Objective Due to the long-term exposure of high-speed EMU (electric multiple unit) bogies to harsh environments such as moisture, salt spray, and sand particle impact, the static protection mechanism of traditional epoxy coatings is insufficient to cope with dynamic damages. UIO-66-NO₂ is a metal-organic framework material. To improve the corrosion resistance and wear resistance of coatings, it is necessary to investigate the effect of UIO-66-NO₂ as a multifunctional filler on the performance of epoxy coatings, with the aim of developing a novel coating that integrates active protection and wear-resistant synergistic functions.

Method UIO-66-NO₂ with different ratios (ZrCl₄:NO₂-BDC=1:1 to 1:1.8) is prepared by the solvothermal method. The morphology and crystallinity of the materials are characterized by SEM (scanning electron microscopy) and XRD (X-ray diffraction). UIO-66-NO₂ is loaded with the corrosion inhibitor BTA (benzotriazole) through pore adsorption to prepare a composite UIO-66-NO₂@BTA/epoxy coating. The corrosion resistance and wear resistance of the coating are evaluated by salt spray tests, EIS (electrochemical impedance spectroscopy) analysis, and friction coefficient measurements.

Result & Conclusion  When ZrCl₄:NO₂-BDC=1:1.8, UIO-66-NO₂ particles exhibit regular morphology and optimal dispersion. Increasing the NO₂-BDC content in the UIO-66-NO₂ composition will enhance crystallinity. As a filler, UIO-66-NO₂@BTA can significantly improve the corrosion resistance and wear resistance of epoxy coatings. The optimal filler content is 3 wt%; under this condition, corrosion in the coating scratch area is the mildest, and EIS results show the highest impedance value of 9.545×10¹⁰ Ω·cm², and the coating exhibits the lowest friction coefficient of 0.35. Excessive addition of this filler, however, leads to a deterioration in coating performance.