The results of calculations of the surface tension isotherms (ST) for ternary alloys of a Na-K-Rb system using the computational-graphic method and approximation equation are presented in this paper. Ternary-alloy ST isotherms of cross sections reaching the apexes of rubidium and potassium on the ternary plot of a Na-K-Rb system were constructed. It was found that rubidium exhibits surface activity in a concentration range from about 25 at.% to 60 at.%. A comparative analysis was conducted on the calculation results of the ST with the data obtained from field experiments.

surface tension isotherm, computational-graphic method, approximation equation, triple alloys.