The inhibition performance of a non-oxidising surfactant, namely cetyl trimethyl ammonium bromide (CTAB), and its co-adsorption behaviour with zinc ion on carbon steel in well water was studied by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), weight loss, as well as atomic force microscopy (AFM) and scanning electron microscopy. Results indicated that the formulation acted as an anodic inhibitor. Adsorption of the used inhibitor led to a reduction in the double layer capacitance and an increase in the charge transfer resistance. A synergistic effect was also observed for the studied inhibitor with Zn 2+ in weight loss measurements and electrochemical studies.

The inhibition of corrosion of carbon steel in well water using diethylenetriamine penta (methylene phosphonic acid) (DETPMP), Zinc ions and dodecyltrimethylammonium bromide (DTAB) was investigated using weight-loss measurement, electrochemical polarization and impedance methods. Inhibition efficiency of above ternary inhibitor reaches maximum values at 93 %. The biocidal efficiency of DTAB was studied which reaches maximum of 88 % at 125 ppm DETPMP, 10 ppm Zn 2? and 150 ppm DTAB. The shape of DC polarization profile revealed the new ternary system which acts as anodic type inhibitor. AC impedance spectroscopic studies indicated the formation of a protective film onto the metal surface in the presence of inhibitors. Analyses of the protective film using scanning electron microscope, energy dispersive X-ray analysis, atomic force microscopy and Fourier transfer infrared spectroscopy have revealed that the film consists of Zn(OH) 2 , oxides and hydroxides of iron and the inhibitor molecules in the form of a complex.

The corrosion behaviour of cationic surfactants, namely: cetyl trimethyl ammonium bromide (CTAB) and dodecyl trimethyl ammonium bromide (DTAB), have been used as corrosion inhibitors for carbon steel in well water. Protection efficiencies of the studied surfactants were depended on the hydrophobic chain length and concentration of the surfactants. The results shows that the order of protection efficiency is CTAB > DTAB. Tafel curves showed these surfactants are acting as an anodic inhibitors. Nyquist curves revealed that a protective film is formed on the metal surface. FTIR spectra suggest that the tested surfactants protective film consists of Fe2+-CTAB, Fe2+-DTAB and Zn(OH)2. Protection efficiency values and synergism parameters obtained weight loss; potentiodynamic polarization and electrochemical impedance spectroscopy are consistent.

The corrosion behaviour of cationic surfactants, namely: cetyl trimethyl ammonium bromide (CTAB) and dodecyl trimethyl ammonium bromide (DTAB), have been used as corrosion inhibitors for carbon steel in well water. Protection efficiencies of the studied surfactants were depended on the hydrophobic chain length and concentration of the surfactants. The results shows that the order of protection efficiency is CTAB > DTAB. Tafel curves showed these surfactants are acting as an anodic inhibitors. Nyquist curves revealed that a protective film is formed on the metal surface. FTIR spectra suggest that the tested surfactants protective film consists of Fe2+-CTAB, Fe2+-DTAB and Zn(OH)2. Protection efficiency values and synergism parameters obtained weight loss; potentiodynamic polarization and electrochemical impedance spectroscopy are consistent.

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