A new thermodynamic approach for determining the activities from ternary miscibility gaps: the Cu-Pb-O system

A new thermodynamic approach has been developed for calculating the activities of components along the miscibility gap in ternary systems consisting of two metals and a nonmetal. In this new treatment, the knowledge of the tie-line distribution within a two-phase region and the graphical integration, which both are required by normal methods, are not necessary. Therefore it will give better calculation accuracies and gain more applications. An application of the present method to the Cu-Pb-O system is illustrated in this paper.