Development of Al2O3.ZnO/GO-phenolic formaldehyde amine derivative nanocomposite: A new hybrid anticorrosion coating material for mild steel

Abstract

The hybrid nanocomposites are least explored materials in anti-corrosion application. In this context, Al2O3.ZnO and Al2O3.ZnO/GO nanocomposites were prepared and dispersed in the synthesized phenolic formaldehyde amine derivative (PFAd) polymer. The structural and the elemental composition of the nanocomposites and PFAd were ascertained through Fourier transfer infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Energy dispersive X-ray spectroscopy (EDX) and Transition electron microscopy (TEM). The 0.2 wt.% of nanofiller was chosen as an optimum composition to obtain uniform dispersion in PFAd matrix. The surface morphology, texture and chemical composition of the coatings on mild steel (MS) surface have been studied by XRD and Scanning electron microscopy (SEM). The anti-corrosion performance of the coatings on MS in 3.5 wt.% NaCl solution was evaluated by electrochemical techniques. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PP) data revealed that, Al2O3.ZnO/GO dispersed PFAd shows very good Rcoat (3.81 × 102 ohm cm2) and Rct (1.84 × 103 ohm cm2) with reasonably lower icorr (1.233 × 10-3A/cm2) values even after 68 days of immersion. Further, it was found that, the barrier property of the coating depends on the composition and dispersibility of the fillers in the polymer matrix.