Surface Tension of Alloys with Additives of Alkali Metals

The results of studies of surface tension of metal melts with addition of alkali metals, mainly as small additives, are discussed. It is shown that small additives of alkali metals exhibit a high surface activity. The extrema that are observed on the surface tension isotherms of a number of binary systems are built using very few experimental points; hence, their authenticity seems unreliable. The main disadvantages of the methods and the measuring cells used to define the surface tension, etc., which may violate the conditions of thermodynamic equilibrium of the surfaces under study with their saturated vapor, are discussed. In the authors' opinion, a number of experimental and theoretical problems remain unsolved in the field of the temperature and concentration dependences of the surface tension of alloys with small additions of alkali metals.