Article ID Journal Published Year Pages File Type
1477377 Journal of the European Ceramic Society 2006 7 Pages PDF
Abstract

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 Y2O3 as 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 Y10Al2Si3O18N4 as 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.

Related Topics
Physical Sciences and Engineering Materials Science Ceramics and Composites
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