Behavior of Fe/nano-Si particles composite electrodeposition with a vertical electrode system in a static parallel magnetic field

• Fe-Si coatings were prepared by nano-composite electroplating in magnetic field.
• A wavy and striped surface appeared on the surface of coatings with magnetic field.
• The silicon particles content of coating showed an obvious tendency of increasing.
• The surface distribution of silicon element showed like some stripes in 1.2 T.
• Natural convection was a key point of the mechanism for explanation.

Composite iron coatings containing nano-silicon particles were produced using a vertical electrode system in the presence of and the absence of magnetic field parallel to the current at 25 °C. The surface morphology, the surface distribution of elements, the cathode current efficiency and the silicon particles content of coatings have been investigated respectively under the influence of magnetic field. Compared to the rather smooth surface morphology of Fe-Si composite coating without magnetic field, it became wavy and striped obviously with imposing magnetic field, meanwhile, the surface roughness Ra in the right region of composite coatings was significantly larger than that in the left region due to the existence of more needlelike iron deposits. Furthermore, silicon particles dispersed uniformly on the surface of coating when no magnetic field was applied, whereas silicon particles connected gradually to form the distribution of some stripes under the influence of magnetic field. Meanwhile, the silicon particles content of coatings presented a trend of increasing with increasing the magnetic flux density. Finally, a possible mechanism has been put forward to illustrate those phenomena in this paper.