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-stabilized cubic zirconia (8Y-CSZ) was studied. The results show that TiO2 (up to 10 wt%) can be dissolved in solid solution in the zirconia matrix. When the dopant amount is less than 5 wt%, TiO2 doped 8Y-CSZ remains single phase cubic zirconia. Increased additions of TiO2 destabilize the cubic phase and cause the formation of tetragonal zirconia with a resultant microstructure consisting of large cubic zirconia grains and small tetragonal zirconia grains. EDS analyses show that yttria is partitioned between these two types of grains. The solubility of TiO2 is the highest for cubic grains which also have higher yttria concentrations. Room temperature mechanical property measurements show that hardness does not change significantly with additions of TiO2, but fracture toughness is more than doubled for 10 wt% TiO2 doped 8Y-CSZ.