Significant improvement of ultra-high temperature oxidation resistance of C/SiC composites upon matrix modification by SiHfBCN ceramics

Advanced C/SiC-SiHfBCN composites were prepared by modification of the matrix of C/SiC composites with single-source-precursor derived SiHfBCN ceramics. Ultra-high temperature oxidation behavior of the C/SiC-SiHfBCN composites under laser heating were systematically studied. The influence of temperature, preform structure and precursor on oxidation resistance of the composites were analyzed. The results revealed that the preform structure and precursor can influence the oxidation behavior of C/SiC-SiHfBCN composites by effecting its thermal conductivity in the thickness direction. The Hf-containing oxide layer formed during ultra-high temperature oxidation test can effectively protect the internal carbon fibers from being oxidized. Linear ablation rate of C/SiC-SiHfBCN composites was more than an order of magnitude lower than that of other reported C/SiC composites, indicating an enhanced ablation resistance of the C/SiC-SiHfBCN composites.