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The effect of magnetic fields on the electrodeposition of Fe
J. Koza, M. Uhlemann, A. Gebert, L. Schultz Leibniz-Institute for Solid State and Materials Research Dresden P.O.Box 270016, D-01171 Dresden, Germany E-mail: M.Uhlemann@ifw-dresden.de |
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The effect of a uniform magnetic field with flux density up to 1 T and different configuration relative to the electrode surface on the electrodeposition of Fe from sulphate electrolyte has been investigated. Voltammetric and chronoamperometric experiments have been carried out coupled with the electrochemical quartz crystal microbalance for in situ mass change measurements. The structure and morphology of the deposited films were determined by scanning electron microscopy, atomic force microscopy and X-ray diffraction measurements.
Results show that when the magnetic field is applied parallel to the electrode surface the limiting current density and deposition rate are increased due to the MHD-effect. The nucleation process is also affected in this parallel configuration. From the current time transient an additional nucleation step (III) might be observed in Figure 1 and is discussed with respect to different models. The morphology of the deposits is more homogeneous and the roughness is lower compared to layers deposited without magnetic field. When magnetic field was applied perpendicular to electrode no significant influence on electrochemical reaction was observed. But in this configuration the morphology of deposited layers is strongly changed by the magnetic field. The shape of the grains is polyhedral and the grains are oriented perpendicular to the electrode surface in the direction of the field. No effect of the magnetic field on the crystallographic structure was observed independently of the flux density and the orientation.
Fig. 1: I(t) and dm(t) transients in dependence on the orientation and strength of the magnetic field; (a), (b) parallel and (c),(d) perpendicular configuration.