Waterborne epoxy resin (WEP) has been widely used as an anti-corrosive coating for metals. However, it is still a big challenge to further improve its anti-corrosion performance due to the poor barrier properties to corrosive media. In this study, fluorinated graphene (FG) was used as a filler in WEP to improve its barrier properties, which contributes to corrosion resistance enhancement. The chemical composition and microstructures of FG and FG-modified WEP were systematically analyzed, and its corrosion resistance was also studied. Results reveal that the addition of FG sheet to WEP not only can significantly improve the tensile strength of WEP coating, but also increase the barrier properties of WEP coating and block the penetration of corrosive agent throughout the coating to the interface between coating and substrate. Meanwhile, the results also declare that the F content of FG has a significant effect on mechanical properties and long-term corrosion resistance, and the performance of FG-modified WEP coating will deteriorate with the increase of F content.

This study provides an enhanced corrosion resistance of epoxy resin (EP) by embedding fluorinated graphene (FG) into the epoxy matrix. FG with different fluorine contents was obtained by reacting nitrogen trifluoride (NF₃) gas with GO and then incorporated into the EP matrix to fabricate the different composites. Through a series of characterization methods, the chemical composition and microstructures of FG were systematically analyzed, and its corrosion resistance was also studied. Results revealed that F atoms were bonded to the GO surface to form C–F covalent bonds, and an FG lamellar thickness less than 2 nm. The contact angle of the coatings increased with the incorporation of FG, and the coating resistance of FG2/EP coating was 3 orders of magnitude more than that of the EP coating after immersion for 4080 h. Thus, the incorporation of FG into epoxy matrix significantly enhanced its hydrophobic properties and barrier performance, which was beneficial to improving the long-term corrosion resistance of the coating.

In this work, a novel zinc–aluminum–magnesium (Zn-Al-Mg, ZM) coated steel was prepared using the hot-dip method. The microstructure and corrosion resistance of the ZM-coated steel were investigated. Compared to the conventional galvanized steel (GI), the ZM coating demonstrated a distinctive phase structure, consisting of Zn phase, binary eutectic (Zn/MgZn₂), and ternary eutectic (Zn/Al/MgZn₂). The corrosion resistance of the ZM-coated and GI-coated steels was evaluated by neutral salt spray test (NSST), polarization and electrochemical impedance spectroscopy (EIS). The results indicated that ZM-coated steel provided superior long-term corrosion protection in a NaCl environment compared to GI-coated steel. The scanning vibrating electrode technique (SVET) proved to be an effective method for investigating the evolution of the anodic and cathodic on the local coating surface. GI-coated steel exhibited a potential and current density distribution between the cathodic and anodic sites nearly three orders of magnitude higher than that of ZM-coated steel, suggesting a higher corrosion rate for GI-coated steel.