Inhibitory action of 8-hydroxyquinoline on the copper corrosion process

The effect of 8-hydroxyquinoline (HQ) on the corrosion inhibition of copper has been investigated in neutral aqueous NaCl solutions. Weight-loss measurements and electrochemical methods (impedance spectroscopy and potentiodynamic polarisation) were applied to analyse the metal corrosion behaviour in the absence and presence of the inhibitor, which is a copper ion complexing agent. Surface analysis using XPS, FTIR, and SEM-EDX allowed us to clarify the mechanistic aspects and evaluate the relative inhibitory efficiency. It was stated that a protective film is formed on the surface by polymerisation of Cu(II)-hydroxyquinoline complexes, films that plays an essential role in the inhibition of Cu corrosion. The inhibitory mechanism on the Cu dissolution process was also related to the adsorption of the HQ molecules on the surface, avoiding the adsorption of aggressive ions in solution, such as Cl- or OH-. (C) 1998 Elsevier Science Ltd. All rights reserved.