1993 Volume 57 Issue 7 Pages 774-780
A study of thermodynamic properties of the liquid Te-Pb alloys has been carried out by the galvanic cells of
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The reliable values of E.M.F. were obtained for the alloys.
Activities of lead at 1210 K show remarkably negative deviations from Raoult’s law in the wide concentration range and abruptly increase from negative to positive around NPb=0.45∼0.65 and show slightly positive deviations on the lead-rich side. Activities of tellurium at 1210 K exhibit significantly negative deviations from Raoult’s law over the whole concentration range. aPb values agree well with the data measured by Moniri and Petot but aTe values differ from those of Predel et al.
The γPb° and γTe° values are estimated to be 6.4×10−3 and 3.1×10−2 at 1210 K. From the features of α functions of lead for the system, the alloys are not considered as regular solutions. The minimum values of the heat of mixing for the system are −27.2 kJ/mol at about NPb=0.48.
It is observed that the anomalous behaviors in heats of mixing, ξ function, entropy of mixing and concentration fluctuation at long wave length limit at the composition of PbTe are affected by the stable compound in the liquid state.
