Experimental Studies for Carbon Steel Corrosion Inhibition in 3.5% NaCl Solution by Two New N-Benzyl-5-Bromo Isatin Derivatives

Abstract The inhibition ability of two newlysynthesized isatin derivativesnamely N-benzyl-5-bromo isatin derivatives which are N-benzyl- 5-bromo-3-[(imine aceto) urea]-2-oxo indole (5IBO) and N-benzyl-5-bromo-3-[(imine aceto) thiourea]-2-oxo indole (5IBS) toward carbon steel corrosion in 3.5% NaCl solution was evaluated using potentiodynamic polarization and Scanning Electron Microscopy (SEM) measurements. Polarization curves showed that the evaluated compounds acted as mixed inhibitors. The adsorption of the evaluated inhibitors obeys the Langmuir adsorption isotherm. Scanning Electron Microscope (SEM) plots indicated that the presence of the inhibitors increases the charge transfer resistance of the corrosion process, and increasing the inhibition efficiency. The experimental data showed that the 5IBSisatin derivative is a better corrosion inhibitor than the 5IBO.