.15:1, 0.18:1, and 0.2:1; by controlling the amount of dispersant added, the carbon powder in the prefabricated carbon mixed solution can be further controlled to form millimeter-sized carbon powder clusters in the aqueous environment.

[0043] In some examples, in step S10 , the mass ratio of the binder to the carbon powder is (2-5):1.

[0044] It can be understood that the mass ratio of adhesive to carbon powder includes but is not limited to 2:1, 2.5:1, 3:1, 3.5:1, 4:1, 4.5:1, and 5:1; in some examples, it can be within a range consisting of any two of these point values as end values, the same below.

[0045] In some examples, in step S10 , the particle size of the carbon powder is 5 μm to 50 μm.

[0046] It is understood that the particle size of the carbon powder includes but is not limited to 5 μm, 10 μm, 15 μm, 20 μm, 25 μm, 30 μm, 35 μm, 40 μm, 45 μm, and 50 μm.

[0047] By controlling the particle size of the carbon powder, the porosity of the carbon particles can be controlled, thereby controlling the degree of reaction between the carbon particles and silicon. It can be understood that the smaller the particle size, the more binder is required, the greater the porosity of the resulting carbon particles, the more thorough the reaction between the carbon particles and silicon, and the lower the elemental silicon (free silicon) content in the final silicon carbide powder.

[0048] In some examples, in step S10 , the organic solvent is selected from at least one of ethanol, acetone, and ethyl acetate.

[0049] In some examples, in step S10 , the mass ratio of the organic solvent to the adhesive is (0.5-2):1.

[0050] It is understood that the mass ratio of the organic solvent to the adhesive includes but is not limited to 0.5:1, 0.8:1, 1:1, 1.2:1, 1.5:1, and 2:1.

[0051] In some examples, in step S10 , after the step of mixing the carbon powder, the binder, the dispersant and the organic solvent, a step of stirring the mixture to obtain a prefabricated carbon mixed solution is further included.

[0052] Step S20: placing the prefabricated carbon mixed solution in water to obtain a suspension.

[0053] In some examples, after the step of placing the prefabricated carbon mixed solution in water in step S20, the method further includes subjecting the mixture of the prefabricated carbon mixed solution and water to ultrasonic treatment.

[0054] In some examples, in step S20, after the ultrasonic treatment step, the method further includes stirring the ultrasonically treated mixed solution.

[0055] Step S30: heating the suspension to the cross-linking temperature T1 of the binder, performing solid-liquid separation, and obtaining a carbon particle precursor.

[0056] In some examples, in step S30 , the solid-liquid separation is performed by filtration.

[0057] It can be understood that the carbon particle precursor obtained in step S30 contains cross-linked adhesive.

[0058] In some examples, in step S30 , the suspension is heated to the cross-linking temperature T1 of the adhesive and then cured for 0.5 h to 2 h.

[0059] It can be understood that the curing time includes but is not limited to 0.5h, 0.8h, 1h, 1.2h, 1.5h, 1.8h, and 2h.

[0060] Step S40: carbonizing the carbon particle precursor to obtain carbon particles.

[0061] In some examples, in step S40 , the carbonization temperature is 500° C. to 800° C.

[0062] It will be appreciated that the carbonization temperature includes but is not limited to 500°C, 520°C, 550°C, 580°C, 600°C, 650°C, 680°C, 700°C, 720°C, 750°C, and 800°C.

[0063] In some examples, step S40 further includes drying the carbon particle precursor before the carbonization step.

[0064] In some examples, in step S40 , the drying temperature is 110° C. to 150° C.

[0065] One embodiment of the present application provides carbon particles prepared by the above-mentioned carbon particle preparation method.

[0066] In some examples, the carbon particles have a particle size of 1 mm to 3 mm.

[0067] It will be appreciated that the particle size of the carbon particles includes but is not limited to 1 mm, 1.2 mm, 1.3 mm, 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 2 mm, 2.2 mm, 2.5 mm, 2.8 mm, and 3 mm.

[0068] Carbon powder, adhesive, dispersant and organic solvent are mixed, and when the obtained prefabricated carbon mixed solution is placed in water, under the action of the dispersant, the carbon powder in the prefabricated carbon mixed solution forms millimeter-sized carbon powder clusters in the aqueous environment; the suspension containing the carbon powder clusters is further heated to the cross-linking temperature T1 of the adhesive to complete the solidification of the carbon powder clusters, and the cross-linking temperature T1 of the adhesive is controlled to be lower than the boiling point of water to ensure that the solidified carbon particle precursor sinks to the bottom of the aqueous environment, and a millimeter-sized carbon particle precursor is obtained through solid-liquid separation; the carbon particle precursor is carbonized, and the adhesive in the carbon particle precursor is carbonized, which can further increase the size of the carbon particles; small-sized carbon powder on the market can have higher purity, and by controlling the purity of the carbon powder and the adhesive, and adopting the above-mentioned specific preparation method, the purity of the obtained millimeter-sized large-sized carbon particles can be made higher.

