The diffusion of all stable lanthanides was measured both in calcia-stabilized zirconia and in yttria-stabilized zirconia at 1286 to 1600C. The lanthanide diffusion coefficients increased with increasing ionic radius. The activation enthalpy for diffusion was near to 6eV for calcia-stabilized zirconia and was between 4 and 5eV for yttria-stabilized zirconia. It was not strongly affected by the type of lanthanide. The results were correlated with defect-energy calculations, of the lanthanide diffusion enthalpy, using the Mott-Littleton approach. The association enthalpy of cation vacancies with O vacancies was deduced to be about 1eV (96kJ/mol) in the case of calcia-stabilized zirconia. There was no association in the case of yttria-stabilized zirconia. The change in diffusion coefficients could be related to the interaction parameter for the interaction between the lanthanide oxide and zirconia: the higher the interaction parameter, the higher was the lanthanide diffusion coefficient.

Lanthanide Transport in Stabilized Zirconias - Interrelation between Ionic Radius and Diffusion Coefficient. M.Kilo, M.A.Taylor, C.Argirusis, G.Borchardt, S.Weber, H.Scherrer, R.A.Jackson: The Journal of Chemical Physics, 2004, 121[11], 5482-7