Electrodeposition of aluminium film on P90 Li–Al alloy as protective coating against corrosion

Abstract

In this paper we report on the electrodeposition of thin aluminium layers on P90 lithium–aluminium alloy at room temperature from a chloroaluminate ionic liquid (1-butyl-3-methyl imidazolium heptachloroaluminate [BMIm]Al 2Cl 7). We found that the treatment of the P90 sample's surface is a key point to obtain good quality coatings. On freshly mechanically polished surfaces, thin (about 24 µm), homogeneous and dense aluminium layers were obtained at 10 µm h − 1 deposition rate. Finally, the corrosion resistance of the uncoated and Al-coated samples was investigated by means of electrochemical techniques such as open-circuit voltage curves, impedance spectroscopy and potentiodynamic polarization in 3.5 wt.% NaCl aqueous solution. We found that the protective aluminium layer significantly reduces the corrosion rates of the P90 Li–Al alloy.