Improvement of the corrosion resistance of acrylic electrocoating in the presence of acid-modified montmorillonite nano clay

Abstract

This study presents a novel approach to enhance the corrosion resistance of acrylic electrocoating by incorporating acid-modified montmorillonite nano clay particles at varying concentrations (0.0–0.5 wt%) into the coating matrix. The nanostructure and laminar shape of the nano clay particles were confirmed by field emission scanning electron microscopy (FE-SEM). XRD and FE-SEM/EDS analyses revealed successful modification of the nano clay and its uniform dispersion in the electrocoating film. The effect of the nano clay on the rheology of the coating was also investigated using rheometric methods. The anti-corrosion properties of the nanocomposite coatings were evaluated using salt spray and electrochemical impedance spectroscopy (EIS). The EIS results showed that the nanocomposite electrocoating containing 0.3 wt% of acid-modified montmorillonite nano clay exhibited remarkable improvement in anti-corrosion properties and corrosion resistance, with an impedance value of up to 10 Gohm after 21 days of immersion in NaCl 3.5 wt%.