Long-time oxidation resistance of KD-SiC fibers with different composition and structure in air atmosphere

Abstract

Continuous silicon carbide (SiC) fibers, as reinforcement of ceramic matrix composites, have broad application prospects in the fields of aviation, aerospace and nuclear energy. Three typical KD-SiC fibers were adopted to explore the relationship of the composition and structure with their long-term oxidation (1–100 h) resistance in air environment. The mechanical strength retention of the nearly stoichiometric polycrystalline SiC fiber (C-1) was generally higher than that of the SiC fiber (C-3) with excess carbon and low oxygen, also higher than the nearly stoichiometric SiC fiber (C-2), especially under oxidation conditions of higher temperature and longer holding time. By comparing the high-temperature resistance with oxidation resistance at 1200–1600 °C, it was found that the oxidation reaction was the dominant factor affecting the mechanical properties. This work could provide theoretical and practical references for improvement of oxidation resistance of SiC fibers and their composites.