Phase transitions in Sr1 + xCo0.8Fe0.2O3 − δ oxides

The phase transitions that take place in Sr1 + xCo0.8Fe0.2O3 − δ (− 0.2 ≤ x ≤ 0.1) oxides are reported here. Thermogravimetric analysis (TGA) showed that the oxides with − 0.2 ≤ x ≤ 0 were prone to undergo oxygen-vacancy disorder–order phase transitions, while others with x = 0.05, 0.1 had more stable crystal structures during oxygen-desorption processes in nitrogen. These results were further confirmed by high-temperature in-situ X-ray techniques. The changes in activation energies of three typical oxides, Sr1 + xCo0.8Fe0.2O3 − δ (x = − 0.2, 0, 0.1), used as oxygen-permeable membranes were investigated. The phase transitions in Sr1 + xCo0.8Fe0.2O3 − δ (x = − 0.2, 0) have also been detected in differential scanning calorimetry (DSC) profiles.