Combined impedance and volumetric investigation of inhibition effect of an ecological inhibitor for carbon steel in HCI solution

摘要

Acidic pickling of carbon steel has been one of the major technological processes aiming at steel surface preparation prior further treatment. For that purpose two basic acids: sulphuric and hydrochloric acids are commonly employed. In order to limit weight loss of the steel, various additives such as synthetic organic compounds are used. Benzylaminopurine, azoles, Schiff base, pyridine derivatives, pyrazole derivatives, benzimidazole derivatives all play an effective role as corrosion inhibitors in acidic environment. But they all have some level of toxicity. In recent years a new trend of replacing toxic inhibitors with natural, environment friendly compounds has been noticeable. This work involved impedance and volumetric methods in order to study an effect of natural extract on corrosion protection of carbon steel. Such an approach enables direct correlation of charge transfer resistance parameter with real corrosion rate. Moreover employing Dynamic Impedance Spectroscopy (DEIS) technique allows tracking changes while the samples are immersed in acidic solutions.