Emulsion Precipitation and Characterization of Zirconia

Abstract

ABSTRACTZirconia and yttria-stabilized zirconia (YSZ) powders were prepared from water/oil emulsions followed by high temperature calcination. The morphology and particle size were correlated with several variables such as composition of emulsions, concentration of starting materials and surfactants, stirring rate, hydrolysis rate and calcination temperature. The powders were characterized according to crystalline phase, particle size distribution, and flow rate. Emulsion precipitation typically yielded spherical zirconia particles which were either solid or hollow. Particle size could be controlled from submicron to a few hundred microns depending primarily on the composition of the emulsion and stirring rate during hydrolysis. SEM/EDX results showed that yttria was uniformly distributed throughout the zirconia particles. The crystalline phase of the powders after calcination at 800°C was entirely non-transformable tetragonal. The flow rate increased with increasing particle size and with increasing sphericity.