Evaluation of Artichoke Extract as a Corrosion Inhibitor for Copper and OL45 in Aggressive Environments

Abstract Metal corrosion is a significant issue in areas such as transport, construction, or production, with effects on equipment productivity, user safety, and finally, the costs related to the replacement of affected components. Research in recent years has focused on the discovery of substances capable of significantly reducing the corrosion rate of metals and alloys with a minimal impact on the environment. A promising category of green corrosion inhibitors represents active components from natural extracts. Corrosion experiments have been focused on the use of artichoke (Cynara scolymus) stem extract as a corrosion inhibitor for copper and mild steels such as OL45 in H2SO4 0.5 mol L-1 and NaCl 3.5% environments. The electrochemical behaviour of the active components in the artichoke extract was studied using cyclic voltammetry on Pt electrode, and their inhibitory effect has been demonstrated by using electrochemical techniques such as linear voltammetry at a speed of 1 mV s-1 and chronoamperometry method in the absence, respectively, presence of 1, 2, 4, and 8 g L-1 extract. The variation of parameters such as corrosion potential Ecorr , corrosion current icorr , and impedance values with increasing concentrations shows that the artichoke extract greatly reduces the corrosion rate. To complement the corrosion studies carried out, quantum chemical calculations were performed by using the B3LYP/6-31G* basis set, and the descriptors EHOMO, ELUMO, dipole moment, ionization energy, and molecular hardness substantiated the inhibitory effect. Considering artichoke extract components, this study presents a potential prospect for using natural extracts in anti-corrosion protection as well as an ecological alternative to standard corrosion inhibitors.