SILICON CARBIDE-BASED MATERIAL

摘要

PURPOSE:To prevent the diffusion of impurities at high temp. and to improve heat resistance and mechanical durability by treating a reacted and sintered SiC material contg. unreacted metallic Si with an acid or alkali. CONSTITUTION:A reacted and sintered SiC material having >=3.05g/cm<3> density is treated by a desired surface thickness by immersion or other method with an HF-HNO3 mixed acid or alkali such as NaOH or KOH to remove a part or all of unreacted metallic Si and a treated SiC-based material is obtd. Gaseous starting material such as CH3SiCl3 is then fed to the SiC-based material at 1,000-1,400 deg.C and an SiC-based material surface-coated with a high purity SiC coating film of >=30mum thickness by chemical vapor deposition or other method is produced.