RETRACTED ARTICLE: Dynamic Mechanical and Electrochemical Analysis of Newly Synthesized Polyurethane/CuO–NiO Mixed Metal Oxide Nanocomposite Coated Steel in 3.5% NaCl solution

CuO–NiO mixed metal oxide nanoparticles were synthesized and characterized by Fourier transformed infrared spectroscopy (FTIR) and X-ray diffractometry (XRD) analysis. The inclusion of mixed CuO–NiO nanoparticles in the polyurethane (PU) results in the formation of PU/CuO–NiO nanocomposite which was coated on the mild steel. The anticorrosion behaviour of PU/CuO–NiO nanocomposite coating was electrochemically studied and compared with pure polyurethane coating by scanning electrochemical microscopy (SECM), potentiodynamic polarization studies and electrochemical impedance spectroscopy (EIS) for 1, 240, 480, and 720 h of immersion in 3.5% NaCl solution. EIS studies showed a pronounced protection performance for PU/CuO–NiO coating in 3.5% NaCl solution. SECM analysis measured lower current for the PU/CuO–NiO at the scratch of the coated surface compared to PU coating. Dynamic mechanical analysis (DMA) test was also carried out to investigate the coated nanocomposite. The results provided valuable information about the protective performance and failure analysis of PU/CuO–NiO nanocomposite coated surface. Field emission-scanning electron microscopy/energy dispersive X-ray (FE-SEM/EDX) analysis was used to examine the corrosion products formed on the surface of coated sample. The formation of thin films of oxides and chlorides of Cu and Ni blocks the penetration corrosive ion in the coating/metal interface. It was revealed from the mechanical properties of the nanocomposite and pure PU coatings that the mixed metal oxide nanoparticles (CuO–NiO) enhanced mechanical as well as barrier properties of the polyurethane coating against corrosion.