Abstract
The Si3N4-ZrO2 composite was fabricated by sintering at 1500°-1700°C using Y2O3 and Al2O3 additives. The needle-shaped particles precipitated in the sintered body. They were identified as α-Si3N4 single crystal whiskers by EPMA and TEM observation. The growth of whiskers depended on the amount of additives and the purity of starting powders. It was obvious that the transformable t-ZrO2 and the precipitation of the whiskers contributed to the enhancement of the fracture toughness.
