Corrosion inhibition of steel by benzotriazole in sulphuric acid

The corrosion behaviour of low-carbon steel in different concentrations ( 10(-3) to 9 x 10(-3) M) of benzotriazole (BTA) in 1 M H2SO4 has been studied by potentiodynamic polarization measurements at a scan rate of 0.166 mV s(-l). It is found that passivation current, corrosion potential, passive potential and polarization resistance increase with increasing benzotriazole concentrations, while critical current, corrosion current and corrosion rate decrease. It is established that the corrosion rate depends on the concentration of the inhibitor and chloride ions along with the sweep rate of polarization. A maximum inhibition efficiency (98.5%) was obtained at 9 x 10(-4) M BTA. Thermodynamic parameters for adsorption of BTA are calculated. (C) 1998 Elsevier Science S.A. All rights reserved.