Preparation of Nanocrystalline Zirconia Microspheres By Sol-Gel Process in Oil-in-Water Emulsion

Zirconia microspheres were prepared by a sol-gel process in oil-in-water emulsion.The effects of hydrothermal treatment and heat treatment on the crystalline structure and microstructure of the microspheres were analyzed by scanning electron microscopy,X-ray diffraction and thermogravimetric-differential thermal analysis,respectively.The results show that after the hydrothermal treatment,the spherical shape of the microspheres is not spoiled and the microspheres appear amorphous. When the heat-treatment temperature is 500℃,the tetragonal phase forms in zirconia microspheres,and the average grain size of tetragonal phase increases from 3.3nm to 14.5nm at 700℃.After heat-treatment at 900℃,the monoclinic phase in the zirconia microspheres is generated and the resulting grain size is 18.7nm.