PREPARATION OF MONODISPERSE ZRO2 BY THE MICROWAVE-HEATING OF ZIRCONYL CHLORIDE SOLUTIONS

Based on the principle that the solubility of a salt decreases as the dielectric constant of the solvent decreases, zirconia powders were prepared by heating a zirconyl chloride solution with a 2-PrOH-water mixture as the solvent, The morphology, size, and size distribution of the resulting particles were highly sensitive to the heating method used on the starting solution. Particles formed under conventional heating methods were polydisperse, agglomerated spherical, or irregularly shaped because of inhomogeneous precipitation through the temperature gradient, the shear force induced by stirring, compositional nonuniformity, and the low heating rate, The present study demonstrated that microwaves provide an excellent means of heating uniformly and rapidly without stirring, The particles resulting from microwave treatment were monodisperse and spherical, with a mean diameter of 0.28 mu m.