Activity of Iron Oxide in Magnesiowustite in Equilibrium with Solid Metallic Iron

By employing an electrochemical technique incorporating magnesia-stabilized zirconia electrolyte, the activities of iron oxide, FexO, were measured in magnesiowustite, FexO–MgO solid solution, in equilibrium with solid metallic iron at temperatures between 1373 and 1573 K. The sub-regular solution model was applied to the FexO activities, and the calculated FexO activities were in good agreement with the experimental values in this study and the literatures at temperatures between 1073 and 1573 K with an accuracy of (plus-minus) 0.02.