Lanthanide transport in stabilised zirconias interrelation between ionic radius and diffusion coefficient

M. KILO, M.A. TAYLOR, CHR. ARGIRUSIS, G. BORCHARDT, S. WEBER, H. SCHERRER, R.A. JACKSON

JOURNAL OF CHEMICAL PHYSICS

AMER INST PHYSICS

Año: 2004 vol. 121 p. 5482 - 5486

0021-9606

The diffusion of all stable lanthanides was measured both in calcia stabilized zirconia (CSZ) and in yttria stabilized zirconia (YSZ) in the temperature range between 1286 and 1600 °C. The lanthanide diffusion coefficients obtained increase with increasing ionic radius. The experimental activation enthalpy of diffusion is near 6 eV for CSZ and between 4 and 5 eV for YSZ and is 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. An association enthalpy of cation vacancies with oxygen vacancies of about 1 eV ~96 kJ/mol! was deduced in the case of CSZ, while there is no association in the case of YSZ. Furthermore, the change in diffusion coefficients can be correlated to the interaction parameter for the interaction between the lanthanide oxide with zirconia: The higher the interaction parameter, the higher the lanthanide diffusion coefficient.