Sol-gel synthesis and characterization of zirconia and yttria stabilized zirconia powders

Powders of pure zirconia and zirconia containing 3 mol% yttria were prepared by sol-gel transformation followed by calcination techniques. The powders were characterized for their purity, chemical homogeneity, thermal behaviour, particle size, surface area, crystallite size and content of the tetragonal and monoclinic phases. The results show that as-prepared powders were of high purity, chemically homogeneous, X-ray amorphous and contained sub-micron particles. Addition of yttria increased the temperature stability of the tetragonal phase, while the critical crystallite size for the transformation remained unchanged. Yttria stabilized zirconia powders could be hotpressed to 97% theoretical density at 1450degC and the sintered body consisted of uniform 0.70 μm grains having about 45% tetragonal phase. (author). 20 refs., 5 figs., 3 tabs