Early-stage thermal oxidation (below 1100°C) of carbothermally synthesized β-sialon powder was monitored by X-ray powder diffraction, solid-state 29Si and 27Al MAS NMR spectroscopy, and thermogravimetry. No crystalline oxidation products were detected by XRD but 29Si and 27Al MAS NMR indicated the early formation of amorphous silica, followed by the formation of an amorphous aluminosilicate with an atomic environment similar to that of mullite. The initial oxidation was described by a linear kinetic law with an activation energy of 170 kj·mol -1, suggesting the rate-limiting step to be due to dissolution of O 2 in an amorphous silica surface layer on the β-sialon particles.
|Number of pages||3|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - 1998 Jan 1|
ASJC Scopus subject areas
- Ceramics and Composites
- Materials Chemistry