Critical evaluation and optimization of the thermodynamic properties and phase diagrams of the CrO-Cr2O3, CrO-Cr2O3-Al2O3, and CrO-Cr2O3-CaO systems

Available thermodynamic and phase diagram data have been critically assessed for all phases in the CrO-Cr2O3, CrO-Cr2O3-Al2O3, and CrO-Cr2O3-CaO systems from 298 K to above the liquidus temperatures and for oxygen partial pressures ranging from equilibrium with metallic Cr to equilibrium with air in the case of the first two systems and to P-O2 = 10(-3) atm for the CrO-Cr2O3-CaO system, All reliable data have been simultaneously optimized tb obtain one set of model equations for the Gibbs energy of the liquid slag and all solid phases as functions of composition and temperature, The modified quasi-chemical model was used for the slag, The models permit phase equilibria to be calculated for regions of composition, temperature, and oxygen potential where data are not available.