1993 Volume 101 Issue 1180 Pages 1379-1383
The pyrolysis of the low oxygen (1.7% O) SiC fiber prepared by the electron-irradiation curing method has been investigated. The pyrolytic rate was measured with a thermobalance in Ar at temperatures from 1673 to 1973K. The pyrolyzed fiber was examined by X-ray diffraction, SEM observation, specific resistance measurement and tensile test. Lowering of oxygen content in the fiber was found to be effective for the suppression of pyrolysis. The pyrolyzed fiber was composed of β-SiC and amorphous carbon. The growth and coarsening of SiC crystals were observed on the skin of the fiber, while the core was smooth and remained in the microcrystalline state. The tensile strength of the fiber, which was heated at 1973K for 3.6ks, retained 34% of that of the original fiber. The strength was correlated closely with the size of the β-SiC crystal in the fiber.
