Oxygen transport properties of Ba0.5Sr0.5Co0.8Fe0.2O3 − x and Ca0.5Sr0.5Mn0.8Fe0.2O3 − x obtained from permeation and conductivity relaxation experiments

The oxygen exchange and transport properties of the perovskite-type oxides Ba0.5Sr0.5Co0.8Fe0.2O3 − x (BSCF5582) and Ca0.5Sr0.5Mn0.8Fe0.2O3 − x (CSMF5582) are investigated by oxygen permeation as well as electrical conductivity relaxation experiments. The temperature dependence of the oxygen permeation flux JO2of BSCF5582 in the range 600 ≤ T/°C ≤ 950 shows a transition from a low temperature region with higher activation energy to a high temperature region with lower activation energy. Complementary, the chemical surface exchange coefficient kchem, the chemical diffusion coefficient Dchem and their activation energies are determined from conductivity relaxation experiments in the ranges 600 ≤ T/°C ≤ 750 and 70 < pO2/Pa < 3000.