[0069] The above-mentioned method for preparing carbon particles uses commercially available high-purity nano- or micron-sized carbon powder as raw material to prepare high-purity millimeter-sized large-sized carbon particles, which can be further synthesized into high-purity millimeter-sized large-sized silicon carbide powder.

[0070] An embodiment of the present application provides a method for preparing silicon carbide powder, comprising the following steps:

[0071] The carbon particles and silicon powder are mixed and reacted at 1800°C to 2000°C.

[0072] It will be appreciated that the reaction temperature includes, but is not limited to, 1800°C, 1820°C, 1850°C, 1880°C, 1900°C, 1920°C, 1950°C, 1980°C, and 2000°C.

[0073] In some examples, in the method for preparing silicon carbide powder, the reaction time is 3 hours to 4 hours.

[0074] It is understood that the reaction time includes but is not limited to 3h, 3.2h, 3.4h, 3.5h, 3.8h, and 4h.

[0075] In some of the examples, in the method for preparing silicon carbide powder, the mass ratio of carbon particles to silicon powder is (1-1.1):1.

[0076] It is understood that the mass ratio of carbon particles to silicon powder includes but is not limited to 1:1, 1.02:1, 1.05:1, 1.07:1, and 1.1:1.

[0077] The method for preparing silicon carbide powder has low energy consumption, high efficiency, a powder yield higher than 90%, and low cost.

[0078] One embodiment of the present application provides a silicon carbide powder prepared by the above-mentioned method for preparing silicon carbide powder.

[0079] One embodiment of the present application provides the use of the above-mentioned silicon carbide powder or the silicon carbide powder prepared by the above-mentioned method for preparing silicon carbide powder in preparing semiconductor materials. Another embodiment of the present application provides a semiconductor material, the raw materials for its preparation include the above-mentioned silicon carbide powder.

[0080] The silicon carbide powder is used to prepare semiconductor materials, which can give the semiconductor materials higher crystal quality and process controllability.

[0081] In some embodiments, the semiconductor material includes, but is not limited to, a Schottky diode (SBD / JBS), an insulated gate bipolar transistor (IGBT), a thyristor (GTO), and a metal-oxide semiconductor field effect transistor (MOSFET). Specific embodiments

[0083] The following examples are given according to the preparation method of the carbon particles and silicon carbide powder and the application of the silicon carbide powder of the present application. It can be understood that the preparation method of the carbon particles and silicon carbide powder and the application of the silicon carbide powder of the present application are not limited to the following examples.

[0084] Example 1

[0085] (1) Carbon powder (particle size 5 μm, purity 99.999%), water-based epoxy resin (F0707 model purchased from Shenzhen Jitian Chemical Company, cross-linking temperature 80°C), alcohol solvent and CMEA (coconut monoethanolamide) were mixed in a mass ratio of 20:100:100:1 and stirred for 2 h to obtain a prefabricated carbon mixed solution;

[0086] (2) adding the prefabricated carbon mixed solution into a deionized water tank, ultrasonically pre-treating for 2 h, and then stirring the solution with a stirring bar for 1 h, so that the carbon powder forms suspended dispersed particles under the action of the dispersant to obtain a suspension;

[0087] (3) heating the suspension to the crosslinking temperature of the waterborne epoxy resin and maintaining it constant for 1 hour. The solidified particles will sink to the bottom of the aqueous environment and be filtered to obtain a carbon particle precursor;

[0088] (4) drying the carbon particle precursor at 120° C. and then carbonizing the carbon particle precursor at 500° C. to obtain carbon particles; the carbon particles have a purity of 99.999%, a particle size of 1 mm, and a porosity of 40%;

[0089] (5) Based on the self-propagating high-temperature synthesis method, the carbon particles obtained in step (4) and silicon powder are mixed in a molar ratio of 1:1, and in a powder synthesis furnace, the pressure is increased to 50 mbar after vacuum pretreatment, the temperature is increased to 1900°C, the reaction is carried out for 4 hours, and then the temperature is naturally cooled to obtain silicon carbide powder; the purity of the silicon carbide powder is 99.999%, the particle size is 1.2 mm, and the yield is 95%.

