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 a nd graphite mixed powders at room temperature has been reported, and detail ed reaction process has been characterized by high-resolution electron micr oscopy (HREM). High-resolution electron microscopy (HREM) observations pres ented herein suggest that amorphous graphite (a-graphite), amorphous silico n (a-Si) and nano-sized crystalline Si (c-Si) with many defects are produce d during BM, which is prerequisite to the reaction. In some areas, SIC is s ynthesized through a diffusion of C atoms into the a-Si/and c-Si. In the fo rmer, a-Si(C) forms, and then mechanically-driven crystallization of the a- Si(C) occurs to form SIG. In the latter, C atoms directly replace Si atoms to form SIC with an orientation relationship of (111)(SiC)//(111)(Si). In o ther areas, localized self-sustained reaction occurs to form slightly large r SIC grains. (C) 2001 Elsevier Science B.V. All rights reserved.