Thermodynamics of Mn₃O₄ — Co₃O₄, Fe₃O₄ — Mn₃O₄, and Fe₃O₄ — Co₃O₄ Spinels by Phase Diagram Analysis

Abstract

Abstract High temperature phase equilibrium data are compiled from the literature for the Mn—Co—O, Fe—Mn—O, and Fe—Co—O systems. These data are then analyzed with a view to examining the thermodynamics of the spinel phases. It is shown that the results are consistent with a simple “ideal” model of cation distribution in the spinel phases. The representation and subsequent analysis of the phase equilibria are greatly facilitated through the use of isothermal log p o ,‐composition phase diagrams and through the use of a computer program to calculate these diagrams.