The electrodeposition of aluminium molten aluminium chloride-sodium

The electrodeposition of aluminium on mild steel from a dry and HCl-free A1C13/NaC1 melt (80 wt% purified A1C13, 20 wt% NaC1) has been studied. Electropolishing the substrate in the same electrolytic bath produced satisfactory electroplates with almost 100% current efficiency. The quality of the plate has been examined through photomicroscopy of the cross-section, profilometry, electron microscopy, and electron microprobe analysis of the surface of the electroplate. It has been suggested that the greyish colour of the plate is most probably due to the'presence of iron as an impurity in the electroplated aluminium.