Effect of Temperature and Oxidizing Medium on the Properties of Silicon Carbide Fiber

We have studied the effect of heat treatment in an oxidizing medium and under vacuum on the properties of Russian-made silicon carbide fiber. The fiber has been characterized by a variety of physicochemical analysis techniques, including scanning electron microscopy, Raman spectroscopy, IR spectroscopy, and X-ray diffraction, before and after heat treatment under vacuum and in air. The kinetics of fiber oxidation in air have been studied in the range 900–1000°C. The activation energy for the oxidation process has been determined to be 72.0 ± 7.8 kJ/mol. The tensile strength of the fiber has been determined before and after heat treatment in different media. The results demonstrate that heat treatment under vacuum and in an oxidizing medium causes substantial degradation of the properties of the fiber.