Corrosion protection performance of epoxy coating containing alumina/PANI nanoparticles doped with cerium nitrate inhibitor on Al-2024 substrates

•Cerium doped alumina/PANI nanocomposite particles were prepared.•The nanocomposite particles are proven to be pH responsive.•Ce(III) is released in acidic or alkaline solutions.•The nanocomposite particles were incorporated into epoxy coatings.•Protective system with superior corrosion protection performance was achieved. Alumina/polyaniline hybrid nanoparticles doped with cerium nitrate corrosion inhibitor was synthesized via a chemical polymerization method. The morphology and structure of the synthesized nanoparticles were investigated by field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), and X-Ray diffraction (XRD) techniques. Incorporation of alumina/polyaniline nanocomposite particles doped with cerium nitrate into epoxy coating on aluminum alloy 2024-T3 resulted in a protective system with superior corrosion protection performance confirmed by potentiodynamic scanning method (PDS) and electrochemical impedance spectroscopy (EIS). The corrosion current density of the nanocomposite coating was (7.35 ± 0.22)×10−9 A/cm2, which was reduced by two orders of magnitude compared with that of the control epoxy sample. Moreover, the embedding of cerium nitrate doped alumina/polyaniline nanoparticles into epoxy coating provides active protection against corrosion. The low frequency impedance values of the scratched area of this coating after 6 days immersion was three orders of magnitude higher than that of the control sample.