Corrosion and anodic oxidation of copper in 1-butyl-3-methylimidazolium bromide–copper(II) bromide ionic liquid

Abstract

Using the gravimetric and polarization methods, the corrosion behavior of copper in 1-butyl-3-methylimidazolium bromide (BMImBr) ionic liquid in its pure state and with additions of CuBr2 (from 0.4 to 1.2 mol kg–1) has been investigated. It is found that the corrosion in naturally aerated BMImBr ionic liquid is accompanied by oxygen depolarization. Copper dibromide in BMImBr–CuBr2 ionic liquid plays the role of an oxidant, and the rate of copper corrosion in this case is higher by about an order of magnitude than for the pure ionic liquid. The method of cyclic voltammetry shows that the anodic dissolution of copper in BMImBr–CuBr2 ionic liquid proceeds via the EC mechanism. It is shown that the chemical-reaction rate of dissolving the surface layer and the rate of copper corrosion (according to gravimetric and polarization data) are comparable. Copper corrosion in the studied ionic liquid is accompanied by the effect of surface polishing, as is confirmed by the atomic force microscopy and profilography.