Phase relations in the SrO – GdO1.5 – FeO1.5 system

Abstract

The lack of data systematization on the coexistence and stability of compounds formed in the SrO – GdO_1.5 – FeO_1.5 system at temperatures above 1100°C determines the interest in a more detailed study of this system. The research was focused on studying the stability of phases formed in the pseudobinary section (1-х)GdFeO₃ – хSrO in the temperature range 1200- 1400°C in air. The interaction of components in the SrO – GdO_1.5 – FeO_1.5 system was studied by the method of annealing and quenching followed by physicochemical analysis. The phase composition and sequence of phase transformations were characterized by powder X-ray diffraction.

Phase relations results in the SrO – GdO_1.5 – FeO_1.5 system in air were systematized. The formation of three complex perovskite-like oxides GdSr₂FeO₅, GdSrFeO₄, Gd₂SrFe₂O₇, located on the GdFeO₃ – SrO binary section was established. Information on interplanar distances and reflection intensities of the GdSr₂FeO₅ compound has been supplemented and the existence of a miscibility gap for Gd_1-xSr_xFeO_3-α solid solutions existing in the range 0.05≤x≤0.51 at 1400°C has been shown. Data on thermal stability of complex gadolinium ferrites based on GdO_1.5 – SrO – FeO_1.5 system has been expanded.