Effects of TiO2 on the microstructure and mechanical properties of Al2O3/ZrO2 composites

Abstract

The microstructure and mechanical properties of hot-pressed zirconia-toughened alumina (ZTA), fabricated from the ZTA powders containing (Zr, Ti)O2 in Ar gas were investigated. In hot-pressed ZTA, the presence of Ti concentration in the grains of Al2O3 or (Zr, Ti)O2 was analyzed by the energy dispersive spectroscopy (EDS) attached to the analytical electron microscope (AEM) apparatus. Experimental results showed that some Ti ions diffused to the grain boundary and into the Al2O3 grains, thereby enhancing the densification of hot-pressed ZTA. It was possible to retain tetragonal ZrO2 at room temperature in the ZTA specimens containing ≥5.5 mol% TiO2 and hot pressed at 1350 °C for 1 h. The bending strength and toughness of hot-pressed ZTA were enhanced by the addition of TiO2.