MICROBEAM ANALYSIS STUDIES OF THE COPPER SILVER INTERFACE

Copper-silver bimetallic samples have been examined by microbeam analytical techniques. Composition studies have concentrated on the interface region between the two metals. In this region two distinct phases characteristic of a eutectic structure were observed by backscatter electron imaging in the SEM. X-ray microanalysis has shown that the eutectic is composed of a copper-rich and a silver-rich phase. The crystal structure and composition of the constituent phases of the eutectic material have been confirmed by electron diffraction studies of a thinned foil of the eutectic composition. The surface structure of ion-beam etched eutectic material has been examined at high resolution. The silver-rich constituent of the eutectic is found to etch preferentially. The surface composition of the eutectic has been explained in terms of this ion-beam-induced surface structure.