Synergistic Effect of Thiourea and Surfactants on Corrosion Inhibition of Stainless Steel-410 in Presence of Sulfuric Acid

The inhibition of corrosion of stainless steel (SS)-410 in sulfuric acid using thiourea and three different surfactants, cetyle trimethyl ammonium bromide (CTAB), sodium dodecyl sulfate (SDS) and X-Triton was studied. Corrosion rates were determined by using corrosion coupons. The corrosion rate was found to be decreased with increase in inhibitor concentration. It was observed that the maximum corrosion inhibition occurred in the post micellar concentration of the surfactants. By optimizing the corrosion inhibition performance of different blends of surfactants and thiourea in 3 M H2SO4, the corrosion inhibition order was found as: Triton X-100 + thiourea > CTAB + thiourea > SDS + thiourea. The best results obtained by the addition of 200 ppm thiourea in 500 ppm of Triton X-100 in 3 M H2SO4 acid solution. This blend decreased the corrosion rate of SS-410 to 657.66 mpy.