The synergistic inhibition between hexadecyl trimethyl ammonium bromide (HTAB) and NaBr for the corrosion of cold rolled steel in 0.5 M sulfuric acid

The synergistic effect of the mixture of hexadecyl trimethyl ammonium bromide (HTAB) and various concentrations of NaBr on the corrosion of cold rolled steel in 0.5 M sulfuric acid has been investigated using weight loss method and polarization method. The results reveal that the corrosion of cold rolled steel has been efficiently inhibited by HTAB in the presence of NaBr in sulfuric acid, and inhibition efficiency increases with increasing concentration of NaBr at the same temperature. A synergistic effect has been observed for HTAB with NaBr at every experimental temperature. The polarization curves show that the complex of HTAB and NaBr is a mixed-type inhibitor. The experimental results suggest that the presence of bromide ion in the solution stabilizes the adsorption of HTAB molecules on the metal surface and improves the inhibition efficiency of HTAB. Langmuir adsorption isotherm equation was obeyed at all the temperatures studied. The synergism parameters have been calculated and discussed. The results obtained from weight loss method and polarization method are in good agreement. C 2006 Springer Science + Business Media, Inc. 1. Introduction Corrosive environments have received a considerable amount of attention because of their attack on materials. Using inhibitors is one of the most important applications in corrosion protection, and many compounds containing nitrogen, oxygen, sulphur or phosphorous have been widely reported as efficient corrosion inhibitors in acidic solutions [1–5]. Except for these traditional inhibitors, the applications of various surfactants as inhibitor have ∗Author to whom all correspondence should be addressed. been