Enhanced anti-corrosion properties of epoxy coatings through chemical interaction with NH2-MIL-53 (Al) metal-organic frameworks

PurposeThe purpose of this study is to improve the corrosion protection of epoxy coating on ST37 steel through chemical interaction by incorporating NH2-MIL-53(Al), a metal-organic framework (MOF), as a nanofi ler (1 Wt.%).Design/methodology/approachScanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy and atomic force microscopy (AFM) were used to identify the MOFs and applied coatings. Electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP) experiments in 0.1 M HCl were used to assess the corrosion protection of the coatings. Morphological analyses were also performed to validate the corrosion tests.FindingsSEM analysis showed no MOF aggregation and TEM confirmed their proper dispersion within the epoxy matrix due to the amine groups' interaction with the epoxide groups. The contact angle of water on the epoxy coating was decreased from 90.7 degrees to 89.0 degrees due to the MOFs' hydrophilicity. After MOFs incorporating, the EIS tests showed a substantial increase in polarization resistance (Rp) from 14.09 to 377.35 M Omega. cm(2) after four weeks and PDP tests confirmed a reduction in the corrosion current from 1.523 to 0.274 nA. cm-(2).Originality/valueThis study innovatively uses NH2-MIL-53(Al) as nanofillers in epoxy coatings to enhance its corrosion protection. Unlike traditional studies, it focuses on chemical interactions between the MOFs' amine groups and the epoxy matrix to improve dispersion, coating density and pore filling. Comprehensive characterization using SEM, energy dispersive X-ray spectroscopy, TEM, AFM, X-ray diffraction, thermogravimetric analysis, Brunauer-Emmett-Teller and EIS methods highlights its novel approach to enhance the corrosion protection.