The effect of magnetic field on the electrodeposition of CoFe alloys

The superimposition of a homogenous magnetic field during an electrodeposition of CoFe alloy was investigated. A magnetic field superimposed parallel to the electrode surface increases the limiting current density and the deposition rate due to the magnetohydrodynamic (MHD) effect. The deposits obtained in this field configuration appear smoother and more homogenous than the ones obtained without the magnetic field. On the contrary, a magnetic field superimposed perpendicular to the electrode surface does not influence significantly the electrochemical reaction but the morphology of the deposited layers is strongly affected. The roughness is strongly increased in this field configuration and grains grow as separated columns aligned perpendicular to the electrode surface, in the field direction. A magnetic field applied during the deposition affects the magnetic properties of the deposited layers as well. These changes are discussed with respect to the surface roughness and the internal stress state of the layer.