Near room temperature synthesis of ceria-zirconia solid solution by solid phase reaction

The surprisingly low temperature (similar to 323 K) synthesis of the ceria-zirconia solid solution upon milling ceria powder with zirconia mill and zirconia balls (in ethanol and/or water) was studied. Solid solutions up to 60 mol%ZrO2 were obtained, whose formation was proved to result from solid phase reaction between ceria and zirconia powders, enhanced by contact stress (either shear or compressive one). Furthermore, the occurrence of large plastic deformation, breaking and mutual combining was found on the ceria powder before and after solid solution. The grain size of ceria-zirconia solid solution was less than or equal to 20 nm, which would cause on easy rearrangement of low diffusion atoms of cerium and zirconium to form the solid solution at such a low temperature. In addition, the possible existence of a solid solution for which the migration of the constituents is much faster (or the stability of the solid at the composition is much higher) than that of other composition, was suggested around 50 mol%CeO2-50 mol%ZrO2.