Incorporation of NH₄⁺ in flower-like zinc phosphate pigment to enhance the corrosion resistance of waterborne epoxy

Herein, the three-dimensional (3D) flower-like pigments of micro-nano scaled zinc phosphate (FZP) and ammonium zinc phosphate (FNZP) were successfully synthesized by hydrothermal synthesis method for improving the corrosion resistance of waterborne epoxy (WEP) coating. The micro-structures, chemical compositions and corrosion resistance of the as-obtained specimens were characterized by SEM, XRD, FT-IR, XPS and EIS, respectively. The results indicated that the 3D flower-like FZP and FNZP pigments were comprised of selfassembled nano-micro sheets with an average thickness of 20 nm similar to 100 nm. Moreover, the remarkable enhancements of compactness and anticorrosion performance, especially for the FNZP-incorporated coating, were principally contributed to the well dispersibility and favourable solubility, which lengthened the permeation pathway and promoted the formation of passivation film.