Miscibility gap and liquid-liquid equilibrium in the system In-Tl-Se

Electrical conductivity measurements were performed on liquid immiscible (InxTl1-x)(0.80)Se-0.20 alloys in a wide temperature range between 1200 K and the crystallization temperature under argon gas pressures up to 45 MPa. The electrical conductivity shows the same behavior as for binary liquid alloys during phase separation. It was revealed that variation of In-to-Tl ratio at constant Se content changes the properties of coexisting liquids and affects the phase-separation temperature Ts in a nonlinear manner. Ts varies from 1035 K for Tl0.80Se0.20 to 949 K for In0.80Se0.20 with a maximum at T-S 1061 IC for In0.22Tl0.58Se0.20 The results are analyzed in comparison with available data for binary and ternary immiscible alloys. The possible influence of sublattice dynamics on formation of the critical-point parameters is discussed.