[0090] Example 2

[0091] (1) Carbon powder (particle size of 50 μm, purity of 99.999%), water-based epoxy resin (purchased from Shenzhen Jitian Chemical Company, model F0707, cross-linking temperature of 80°C), alcohol solvent and acrylic resin dispersant (purchased from Shenzhen Jitian Chemical Company, model E0503) were mixed in a mass ratio of 5:10:10:1 and stirred for 2 h to obtain a prefabricated carbon mixed solution;

[0092] (2) adding the prefabricated carbon mixed solution into a deionized water tank, ultrasonically pre-treating it for 2 h, and then stirring it with a stirring bar for 2 h, so that the carbon powder forms suspended dispersed particles under the action of the dispersant to obtain a suspension;

[0093] (3) heating the suspension to the crosslinking temperature of the waterborne epoxy resin and maintaining it constant for 1 hour. The solidified particles will sink to the bottom of the aqueous environment and be filtered to obtain a carbon particle precursor;

[0094] (4) drying the carbon particle precursor at 130° C. and then carbonizing the carbon particle precursor at 800° C. to obtain carbon particles; the carbon particles have a purity of 99.999%, a particle size of 1.5 mm, and a porosity of 30%;

[0095] (5) Based on the self-propagating high-temperature synthesis method, the carbon particles obtained in step (4) and silicon powder are mixed in a molar ratio of 1:1, and in a powder synthesis furnace, the pressure is increased to 50 mbar after vacuum pretreatment, the temperature is increased to 1900°C, the reaction is carried out for 4 hours, and then the temperature is naturally cooled to obtain silicon carbide powder; the purity of the silicon carbide powder is 99.999%, the particle size is 2 mm, and the yield is 96%.

[0096] Example 3

[0097] The method is basically the same as Example 1, except that the adhesive is phenolic resin (model PR-55738 purchased from Sumitomo Corporation of Japan, with a cross-linking temperature of 91° C.), and step (1) is specifically as follows:

[0098] (1) Carbon powder (particle size of 5 μm, purity of 99.999%), phenolic resin, alcohol solvent and CMEA (coconut monoethanolamide) were mixed in a mass ratio of 20:100:100:1 and stirred for 2 h to obtain a prefabricated carbon mixed solution.

[0099] The purity of the silicon carbide powder obtained in the final step (5) is 99.999%, the particle size is 0.9 mm, and the yield is 93%.

[0100] Example 4

[0101] The method is basically the same as Example 1, except that in step (1), the mass ratio of carbon powder, water-based epoxy resin, alcohol solvent and CMEA is 20:100:100:2.

[0102] The purity of the silicon carbide powder obtained in the final step (5) is 99.999%, the particle size is 0.8 mm, and the yield is 91%.

[0103] Example 5

[0104] The method is basically the same as Example 1, except that in step (1), the dispersant in Example 1 is replaced by an equal amount of polyacrylamide (purchased from Sinopharm Chemical Reagent Co., Ltd., model 30503770).

[0105] The purity of the silicon carbide powder obtained in the final step (5) is 99.999%, the particle size is 1.5 mm, and the yield is 95%.

[0106] Comparative Example 1

[0107] Based on the self-propagating high-temperature synthesis method, carbon particles (particle size of 1mm) purchased from SGL Corporation in Germany and silicon powder are mixed in a molar ratio of 1:1. After vacuum pretreatment in a powder synthesis furnace, the pressure is increased to 50mbar, the temperature is raised to 1900℃, and the reaction is carried out for 4 hours before naturally cooling to obtain silicon carbide powder; the surface of the silicon carbide powder is a silicon carbide shell layer, and there is an unreacted carbon core inside. The purity of the silicon carbide powder is 99.9%, the particle size is 1.2mm, and the yield is 50%.

[0108] Comparative Example 2

[0109] The method is basically the same as Example 1, except that the adhesive is phenolic resin (purchased from Henghao New Materials, model 2123, with a cross-linking temperature of 110° C.), and step (1) is specifically as follows:

[0110] (1) Carbon powder (particle size of 5 μm, purity of 99.999%), phenolic resin, alcohol solvent and CMEA (coconut monoethanolamide) were mixed in a mass ratio of 20:100:100:1 and stirred for 2 h to obtain a prefabricated carbon mixed solution.

[0111] In step (3), since the water environment cannot be heated to the resin curing temperature, the desired large-particle carbon powder cannot be obtained in an environment below 100 degrees Celsius.

[0112] Comparative Example 3

[0113] The process is basically the same as Example 1, except that no dispersant is added. Step (1) is as follows:

[0114] (1) Carbon powder (particle size of 5 μm, purity of 99.999%), water-based epoxy resin (purchased from Shenzhen Jitian Chemical Company, model F0707, cross-linking temperature of 80°C) and alcohol solvent were mixed in a mass ratio of 20:100:100 and stirred for 2 h to obtain a prefabricated carbon mixed solution.

