Critical Particle Size for the Formation of Ceria-Zirconia Solid Solution by Solid Phase Reaction near Room Temperature Estimated from Average Particle Size

Abstract

The formation of ceria-zirconia solid solution by the solid phase reaction of ceria and zirconia powders near room temperature during wet attrition milling was recently reported. The solid phase reaction occurred as a result of a large plastic deformation, breaking and mutual combining on the ceria particle as well as the solid solution. The size of the particle in which the solid phase reaction can occur was examined in this study. The reaction that forms ceria-zirconia solid solution from large ceria particles (4m²/g) begins when the average particle size reaches 28nm or smaller. The reaction does not occur in CeO₂ powder with particle size larger than 30nm. The critical particle size of ceria powder to begin the reaction with zirconia is thought to be approximately 20nm, which was found asymptotically by two methods, X-ray diffraction and specific surface area measurements.