Effect of Sintering Atmospheres on the Processing of SiC/AlN Ceramic Composites

In an attempt to provide a new advanced carbide/nitride ceramic material with high sinterability and density for high-temperature and solar energy applications, this work inspected the effect of different sintering atmospheres on the processing of near-fully dense SiC/AlN ceramic composites. Several SiC/AlN (0 – 40 wt.%) composites were produced by pressureless sintering at a temperature of 2080°C for 2 hrs using a sintering additive of 2.5% yttria + alumina. Influences of argon/vacuum and nitrogen/vacuum atmospheres on the reaction response and the densification behavior of SiC/AlN composites were examined and analyzed. Results show that sintering of SiC/AlN ceramics in a nitrogen atmosphere increases mass loss of the different composites during sintering and leads to a decrease in their densification parameters. However, sintering in an argon atmosphere promotes both the sintering and densification processes, making argon atmosphere more convenient for sintering SiC/AlN ceramics. The use of SiC/AlN composites prepared by pressureless sintering is suitable for high-temperature applications.