In situ microscopic observations of an electroless silver deposition process under high magnetic fields

The mechanism of the morphological effect of magnetic fields on electroless silver deposition was investigated through in situ microscopic observation by using a periscope system that was developed on the basis of a confocal scanning laser microscope. At the growth front of a silver dendrite, under a 12 T magnetic field applied perpendicularly to the sample plane, a silver branch was grown straightly for a while; then, a certain length of the branch at the neighbor of the tip started moving rapidly and was bent in an integrated manner. As a result of the process, a dense silver dendrite in the shape of a vortex was formed. When the sample space was narrowed, the branch did not bend due to the increase in the static friction between the branch and the glass plates. Judging from these observations, the mechanism of the formation of a dense vortex dendrite was thought to be the effect of a Lorentz force acting on the branch due to the electric current flowing through the branch itself accompanied by the silver deposition and the copper dissolution reactions.