Effect of atmosphere on microstructural evolution of pressureless sintered Al2O3/SiC composites

Abstract

The effect of processing parameters, such as sintering atmosphere, SiC content, temperature and time of heat treatment, on densification and microstructural evolution of Al2O3/SiC composites has been investigated. Samples containing 5, 10, 20 and 30 vol% of SiC were treated at temperatures ranging from 1400° to 1750°C using Ar and N2 as sintering atmospheres. When sintering atmosphere is N2, carbothermal reduction was always observed. In Ar, partial oxidation of SiC was detected. In both atmospheres the extent of the reaction depended on the open porosity, which was controlled by the SiC content and heat treatment conditions.