Thermodynamic Properties of the FeS–MnS–CuS0.5 Ternary System at 1473 K

In order to describe the formation of FeS–MnS–CuS0.5 inclusion in γ-Fe, the thermodynamic properties of the FeS–MnS–CuS0.5 system have been investigated at 1473 K. The isothermal section was determined by a chemical equilibration technique. The activities of FeS and CuS0.5 in the liquid phase were determined by equilibrating with carbon saturated iron or molten copper, and the activity of MnS was evaluated by using the Gibbs-Duhem equation with Schuhmann’s tangent intercept procedure. Finally, the composition of solid steel equilibrated with the FeS–MnS–CuS0.5 inclusion was estimated using the determined thermodynamic properties.