Dithiobiurets: A novel class of corrosion inhibitors

The inhibiting action of four substituted dithiobiurets on corrosion of mild steel in 1N-5N HCl and 20% H2SO4 was evaluated by weight loss method. All the investigated compounds gave I.E. in the range of 95-99% in 1N-5N HCl. AC impedance and potentiodynamic polarisation techniques were also used to understand the mechanism of inhibition. A comparative study of the inhibiting action of dithiobiuret, viz., PCDTB and,commercial inhibitor (CP) revealed that synthesized inhibitor PCDTB is a better inhibitor than commercial corrosion inhibitor. The percentage metal loss in presence of PCDTB was nearly 7 times less in H2SO4 as compared with commercial inhibitor. Hydrogen permeation studies also indicated the better performance of PCDTB than commercial inhibitor in H2SO4 solution.