Characterization and corrosion resistance of organically modified silicate–NiZn ferrite/polyaniline hybrid coatings on aluminum alloys

Abstract

Hybrid coatings based on organically modified silicate (Ormosil)–NiZn ferrite/polyaniline (10–30 wt.%) were synthesized through a sol–gel technique. Tetraethylenepentamine, 3-glycidoxypropyltrimethoxysilane, tetraethoxysilane and Ni 0.5Zn 0.5Fe 2O 4/polyaniline were used as precursors for the hybrid coatings. These hybrid films were deposited via spin coating onto an aluminum alloy to improve the corrosion protection. The effects induced by the NiZn ferrite/polyaniline content on the chain dynamics, ferromagnetic behavior and corrosion performances of the coated samples were investigated. The rotating-frame spin–lattice relaxation times and scale of the spin-diffusion path length indicated that the configuration of the hybrid films was highly cross-linked, dense and adhered to the aluminum alloy substrates. The magnetic properties of the resulting hybrids showed super-paramagnetic behavior, such as zero coercive force (coercivity = 0 G) and a low blocking temperatures (45 K). Potentio-dynamic and salt-spray analysis revealed that the hybrid films provided an exceptional barrier and corrosion protection in comparison with untreated aluminum alloy substrates.