Determination of Manganese and Carbon Activities of Mn-C Melts at 1628 K

Abstract

The activity of carbon in a Mn-C alloy has been measured at 1628 K by equilibrating solid MnO with molten Mn-C alloys in an Ar-CO atmosphere according to the following reaction.
[C]_Mn+MnO(s)=[Mn]+CO(g)
The activity coefficients of manganese and carbon relative to pure liquid manganese and solid carbon, respectively, obtained from the carbon content of the Mn-C alloy at different CO partial pressures are expressed as follows:
ln γ_Mn=5.47X_C²–46.8X_C³
ln γ_C=–0.291–10.9X_C+75.6X_C²–46.8X_C³