Large-Bulk Solidified Al<sub>2</sub>O<sub>3</sub>-ZrO<sub>2</sub>(Y<sub>2</sub>O<sub>3</sub>) Prepared by Self-Pressure Assisting Combustion Synthesis under High Gravity

Abstract

By introducing self-pressure processing into combustion synthesis under high gravity, Al2O3-ZrO2(4Y) eutectic composite ceramics without shrinkage cavities and holes were achieved, and the self-pressure processing also made the macro-crack be controlled and the ceramic densification be promoted evidently. XRD results showed the eutectic ceramics were composed of α-Al2O3, t-ZrO2 and a few m-ZrO2 phases, and the volume fraction of the transformable t-ZrO2 increased with self-pressure force increasing. SEM images showed that with increasing self-pressure force, the rod-shaped eutectic colonies were refined and the volume fraction of the colonies increased. Meanwhile, the irregular ZrO2 crystals around eutectic colonies transformed to be fine t-ZrO2 spherical crystals gradually, and thickness of eutectic colonies decreased. With the changes in microstructures of the ceramics, the mechanical properties of the ceramics were improved greatly.