Phase stability, microstructural evolution and room temperature mechanical properties of TiO2 doped 8 mol% Y2O3 stabilized ZrO2 (8Y-CSZ)

The effect of TiO2 dopant on phase stability, microstructural evolution and room temperature mechanical properties of 8 mol% yttria-stabilised cubic zirconia (8Y-CSZ) was studied. The results showed that TiO2 (up to 10 wt%) can be dissolved in solid solution in the zirconia matrix. When the dopant amount was < 5 wt%, TiO2 doped 8Y-CSZ remained single phase cubic zirconia. Increased additions of TiO2 destabilised the cubic phase and caused the formation of tetragonal zirconia with a resultant microstructure consisting of large cubic zirconia grains and small tetragonal zirconia grains. EDS showed that yttria was partitioned between these two types of grains. The solubility of TiO2 was highest for cubic grains which also had higher yttria concentrations. Room temperature mechanical property measurements showed that hardness did not change significantly with additions of TiO2, but fracture toughness was more than doubled for 10 wt% TiO2 doped 8Y-CSZ. 22 refs.