Inhibition of corrosion of carbon steel in dam water (Tamil Nadu, India) by Pentane sulphonicacid as its
sodium salt (SPS)-Zinc ion system has been studied using weight-loss and potentiodynamic polarization methods. Results
of weight loss method indicated that inhibition efficiency (IE) increased with increasing inhibitor concentration.
Polarization study reveals that SPS-Zn2+ system functions as a cathodic inhibitor. AC impedance spectra reveal that a
protective film is formed on the metal surface. The nature of protective film formed on the metal surface has been
analysed by FTIR spectra and AFM analysis. From the results of above studies a suitable mechanism for corrosion
inhibition is proposed.