In situ growth of SiC nanowires by carbothermal reduction using a mixture of low-purity SiO2 and carbon

Carbothermal process parameters such as powder mixing ratio, temperature, holding time and gas flow rate, which affect on the reasonable growth rate of SiC nanowires were investigated using a mixture of low-purity SiO2 containing iron component and carbon in this study. SiC nanowires are being grown at 1400 degrees C for 2 h in an argon flow rate of 2 L/min by a vapor-liquid-solid (VLS) process, which produces a very high-purity product with about 60 nm and several hundreds of micrometers in diameter and length, respectively. This is attributed to the migration of the iron out of the low-purity SiO2 material as finely divided iron-rich droplets acting in the role of catalyst for the architecture of a SiC one-dimensional structure. The growth rate of SiC nanowires increased with increasing holding time and flow gas rate, inducing the supersaturation degree to become lower. (C) 2007 Elsevier B.V. All rights reserved.