Thermodynamic properties of zinc-rich zinc-aluminum melts

A thermodynamic study of molten zinc-aluminum alloys in the range 450 °C to 650 °C and 0 to 0.43 atom fraction of aluminum was carried out by the electromotive force (emf) method using the reversible concentration cell W,pure Al |MgCl₂-NaCl-KCl-AlCl₃| Zn-Al (1),W The activities of aluminum derived from the measured cell potentials show considerable positive deviations from Raoult's law. The Henry's law constants and the self-interaction parameters of aluminum were obtained from the experimental data for the dilute solutions. The activities of aluminum extrapolated from the present experimental data agree well with the data from the literature at 727 °C. The values of relative partial molar enthalpy and entropy are also consistent with the results obtained by previous authors. The behavior of the α-function for aluminum indicates that the solution behaves approximately subregularly in the dilute region over the tem-perature range investigated, and regularly for atom fractions of aluminum greater than 0.1 at temperatures greater than 550 °C.