Effectiveness of sodium dodecyl sulfate for mild steel surface in an acidic medium: energy dispersive X-ray and field emission scanning electron microscopy techniques

Abstract

Mild steel (MS) metal with a wide range of engineering applications in construction as well as infrastructure is often prone to corrosion in acidic environments. In the present study, the inhibitory behavior of sodium dodecyl sulfate (SDS), a surfactant with large organic moiety and sulfur as a heteroatom, towards corrosion of MS was investigated. The inhibited MS samples were prepared by immersing them in 0.01 M SDS solution in 0.5 M sulfuric acid for 9 h at room temperature. Similarly, energy dispersive X-ray (EDX) and field emission scanning electron microscopy (FESEM) techniques were used for the surface characterization. The FESEM analysis revealed a more uniform and smooth surface with a few pits and cracks in the presence of SDS, indicating the formation of a protective film on the MS surface. The presence of an intense high peak of carbon, oxygen and sulfur in the EDX spectra confirmed the adsorption of the SDS molecule on the metal surface. The increased weight composition of elements further supported the adsorption of SDS on the metal surface. These findings confirm SDS as an effective corrosion inhibitor for MS by formation of a protective layer against corrosive environment.