Dresden 2009 – wissenschaftliches Programm

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MA: Fachverband Magnetismus

MA 14: Poster Ib: Magnetic Materials (1-14); Micro Magnetism/Computational Mag. (15-17); Surface Magnetism (18-22); Spin Structures/Phase Transitions (23-25)

MA 14.13: Poster

Dienstag, 24. März 2009, 10:15–13:00, P1B

Magnetic field effect on the anodic behaviour of a ferromagnetic electrode in acidic solutions — •Ralph Sueptitz, Jakub Koza, Margitta Uhlemann, Annett Gebert, and Ludwig Schultz — IFW Dresden, Helmholtzstraße 20, 01069 Dresden

The magnetization of a ferromagnetic electrode in an external homogeneous magnetic field leads to a stray field in front of the electrode. This stray and its gradients can alter the anodic behaviour of the electrode significantly. Potentiodynamic polarisation measurements of an iron wire in two acidic electrolytes without and with applied magnetic fields up to 0.6 T in different orientations to the electrode surface were performed. In sulfuric acid solution an increase of the diffusion-limited dissolution current density and a shift of the active-passive transition potential to more noble potentials was observed when the magnetic field was applied parallel to the electrode surface. In contrast, in perpendicular field configuration the diffusion-limited current density is lowered and the active-passive transition potential is shifted to less noble values. In phthalate buffer a shift of the active-passive transition to less noble potentials occurred irrespective of the magnetic field configuration. The observed effects of a superimposed magnetic field on the anodic behaviour of iron are discussed with respect to an increase of the mass transport due to the magnetohydrodynamic (MHD) effect, the magnetic field gradient force and its interaction with the paramagnetic iron ions. The results show that the effect of the field gradient force can become very important due to the high magnetic field gradient at ferromagnetic electrodes.