Surface freezing transitions in liquid binary alloys

Abstract

In this paper recent results on surface phase transitions at the interface of Ga–Bi alloys are reviewed. The wetting transition in the liquid–liquid demixing region is briefly summarized. Then, the surface freezing transition, which occurs in the concentration range between the eutectic ( x Bi=0.0022) and the monotectic ( x Bi=0.085) compositions, is described. This was discovered recently using second harmonic generation and plasma generation methods. The surface freezing line was found approximately 20 K above the eutectic point; it approaches the liquidus line with increasing Bi mole fraction and presumably merges at the monotectic point. Arguments for the thermodynamic stability of the surface freezing Bi-rich films and a possible correlation between the wetting transition and the surface freezing transition are discussed. Finally, we present preliminary experimental results on a study of surface freezing in Ga–Pb.