Effect of Curing Methods on the Mechanical Property of SiC Fiber Prepared via Hydrogenation

Abstract

Two different polycarbosilane (PCS) fibers were prepared by a new oxygen-free curing method and Chemical Vapor Curing (CVC), respectively. Nearly stoichiometric SiC fiber was prepared via hydrogenation in H2-N2 mixture and subsequent sintering in inert gases. The green PCS fiber and nearly stoichiometric SiC fiber were characterized by FT-IR, XRD, SEM etc. Meanwhile, the effect of hydrogenation on the thermal stability of SiC fibres cured by CVC method was studied. It was found that the oxygen-free curing method can effectively decrease the content of oxygen in the final SiC fiber, while the hydrogenation treatment can dramatically diminish the content of free carbon, so the nearly stoichiometric SiC fiber with C/Si atomic ratio being 1.06 can be obtained. After the heat-treated at 1600°C in inert gases, the strength retaining ratio of the oxygen-free cured SiC achieved 68%, demonstrating that the nearly stoichiometric SiC fiber possesses excellent high-temperature stability and higher anti-oxidation property.