Oxygen transport of mixed ionic-electronic conductors can be measured by a relaxation technique that permits to investigate the material dynamic properties with oxygen partial pressure change. However, for materials exhibiting higher electronic conductivity than ionic, the time for conductivity change is controlled by bulk ionic transport and any surface reaction can be neglected. By fitting the experimental relaxation data of CaTi0.7Fe0.3O3-delta composition, the oxidation and reduction kinetics was found to be independent on oxygen partial pressure (P-O2) and the rate constants were derived therefrom. From a relaxation experiment at a single P-O2 we therefore obtain both the electronic and ionic contributions to the total conductivity as well as the chemical diffusion coefficient.
|Pages (from-to)||269 - 274|
|Number of pages||6|
|Publication status||Published - 2005|