Properties of polycarbosilane-derived silicon carbide fibers with various C/Si compositions

SIC fibers with various C/Si compositions have been synthesized by the use of an irradiation-curing process. The polycarbosilane(PCS) fibers were cure d by irradiation with an electron beam in a helium atmosphere. After curing , the fibers were pyrolyzed at 1573 K under controlled conditions, and SIC fibers with C/Si of 0.84 to 1.68 were obtained. The chemical composition of the fibers was <1 wt% 0, <0.2 wt% N, <0.1 wt% H, and balance of Si and C. Physical and mechanical properties, crystalline growth behavior under therm al exposure, oxidation resistance, and creep properties at elevated tempera ture were examined. As a result, these fibers are revealed to have quite di fferent properties with different C/Si chemical compositions. (C) 1999 Else vier Science Ltd. All rights reserved.