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| Titel: |
THE EFFECT OF IONIC MIGRATION AND DIFFUSION ON THE ROUGHNESS DEVELOPMENT OF GROWING ELECTRODEPOSITS. THE USE OF FRACTALS TO COMPARE THEORY WITH EXPERIMENTAL RESULTS |
| Auteur: |
Godorr, S. A. Young, B. D. Bryson, A. W. |
| Verschenen in: |
Chemical engineering communications |
| Paginering: | Jaargang 117 (1992) nr. 1 pagina's 307-335 |
| Jaar: |
1992-09-01 |
| Inhoud: |
Fractal geometry is used to describe (qualitatively and quantitatively) the surface roughness on electrodes as their surface morphology develops during electrodeposition. The effect of current density on copper deposits is investigated experimentally and the surface roughness of the electrodes found to increase with increasing deposition times and current density, the fractal dimension providing a good measure of this roughness A comprehensive model, based on the principles of random walks within a lattice (Markov processes), is developed to simulate the Brownian motion of ions in a force held, hence describing the transport processes operating in an electrolyte. The surface diffusion mechanism occurring at the cathodic surface is simulated in some detail. This model is used to predict the development of a hypothetical electrode surface as a result of the occurrence of electrodeposition. These results are compared to the profiles and properties of the surfaces grown experimentally and were found to resemble them fairly closely, reproducing some general trends in roughness development The simulations show how increasingly random behaviour of depositing particles produces rougher deposits. The effects of increased electrolyte concentrations in smoothing the deposits are investigated, as is the powerful influence of surface diffusion of adsorbed atoms in retarding roughness development. The development of roughness with time is followed and the effect of initial surface roughness on the subsequent development of irregularities is investigated. When the electric field dominates the motion of the depositing particles, the initial roughness tends to enhance the development of irregularities. As particle motion becomes increasingly random, the influence of initial roughness weakens and finally disappears. |
| Uitgever: |
Taylor & Francis |
| Bronbestand: |
Elektronische Wetenschappelijke Tijdschriften |
Details van artikel 26 van 28 gevonden artikelen
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