Surface Composition of Copper-Nickel Alloys

Abstract

The surface composition of alloys is of great importance in determining their chemical and catalytic properties. In this paper, a presentation is given of the application of Auger electron spectroscopy and photoemission spectroscopy to the study of the surface composition of copper-nickel alloys. An enrichment of copper in the surface region is observed for annealed surfaces. The effects of sputtering and chemisorption on the surface composition are also treated. By applying a nondestructive technique like photoemission, it has been demonstrated for the first time that there is at least one oscillation in the depth profile of the composition. This observation cannot be explained readily by the regular solution theory which, for instance, correctly predicts the copper enrichment at the surface.