Thermodynamic study of liquid lithium-lead alloys using the EMF method

Liquid Li-Pb alloys were investigated by the electromotive force (emf) method at Li concentrations of 0.025≤XLi≤0.965 mole fraction and at temperatures from 775 to 975 K. The experiments were conducted at constant temperature, and the Li concentration was changed by the coulometric-titration technique. The two-phase Li-Bi alloys and liquid lithium were used as the reference electrodes. The dependence of emfs on temperature for each investigated alloy was linear, and from the linear equations (E=a+bT), partial Li excess Gibbs energies, partial enthalpies and entropies of lithium were calculated, and compared with previously published data. The excess stability function ES and the concentration-concentration partial structure factor Scc(0) were calculated and discussed in relation to the neutron diffraction data and other properties. A change in the type of chemical bonding near the composition Li4Pb is indicated. This study was initiated since Pb-17Li eutectic alloy has been proposed as a breeder blanket fluid for fusion reactors. (authors)