A method was developed for determining chemical diffusion coefficients and surface reaction resistances for O in mixed conducting oxides. The method was based upon the impedance analysis of a ZrO2/O pumping cell which contained a sample of the oxide. In the case of La0.85Sr0.15MnO3, the reaction resistance at 1000C in air was found to be 200cm2; corresponding to a surface exchange coefficient of 5 x 10-6cm/s. The chemical diffusion coefficient under the same conditions was 2 x 10-9cm2/s, and the thermodynamic enhancement factor was 200. The corresponding self-diffusion coefficient which was deduced by using this method was 10-11cm2/s.

K.Lade, T.Jacobsen: Solid State Ionics, 1994, 72, 218-23