ELECTROCAPILLARY BEHAVIOR OF LIQUID BISMUTH IN BINARY MELTS OF STRONTIUM CHLORIDE WITH SODIUM AND CESIUM CHLORIDES

A capillary electrometer was used to take measurements of the interfac ial tension for liquid bismuth in melted strontium chloride and its bi nary mixtures with sodium and cesium chlorides against the electrical potential and temperature applied. We have found that the interfacial tension of bismuth in a pure melt of strontium chloride and in mixture s containing small additives of alkali metal chlorides exceeds the met al surface tension; the adhesion work proved to be less than half the cohesion work of the ionic melt and the concentration of the surface-a ctive component at the salt-metal interface was nearly 20% below that in the surface layer of the ionic melt interfacing its vapor. Hypothet ically, this can be caused by the high polarization effect of strontiu m cation on anions of chlorine and weakened by the interaction between these anions and the electrode. Based on the concentration dependence s of adhesion work, metal zero-charge potentials, and composition of t he interfacial layer, a conclusion was drawn that the nature of the su rface layer of ionic melts containing a divalent cation is polyionic a nd that the surface-active salt distribution across the interface laye r is nonuniform.