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CN-122010599-A - High-performance silicon carbide coating embedding process

CN122010599ACN 122010599 ACN122010599 ACN 122010599ACN-122010599-A

Abstract

The application discloses a high-performance silicon carbide coating embedding process, and relates to the technical field of static pressure graphite coating materials. The SiC coating modified graphite matrix is prepared by firstly weighing SiC powder, si powder and carbon powder according to a specific mass ratio, ball milling and mixing the SiC powder, embedding a graphite matrix into the embedding powder, and performing argon protection and programmed heating sintering. And preparing a dendritic polysilazane impregnating solution containing an azo phenyl group, putting the modified substrate into a vacuum impregnating tank, carrying out ultraviolet irradiation assisted vacuum impregnation and gradient drying, and then carrying out programmed heating and curing to obtain the composite coating modified graphite material. The process solves the problems of multiple defects and reduced mechanical properties of a matrix of the traditional embedding method, and improves the density and interface bonding strength of the coating by deep penetration repair of the photosensitive dendritic polysilazane, so that the obtained material has excellent mechanical and thermal properties and structural stability and meets the requirements of high-end working conditions.

Inventors

  • TANG WEI
  • TANG HAO

Assignees

  • 都江堰市苏彭新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260413

Claims (8)

  1. 1. The high-performance silicon carbide coating embedding process is characterized by comprising the following preparation steps: S1, completely embedding a graphite substrate into a corundum crucible containing embedding powder, wherein the thickness of the embedding layer is 9-11 mm, placing the crucible into a sintering furnace, introducing argon for protection, heating according to a program, cooling to room temperature along with the furnace, taking out a sample, and blowing out residual embedding powder on the surface by using compressed air to obtain a SiC coating modified graphite substrate; S2, mixing a polymerization monomer, an isopropyl chloroplatinate solution and p-benzoquinone according to the mass ratio of 1:2.4-2.6:0.55-0.6%, stirring and reacting for 1-2 hours at the temperature of 80-85 ℃, dissolving with diethyl ether after the reaction is finished, precipitating with acetonitrile for three times, separating liquid, collecting lower liquid, evaporating solvent to obtain dendritic polysilazane, adding the dendritic polysilazane into toluene with the mass of 3.4-4.1 times that of the dendritic polysilazane, adding benzoyl peroxide with the mass of 0.45-0.55% that of the dendritic polysilazane, and stirring uniformly to prepare impregnation liquid for later use; S3, placing the SiC coating modified graphite substrate into a vacuum impregnation tank, vacuumizing to-0.093 to-0.097 MPa, keeping for 28-32 min, injecting impregnation liquid until the substrate is completely immersed, starting ultraviolet irradiation 365nm, enabling the light intensity to be 9-11 mW/cm < 2>, vacuum impregnating for 1.8-2.2 h, closing the ultraviolet irradiation, slowly releasing to normal pressure, continuously impregnating for 0.8-1.2 h, taking out the impregnated substrate, naturally airing for 22-26 h, drying for 1.8-2.2 h at 58-62 ℃ and 1.8-2.2 h at 78-82 ℃, removing residual solvent, placing the pre-dried sample into a temperature programming oven, curing according to gradient heating, and naturally cooling to room temperature to obtain the composite coating modified graphite material.
  2. 2. The high-performance silicon carbide coating embedding process according to claim 1, wherein the embedding powder in S1 comprises the following preparation steps of weighing SiC powder 10-20 mu m, si powder 5-10 mu m and carbon powder 1-5 mu m according to a mass ratio of 70:19-21:9-11, and uniformly ball-milling and mixing to obtain the embedding powder.
  3. 3. The high-performance silicon carbide coating embedding process according to claim 1, wherein the temperature-raising conditions in the step S1 are as follows, namely, one-stage 4.5-5.5 ℃ per min, temperature-raising to 490-510 ℃ and heat-preserving for 28-32 min, two-stage 2.8-3.2 ℃ per min, temperature-raising to 1440-1460 ℃ and heat-preserving for 1.8-2.2 h.
  4. 4. The high-performance silicon carbide coating embedding process according to claim 1, wherein the temperature-raising conditions in the step S3 are as follows, namely, one-stage temperature raising is carried out at 1.8-2.2 ℃ per minute, temperature raising is carried out at 118-122 ℃, heat preservation is carried out for 0.8-1.2 h, two-stage temperature raising is carried out at 1.8-2.2 ℃ per minute, temperature raising is carried out at 158-162 ℃, heat preservation is carried out for 1.8-2.2 h, and three-stage temperature raising is carried out at 0.9-1.1 ℃ per minute, and temperature raising is carried out at 178-182 ℃ for 2.8-3.2 h.
  5. 5. The high-performance silicon carbide coating embedding process according to claim 1 is characterized in that the preparation method comprises the following steps of adding dimethylchlorosilane into toluene according to a mass ratio of 1:1.5-1.8 to prepare dimethylchlorosilane solution for standby, adding 4-amino-4 '-methylacrylate azobenzene, triethylamine and hydroquinone into toluene according to a mass ratio of 1:1.4-1.6:0.01-0.05%, stirring uniformly at a temperature of-5~0 ℃, dropwise adding dimethylchlorosilane solution, reacting for 4-5 hours at a temperature of 25-35 ℃ after the dropwise adding, standing for precipitation, filtering for precipitation, adding hydroquinone with a mass ratio of 0.05-0.1% of 4-amino-4' -methylacrylate azobenzene into filtrate, performing rotary evaporation, and performing column chromatography separation on silica gel to obtain the polymerized monomer.
  6. 6. The high-performance silicon carbide coating embedding process according to claim 5, wherein the mass ratio of the 4-amino-4' -methacrylate azobenzene to the dimethylhydrochlorosilane is 1.35-1.45:1.
  7. 7. The process of claim 5, wherein the eluent in the silica gel column chromatographic separation is petroleum ether, ethyl acetate=15:1, in volume ratio.
  8. 8. The composite coating modified graphite material is characterized by being prepared by the high-performance silicon carbide coating embedding process according to any one of claims 1-7.

