ASSOCIATION IN METALLIC SOLUTION

A general thermodynamic expression has been considered regarding the association in metallic solution. When an associated complex is formed with a chemical unit of A// mu B// gamma in the A-B binary liquid and its associated solution is approximated as a regular solution, the excess free energy constructed by three terms of the formation energy of associated complexes, the interaction energy between the complexes and free atoms, and the excess entropy of mixing generated by the existence of associated complexes. Analysis of thermodynamic properties in In-Sb binary and InSb-M (M equals Sn, Pb, and Bi) quasibinary systems confirmed that the approximation model derived for the thermodynamic expression is satisfactorily applicable in the case of small degrees of association. The theoretical structure factor with regard to the concentration, S//c//c (0), is in good agreement with the experimental value in the In-Sb binary system. This means that associated complexes with the composition InSb have a tendency to be surrounded by