Electrodeposition of Gallium on Liquid and Solid Gallium Electrodes in Alkaline Solutions

Abstract

A galvanostatic short time transient method has been used to examine deposition and dissolution on gallium electrodes in alkaline solutions of gallic chloride. The cathodic metal deposition current was distinguished from the total current by current efficiency determinations in steady state.Behavior on the liquid electrode is consistent with a charge‐transfer controlled mechanism in all current density regions, and the rate‐determining step is probably .On the solid electrode, the rate constants of the transfer reaction are nearly those of the liquid electrode. However, the behavior in the low current density regions is qualitatively different from that on the liquid. Analysis of phenomena in this region suggests that surface diffusion begins to control the rate of the over‐all deposition process on the solid cathode. Rate constants of the surface diffusion process evaluated from the low current density region are semiquantitatively applicable to deviations from the Tafel equation which occur on the solid at high current densities (surface diffusion controlled limiting current). The results provide support for the existence of rate‐controlling surface diffusion in metal deposition and dissolution reactions.