Aluminum Deposition from Lewis Acidic 1-Butyl-3-Methylimidazolium Chloroaluminate Ionic Liquid ([Bmim]Cl/AlCl3) Modified with Methyl Nicotinate

The potentiostatic electrodeposition of aluminum (Al) on copper (Cu) substrates from [Bmim]Cl/AlCl3(33.3/66.7mol%) ionic liquid (IL) containing different concentrations of methyl nicotinate (MN) was studied at 303K. It was found that the grain size of the deposits decreased from micron-sized to nanoscale and the preferred Al(200) crystallographic orientation became stronger when increasing the concentration of MN from 2 to 8 mmolL(-1). At a modest potential, a mirror-bright Al coating could be obtained when the concentration of MN was no less than 4mmolL(-1). Furthermore, atomic force microscopy and cyclic voltammetry were used to investigate the effect of MN on the electrodeposition of Al, which demonstrated that MN acted simultaneously as a brightener and a leveling agent by adsorbing on the electrode surface, producing Al coatings with a highly uniform and smooth surface.