Density and surface tension polytherms of gallium-lead melts

The density and surface tension of gallium-lead melts have been determined using the sessile drop technique in the temperature range of $600$–$1000^\circ$C. According to the form of polytherms of surface tension of a system with $\mathrm{Ga}$-$\mathrm{Pb}$ exfoliation, a conclusion was made about the primary distribution of lead ions on the melt-vapor boundary. The excess entropies of melt formation were calculated. The comparison of experimental and calculated values of excess entropies showed that primary interaction between similar ions highlights the linear character of density polytherms.