Corrosion resistance of MWCNTs-nanoZnO composite reinforced chromium-free Zn-Al coating

PurposeThis paper aims to prepare high corrosion-resistant chromium-free zinc-aluminum (Zn-Al) coatings reinforced with multi-walled carbon nanotubes (MWCNTs) and nano-ZnO particle composites.Design/methodology/approachThe morphology, composition and corrosion resistance of the coatings were analyzed by electrochemical tests, water contact angle tests, immersion tests, scanning electron microscopy/energy dispersive spectrometer and X-ray diffraction.FindingsThe composite coating with 0.3% MWCNTs and 0.5% nano-ZnO particles demonstrated both high shielding performance and cathodic protection performance, which was attributed to the porosity filling of MWCNTs and nano-ZnO particles together with the electrical connection of MWCNTs between the zinc and aluminum powders.Originality/valueThis work laid an experimental foundation for the preparation and corrosion mechanism of high corrosion-resistant chromium-free Zn-Al coating reinforced with MWCNTs and nano-ZnO particles.