THE EXCESS-ENTHALPIES OF LIQUID BI-PB-TE ALLOYS

The excess enthalpies of liquid alloys in the ternary system Bi-Pb-Te were measured at 1173 and 1073 K in a heat flow calorimeter. Five sect ions BiyPb1-y-Te with constant concentration ratios x(Bi)/x(Pb) were m easured. The enthalpy surface in the ternary system is characterized b y a valley stretching from the exothermic minimum in the system Pb-Te to the exothermic minimum in the system Bi-Te. The analytical descript ion of the excess enthalpies in the limiting binaries was made with th e Redlich-Kister formalism. For the description of the values in the t ernary system the equation of Bonnier was taken using additional terna ry coefficients. These were obtained by adjusting the curves to the ex perimental data using the least-squares method.