Formation of SiC Whiskers from system of SiO2-Al2O3 Block and Carbon Block under Reducing Atmosphere

초록

Silicon carbide whiskers could be formed on the surface of a carbon block, placed in the mullite block chamber under the hydrogen gas by VLS mechanism at elevared temperatures. The whiskers, formed at lower temperatures, were uneven in diameter due to stacking faults. But those at higher temperatures, were uneven in diameter due to stacking faults. But those at higher temperature were smooth and even on the surface. The reducing gas species such as methane, silicon suboxide and carbon monooxide were newly generated in the process by the hydrogenation of carbon and thermal deposition of silica. The decomposition of mullite was accelerated by increasing either the temperature up to 1500oC or the contact area of carbon with hydrogen gas.