Synthesis of Silicon Carbide Nanofibres Using Simple Chemical Vapour Reaction

Abstract

The reaction between SiO and CO vapours in an argon atmosphere has been employed for the synthesis of SiC nanofibres. The raw materials for the vapour-state formation were silicon and graphite powders; during heating at high temperatures (1523 K), SiO and CO vapours were generated from reaction between silicon and graphite powders and residual oxygen in the chamber. By this simple process, SiC nanofibres with diameters ranging from 10 nm to 100 nm and the lengths more than 10μm have been grown on a graphite substrate with a large area and high surface density. The nanofibres consisted of coaxial two-phase structures: a crystalline β-SiC core and an amorphous silicon oxide (SiO₂) shell. Thus, possible reaction for the growth of coaxial SiC/SiO₂ nanofibres was the following: 2SiO(g) + 2CO(g)(s) + SiO₂(s) + CO₂(g). The basic growth direction of nanofibres was the 111 of crystalline β-SiC core with a high density of microtwlns and stacking faults perpendicular to this growth direction. These nanofibres were synthesized by a vapour-liquid-solid (VLS) growth mechanism using iron catalyst. The process described appears to be suitable for mass production, and provides a potential technique for synthesizing SiC nanofibres.