High Yield Silicon Carbide Whiskers from Rice Husk Ash and Graphene: Growth Method and Thermodynamics

A new stacking bed method to prepare high-quality silicon carbide whiskers (SiCws) with high yield has been proposed. To provide a steady and high concentration SiO atmosphere during the carbothermal reaction, the mixture of graphene and rice husk ash is used as a SiO generator, which is different from the traditional methods using sole silicon sources. The as-prepared whiskers, growing along the direction of [111], show a diameter of 30–120 nm. SiCws obtained by the optimized approach exhibit a higher stacking fault (SF) density. As indicated by thermal gravimetric mass spectrometry results, SiO gas is a key factor affecting the yield and SFs of SiC whiskers. Furthermore, combined with the chemical reaction thermodynamics, the growth mechanism of whiskers is presented following the vapor–solid mode. This contribution provides new insights into the industrial production of high value-added carbide whiskers.