Facile solvothermal synthesis of a MIL-47(V) metal–organic framework for a high-performance Epoxy/MOF coating with improved anticorrosion properties

a facile solvothermal route. This precursor provides a controllable rate of metal ion production depending on the applied reaction conditions. In our method, the synthesis took place at a low temperature and reaction time (180 °C for 20 h, instead of 220 °C for 72 h), yielding MIL-47 microrods. Moreover, among its unique properties, the metal centers of MIL-47 oxidize under the influence of thermal or chemical treatments, preserving the framework structure. This unusual character is not commonly witnessed in comparable MOF structures. This property can be leveraged in anti-corrosion applications, whereby a redox reaction would sacrifice the framework components, protecting the metal in contact. However, the chemical stability of MIL-47 is doubted against a corrosive medium. Thus, an epoxy coating with 10 wt% MOF loading was incorporated in our investigation to extend the aluminum alloy (AA2024) surface protection for prolonged exposure duration. The uniformity of distribution of the prepared MOF within the epoxy matrix was confirmed using SEM/EDX. Electrochemical impedance spectroscopy (EIS) was used to evaluate the corrosion performance of the coated samples. The results showed that the inclusion of V-MOF offers extended corrosion prevention, over 60 days, for the AA2024 alloy against artificial seawater. The neat epoxy coating could not prevent the corrosion of AA2024 over two weeks of immersion, whereby pitting corrosion was clearly observed. The V-MOF could induce a series of redox reactions leading to the precipitation of vanadium on the cathodic sites of metal surfaces.