Surface Phases in Binary Liquid Metal Alloys

TL;DR

This paper uses x-ray scattering to study the microscopic surface structure of three binary liquid metal alloys, revealing phenomena like surface segregation, wetting transitions, and effects of attractive interactions.

Contribution

It provides detailed atomic-scale insights into surface phenomena in binary alloys, including segregation, wetting, and interaction effects, using advanced x-ray techniques.

Findings

In Ga-In, a supercooled In monolayer forms at the surface.

Ga-Bi exhibits a wetting transition at ~220°C.

Attractive interactions influence surface structure in Hg-Au alloys.

Abstract

Surface sensitive x-ray scattering techniques with atomic scale resolution are employed to investigate the microscopic structure of the surface of three classes of liquid binary alloys: (i) Surface segregation in partly miscible binary alloys as predicted by the Gibbs adsorption rule is investigated for Ga-In. The first layer consists of a supercooled In monolayer and the bulk composition is reached after about two atomic diameters. (ii) The Ga-Bi system displays a wetting transition at a characteristic temperature T_w~220 C. The transition from a Bi monolayer on Ga below T_w to a thick Bi-rich wetting film above T_w is studied. (iii) The effect of attractive interactions between the two components of a binary alloy on the surface structure is investigated for two Hg-Au alloys.