Excellent corrosion resistance of FGO/Zn2SiO4 composite material in epoxy coatings

Generally, the anti-corrosion performance of the coating is improved by adding organic or inorganic anti-corrosion materials to the epoxy coating. In this paper, P-phenylenediamine-functionalized graphene oxide/zinc silicate (FGO/Zn2SiO4) composites were synthesized in situ by hydrothermal method as filler in epoxy resin. P-phenylenediamine (PPDA) acts as a spatial barrier between graphene oxide (GO) layers and improves FGO/Zn2SiO4 dispersion in the epoxy coating. The corrosion resistance of FGO/ Zn2SiO4 material is 234.4 % of GO/Zn2SiO4 material and 763.6 % of Zn2SiO4 material. Because GO/Zn2SiO4 composite has numerous oxygen-containing groups that tend to agglomerate, which results in reduced dispersion in epoxy coatings. However, FGO not only prolongs the diffusion path of corrosion ions in the coating and reduces the rate of charge transfer for electrochemical reflection, but the amino group on the PPDA provides additional cross-linking on top of the epoxy cure to improve dispersion. Utilizing the synergistic anti-corrosion effect of inorganic and organic materials, a new type of Zn2SiO4 anti-corrosion filler was designed, which significantly improved the anti-corrosion performance of Zn2SiO4 in epoxy resin coating.