Microstructural characterization of nanocrystalline SiC synthesized by high-energy ball-milling

摘要

Carbide preparation in a conventional route requires a huge instrumentation regarding melting the metal and graphite under vacuum at a very high temperature. However, nanocrystalline metal carbides can be easily produced by mechanical milling of powder ingredients at room temperature. This article reports on the preparation and microstructural characterization of nanocrystalline SiC by mechanical milling of Si and graphite powders under inert atmosphere at room temperature. XRD patterns of ball-milled powders clearly reveal that the SiC phase is initiated after 5 h of milling and the stoichiometric SiC is formed after 15 h of milling. Microstructure in terms of different lattice imperfections of ball-milled samples is characterized by employing Rietveld's method of structure refinement. The phase transformation kinetics studied through Rietveld's method reveals that crystalline Si powder is converted into amorphous Si during ball-milling and SiC phase is formed through the solid-state reaction of nanocrystalline graphite and amorphous Si powders during ball-milling.