Transmission electron-microscopic study on the growth of copper whiskers by halide reduction

Abstract

Transmission electron-microscopic observations have been made, using 100, 500 and 1000 kV electron microscopes, on many thin copper whiskers grown directly on small Cu meshes-as used commonly for electron-microscopic observations — which were obtained by the reduction of CuI melt with a H 2 atmosphere. Various observational facts are reported, but dislocations which might play an important roˆle in the growth process involving the screw-dislocation mechanism have not been detected. Further, the experimental results give no conclusive evidence supporting any other available growth mechanisms. Thus, it is concluded that systematic transmission electron-microscopic or any other “atomic-scale” observations of “growing” whiskers are necessary to make clear the mechanism and kinetics of the reduction growth of metal crystals. It may be that metal whiskers grow from their roots and bases in the hydrogen reduction of their halides of solid and melt states, respectively.