INHIBITING EFFECTS OF BENZOTHIAZOLE AMINE SCHIFF BASES ON THE CORROSION OF MILD STEEL IN ACID ENVIRONMENT

Abstract

The corrosion inhibition of mild steel in 1M H2SO4 solution by Benzothiazol-2-yl- benzylidene amine (BBA) & 2-(Benzothiazol-2-yliminomethyl)-phenol (BIP) has been studied by weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy. The experimental results showed that the inhibition efficiency increases with increasing inhibitor concentration but decreases with increasing temperature. The adsorption of inhibitors on the mild steel surface obeyed the Langmuir adsorption isotherm. Potentiodynamic polarization curves revealed that the compounds act as mixed type inhibitors. The impedance measurements showed a change in the charge transfer resistance and double layer capacitance indicating adsorption of inhibitors on the mild steel surface. Surface analysis of mild steel has been carried out using scanning electron microscopy (SEM) with EDX and Fourier transform infrared (FT-IR) spectroscopy. Quantumchemical calculations have been performed and several quantum chemical indices were calculated in order to complement the experimental results