The investigation of the thermodynamic properties of liquid metal solutions

摘要

The development of thermodynamic models for liquid metal solutions is reviewed and applications of these models are discussed. In addition, directions where new or more work is needed are suggested.;A chemical-physical theory model is developed for compound-forming liquid metal systems. A group contribution technique is applied to linearize the Gibbs energy (and enthalpy) of formation of intermetallic compounds. As a result, the activities or Gibbs energies of a wide range of liquid alloy systems are represented quantitatively with only a single model parameter for chemical interactions and another for the physical interactions. Similarly, the enthalpies of mixing are modeled well using only the temperature derivatives of these two parameters. In addition, the model is extended to the representation and prediction of ternary liquid metal solution properties and the determination of liquidus curves for several binary intermetallic compound forming systems.;A chemical-physical theory model is also developed for representing the interfacial thermodynamics of compound-forming liquid metal systems. The model uses an approach to representing the interfacial thermodynamics wherein the surface is not treated as a separate phase, but rather the system is viewed as consisting of a bulk phase that is acted upon by a surface force. In this treatment the surface force is analogous to other forces which may act upon the system, e.g., electrical and magnetic forces. Compared with previous models this model provides more accurate representations of the surface tension isotherms for compound-forming systems with less model parameters.;The surface tension isotherms of two binary alloy systems (Bi-Sn and In-Sn) have been measured using the sessile drop technique. The Bi-Sn isotherm is nearly linear, while the In-Sn isotherm exhibits a minimum.