An oxygen permeable membrane La0.8Sr0.2(Ga0.8Mg0.2)1 − xCrxO3 − δ for a reduced atmosphere

Mixed electron hole and oxide ion conducting perovskite-type oxides, La0.8Sr0.2(Ga0.8Mg0.2)1 − xCrxO3 − δ (0 ≤ x ≤ 1.0), were prepared by solid state reaction. The phase stability and the oxygen permeation properties of the oxides were examined as a function of the content of Cr. La0.8Sr0.2(Ga0.8Mg0.2)1 − xCrxO3 − δ has a perovskite related tetragonal phase with x = 0.1 to 0.8. The total electrical conductivity of La0.8Sr0.2(Ga0.8Mg0.2)1 − xCrxO3 − δ increases with increasing x. The oxygen permeation flux across the La0.8Sr0.2(Ga0.8Mg0.2)1 − xCrxO3 − δ membranes at higher temperatures increases with x up to x = 04. The maximum oxygen permeation flux of 1.6 × 10− 7 mol− 1 cm− 2 at 1100 °C in a oxygen activity gradient of air/10− 2 Pa is observed in La0.8Sr0.2(Ga0.8Mg0.2)0.6Cr0.4O3 − δ. This perovskite-type oxide is stable under an oxygen partial pressure of 7 × 10− 10 Pa at 1000 °C.