Effect of in-situ grown SiC nanowire and dense SiC on oxidation resistance of carbon fiber/SiC nanowire/SiC matrix composite in high temperature atmospheric environment

摘要

SiC nanowire and dense SiC, grown in-situ in a carbon fiber perform play crucial role in determining oxidation resistance of composite. The composite shows three regimes of oxidation, first two being weight loss (Temperature: 763-933 K and 933-1073 K) and the third (1073 T 1423 K) being weight gain. First weight loss fraction corresponds to oxidation of free carbon in SiC matrix and follows half order reaction mechanism. Second weight loss fraction corresponds to oxidation of carbon fibers and is governed by 3-D diffusion mechanism. The weight gain in third regime is due to the formation of silica layer.