Substrate and current density effects on electrodeposited aluminium coatings

Abstract

Coatings of aluminium were electrodeposited on copper and mild steel substrates in a room temperature ionic liquid (RTIL) using [EMIm]Cl (95%) and AlCl3 (98%) in a glove box having a controlled atmosphere. Formation and purity of aluminium were confirmed by X-ray diffraction, X-ray fluorescence and energy dispersive spectroscopy measurements. Microcrystalline grain morphology of deposited Al was observed in scanning electron microscopy. The present study showed that Al coating electrodeposited in an RTIL exhibited similar morphology on copper and mild steel substrates, and cathode current efficiency depended on purity of the electrolyte and also on the deposition current density. There were indications for build-up of tensile stress in the coating even at low deposition current density.