Subsolidus Phase Equilibria of Fe-Ni-X-O (X = Mg, Al) Systems in Air

Abstract

The phase equilibria of Fe-Ni-X-O (X = Mg, Al) systems, including their lower-order systems, at temperatures between 1200 °C and 1600 °C in air in the subsolidus region, have been experimentally studied. In the present study, the ‘Fe2O3’-MgO, ‘Fe2O3’-Al2O3, and NiO-Al2O3 binary phase diagrams, as well as the ternary phase diagrams in the Fe-Ni-Mg-O and Fe-Ni-Al-O systems projected onto the Fe-Mg-Ni and Fe-Al-Ni planes, have been constructed. Differences have been found between the present measurements, the previously published data, and the FactSage predictions, especially in the lower-order systems. It is suggested that the improved experimental techniques used in the present study, which involve carefully planned equilibration procedures followed by electron probe X-ray microanalyses (EPMA), provide more accurate and precise measurements of the phase boundaries and phase compositions.