Long-term oxidation resistant SiC/SiC-SiHfBCN composites: A promising thermo-structural material aims for hypersonic roundtrip

To expand the application of silicon carbide (SiC) fiber reinforced SiC (SiC/SiC) composites in the field of thermal protection systems (TPS) for reusable hypersonic vehicles, SiC/SiC-SiHfBCN composites was prepared by Chemical Vapor Infiltration combined with Polymer Infiltration and On‐line Pyrolysis (CVI+PIOP) process. The influence of PIOP process on microstructure and elemental composition of SiHfBCN ceramics were revealed. Weight change behavior, bending performance, microstructure evolution and micro-mechanical properties of the samples after oxidation in air for 100 h up to 1500 °C were investigated to evaluate the oxidation resistance of the SiC/SiC-SiHfBCN composites. It was found that SiC-SiHfBCN matrix performs outstanding oxidation resistance and self-healing capability, so that the SiC/SiC-SiHfBCN composites has the potential to be employed as TPS for vehicles performing hypersonic roundtrip.