Effect of Thermal Treatment on Microstructure and Phase of Partially-stabilized Zirconia

ZrO2-MgO-Y2O3-CaO-Al2O3 composites with a multiphase microstructure were fabricated by die pressing process and sintered at various thermal programs. The microstructure of this polycrystalline was examined to clarify the role of Al2O3 on grain growth. Environmental scanning electron microscopy (ESEM) micrographs revealed that spinel was beneficial to refine grain. The effect of thermal treatment on the formation of monoclinic phase was discussed. It can be found that, the grain size and the fraction of the monoclinic phase in this partially stabilized zirconia(PSZ) increases after heat treatment at 1 150 ℃. The temperature of heat- treatment, not the time for holding, is the governing factor of the fraction of monoclinic phase.