HREM observations of the synthesized process of nano-sized SiC by ball milling of Si and C mixed powders

The synthesis of nano-sized SiC through ball milling (BM) of elemental Si and graphite mixed powders at room temperature has been reported, and detailed reaction process has been characterized by high-resolution electron microscopy (HREM). High-resolution electron microscopy (HREM) observations presented herein suggest that amorphous graphite (a-graphite), amorphous silicon (a-Si) and nano-sized crystalline Si (c-Si) with many defects are produced during BM, which is prerequisite to the reaction. In some areas, SiC is synthesized through a diffusion of C atoms into the a-Si/and c-Si. In the former, a-Si(C) forms, and then mechanically-driven crystallization of the a-Si(C) occurs to form SiC. In the latter, C atoms directly replace Si atoms to form SiC with an orientation relationship of (111)SiC//(111)Si. In other areas, localized self-sustained reaction occurs to form slightly larger SiC grains.