Our most recent experiments exploring how surface induced layering is affected by alloying two liquid metals. Typically, the surface layering is suppressed or destroyed when the two components differ considerably in size. In addition, new surface phases that depend on the type of bulk interactions between the two components can be studied. We have studied the exemplary Ga-In system and found surface segregation of In, the lower surface tension component. In addition, we have proven experimentally that this surface segregation is confined to the very first atomic surface layer.
Repulsive interactions result in a miscibility gap.
As an example, we studied Ga-Bi alloys for different temperatures. At temperatures below the monotectic temperature of 220 C , the Ga rich fluid coexists with solid Bi. The Bi monolayer persists above the critical consolute point at 262 C where the subsurface fluid becomes homogeneous whereas the thick Bi rich film vanishes as expected. Attractive interactions between the two components lead to the formation of ordered intermetallic phases in the bulk solid phase. One objective is to find out if the pronounced order that prevails in the bulk solid but is not present in the bulk liquid is preserved at the liquid surface.