Mg-alloys in water – hydrophilic ionic liquid mixtures: Is there a negative difference effect?
By Kurchavov, D.; Haddad, M.; Lair, V.; Volovitch, P.
Published in Corrosion Science
2022
Abstract
Commercial purity Mg and Mg-alloy AZ61 were exposed at open circuit potential and under anodic polarization in two ionic liquids containing 10 wt% of water, formed by acetate anion and methylpyrrolidinium cation, substituted with either aliphatic (ILA) or etheric (ILE) chain. Hydrogen evolution strongly increased under anodic polarization (negative difference effect, NDE) in ILA, but not ILE. In both electrolytes Mg(OH)2-film formed on Mg but not on AZ61. The NDE suppression did not correlate neither with the presence of carboxylate, nor with the absence of Mg(OH)2, indicating strong differences between magnesium-water interactions in IL-water mixtures and in inorganic aqueous solutions.