Electrodeposited Aluminium coatings: effect of deposition parameters on the anticorrosion properties

Since their discovery, ionic liquids (IL) have attracted a wide interest for their potential use as medium for many chemical processes, which vary from extraction, to catalysis, to organic synthesis. In electrochemistry, their use as electrolytes has allowed electrodeposition of metal cations that were previously impossible to reduce in aqueous media. In particular, the first generation ILs (the so called chloroaluminated ILs) have made possible the deposition of Aluminium from his chloride salt. Despite the discovery of this process in the nineties, nowadays aluminium electrodeposition from Chloroaluminate ILs still maintains a number of open issues both on the side of fundamental science and technological aspects. The present communication aims to shed some light on the aluminium electrodeposition process as concerns the effect of deposition parameters. Thick Al-coatings (20 μm) were deposited on brass substrate at different temperature, potential and stirring conditions. Then, the coatings morphology and phase composition was investigated by menans of optical and electronic microscope, rugosimetry and X-ray diffracton. Finally electrochemical corrosion investigation was performed by means of Open Circuit potential recording, potentiodynamic polarization and electrochemical Impedance spectroscopy, to correlate Al-coating structure with their corrosion properties.