Synthesis of Ultrafine β-SiC Particles from SiO_x (x = 0, 1, 2) Powders and C₂H₂

Abstract

Ultrafine (u.f.) silicon carbide (SiC) particles were synthesized from SiO_x (x = 0, 1, 2) silicon (Si), silicon monoxide (SiO), or silica (SiO₂)) powders (1.0–3.0 μm) and acetylene (C₂H₂) in an electric furnace operated under an argon (Ar) atmosphere. The particle products were analyzed by scanning electron microscopy, X-ray diffraction analysis and thermogravimetry-differential thermal analysis. The u.f. particles (25–35 nm) of cubic SiC (β-SiC) could be produced through Si + C₂H₂, SiO + C₂H₂ or SiO₂ + C₂H₂ reaction. SiC selectivity was 43% for the Si/C₂H₂ System (C₂H₂/Si = 1.5), 79% for the SiO/C₂H₂ system (C₂H₂/SiO = 1.2), and 51% for the SiO₂/C₂H₂ system (C₂H₂/SiO₂ = 2.0). The tendency of the experimental results on SiC selectivity for the SiO/C₂H₂ system coincided with the theoretical curve based on thermodynamic equilibrium calculations.