Journal of Applied Electrochemistry | 2021
Superior corrosion protection performance of polypdopamine-intercalated CeO2/polyurethane nanocomposite coatings on steel in 3.5% NaCl solution
Abstract
Newly synthesized polyurethane (PU)–polydopamine (Pda)/CeO2 (cerium oxide) nanocomposite-coated mild steel was investigated for its corrosion protection performance and mechanical properties in 3.5% NaCl by electrochemical techniques. The functionalization of CeO2 nanoparticles by Pda was confirmed by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction analysis (XRD), scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). The results derived from the electrochemical impedance spectroscopy (EIS) and polarization studies indicated the superior anticorrosive activity of PU–Pda/CeO2 nanocomposite coatings compared to those of plain PU coatings due to the synergetic effect of Pda/CeO2 and polyurethane. Decreased corrosion current was detected at the scratch of the PU–Pda/CeO2 nanocomposite-coated mild steel surface by scanning electrochemical microscopy (SECM) compared to other studied coatings. Addition of Pda-wrapped CeO2 nanoparticles into the PU coating resulted in the blockage of charge transfer at metal/electrolyte interface which reduced the dissolution of mild steel. It is due to the synergistic effect of Pda and CeO2 which strengthens the anticorrosive property. It was revealed from the SEM/EDX analysis that the formation of the corrosion products at the metal/electrolyte interface behaved as the passive layer which reduced the dissolution of steel. The incorporation of Pda-functionalized CeO2 nanoparticles to PU enhanced the mechanical properties of the coated surface which complimented the electrochemical studies. The superior anticorrosive property of the proposed nanocomposite coatings provides a new horizon in the development of high-performance anticorrosive coatings for various industries.