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In this study, HAp(hydroxyapatite) was prepared by hydrothermal method and was successfully modified by APTES (aminopropyltriethoxysilane) to obtain APTES‐HAp nanomaterial. Firstly, the microstructure and surface morphology of HAp and APTES‐HAp were studied by Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), X‐ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM), and it was confirmed that HAp and APTES‐HAp composites were successfully synthesized. Secondly, SEM analysis is used to study the dispersion of APTES‐HAp in epoxy resin, and it is proved that the dispersion of HAp modified by APTES is greatly improved. Finally, the corrosion resistance of the composite coating was studied in detail by electrochemical impedance spectroscopy (EIS). The results show that the APTES‐HAp /EP composite coating impedance modulus remains 107. The breakpoint frequency (fb) is always the minimum after 30 days of immersion, which proves that the corrosion resistance of APTES‐HAp /EP composite coating is significantly improved APTES‐HAp/EP. The improvement of corrosion resistance is mainly attributed to the following two points: APTES‐HAp has good uniform dispersion and interfaces compatibility in epoxy resin, forming an effective barrier network. On the other hand, layered HAp forms physical barriers and maze effects on corrosive media.

Numerous challenges arise from metal corrosion, including economic loss, environmental pollution, and safety issues. Epoxy coatings, as a solution to metal corrosion problems, have been widely used worldwide. The improvement of epoxy coating performance is also a major focus of research. In this paper, we employed a hydrothermal method to load UIO‐66 crystals onto a two‐dimensional mica substrate, while simultaneously modifying the surface with polyethyleneimine (PEI) to enhance the compatibility of the filler in the epoxy coating. The water absorption and adhesion of the PMC‐UIO(4:1)/EP coating were optimized after the addition of the modified filler, with the adhesion strength of the PMC‐UIO(4:1)/EP coating improved to 8.28 MPa. In terms of electrochemical impedance spectroscopy, the PMC‐UIO(4:1)/EP coating manifested long‐lasting and superior corrosion resistance. Specifically, the electrochemical impedance modulus of this coating reached as high as 1011. Remarkably, even after immersion in a 3.5 wt% sodium chloride solution for 30 days, the coating maintained an impedance value order of magnitude at 109, which is unparalleled among all the composite coatings studied, demonstrating its exceptional corrosion resistance.