Effects of ZrC coating on mechanical properties of PIP-C/SiC composites

Owing to the degradation of mechanical properties of carbon fiber reinforced SiC matrix (C/SiC) composites under oxidation environment, single layer ZrC coating prepared by molten salt method process were employed. A KCl-NaCl-Zr-K2ZrF6 salt mixture was used as reaction medium, Zr reacted carbon fibers to form ZrC coating. The structure and morphology of ZrC coating were characterized by XRD, SEM and EDS analyses. Effects of ZrC coating on mechanical properties and anti-oxidation capability of C/SiC composites fabricated by precursor infiltration and pyrolysis (PIP) process were investigated. The results showed that a uniform, adherent and crack-free ZrC coating was obtained. ZrC-coated C/SiC composites showed brittle fracture behavior and better oxidation resistance. Even after thermal shock tests, the original structure of ZrC-coated C/SiC composites was not destroyed, which showed a higher mechanical properties.