Thermodynamic study of zinc-rich zinc-sodium alloys

The following conclusions were drawn from the present work. The activity, activity coefficient, and relative partial and excess partial molar Gibbs free energies of sodium in zinc-rich Zn-Na melts were derived from the titration curves at 703 and 738K, where the activities of sodium at 703 and 738K show considerable positive deviations from Raoult's law. The activities of sodium within the two-phase Zn(l)+NaZn sub 13 (s) region were also determined experimentally over the temperature range 703-773K. Sodium obeys Henry's law in zinc-rich Zn-Na melts at the concentrations up to the phase boundary of solid NaZn sub 13 at 703 and 738K. A zero value was obtained for the self-interaction coefficient of sodium, and this indicates a random distribution for neighboring atoms in zinc-rich Zn-Na melts at 703 and 738K. The liquidus points in the zinc-rich region of the Na-Zn phase diagram were determined experimentally at 703 and 738K. The saturation concentrations of sodium in zinc-rich Zn-Na melts saturated with sodium can be calculated at temperatures < 773K.