Indole-3-acetic acid and N-acetyltryptophan corrosion inhibition effects on mild steel in 1M hydrochloric acid solution

摘要

Corrosion inhibition of indole-3-acetic acid and N-acetyl tryptophan on carbon steel was investigated using polarization and electrochemical impedance spectroscopy (EIS). Polarization results revealed that corrosion inhibitors could reduce the rate of cathodic and anodic reactions on metal surface. EIS analysis showed inhibition efficiency of indoles increases by increasing the inhibitor concentration. The maximum inhibition efficiency was 97% and 80% in solutions containing 10mM indole-3-acetic acid and 10mMN-acetyl tryptophan, respectively. The adsorption of inhibitors was found to follow Langmuir isotherm. Adsorption and film formation of inhibitors on the metal substrate were confirmed by calculating thermodynamic adsorption parameter (G(ads)(0)) and characterization of exposed metals' surface through contact angle measurements. Copyright (c) 2014 John Wiley & Sons, Ltd.