Thermodynamic Modeling of the Cr-Fe-S System

All known phases of the chromium-iron-sulfur ternary system are taken into consideration within a thermodynamic analysis of phase equilibria and thermodynamic data at 1 bar total pressure over the entire composition range between 298.15 K (25 degrees C) and temperatures greater than the liquidus. The modeling is based on recent evaluations of the Fe-S and Cr-S binary subsystems. The extended modified quasi-chemical model is applied for the liquid chromium-iron- sulfur phase. The Gibbs energy of solid solution phases as high-temperature chromium-iron pyrrhotite and the thiospinel Daubreelite is described by sublattice models within the framework of the compound energy formalism. Analysis of complex phase relations is now possible on the basis of a consistent thermodynamic description of the system. The thermodynamic modeling presented can be combined with models of other metal-sulfur systems to develop a thermodynamic multicomponent/multiphase database. (C) The Minerals, Metals & Materials Society and ASM International 2013