Schiff Bases of 2,5-Thiophenedicarboxaldehyde as Corrosion Inhibitor for Stainless Steel under Acidic Medium: Experimental,Quantum Chemical and Surface Studies

摘要

Corrosion of stainless steel(SS)under acidic medium were studied with and without the presence of N’,N’’’-(thiophene-2,5-diylbis(methanylylidene))di(isonicotinohydrazide)(SS1)and 2,2’-(thiophene-2,5-diylbis(methanylylidene))bis(N-phenylhydrazinecarbo thioamide)(SS2).Different techniques like weight loss,potentiodynamic polarization,Electrochemical Impedance Spectroscopy(EIS),Scanning Electron Microscopy(SEM),Fourier Transform Infrared spectroscopy(FT-IR)and Atomic Force Microscopy(AFM)were employed to demonstrate the corrosion inhibitive behaviour of studied Schiff bases.Results of all the experiments proved that SS2 functions as more convincing inhibitor than SS1 under the studied condition.Corrosion inhibition performance of Schiff base with more sulphur atoms(SS2)against corrosion of SS under acidic medium is comparatively high.Theoretical analysis was further implemented to derive various molecular parameters of the Schiff bases.Energy values of molecular orbitals such as E_(HOMO),E_(LUMO)and ΔE etc.have provided helpful information regarding electron transfer during adsorption of Schiff bases on stainless steel surface.