Preparation and characterization of yttria stabilized zirconia minispheres by the sol-gel drop generation method

Near-net-shaped zirconia minispheres were prepared by a novel processing technique based on the sol-gel method. Yttrium was used as a stabilizing agent. Formation of minispheres was achieved in a setting solution by drop generation. The impact of the stabilizing agent on sintering conditions was analysed in detail. The spheres were crystallized into tetragonal phase at 472 °C, and the tetragonal phase was retained up to 900 °C. Maximum theoretical density (97%) was achieved for spheres sintered at 900 °C. Sintering temperatures higher than 900 °C led to the formation of monoclinic phase and reduction in density. The grain size and crystallite size were identified as 0.8 μm and 24 nm, respectively. The phase identification, density variation, chemical decomposition, functional group specification and microstruc-tural features of the dried and sintered final product were also studied Key words: sol-gel method; zirconia minispheres; sintering; X-ray diffraction; thermal analysis 1