HYDRODYNAMIC STABILIZATION IN ELECTRODEPOSITION UNDER

S. DENGRA, G. A. GONZÁLEZ

Bariloche, Argentina

Workshop; IX Latin American Workshp on Nonlinear Phenomena; 2005

Abstract Convective due to electric and gravity forces increase complexity in thinlayer electrochemistry (ECD). Here we show that an ECD experiment with thecell in a vertical position relative to gravity and with the cathode abovethe anode, suppresses global convection and produce a dense branchedmorphology dendrite-like structure with a smooth front.We report that under galvanostatic or potenciostaticelectrochemical growth processes in vertical steady thin layerelectrolytes, for some control parameter values, the system reach a globalequilibrium and the deposit stops growing The origin of this event isdiscussed in terms of the competition between the transport processes andthe forces involved. The hydrostatic pressure due to the gravity forcesand the electrostatic forces compensate in a similar way to the thermalproblem of Rayleigh-Benard.We analyze the experimental data in the context of the theoretical modelalready presented which consist on first principles, including theNernst-Planck equation for ion transport, the Poisson equation for theelectric potential, and the Navier-Stokes equations for the fluid flow.Finally we extrapolate some critical values.keywords{electrodeposition, hydrodynamic flow.