Evaluation of Boundary Layer Thickness in Electrolytic Systems from Decay of Anode Concentration Polarization

Abstract

THE boundary layer produced in the vicinity of a dissolving anode in an electrolytic system is maintained by a supply of ions from the electrode, which supply balances the migration away from the layer due to the combined effects of electrical transport, diffusion and convexion. On interruption of current, the excess concentration of the existing boundary layer is reduced by convexion and diffusion into the bulk of the electrolyte. The convexion conditions may be very complex since a natural convexion mode occurs as a result of changes in solution density in the immediate vicinity of the electrode.