[0115] The purity of the carbon particles obtained in step (3) is 99.999%, the particle size is 0.05 mm, and the porosity is 10%. The purity of the silicon carbide powder obtained in step (4) is 99.999%, the particle size is 0.055 mm, and the yield is 99%.

[0116] Comparative Example 4

[0117] The process is basically the same as Example 1, except that step (2) is omitted. The details are as follows:

[0118] (1) Carbon powder (particle size of 5 μm, purity of 99.999%), water-based epoxy resin (F0707 model purchased from Shenzhen Jitian Chemical Company, cross-linking temperature of 80°C), alcohol solvent and CMEA (coconut monoethanolamide) were mixed in a mass ratio of 20:100:100:1 and stirred for 2 h to obtain a prefabricated carbon mixed solution;

[0119] (2) heating the prefabricated carbon mixed solution to the crosslinking temperature of the waterborne epoxy resin and maintaining it constant for 1 hour to complete the curing and obtain a carbon particle precursor;

[0120] (3) drying the carbon particle precursor at 130° C. and then carbonizing the carbon particle at 500° C. to obtain carbon particles; the carbon particles have a purity of 99.999%, a particle size of 0.1 mm to 1 mm (uneven agglomeration), and a porosity of 10% to 40%;

[0121] (4) Based on the self-propagating high-temperature synthesis method, the carbon particles obtained in step (3) and the silicon powder are mixed in a molar ratio of 1:1, and in a powder synthesis furnace, the pressure is increased to 50 mbar after vacuum pretreatment, the temperature is increased to 1900°C, the reaction is carried out for 4 hours, and then the temperature is naturally cooled to obtain silicon carbide powder; the purity of the silicon carbide powder is 99.999%, the particle size is 0.15 mm to 1.1 mm, and the yield is 97%.

[0122] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0123] The embodiments described above only express several implementation methods of the present application, which are convenient for understanding the technical solutions of the present application in a specific and detailed manner, but they cannot be understood as limiting the scope of protection of the invention patent. It should be pointed out that for ordinary technicians in this field, without departing from the concept of the present application, several variations and improvements can be made, which all fall within the scope of protection of the present application. It should be understood that the technical solutions obtained by those skilled in the art through logical analysis, reasoning or limited experiments on the basis of the technical solutions provided in the present application are all within the scope of protection of the claims attached to the present application. Therefore, the scope of protection of the patent of this application shall be based on the content of the attached claims, and the description can be used to interpret the content of the claims.

Claims

1. A method for preparing carbon particles, characterized in that: The following steps are involved: Mixing carbon powder, a binder, a dispersant, and an organic solvent to obtain a prefabricated carbon mixed solution; the binder has a crosslinking temperature T1 less than 100° C.; the binder is selected from at least one of epoxy resin, asphalt, and phenolic resin; and the dispersant is selected from at least one of acrylic resin, coconut monoethanolamide, and polyacrylamide; placing the prefabricated carbon mixed solution in water to obtain a suspension; Heating the suspension to the cross-linking temperature T1 of the binder, performing solid-liquid separation, and obtaining a carbon particle precursor; The carbon particle precursor is carbonized to obtain carbon particles.

2. The method for preparing carbon particles according to claim 1, wherein: The purity of the carbon powder is ≥99.99%, and the purity of the adhesive is ≥99.99%.

3. The method for preparing carbon particles according to claim 1, wherein: The mass ratio of the dispersant to the carbon powder is (0.05-0.2):

1.

4. The method for preparing carbon particles according to claim 1, wherein: The organic solvent is selected from at least one of ethanol, acetone and ethyl acetate.

5. The method for preparing carbon particles according to any one of claims 1 to 4, characterized in that: The carbonization temperature is 500°C to 800°C.

6. The method for preparing carbon particles according to any one of claims 1 to 4, characterized in that: The particle size of the carbon particles is 1 mm to 3 mm.

7. A method for preparing silicon carbide powder, characterized in that: The following steps are involved: Mixing carbon powder, a binder, a dispersant, and an organic solvent to obtain a prefabricated carbon mixed solution; the binder has a crosslinking temperature T1 less than 100° C.; the binder is selected from at least one of epoxy resin, asphalt, and phenolic resin; and the dispersant is selected from at least one of acrylic resin, coconut monoethanolamide, and polyacrylamide; placing the prefabricated carbon mixed solution in water to obtain a suspension; Heating the suspension to the cross-linking temperature T1 of the binder, performing solid-liquid separation, and obtaining a carbon particle precursor; carbonizing the carbon particle precursor to obtain carbon particles; The carbon particles and silicon powder are mixed and reacted at 1800° C. to 2000° C.

8. Use of the silicon carbide powder prepared by the method for preparing silicon carbide powder according to claim 7 in preparing semiconductor materials.