Thermal expansion study of spinel-sialon

Abstract The thermal expansion behaviour of a high pressure-derived spinel sialon ( γ -Si 3− x Al x O x N 4− x ) with a single composition x = 1.1 (and its low-pressure pendant with β -Si 3 N 4 structure) was studied between room temperature and 1220  ° C, using X-ray diffraction at a synchrotron radiation source and a halogen mirror furnace. No evidence for a phase transformation or decomposition of the spinel-sialon was found, thus demonstrating a good metastability of this novel hard material.