Isothermal Tetragonal-to-Monoclinic Phase Transformation in Y_2O_3-Partially Stabilized Zirconia: The Influence of Grain Size

摘要

Phase transformation in ZrO_2-2mol% Y_2O_3 ceramics, with average grain sizes of 0.51 to 0.96 μm, was investigated to explore the influence of grain size on isothermal phase transformation associated with the low-temperature degradation during ageing in different environments (water and vacuum). Contrary to expectations, water-assisted phase transformation did not accelerate monotonously with increasing grain size. Such interesting results can be explained satisfactorily by a new model of phase transformation, which emphasises a synthetic grain-size effect on the nucleation process and the intrinsic phase stability.