The surface tension of melts of aluminum–indium binary system

The temperature and concentration dependences of the surface tension (ST) of alloys of the $\mathrm{Al}$–$\mathrm{In}$ system are investigated by the sessile drop method. It is shown that small (up to $0.6$ at. $\%$) additions of indium significantly lower the ST of aluminum, and the temperature coefficients of ST of the investigated alloys have positive values in this range of compositions. The obtained data are used to calculate the adsorption of indium (according to Guggenheim–Adam, $N$ option) and the number of its monolayers (according to Rusanov) in the surface layer of $\mathrm{Al}$–$\mathrm{In}$ solutions. It follows from these data that the adsorption of indium on the melt surface reaches the maximal value with a bulk content of indium of about $0.1$ at. $\%$, and the excess of indium in the surface layer corresponds to three monolayers of indium.