Chemical Expansion, Crystal Structural Stability, and Oxygen Permeability of SrCo 0.4 Fe 0.6− x Al x O 3−δ Oxides

A series of SrCo 0.4 Fe 0.6− x Al x O 3−δ ( x =0, 0.1, 0.2, 0.3) perovskite oxides were synthesized using a gel‐combustion method. The doping of Al ions and its effect on the crystal structural stability, chemical expansion, and oxygen permeability of SrCo 0.4 Fe 0.6− x Al x O 3−δ have been investigated. The introduction of Al ions suppressed the oxygen loss and reduced the chemical‐induced expansion at high temperature. The oxygen permeability of SrCo 0.4 Fe 0.6− x Al x O 3−δ membranes decreased with increasing Al content. When x =0.2, the order–disorder phase transition of SrCo 0.4 Fe 0.6 O 3−δ in nitrogen atmosphere was suppressed, and oxygen permeation was not deleteriously affected.