Physical characteristics and sintering behavior of ultrafine zirconia–ceria powders

Ultrafine zirconia–12 mol% ceria powders have been prepared by the coprecipitation technique. The azeotropic distillation with n-butanol has been carried out to ensure complete elimination of the residual water in the precipitate. This procedure has proved to be quite effective in preventing the formation of agglomerates, which are responsible for inhomogeneities in the sintered microstructure, and for non-densification at low temperatures. The crystallization of the solid solution occurs at 430 °C as determined by thermal analyses. The specific surface of the calcined powder is 127.9 m2 g−1 and the pore size distribution exhibits only a maximum at approximately 9 nm. Total shrinkage of the compacted powder reached 30% at 1200 °C. Sintered specimens show six bands characteristics of the tetragonal phase in the Raman spectrum. Specimens with apparent densities >95% of the theoretical density and average grain size of 230–400 nm were obtained after sintering at 1200 °C.