Corrosion inhibition of aluminum in 1.0M HCl solution by some nonionic surfactant compounds containing five membered heterocyclic moiety

Abstract

Abstract Three nonionic surfactant (NIS) compounds containing five membered heterocyclic moiety were synthesized and identified from spectral data such as IR and 1HNMR spectra. The inhibiting effect of NIS compounds toward the corrosion of aluminium (Al) in 1.0MHCl solutions was examined using weight loss, thermometric, electrochemical impedance spectroscopy and galvanostatic polarization techniques. The results obtained indicated that the three compounds are good corrosion inhibitors. The inhibition efficiency increases as the concentration of the NIS compounds increases, as well as the decrease in temperature, surface tension and interfacial tension. The polarization measurement showed that these inhibitors are acting as mixed inhibitors mainly cathodic. The inhibition was interpreted in view of spontaneous adsorption of NIS compounds onto the Al surface by forming a stable chelating ring between the Al surface and NIS molecules. The adsorption mechanism obeys Freundlich isotherm. The activated thermodynamic parameters such Ea, ΔH* and ΔS*were calculated and clarified.