Liquid-liquid equilibrium in immiscible In-Se alloys suffering metal-nonmetal transition

Electroconductivity sigma(T) measurements for liquid immiscible In1-xSex(x = < 1/3) alloys are carried out under excess pressure of argon gas (up to 50 MPa) at temperatures up to 1200 g. In the transition region, the electroconductivities of coexisting liquids vary greatly, The liquid-liquid coexistence curve on the phase diagram of the In-Se system is determined from sigma(T) measurements, The coordinates of the critical point were found to be x(c) = 19.2 +/- 0.1 at.% Se and T-c = 949 +/- 1.8 K. The critical indices beta and 1 - alpha are estimated to be 0.35 +/- 0.02 and 0.87 +/- 0.02, respectively, An asymmetry of the coexistence curve and the nonlinearity of its diameter are analyzed in comparison with available data for fluid metals in the vicinity of the liquid-vapor critical point.