An oxalate co-precipitation method was used to prepare rare-earth doped ceria powders of the form, Ce0.8R0.2O1.9, where R was Yb, Y, Gd, Sm, Nd or La. Powders which had been calcined at 600C were isostatically compacted and sintered at 1600C in air to obtain a relative density of above 98%. The conductivity of the doped ceramics was dominated by the migration of O ions in the bulk, and ranged from 6.7 to 13.6S/m at 800C. The activation energies for the diffusion of O ions in the bulk ranged from 75.3 to 93.4kJ/mol. The lattice-energy theory for the fluorite structure was used to estimate the activation energy. The calculated energy was close to the measured value.

Electrical Conductivity and Diffusion of Oxygen Ions in Rare-Earth-Doped Ceria. S.Sameshima, H.Ono, K.Higashi, K.Sonoda, Y.Hirata, Y.Ikuma: Journal of the Ceramic Society of Japan, 2000, 108[12], 1060-6