<Original Papers>Interaction Parameters of Alloying Elements in Binary Systems of Molten Iron

The interaction paramrters of alloying elements in dilute binary iron solutions were calculated by a statistical-thermodynamical method similar to that used in the previous work on ternary alloys. The interaction parameter [numerical formula] of a substitutional alloying element X is given by [numerical formula] and that of an interstitial alloying element X by [numerical formula] The interchange energy W in the above equation was estimated from the following modified Mott\u27s equation : [numerical formula] where δ_ and δ_X are the solubility parameters, X_ and X_X the electronegativities of iron and X respectively, V^M the molar volume of mixture, and n^- the appropriate number of Fe-X bond in the mixture. The values of the interaction parameters thus calculated for the substitutional alloys were compared with the experimental ones, and reasonable agreements were obtained. For the interstitial alloys, discussion was omitted as the data on χ_X are not yet available