Gravimetric and electrochemical evaluation of environmentally friendly nonionic corrosion inhibitors for carbon steel in 1 M HCl

Four environmentally friendly corrosion inhibitors were derived from vanillin and were evaluated gravimetrically and electrochemically as corrosion inhibitors for carbon steel in 1 M HCl. The inhibition efficiencies of these inhibitors were depending on their concentration and the chemical structures. The adsorption of these inhibitors was found to obey Langmuir adsorption model. Polarization measurements showed the mixed type behavior of these inhibitors, which inhibits the cathodic and anodic parts of the corrosion reaction in 1 M HCl.

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► Nonionic inhibitors inhibit the carbon steel dissolution in 1 M HCl media.
► Efficiency increased by increasing their concentration and the alkyl chain length.
► Tafel polarization shows that inhibitors are mixed-type inhibitors.
► One equivalent circuit fitted the experimental data of the impedance diagrams (EIS).
► Inhibitors adsorption on carbon steel interface obeys Langmuir adsorption model.