Colloidal formation of monodisperse YSZ spheres: Kinetics of nucleation and growth

Sub-micrometer monodisperse spherical yttria-stabilized zirconia (YSZ) particles were synthesized with a narrow size distribution, through a colloidal precipitation synthesis process. The narrow particle size range was achieved by controlling the kinetics of nucleation and growth of the particles in a composite precursor solution. The effect of a crucial variable, water to alkoxide ratio, on the formation of spherical colloid particles was determined. An alcohol-based yittria–zirconia (YZ) sol was prepared with enough hydrolysis water to initiate the nucleation of nanosize YZ particles. The results suggest that further growth of the particles was induced in the presence of excess water (growth stage), where YZ colloidal particles were dissolved partially, and subsequently precipitated on the larger preformed spheres. The amorphous spherical particles produced were then heat treated to obtain cubic YSZ. The crystallinity and microstructure of the YSZ particles obtained were evaluated.