Corrosion Inhibition of Carbon Steel in Hydrochloric Acid Solution using Non-Ionic Surfactants Derived from Phenol Compounds

Nonionic surfactants derived from phenol compounds inhibit the corrosion of carbon steel in 1.0 M HCl solution using galvanostatic polarization, electrochemical impedance spectroscopy, potentio-dynamic anodic polarization and weight loss techniques. The percentage inhibition efficiency of these compounds increases with increasing the concentration of inhibitors and number of ethylene oxide units per molecule. Inhibition was explained on the basis of adsorption of these compounds on the steel surface. The adsorption process obeys Langmuir isotherms. Polarization data suggested that the non ionic-surfactant molecules used as mixed type inhibitors. All impedance spectra tests exhibit one capacitive loop indicating that the corrosion reaction is controlled by charge transfer process. Nonionic surfactant compounds inhibit the pitting corrosion in chloride containing solutions by shifting the pitting potential into the noble direction.