Author : C. Mary Anbarasi and Susai Rajendran

The corrosion inhibition efficiency of octane sulphonic acid as its sodium salt C8H17SO3Na (SOS) in combination with a bivalent cation like Zinc ion(Zn2+) in controlling corrosion of carbon steel immersed in dam water have been evaluated by weight loss method. A significant decrease in the corrosion rate was observed in presence of the investigated inhibitor system. The formulation consisting of 1.16×10-3 mol/l of (SOS) and 1.04×10-4 mol/l of Zn2+ offers the maximum inhibition efficiency ( IE=88 % ) to carbon steel. A synergistic effect exists between SOS and Zn2+. As the immersion period increases IE decreases. AC impedance spectra reveal that a protective film is formed on the metal surface. These observations have been supported by surface morphology studies using atomic force microscopy (AFM) carried out on the carbon steel samples in the absence and presence of inhibitor.

Keywords: Carbon steel, Corrosion inhibition, Synergistic effect, surface morphology, atomic force microscopy

Article published in International Journal of Current  Engineering  and Technology, Vol.3,No.5(Dec- 2013)