Temperature-programmed C18O2 SSITKA for powders of fast oxide-ion conductors: Estimation of oxygen self-diffusion coefficients

For powders of oxide-ion conductors based on Al/Fe- doped lanthanum silicates as well as Sc+Ce-doped zirconia, the temperature -programmed exchange with (CO2)-O-18 in the SSITKA mode was applied for estimation of the oxygen self-diffusion coefficients D-o. Comparison with results obtained for dense ceramics of these electrolytes using SIMS isotope profiling and conductivity measurements demonstrated a reasonable agreement for powders sintered at high temperatures, thus providing required verification of (CO2)-O-18 SSITKA approach. For powders calcined at moderate temperatures much lower values of Do were obtained thus suggesting a strong negative effect of inhomogeneity of dopants spatial distribution on the oxygen mobility. (C) 2014 Elsevier B.V. All rights reserved.