Olive leaf extract as natural corrosion inhibitor for pure copper in 0.5 M NaCl solution: A study by voltammetry around OCP

Abstract The inhibiting action of olive leaf extract on corrosion of copper in 0.5 M NaCl solution was investigated via potentiodynamic polarization and electrochemical impedance spectroscopy. For the highest inhibitor concentration considered here the inhibition efficiency reached 90% after 24 h of immersion. Polarization curves recorded around OCP were computer fitted with various kinetic laws to obtain detailed information on the inhibition process. This innovative procedure led to results consistent with those deduced from electrochemical impedance spectroscopy and confirmed that the olive leaf extract act as a cathodic-type corrosion inhibitor mainly hindering the transport and thus the reduction of dissolved O 2 . High performance liquid chromatography showed that oleuropein was the major compound of the leaf extract and thus more likely the main inhibiting species.