Supplementary material from "Effectiveness of SDS for mild steel surface in an acidic medium: Energy dispersive X-ray and field emission scanning electron microscopy techniques"

Mild steel (MS) metal with a wide range of engineering applications in construction as well as infrastructure, is often prone to corrosion in acidic environment. In the present study, the inhibitory behavior of Sodium dodecyl sulphate (SDS), surfactant with large organic moiety and sulphur as heteroatom, towards corrosion of MS was investigated. The inhibited mild steel samples were prepared by immersing them in 0.01M SDS solution in 0.5M sulfuric acid for 9 hours at room temperature. Similarly, Energy dispersive X-ray (EDX) and Field Emission Scanning Electron Microscopy (FESEM) techniques were utilized for the surface characterization. The FESEM analysis revealed a more uniform and smooth surface with a few number of pits and cracks in the presence of SDS indicating the formation of a protective film on 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 metal surface. These findings confirm SDS as an effective corrosion inhibitor for mild steel by formation of protective layer against corrosive environment.