Comparative Investigation of Benzotriazole and Humid Air Plasma on Corrosion Inhibition of Carbon Steel

Abstract

Current research trends to focus on finding an alternative to the toxic 1H-BTA Benzotriazole for its corrosion inhibition properties on metal surfaces. Therefore, our study investigates the chemical properties of 1 H-BTA and simultaneously the gliding arc discharge (GAD) in humid air as a potential substitute. The inhibiting oxidation property of 1H-BTA benzotriazole on a carbon steel C75 sample in 0.5M NaCl has been compared to the oxidative properties obtained by exposing the same sample to GAD using weight loss measurement and electrochemical methods, e.g., electrochemical impedance spectroscopy (EIS), potentiodynamic polarization. The inhibition efficiency increases with 1H-BTA concentration to attain 75% at 10 mM. Polarization curves indicate that 1H-BTA acts as a mixed-type inhibitor. Inhibition efficiency values obtained from various methods were in good agreement. EIS measurements showed an increase of the transfer resistance with the inhibitor concentration. The adsorption of the inhibitor on the carbon steel surface in the NaCl solution was found to obey Langmuir’s adsorption isotherm and the adsorption free energy ∆Gads° has been deduced. The data obtained when treating carbon steel by GAD show similar behaviour with the formation of a passivating layer (barrier) on its surface. Data analysis reveal that 60 minutes plasma treatment have similar results with a concentration of 10 mM of 1H-BTA and an inhibition efficiency of the order of 75 %, which not only shows the importance of gliding arc discharge in surface treatment but also that discharges be used preferentially  to 1H-BTA benzotriazole.