Polycrystalline oxide was prepared by sintering, and was used for O diffusion experiments that involved gas-phase analysis. Lattice-constant measurements confirmed the stoichiometric nature of the sample. Although Si was present in the specimens as an impurity, it was considered that point defects were not created by the Si, because both Si and Ce had the same valence. The O diffusivity could be described by:

D (m2/s) = 0.364 exp[-322(kJ/mol)/RT]

These results were similar to O self-diffusivities in other stoichiometric oxides with the fluorite structure. This agreement was considered to confirm that the present diffusivity was truly that of O in stoichiometric CeO2.

Oxygen Self-Diffusion in Cerium Oxide. M.Kamiya, E.Shimada, Y.Ikuma: Journal of the Ceramic Society of Japan, 1998, 106[10], 1023-6