Reaction formed coatings for SiC fibers in ceramic matrix composites

摘要

A layer of compliant material is usually deposited on fibers for ceramic matrix composites to permit toughening by fiber pull out during failure. Chemical vapor deposition or sol gel techniques have usually been used to produce these coatings. These processes are expensive and sometimes fail to produce uniform, coherent coatings. Carbon films can be formed on SiC by selective chlorination of the silicon at high temperature and atmospheric pressure. The process is low cost and amenable to most SiC based fibers and whiskers. These films are generally of graphitic structure and can be further reacted to produce other coatings with better oxidation resistance.