Purpose -The paper aims to study the dissolution of Al, Al-3.84%Cu, Al-5.22%Cu and Al-11%Cu alloys in different concentrations of NaCl (10-5-10-1 M). Design/methodology/approach -The approach is to use open circuit potential (OCP) and potentiostatic polarization measurements. Findings -Results obtained showed that, as the Cu content was increased in the Al-Cu alloys, a steady state potential was rapidly reached. Addition of different concentrations of CuCl 2 to 0.5 M NaCl demonstrated that by increasing the concentration of CuCl 2 up to 2 ppm a greater increase in the OCP towards more anodic value occurred from the moment of immersion. Further increases in the concentration of CuCl 2 , up to 600 ppm, exhibited the same behavior.Originality/value -The results of the study reveal that cathodic current was controlled by the oxygen in solution, while the anodic current increased with increased Cu content in the alloy.

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Optical microscope (O.M) and scanning electron microscope (SEM) equipped with energy dispersive X‐ray (EDX) were used to follow the changes that occurred on the surfaces of copper after treated electrochemically in concentrated solutions of LiBr (up to 9 M). Results showed the existence of protective film of CuO and Cu(OH)2 which are recorded during the passive film formation in 5 × 10–1 M LiBr at 200 mV. At 1 M LiBr and during the partial passive region (600 mV) a porous film of Cu2O with a small ratio of CuOH and Cu(OH)2 were detected which confirmed the higher current density recorded. On the other hand and at the same concentration (1 M LiBr at 1000 mV), surface examination confirmed the detection of CuBr2 with small ratio of CuO which explain the deleterious effect of bromide and the autocatalytic dissolution of Cu at this higher potential. At higher concentrations from 4 to 9 M, the film formed is non homogeneous with a more porous structure which is mainly CuBr and some area of the film suffered from cracking. This proves the general dissolution through the complexing formation of soluble CuBr2–.

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