Thermodynamics of aluminum and manganese deoxidation equilibria in Fe-Ni and Fe-Cr alloys

Aluminum deoxidation equilibrium and manganese distribution have been studied at 1 873 K in the equilibrium experiment between CaO-Al2O3 slags and Fe-10, 20, 40 and 60mass%Ni alloys or Fe-10, 20 and 40mass%Cr alloys containing Mn and Al. On the basis of these results, the effect of Ni or Cr on the activity coefficients of Al and Mn based on liquid iron is discussed and the interaction coefficient between Al and 0 in liquid iron has been estimated. Some experiments in which Fe-18mass%Cr-8mass%Ni alloy containing Al and Mn was equilibrated with CaO-Al2O3 slags have been carried out at 1 873 K. It was found that the observed values for the oxygen content and the Mn distribution ratio in Fe-18mass%Cr-8 mass%Ni alloy are in good agreement with the calculated values by using the activity coefficients of Al and Mn obtained in this study.