High temperature synthesis of Si-based nanomaterials from silica rich oxide

Silicon based nanoparticulates were produced by smelting reduction method including a high temperature carbothermic reduction of silica-rich SiO ₂-Al₂O₃-CaO melt to SiO and transfer of the SiO vapor with an Ar carrier-gas to cooler parts of experimental reactor where the vapor was condensed and deposited as nanostructures of different morphology. The obtained nanostructures were characterized with XRD, SEM, TEM and EDX/WDX. The amorphous SiOx nanoparticles of 30-50 ran in diameter were deposited at locations of lower temperatures, T < 920 K. The SiC nanowires were grown under high temperature conditions, T > 1320 K. The nanowires had diameter ranging from 20 to 60 nm and length up to several micrometers. The high temperature deposit included particles of crystalline Si with diameter ranged from 20 to few hundred nanometers. At the intermediate temperature range, nanoparticles formed chains and agglomerates containing all the above phases.