Inhibition Effect of Tetraethanol-b-Octadecenyl Succinylamide

in Acidic Corrosion of Carbonized Steel

Florida L.Halilova and Ramiz M.Aligulyev

Azerbaijan State Research Institute of Olefins, 370025 Baku, Azerbaijan

Abstract

The influence of tetraethanol-b-octadecenyl succinylamide (TOSA) on the corrosion of steel in H2SO4 and HCl solutions of divers concentrations has been studied using gravimetrical, electrochemical and polarization corrosion test methods. It has been observed that the TOSA behaves as an inhibitor of molecular active cathodic type and has inhibition effect at the beginning stage of corrosion in both acids, but more effectively in H2SO4. It is shown that the inhibition effect of the TOSA increases with temperature increasing from 91 % at 20C to 100 % at 80C in 0.5 N H2SO4 solution and decreases with temperature increasing for higher concentrations of acid solutions. From obtained electrocapillary curves it is evidenced that the TOSA is a primarily additive of molecular type (insignificant shift of the maximum to the positive side on the curves). Moreover, it is surface active compound those superficial strength substantially decreases in H2SO4 (30 dyn/cm) and HCl (34.9 dyn/cm) solutions. It has been shown that the TOSA has a high protection effect and high formation rate of adsorption layer on the metal surface in H2SO4 (y = 96.4 % and t = 8.0 min) and HC1 (y = 91.5 % and t = 4.0 min).