Single-source-precursor derived SiHfBCN enhancing oxidation resistance of SiC/SiC composites in wet oxygen

Abstract

Semi-dense SiC fiber reinforced SiC (SiC/SiC) composites were modified by single-source-precursor derived SiHfBCN ceramics to obtain SiC/SiC-SiHfBCN composites with enhanced wet oxidation resistance. Wet oxidation behavior of SiC/SiC-SiHfBCN composites at 1200–1400 ℃ in different atmospheres were investigated. It was found that the SiC-SiHfBCN ceramic matrix can provide at least 100 h of damage-free protection for SiC fibers up to 1300 ℃ in wet oxygen. HfSiO4 with low oxygen diffusivity is found on the surface of SiC/SiC-SiHfBCN composites after oxidation, which is discussed in terms of diffusion of HfO2 from the bulk to the surface via liquids.