Simulacion numerica del transporte ionico en electrodeposicion en condiciones mas realisticas

G. D. SANTIAGO; A. L. PEURIOT; G MARSHALL; F. V. MOLINA

METODOS NUMERICOS PARA CALCULO Y DESENO EN INGENIERIA

Universidad politécnica de cataluña

Lugar: Barcelona; Año: 2003 vol. 19 p. 159 - 170

0213-1315

Electrochemical deposition in thin layer cells reveals two scales notablydiffering between themselves: a quasi neutral zone ocupying most of the celland a boundary layer charge whose thickness is many orders of magnitudesmaller. Most of the potential drop and concentration variation are producedat the boundary layer, thus a special treatment is required when accuratenumerical simulations are sought. This problem becomes critical when thereis need to simulate concentration solutions close to those used inexperiments. Here we present a numerical model for ion transport equationsin ECD in which that problem is overcome. The model consists in a finitedifference approximation of the one- dimensional Nernst-Planck equations forion transport and the Poisson equation for the electrostatic potential. Dueto the extreme disparity of scales present, an implicit iterative method isintroduced consisting in a non uniform spatial grid varying exponentiallyand an adaptive time step. With this simple strategy a robust algorithm isobtained, yielding for the first time in the literature, stable and accuratenumerical solutions for concentrations of the order of 10$^{17}$ cm$^{-3}$corresponding to diluted solutions of the order of 10$^{-4}$ M.