Liquid-vapor phase equilibrium in the stratifying thallium-zinc system

The pressure of the zinc vapor over liquid alloys with thallium at temperatures above the region of limited solubility in the liquid phase is determined by the method of stream and boiling points. The procedure of finding thermodynamic functions inside the stratifying region is based on the fact that chemical potentials at a constant temperature at the interface between the two-phase and homogeneous regions of the existence of liquid solutions are equal. The partial and integral thermodynamic characteristics of the vapor and condensed phases are determined and represented in the form of temperature-concentration dependences. This system is characterized by a positive deviation from the law of ideal solutions. The boundaries of the liquid-vapor phase transition of the Tl-Zn system under atmospheric pressure and under the rarefaction to 100 and 10 Pa are obtained by extrapolating the dependences of the vapor pressure of components on a high-temperature region. The region of coexistence of liquid alloys and vapor restricts a relatively small region of coexistence of liquid solutions from above, near the zinc edge of the phase diagram.