Abstract: The chemical damage of carbon fibers during the preparation of Cf/SiC composites by precursor infiltration pyrolysis(PIP) with polycarbosilane(PCS) was investigated systematically. The results show that the chemical damage includes interface reaction and interface diffuse, in which the active groups of PCS hardly react with carbon fibers. However, the oxygen and impurities can hurt carbon fibers largely. Silicon diffuses to carbon fibers more and more with the increasing of heat treatment time, and it is the main way of chemical damage of carbon fibers. The chemical damage of carbon fibers is slight in the first cycle, and turns heavier in the following cycles.

Key words: Cf/SiC composites, Carbon fibers, Chemical damage