Structural Stability of SrCo1 − x FexO3 − δ Solid Solutions

Abstract

SrCo1 − xFexO3 − δ solid solutions with 0.3 ≤ x ≤ 0.9 are shown to have the cubic perovskite structure. The unit-cell parameter and volume of the solid solutions are nonmonotonic functions of Fe content, with a minimum at x = 0.4. Dilatometric data are used to determine the thermal expansion coefficients of the solid solutions. At low oxygen partial pressures (\(p_{\operatorname{O} _2 }\) ≤ 40 Pa), the high-temperature, disordered perovskite phase exists between 850 and 1000°C, which is the optimal temperature range for the effective use of SrCo1 − xFxO3 − δ ceramics as oxygen membranes in oxygen partial pressure gradients of 104–105/10–100 Pa.