Anti-Corrosion Epoxy Coating Enhanced by the Modified Boron Nitride Coupled with Ce-MOF

Both boron nitride (BN) and metal-organic framework (MOF) are ideal nanofillers to enlarge corrosion resistance of coating due to their two-dimensional layered or porous structure with special physical-chemical property. However, the agglomeration and weak interaction with epoxy resin (EP) blocks their effects on enhancing anticorrosion performance of EP coatings. In this work, BN was hydroxylated and subsequently coated with polydopamine (PDA), then onto which cerium metal-organic frameworks (Ce-MOFs) was in-situ grown to get BNOH@PDA-Ce-MOFs. This technology not only ensures good dispersibility of BN and Ce-MOF, but strengthens their interaction with EP through PDA modified layer. BN uniformly dispersed in EP can elongate the diffusion path of corrosive media to enhance the barrier properties of the coating. Meanwhile, Ce-MOF can form a dense passivation layer composed of hydroxide and oxides of cerium to further protect the metal from corrosion. Therefore, the electrochemical impedance spectroscopy (EIS) measured |Z| 0.01 Hz value of BNOH@PDA-Ce-MOFs/EP coating only relatively decreased after 56 days, remaining three orders of magnitude higher than that of pure EP coatings. Moreover, the accelerated salt spray test of 28 days, there are no obvious corrosion pits, confirming the excellent corrosion resistance of BNOH@PDA-Ce-MOFs/EP coating.