The ZrO₂ microspheres with a smooth surface have been successfully synthesized by a novel quasi-gaseous state reaction method. The scanning electron microscopy, transmission electron microscopy, and X-ray diffraction have been used to evaluate the structure of synthesized ZrO₂ microspheres. The calcination temperature has a significant effect on the structure: after they were calcinated at 600～800 ℃, the synthesized ZrO₂ microspheres possess the homogeneous porous structure with peanut-like nano-grains, which consist of major c-ZrO₂ and minor t-ZrO₂ phases.

Key words: ZrO₂ microsphere, quasi-gaseous state reaction method, calcination temperature, microstructure, phase composition