Preparation of Gallic Acid Intercalated Layered Double Hydroxide for Enhanced Corrosion Protection of Epoxy Coatings

In the field of corrosion protection coatings, layered double hydroxide (LDH) has gained wide attention as a novel controlled-release nanocontainer. In this paper, by using a co-precipitation to store corrosion inhibitors in layered double hydroxide with barrier properties, an environmentally friendly gallic acid (GA) intercalated layered double hydroxide corrosion protection filler (GA-LDH) was prepared. The epoxy coating was then modified with GA-LDH to improve its corrosion protection performance. The structure, composition, and release behavior of GA-LDH were investigated by a series of characterizations, such as field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and ultraviolet-visible spectrophotometry (UV-vis). Electrochemical impedance spectroscopy (EIS) and a neutral salt spray test (NSS) were performed to evaluate the effect of EP coating containing GA-LDH on corrosion protection for Q235 steel. The results show that GA-LDH added to an epoxy coating can achieve excellent corrosion protection performance and is expected to be widely used in marine corrosion protection contexts.