METASTABLE PHASE-FORMATION IN THE TIO2-ZRO2 AND CDO-ZRO2 SYSTEMS

Samples of zirconium oxide doped with titanium oxide or cadmium oxide, prepared as a divided state, were examined to investigate the effect of the foreign ions on the zirconia phase transition. Thermal treatmen ts (1173 K in H-2 for TiO2-ZrO2; 1073 K in air for CdO-ZrO2) caused th e incorporation of titanium or cadmium in solid solution in the zircon ia structure (tetragonal or cubic metastable phases). The solid soluti on formation hindered the retragonal --> monoclinic transformation tha t takes place in undoped ZrO2 during the cooling step.