▎ 摘　　要

NOVELTY - Silicon carbide composite coating comprises carbon sealing filling layer, silicon carbide transition layer and silicon carbide outer coating layer from inside to outside. The carbon sealing layer is obtained by carbonization treatment after repeated brushing, curing and drying of the carbon black resin mixed solution. The silicon carbide transition layer is obtained by sintering a silicon carbide mixed slurry by using silicon carbide powder, graphene powder, phenolic resin powder and silicon powder as raw materials after repeated brushing, curing, and drying. The silicon carbide outer coating is prepared by chemical vapor deposition method. USE - Silicon carbide composite coating for porous thermal insulation carbon material. ADVANTAGE - The silicon carbide composite coating has simple device technique, easy operation, wide industrial application prospect, prepares large and complex shape of special-shaped piece, effectively prevents coating raw material from permeating into porous carbon felt, forms binding interface with porous carbon felt, forms firm chemical bonding with silicon carbide transition layer, improves bonding ability of coating and porous carbon felt, has low requirement to surface and device of base material, and is not limited by shape and size of base body. DETAILED DESCRIPTION - An INDEPENDENT CLAIM is included for a method for preparing silicon carbide composite coating for porous thermal insulation carbon material, which involves: (A) preparing carbon sealing layer by brushing, curing and drying of the carbon black resin mixed solution on surface of porous carbon felt, and placing it in high temperature furnace with a protective atmosphere for carbonization treatment to obtain a carbon sealing layer; (B) preparing silicon carbide transition layer by brushing, curing and drying silicon carbide mixed slurry on surface of carbon sealing layer, and placing it in a protective atmosphere and sintering it to obtain silicon carbide transition layer, where silicon carbide mixed slurry comprises 35-45 wt.% silicon carbide powder, 8-12 wt.% graphene powder, 15-25 wt.% phenolic resin powder, and 20-40 wt.% silicon powder; and (C) preparing silicon carbide outer coating by putting carbon felt with carbon sealing layer and silicon carbide transition layer into silicon carbide chemical vapor deposition furnace, and preparing silicon carbide outer coating by chemical vapor deposition on the surface of the carbon felt to obtain final product.