Inhibition Effects of Non-Steroidal Anti-Inflammatory Drugs (Naproxen Sodium and Ibuprofen Sodium) on the Corrosion of Copper in 0.5 M HCl: Experimental and Theoretical Studies

The corrosion inhibitive efficiencies of naproxen sodium (NAP) and ibuprofen sodium (IBU) for copper in 0.5 M HCl solution were investigated by Tafel polarization method. Corrosion potential, corrosion current density, cathodic and anodic Tafel slopes, and inhibition effectiveness were determined. The experimental results suggest that NAP is a good corrosion inhibitor at different concentrations whereas IBU shows low-efficiency values. The reactivity of NAP and IBU was analyzed through quantum chemical calculations based on density functional theory (DFT) in gas and aqueous phases to explain the different efficiencies of these compounds as corrosion inhibitors both in the neutral and protonated forms. Electrophilic and nucleophilic sites of molecules were investigated by Fukui functions.