This paper describes the results of the investigation of the oxidation behaviour of 50 wt.% SiC-50 wt.%AlN composites obtained by means of pressureless sintering with Y2O3as sintering-aid and without using a powder bed to limit the weight loss. Sintered bodies show high density (>98%T.D.) and the microstructure reveals a matrix composed by SiC-AlN solid solution with Y10Al2Si3O18N4as grain boundary phase. This material exhibits a parabolic oxidation kinetic in the temperature range 1200-1500 °C. Long term oxidation (200 h) induces the formation of a protective oxide scale, composed by mullite, cristobalite and yttrium disilicide, up to 1400 °C. At higher temperature (1500 °C), SiC oxidation behaviour changes from "passive" to "active" and the oxide layer consequently shows porosity due to the formation of gaseous species like SiO and CO. © 2005 Elsevier Ltd. All rights reserved.
|Pages (from-to)||3407 - 3413|
|Number of pages||7|
|Journal||Journal of the European Ceramic Society|
|Publication status||Published - 2006|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry