화학공학소재연구정보센터
Journal of Materials Science, Vol.31, No.9, 2367-2371, 1996
Synthesis of Silicon-Carbide Whiskers Using the Vapor-Liquid-Solid Mechanism in a Silicon-Rich Droplet
SiC whiskers can be produced from 1350-1500 degrees C by carbothermal reduction of the silica in a fixed bed percolated by a hydrogen flow. At 1450 degrees C and above, the addition of iron to the silica-carbon mixture leads to the formation of submicrometre whiskers in the bed, ending with a silicon-rich droplet. The iron has evaporated and condensed at a lower temperature, a few centimetres downstream from the bed, allowing the formation of silicon carbide whiskers ending with an iron droplet according to the vapour-liquid-solid (VLS) mechanism. Submicrometre whiskers are also obtained without iron over a broader range of temperatures. Silicon carbide whisker production in a fixed bed is then possible using a (VLS) mechanism in a silicon-rich droplet and may be controlled without the addition of transition metals, thus improving the purity.