News Coatings Technologies
Ti-MOF hybrid particles enhance epoxy anticorrosion performance
Researchers have developed a Ti-based metal-organic framework combined with TiO₂ nanoparticles as a hybrid filler for epoxy coatings. At just 0.2 wt.-%, the additive delivers a four-orders-of-magnitude improvement in impedance and preserves corrosion protection of mild steel for 70 days in saline conditions.
Ensuring durable corrosion protection for epoxy (EP) coatings in chloride-containing environments remains a persistent challenge for the protective coatings sector. A recent study addresses this issue by introducing NH₂-MIL-125/TiO₂ hybrid particles (NMT), based on a titanium-containing metal-organic framework (MOF) modified with TiO₂ nanoparticles. The hybrid filler was synthesised via a solvothermal route and incorporated at a low loading of 0.2 wt.-% into an epoxy matrix designed for the protection of mild steel.
Structural and morphological characterisation using FTIR, Raman spectroscopy, XRD, TGA, BET, TEM and FESEM/EDX confirmed both the successful formation of the hybrid filler and its uniform dispersion in the epoxy matrix. Compared with neat epoxy and with coatings containing only NH₂-MIL-125 or TiO₂, the EP/NMT coating exhibited increased hydrophobicity and improved surface properties, indicating a beneficial synergistic effect between the two components.
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Long-term barrier performance and interfacial stability
Electrochemical impedance spectroscopy (EIS) measurements in a 3.5 wt.-% NaCl solution demonstrated the strong protective behaviour of the composite coating. The EP/NMT system maintained an impedance modulus at 10 mHz above 10⁹ Ω·cm² after 70 days of exposure, outperforming the neat epoxy reference by four orders of magnitude. In contrast, coatings based on neat epoxy, EP/TiO₂ and EP/NM failed to provide long-term protection under the same conditions.
The EP/NMT coating also preserved a single-time-constant EIS response throughout the entire exposure period, indicating that the corrosive electrolyte did not reach the coating–steel interface. Density functional theory (DFT) calculations further supported the superior protective mechanism of the hybrid system. According to the authors, the combination of NH₂-MIL-125 and TiO₂ enables a low-loading design strategy for developing robust and sustainable anticorrosive coatings, offering a promising route to prolonged service life for protective coatings in aggressive chloride-rich environments.
Source: Majidi, R. et al., Sustainable anticorrosion performance of Ti-MOF/TiO2-reinforced polymeric coating. Progress in Organic Coatings (2026). https://doi.org/10.1016/j.porgcoat.2026.110291
