Formation of AlN-polytypoid phases during {alpha}-SiAlON decomposition
- Monash Univ., Melbourne (Australia). Dept. of Materials Engineering
Phase transformations from {alpha}- to {beta}-SiAlONs (i.e., from {alpha}{prime} to {beta}{prime}) have been recently reported in a number of rare-earth SiAlON systems during postsintering heat treatment. In the present work, this transformation process in a Sm ({alpha} + {beta})-SiAlON material is studied by using XRD, TEM, and EDS X-ray mapping techniques. It is observed that in addition to the formation of {beta}{prime} and M{prime} phases, the {alpha}{prime}-to-{beta}{prime} transformation is accompanied by a significant increase in the amount of an AlN-polytypoid phase. The results suggest that some {alpha}{prime} phases are thermodynamically unstable at temperatures lower than the material sintering temperature and will decompose when conditions allow. For the composition studied in this work, the {alpha}-SiAlON decomposition can be described in general as {alpha}{prime} {yields} {beta}{prime} + M{prime} + AlN polytypoid.
- Sponsoring Organization:
- Australian Research Council, Canberra, ACT (Australia)
- OSTI ID:
- 554030
- Journal Information:
- Journal of the American Ceramic Society, Vol. 80, Issue 9; Other Information: PBD: Sep 1997
- Country of Publication:
- United States
- Language:
- English
Similar Records
Melilite formation in a samarium-stabilized {alpha}-sialon ceramic during postsintering heat treatments
Reaction densification of {alpha}{prime}-SiAlON. 2: Densification behavior