Thermodynamics and Phase Equilibria Involving Nano Phases in the Cu-Ag System

The surface tensions of the Cu-Ag system have been evaluated using Butler's equations. Since the evaluation is dependent on the thermodynamic properties of the surface phases, they are calculated based on the first and second order differentials of the surface tension at infinite dilution. The present study establishes significant differences in the properties between the surface phase and bulk phases of the system. The study of the adsorption behaviour finds silver to be surface active relative to copper, which results in the preferential adsorption of silver in the alloys. Furthermore, in view of the differences in terms of fundamental thermodynamic properties between the two phases coupled with the volume-to-radius ratio as depicted by the Thomson-Freundlich concept, the nano phases of the system exhibit a pronounced increase in the adsorption behaviour relative to that of the planar interface of the system. As expected based on the above combined effect of the surface properties, present research shows a considerable decrease in the melting points of the metals, solid-solid, solid-liquid transition and eutectic temperature with a consequent increase in the solubilities of the terminal phases of the system.