Abstract
In order to develop the most suitable process for the preparation of low-oxygen SiC fiber, EB-cured PCS fibers were heated from room temperature to 1573K by using different combinations of heat treatment conditions such as heating rate, keeping temperature and keeping time. Subsequently, the fibers were exposed to 1873K in argon. While slow heating rate and long keeping periods were required for the improvement of thermal stability of fibers during heat treatment above 1200K, the heat treatment time could be shortened below 1200K. No change in specific resistivity and composition profile of fibers heat-treated under optimum conditions was observed before and after high-temperature exposure. In addition, fiber surface was dense and pore-free after high-temperature exposure. Consequently, the fibers showed a high level of strength both in the as-heat-treated state and after high-temperature exposure. For example, the tensile strength was 3.6GPa in as-heat-treated state and 2.2GPa after high-temperature exposure for the fiber which was prepared by heating at 600K/h below 1073K and at 50K/h above 1073K.
