PREPARATION OF TETRAGONAL ZRO2-GD2O3 POWDERS

ZrO2-Gd2O3 alloys containing 2, 3, 5 and 8 mol. % Gd2O3 have been prepared by mixed oxide (MO), hybrid sol-gel(SG), and co-precipitation (CP) routes. No tetragonal (t) phase is retained in the MO method, while 100% t phase is obtained in the calcined CP samples; the SG method leads to on ly partial stabilization of the t phase. Washing of the CP powders with propan-2-ol leads to unagglomerated powders with increased specific surface area (145 versus 89 m(2)g(-1)) and sintered density (98% versus 79%). Cubic and t' phase also appear on sintering the samples with >2 mol. % Gd2O3.