Abstract
The Si3N4-SiC composites which is composed of Si3N4 matrix doped with 2wt% Al2O3 and 5wt% Y2O3, and 50wt% SiC powder having a different mean particle sizes, were fabricated by hot-pressing. Their oxidation behavior was investigated and compared with the commercial Si3N4 sintered material. An oxidation test was carried out in an electric furnace at 1300°C for 100 hours. The measurement of bending strength, weight gain, surface roughness and microscopic observation of sintered materials were carried out after oxidation. Weight gain of the Si3N4-SiC composite was lower than that of the commercial Si3N4 sintered material. The crystalline phases of sintered materials after oxidation test were β-Si3N4, α-SiO2, Y2O3⋅2SiO2 and SiC. The bending strength of Si3N4-SiC composites slightly increased the value after oxidation.
