Sintering of Si₃N₄-SiC Whisker Composite

Abstract

Si₃N₄-SiC whisker composites with whisker content up to 30wt% were prepared by heating 1700° to 2000°C for 60min in 1MPa N₂. Fully dense composites were obtained at 2000°C. The optimum content of sintering aids, Y₂O₃ plus La₂O₃, was 20 and 30mol% for the whisker content of 10 and 20wt% respectively. The room temperature bending strength were 596 and 560MPa for 10 and 20wt% additions of whisker, respectively. Moreover, these composites had strengths more than 80% of the room temperature value at 1300°C. Improvement in the strength was achieved by using sieved whisker.