Microstructure and Short‐Term Oxidation of Hot‐Pressed Si3N4/ZrO2(+Y2O3) Ceramics

Composite ceramic materials based on Si 3 N 4 and ZrO 2 stabilized by 3 mol% Y 2 O 3 have been formed using aluminum isopropoxide as a precursor for the Al 2 O 3 sintering aid. Densification was carried out by hot-pressing at 1650° to 1800°C, and the resulting microstructures were related to mechanical properties as well as to oxidation behavior at 1200°C. Densification at the higher temperatures resulted in a fibrous morphology of the Si 3 N 4 matrix with consequent high room-temperature toughness and strength.