Thermodynamic investigation of the Pb - Sb system

The enthalpies of mixing of lead - antimony alloys were determined at 973 K in the range 0.2 < XSb < 0.6 by direct liquid-liquid reaction calorimetry (DLLRC). The results are compared with data of the literature. The mixing enthalpies in the Pb - Sb liquid phase are weakly negative over the entire investigated concentration range with a minimum at ΔmixHm = -70 J mol-1 at XSb = 0.4. In addition, the Pb - Sb phase diagram on the Pb-rich side was revised using differential scanning calorimetry (DSC). The coordinates of the eutectic point have been ensured. An optimization of the binary Pb - Sb system was finally performed. The calculated phase diagram and thermodynamic functions agree well with experimental data.