THE EFFECTS OF TIO2 ADDITION ON THE MICROSTRUCTURE AND TRANSFORMATION OF ZRO2 WITH 3 AND 6 MOL-PERCENT Y2O3

Up to 30 mol.% TiO2 was added to ZrO2 with 3 and 6 mol.% Y2O3 and sintered in air at 1600°C for 4 h. The contents and lattice parameters of cubic (c-) and tetragonal (t-) ZrO2 were determined by X-ray diffraction. The solution of TiO2 is found to stabilize the t-ZrO2 phase but destabilize the c-ZrO2 phase. The solubility of TiO2 in t-ZrO2 in ZrO2-3mol.%Y2O3 is about 14-16 mol.% and in c-ZrO2 in ZrO2-6mol.%Y2O3 is about 18 mol.% at 1600°C. The grain size of both c- and t-ZrO2 increases with TiO2 addition. The Ms temperature of the tetragonal-to-monoclinic ZrO2 martensitic transformation was lowered by TiO2 by a cold stage study. © 1990.