Effect of Nd2O3 concentration on the defect structure of CeO2-Nd2O3 solid solution

An extensive X-ray study of CeO(2)-Nd(2)O(3) solid solutions was performed, and the densities of solid solutions containing various concentrations of NdO(1.5) were measured using several techniques. Solid solutions containing 0-80 mol% NdO(1.5) were synthesized by coprecipitation from Ce(NO(3))(3) and Nd(NO(3))(3) aqueous solutions, and the coprecipitated samples were sintered at 1400 degrees C. A fluorite structure was observed for CeO(2)- which changed NdO(1.5) solid solutions with 0-40 mol% NdO(1.5) to a rare earth C-type structure at 45-75 mol% NdO(1.5). The change in the lattice parameters of CeO(2)-NdO(1.5) solid solutions, when plotted with respect to the NdO(1.5) concentration, showed that the lattice parameters followed Vegard's law in both the fluorite and rare earth C-type regions. The maximum solubility limit for NdO(1.5) in CeO(2) solid solution was approximately 75 mol%. The relationship between the density and the Nd concentration indicated that the defect structure followed the anion vacancy model over the entire range (0-70 mol% NdO(1.5)) of solid solution.