Surface properties of melts of binary systems of alkali metals

The results of calculations of the surface properties of melts of alkali-metal systems based on experimental surface tension isotherms are presented. It is shown that the authors of the equation of the surfacetension isotherm have described experimental isotherms of the surface tension of binary alkali-metal systems with high accuracy. The results of calculations of the parameters of the surface-tension isotherm $\beta$ and $F$, the component adsorption, and the surface composition of the melts of binary alkali-metal systems in approximations of ideal and real solutions are given. Analysis of the results shows that the binary systems $\rm Na$–$\rm K{,}\,\rm K$–$\rm Rb$, and $\rm Rb$–$\rm Cs$ are closer than others to the ideal system. It is noted that one of the determining factors in the adsorption processes of components of binary alkali-metal systems is geometric: the greater is the ionic radius of the added component of the solvent radius, the stronger is the adsorption of the added (second) component of the binary system.