Crystallization-stabilization mechanism of yttria-doped zirconia by hydrothermal treatment of mechanical mixtures of zirconia xerogel and crystalline yttria

摘要

Mechanical mixtures of zirconia xerogel and crystalline Y_2O_3 were hydrothermally treated by microwave and traditional route, respectively. Some mixtures were used either as powders form or as cylindrical compacts isostatically pressed at 150MPa. The microwave-hydrothermal treatments were performed at 110, 150 and 200℃ for reaction times up to 2h, whereas the traditional hydrothermal treatments were performed at 110℃ at increasing reaction times up to 7 days. All the treatments were performed in the presence of diluted (0.2M) or concentrated (2.0M) solution of (K_2CO_3 + KOH) mineralizer. The crystallization-stabilization mechanism of synthesized Y-based zirconia powders and the reaction times for the full crystallization at the low temperature of hydrothermal treatments are discussed.