Abstract: Coprecipitation supercritical fluid drying technology has been employed to synthesize calcia-stabilized zirconia ultrafine powder with low-cost inorganic salts as the starting materials. The sintering behaviors of these powders were also investigated. The results showed that supercritical fluid drying could effectively alleviate the hard agglomeration of grains during the gel drying process, and the morphology of the powder retained the network texture of the original gel. The resulting particles were characterized by small particle size (5~20 nm), better monodispersity and high surface area, which gave rise to high activity and sinterability. Consequently, these powders could readily be compacted into the desired shape and their densification could be carried out in shorter time and at lower temperatures. For instance, nanometer-sized powder calcined at 600ºC for 2 h could be cold-pressed into a green body and sintered at 1100º for 0.5 h to attain a dense body with bulk density of 5.9718 g/cm3 and specific pore volume of 0.0008 cm3/g.

Key words: Calcia-stabilized zircornia, Ultrafine powder, Supercritical fluid drying, Sintering