Anti‐corrosion improvement of epoxy coating by the synergistic effect of barrier shielding and slow‐release based on phytic acid intercalated hydrotalcite

Abstract

AbstractEpoxy resin has been widely applied in coating preparation, due to its excellent properties. The anti‐corrosion performance improvement of epoxy‐based coatings has attracted much attention. The synergistic effect of the barrier function of two‐dimensional fillers and the slow release of inhibiter has been proven to be an effective way to improve the anti‐corrosion of coatings. In this work, the phytic acid (PA) intercalated hydrotalcite (HT) was fabricated by a one‐pot method. First, HT was synthesized by magnesium nitrate hexahydrate (Mg(NO3)2·6H2O) and aluminum nitrate nonahydrate (Al(NO3)3·9H2O) in the water solution. Subsequently, PA was added to the dispersion to obtain PA intercalated HT fillers (PA‐HT). The obtained PA‐HT fillers were incorporated into the epoxy resin (EP) to prepare the anti‐corrosion coating (PA‐HT/EP). The prepared PA‐HT/EP coating exhibits excellent anti‐corrosion properties at 1 wt% filler loading that the impedance modulus maintains above 109 Ω cm2 after 30 days of soaking in 3.5 wt% NaCl solution. Moreover, the anti‐corrosion mechanism of the synergy of the physical barrier of two‐dimensional fillers and the release slow of inhibitors was thoroughly discussed, particularly the formation and anti‐corrosion mechanism of the passivation protection film constituted by PA.