Phase Diagram of The SrO-Fe₂O₃ System in It's Fe₂O₃-Rich Region and The Growth of SrO⋅6Fe₂O₃ Single Crystal in Composition-Deviated Melts

Abstract

Phase diagram of the quasi-binary SrO-Fe₂O₃ system has been determined by X-ray diffraction, DTA measurement and microscopic method in the composition range of 100-33 mole% Fe2O3 above 750°C in air. The existence of the four compounds, SrFeO_3-x, 3SrO⋅2Fe₂O₃, SrO⋅6Fe₂O₃ and SrFe₁₈O₂₇ has been confirmed under the present experimental conditions. Crystal structure of 3SrO⋅2Fe₂O₃ seems to be hardly influenced by the oxygen partial pressure of the atmosphere. The temperature of eutectic reaction between SrO⋅6Fe₂O₃ and 3SrO⋅2Fe₂O₃ is 1195°±10°C, and the latter compound melts incongruently at 1225°±10°C. SrO⋅6Fe₂O₃ melts also incongruently at 1390°±10°C to form SrFe₁₈O₂₇ and liquid. Single crystals of SrO⋅6Fe₂O₃ have been grown from the melt containing an excess amount of SrO.