The corrosion behavior of carbon steel in 1.0M HCl solution in the absence and presence of some nonionic surfactant derived from hydroquinol compounds was investigated using galvanostatic polarization, electrochemical impedance spectroscopy and potentiodynamic anodic polarization techniques. The results of these techniques indicated that the percentage inhibition efficiency, increased with increasing the concentration of inhibitors and number of ethylene oxide unit. Polarization curves revealed that the studied inhibitors act as mixed type inhibitors. Inhibition was interpreted by the horizontal adsorption of inhibitors on the steel surface due to the presence of more than one active center for adsorption. The adsorption process obeys Langmuir isotherms. All impedance spectra in the EIS technique exhibit one capacitive loop indicating a charge transfer process, mainly controlling the corrosion of carbon steel. Double layer capacitances decrease with respect to the blank solution when these inhibitors added due to the adsorption of these inhibitors on the steel surface. It is also found that these compounds inhibit the pitting corrosion of carbon steel in chloride containing solutions by shifting the pitting potential into more noble direction. |
