The oxygen permeation flux measured as the oxide ion current density (Jo(2)-) through La0.75Ca0.25CrO3-δ was determined at steady state by using an electrochemical method in the po2 range from 105 to 10-11 Pa at T = 1273 K. The oxygen vacancy diffusion coefficient (Dv) is estimated to be 1.5 × 10-9 m2 s-1 in the po2 region from 1 to 10-5 Pa. When po2 is lower than 10-5 Pa, Jo(2)- seems to depend on a surface reaction as the rate-determining step. The contribution of grain-boundary diffusion on permeation was considered in the oxidizing atmosphere. The oxygen permeation current density through a 1 mm thick plate is estimated as 0.03 A cm-2 in the solid oxide fuel cell operation.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry