一种具有稳定富碳表层的SiC纤维的制备与性能

采用不饱和烃不熔化处理后的聚碳硅烷（PCS）纤维经高温烧成可制得一种新型的SiC纤维,纤维的抗张强度达2.5~2.8GPa,氧含量4wt%~6wt%,电阻率仅为0.5Ω·cm左右,大大低于采用传统空气不熔化方法得到的SiC纤维.研究表明:该纤维表面存在厚度约50nm的富碳层,并且在Ar气中进行高温热处理后,表面富碳层结构无明显变化.与日本通用级SiC纤维Nicalon NL202 相比,纤维的耐热性提高200~300℃.纤维具有低电阻率稳定性,从室温到1600℃,其电阻率始终保持在0.4~0.8Ω·cm.

Preparation and Properties of SiC Fiber with a Stable Excess Carbon Layer on the Surface

A new SiC fiber was prepared by the pyrolysis of polycarbosilane (PCS) fiber cured with unsaturated hydrocarbons. The fiber with oxygen content of 4wt%-6wt%, has high tensile strength of 2.5-2.8GPa. The specific resistance of the fiber is only about 0.5Ω·cm, which is much lower than general SiC fiber obtained from traditional air curing process. Results show that the fiber has an excess carbon layer with a thickness of about 50nm in the circular outer part, and the layer changes little after thermal exposure in argon. Compared with the ceramic grade fiber Nicalon NL202, thermal resistance to degradation of the fiber's mechanical property is improved by 200-300℃. The low specific resistance of the fiber also exhibits excellent thermal stability, which almost remains at 0.4-0.8Ω·cm after thermal exposure test from the room temperature to 1600℃ in argon.