Improving the anti-oxidation and water wettability of graphite through the design of coating structure for the preparation of Al2O3–SiC–C castables

Abstract

C/SiC composite powders with different SiC morphologies were prepared by various methods, and the effects of composite powders on the microstructure, mechanical properties, oxidation resistance, and slag corrosion resistance of Al2O3–SiC–C castables were studied. The results show that compared with wet mixing and catalytic modification, the modified graphite with nano SiC prepared by the molten salt method has a prominent “coating” structure, which cooperatively improves the water wetting and oxidation resistance of graphite. At the same time, it was found that the dried strength of castables increased significantly with the gradual replacement of graphite by C/SiC composite powder prepared by the molten salt method. After heat treatment, the bending strength, cold crushing strength, residual strength after thermal shock, and refractoriness under load of the sample increase with the additional increase. In addition, the sample that completely replaces graphite has the smallest decarburization area and slag erosion penetration depth.