Numerical Analysis on Si Deoxidation of Molten Ni and Ni-Cu Alloy by Quadratic Formalism

Abstract

Relation between the activity coefficient expressed by Darken’s quadratic formalism and the excess Gibbs energy change of mixing described by Redlich-Kister type polynomial was discussed in Si deoxidation of Ni alloy. The activity coefficients of Si and O in metal expressed by quadratic formalism have been converted into formula using interaction parameters Ωi−j under the condition where concentration of Si and O are dilute. Numerical analysis on Si deoxidation of molten Ni and Ni–Cu alloy has been carried out. It has been found to be outstanding in the agreement of equilibrium Si and O contents in molten Ni and Ni–Cu alloy analyzed in the present work with the experimental results. The deoxidation equilibrium of not only pure metal but also alloy can be analyzed numerically using the formula determined in the present work.