Description

High-performance silicon carbide coating embedding process Technical Field The invention relates to the technical field of static pressure graphite coating materials, in particular to a high-performance silicon carbide coating embedding process. Background Graphite materials are widely applied to the high-end manufacturing fields of semiconductor thermal fields, photovoltaic equipment, aerospace and the like because of low thermal expansion coefficient, high heat and electric conductivity and excellent high-temperature stability. However, graphite is easily oxidized and ablated in a high-temperature oxygen-containing environment, the surface strength and the wear resistance are insufficient, and a SiC coating is generally prepared on the surface of the graphite for protection. The embedding method is a common technical route for large-scale preparation of the SiC coating due to simple process, lower cost and better combination of the coating and the matrix. However, the SiC coating prepared by the traditional embedding method has obvious technical defects of easiness in residual micropores, cracks and the like in the coating, low density, insufficient bonding strength of the interface between the coating and a matrix, easiness in cracking and falling under high-temperature working conditions, difficulty in realizing defect closed-loop repair by simple embedding and sintering, and limited mechanical property, oxidation resistance and structural stability of the material. In addition, the conventional dipping modification process has poor permeability and insufficient curing, can not carry out deep filling and interface enhancement on coating micropores, and is difficult to meet the requirement of high-end equipment on long-term reliable service of the graphite-based composite material. Disclosure of Invention The invention aims to provide a high-performance silicon carbide coating embedding process for solving the problems in the prior art. In order to solve the technical problems, the invention provides the following technical scheme: the high-performance silicon carbide coating embedding process comprises the following preparation steps: S1, completely embedding a graphite substrate into a corundum crucible containing embedding powder, wherein the thickness of the embedding layer is 9-11 mm, placing the crucible into a sintering furnace, introducing argon for protection, heating according to a program, cooling to room temperature along with the furnace, taking out a sample, and blowing out residual embedding powder on the surface by using compressed air to obtain a SiC coating modified graphite substrate; S2, mixing a polymerization monomer, an isopropyl chloroplatinate solution and p-benzoquinone according to the mass ratio of 1:2.4-2.6:0.55-0.6%, stirring and reacting for 1-2 hours at the temperature of 80-85 ℃, dissolving with diethyl ether after the reaction is finished, precipitating with acetonitrile for three times, separating liquid, collecting lower liquid, evaporating solvent to obtain dendritic polysilazane, adding the dendritic polysilazane into toluene with the mass of 3.4-4.1 times that of the dendritic polysilazane, adding benzoyl peroxide with the mass of 0.45-0.55% that of the dendritic polysilazane, and stirring uniformly to prepare impregnation liquid for later use; S3, placing the SiC coating modified graphite substrate into a vacuum impregnation tank, vacuumizing to-0.093 to-0.097 MPa, keeping for 28-32 min, injecting impregnation liquid until the substrate is completely immersed, starting ultraviolet irradiation 365nm, enabling the light intensity to be 9-11 mW/cm < 2>, vacuum impregnating for 1.8-2.2 h, closing the ultraviolet irradiation, slowly releasing to normal pressure, continuously impregnating for 0.8-1.2 h, taking out the impregnated substrate, naturally airing for 22-26 h, drying for 1.8-2.2 h at 58-62 ℃ and 1.8-2.2 h at 78-82 ℃, removing residual solvent, placing the pre-dried sample into a temperature programming oven, curing according to gradient heating, and naturally cooling to room temperature to obtain the composite coating modified graphite material. Further, preferably, the embedding powder in the S1 comprises the following preparation steps of weighing 10-20 mu m of SiC powder, 5-10 mu m of Si powder and 1-5 mu m of carbon powder according to a mass ratio of 70:19-21:9-11, and carrying out ball milling and mixing uniformly to obtain the embedding powder. Further, preferably, the temperature-raising condition of the program in the step S1 is as follows, wherein the temperature-raising condition is that the temperature is raised to 490-510 ℃ at one stage of 4.5-5.5 ℃ per minute, and the temperature is kept for 28-32 min; two stages of 2.8-3.2 ℃ per minute, heating to 1440-1460 ℃, and preserving heat for 1.8-2.2 h. Further, preferably, the temperature-raising conditions of the program in the step S3 are that the temperature is raised to 118-122 ℃ in one stage at 1.8-