Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

The contribution will give an overview of recent results regarding the influence of magnetic fields on the electrochemical deposition of metal. Magnetic fields give rise to forces on the electrolyte which, if properly applied, can be useful. Lorentz forces have been known long-since for causing convection of the electrolyte, and thus, to affect mass transfer. Magnetic gradient forces are well established for the purpose of magnetic particle separation and also influence electrolytes that consist of para- or diamagnetic ions and molecules. The presentation will mainly discuss two different ways of controlling the metal deposition by tailored magnetic fields. First it will be shown that Lorentz forces originating from specific inhomogeneous magnetic field configurations can be utilized for improving the uniformity of the metal deposit at vertical electrodes, despite of the influence of buoyancy [1].
On the contrary, magnetic fields can also be beneficial for obtaining a desired non-uniform deposition at length scales down to the micrometer range. Here, the Kelvin force resulting from small-scale gradient fields can be utilized. Depending on the electrolyte composition, structured deposits of paramagnetic and also of diamagnetic metal ions can be obtained, despite of the small modulus of the magnetic susceptibility of the latter. In both examples, analytical reasoning, simulations and experimental results of lab-scale electrochemical systems will be presented which elucidate the interplay of forces, the electrolyte flow and the effect on mass transfer [2-3].

References:

[1] S. Mühlenhoff et al.; On the homogenization of the thickness of Cu deposits by means of MHD convection within small dimension cells. Electrochem. Comm. 36 (2013) 80–83.
[2] G. Mutschke et al.; Comment on "Magnetic Structuring of Electrodeposits". Phys. Rev. Lett. 109 (2012) 229401.
[3] M. Uhlemann et al.; Structured Electrodeposition in Magnetic Gradient Fields. Eur. Phys. J. Spec. Top. 220 (2013) 287-302.