Phase relations in the Ba-Sr-Co-Fe-O system at 1273 K in air

Selected compositions of the Ba-Sr-Co-Fe-O system were synthesized from powders by the solid-state reaction method. Samples were equilibrated at 1273 K for 36 000 s in air. The resulting powders were characterized by X-ray diffraction (XRD) at room temperature and by high-temperature in situ XRD. The phases present in the Ba(x)Sr(1-x)Co(y)Fe(1-y)O(3-delta) system are outlined for 1273 K in air. For most of the quaternary compositions, the cubic perovskite is formed, except for the compositions with x = 1 (excluding y = 0.4), y = 1 and x, y = 0.8, where the phases mainly show hexagonal distortions, and x, y = 0, for which a predominant cubic phase is mixed with other phases.