Enhancement of protection of copper through electropolymerised poly-2-amino-1,3,4-thiadiazole and its composite films

Abstract

Fabrication of an impervious adherent polymeric coating over metallic surfaces has become a robust strategy for the protection of metals from the hazards of corrosion. As part of this strategy, in the present work, poly-2-amino-1,3,4-thiadiazole (p-ATD) films were electrodeposited over copper surface by cyclic voltammetric (CV) technique to prevent its corrosion in 3.5% NaCl medium. Further, the effect of addition of metal oxides such as (La2O3, CeO2, TiO2 and nano TiO2) on the corrosion protection was also studied. The composite coatings on copper surface resulted in the blockage of charge transfer at metal/electrolyte interface which suppressed dissolution of copper in a corrosive medium. The electropolymerised films were characterized using FT-IR and Raman spectra which revealed the formation of polymer through C–N and Cu–N linkages. Further, the X-ray diffraction (XRD) studies confirmed the incorporation of metal oxides into p-ATD. The morphological studies confirmed the formation of protective layer of p-ATD and its metal oxide composites over Cu.. Based on the results of electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization studies (PDS), nano TiO2 composite has a higher corrosion resistance (Inhibition efficiency: 97.53%) compared to other metal oxide incorporated composites. The shift in corrosion potential values from −250 mV to −426 mV upon modification with p-ATD and its metal oxide composites have revealed that the hydrogen evolution reaction of the corrosion process was suppressed significantly by polymer and metal oxide composites of ATD.