ELECTROCAPILLARY PHENOMENA AT SOLID GOLD IN MOLTEN CHLORIDES OF ALKALINE-EARTH METALS

The interfacial free energy and contact angles intrinsic to the bounda ry between solid gold and molten chlorides of alkaline-earth metals an d magnesium are determined by measuring the forces due to capillary ri se. It is shown that, in a wide potential range, electrocapillary curv es for BaCl2, SrCl2, and CaCl2 exhibit a maximum associated with the p otential of zero charge (PZC). At potentials more anodic than PZC, a r egion is discovered in molten magnesium chloride, where the interfacia l energy is virtually potential-independent, which is ascribed to part ial charge transfer from the anions onto the metal. The angles of cont act diminish in the series from BaCl2 to MgCl2.