SiC fiber with low electrical resistivity and oxygen content

Abstract

A new SiC fiber was prepared by the pyrolysis of polycarbosilane (PCS) fiber cured with unsaturated hydrocarbons. The fiber, with oxygen content of 4–6 wt%, offers high tensile strength of 2.5–2.8 GPa. The electrical resistivity of the fiber is only about 0.5 Ω·cm, much lower than general SiC fiber obtained from traditional air curing process. Degradation of mechanical property in argon and air at high temperature is retarded by 200–300°C with respect to the Nicalon NL-202 fiber. The low electrical resistivity of the fiber exhibits excellent thermal stability, it almost remains 0.4–0.8 Ω·cm after thermal exposure test from the room temperature to 1600°C in argon. The low electrical resistivity mainly attribute to an excess carbon layer which is about 50 nm in the circular outer part.