Nanocarbon-dependent synthesis of one-dimensional bead-chain-like β-SiC

Thermodynamically, SiO2 should react with carbon to form CO and SiC at and above a temperature of 1515 °C. However, this reaction is incomplete at 1550 °C, even with the use of metastable reactants, such as amorphous SiO2 and active carbon powders. In contrast, complete decomposition of SiO2 is achieved at 1450 °C using nanocarbon powders instead of active carbon. Additionally, to clarify the effects of size and morphology of SiO2 on the SiC product, we synthesized different SiO2 precursors. Experimental results reveal that the effects of porous SiO2 on both the size and morphology of SiC particles are evident, but not a decrease in carbothermal reduction temperature. Nanocarbon powders reduce the temperature required for the reaction and also strongly affect the transformation kinetics.