Density and surface tension of the Pb-Sn liquid alloys

The maximum bubble pressure method and the dilatometric method were used, r espectively, in measurements of surface tensions and densities of Pb-Sn liq uid alloys. The experiments were carried out in the temperature range from 573 to 1200 K for the pure Pb, pure Sn, and 7 alloys of,the compositions 0. 1, 0.2, 0.26, 0.36, 0.5, 0.7, and 0.9 mole fraction of Pb, A straight-line dependence on temperature was observed and fitted by the method of least sq uares both for the densities and the surface tensions. The calculated densi ty isotherm at 673 K showed a positive deviation from the linearity over th e entire range of composition, and the same tendency was seen at 1173 K for compositions higher than X-Pb = 0.26, At the lower concentration of Pb, a nearly linear character of 1173 K isotherm was noted. In the case of surfac e tensions, both at the lowest and the highest temperatures (673 and 1173 K ), the deviation from linearity with composition was negative, but deviatio n decreased with increasing temperature. The isotherms of the compositional dependence of surface tension calculated from the Butler model exhibit goo d agreement with experimental data.