Evaluation of newly synthesized multifunctional nanocomposite coated cupronickel alloy in marine environment

Abstract

Abstract In this study, the influence of functionalized silicon carbide (SiC) nanoparticles on the electrochemical and mechanical properties of silicon carbide/epoxy nanocomposite was investigated. The reactive SiC nanoparticles were synthesized using 3-amino-1, 2, 4-triazole-5-thiol (ATT) and 2-methoxy pyridine (MP) and characterized by Transmission electron microscopy (TEM), X-ray diffraction (XRD), Field emission scanning electron microscopy (FE-SEM), atomic force microscopy (AFM), Fourier transform infrared (FTIR) spectroscopy and thermogravitric analysis (TGA) techniques. The resultant novel nanocomposite coating on Cu-Ni alloy in natural seawater was investigated with the help of the Tafel polarization, electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM). Electrochemical studies revealed excellent corrosion protection efficiency and a decreased corrosion current density, with an optimum concentration of 2 wt% SiC nanoparticles. The results indicated that the reactive SiC nanoparticles dispersed uniformly and retarded the propagation of corrosive ions to the Cu-Ni alloy sample and coating interface through the deflected route and minimized the electron movement between the electrolyte and alloy surface. SECM observations confirmed the detection of least current at the scratched area of the coated alloy. SEM observations showed that reactive SiC nanofillers are dispersed uniformly. The changes in surface morphology, phase structure and composition were analyzed using SEM/EDX and XRD techniques. The strong attachment of the reactive SiC and epoxy resin resulted in an enhanced mechanical properties with a defectless compact film. It was found that the reinforcement of reactive SiC nanoparticles in the epoxy coatings exhibited a smooth microstructure surface producing superior corrosion protection and mechanical properties. Corrosion mechanism has been suggested based on the investigations.