Abstract
Five compounds of 5-arylazothiazole derivatives were studied as inhibitors for corrosion of 1018 carbon steel in 0.5 M H2SO4 solution using weight loss and galvanostatic polarization techniques. The percentage inhibition efficiency increases with increasing the concentration of inhibitor, with decreasing the temperature and the presence of the electron donating group in the chemical structure of the inhibitor. Inhibition was interpreted in view of adsorption of these compounds on the steel surface. The adsorption mechanism obeys Freundlish isotherm. The addition of KI to 5-arylazothiazole derivatives improved the inhibition efficiency due to the synergistic effect. Some thermodynamic parameter functions were computed and explained. The polarization curves revealed that the inhibitors were of mixed type. (C) 2016 Elsevier B.V. All rights reserved.