Surface Properties and Aqueous Processing of Rare Earth-Doped Ceria Powders by Coprecipitation Method

摘要

Rare earth (R)-doped ceria powders were prepared by heating oxalate coprecipitate. The structures of solid solutions of 20 mol% R_2Q_3 - 80 mol% CeO_2 were analyzed by the measurements of lattice parameters and powder densities. Rare earth elements were substituted for Ce ions with the formation of oxygen vacancy. The surface properties of the powders were characterized by electrophoretic mobility, sedimentation test and shear stress-shear rate relations of suspensions. The isoelectric points shiftted to higher pH with increasing dopant size. Y-doped CeO_2 powder was well dispersed in acidic suspensions than basic suspensions. Addition of polyacrylic ammonium in the basic suspensions was effective to disperse those particles and provided a high concentrated suspension of 40 vol% solids.