Effective corrosion protection by PDA-BN@CeO2 nanocomposite epoxy coatings

Abstract

Adding functional inorganic two-dimensional nanomaterials is an effective means to improve the long-term anti-corrosion ability of polymer coatings. Here, due to the mussels’ adhesive ability to various substrates, polydopamine (PDA) was used to modify hexagonal boron nitride (h-BN) and a novel PDA-BN@CeO2 nanohybrid was synthesized through an in situ hydrothermal approach. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectroscopy, and X-ray photoelectron spectroscopy (XPS) were employed to characterize the as-prepared nanomaterials. The results of salt spray test and electrochemical measurement showed that the composite coatings exhibited a notable superiority in enhancing the anti-corrosion performance, in which the |Z|0.01 Hz was nearly three orders of magnitude higher than that of the neat epoxy coatings when soaked for 35 days. The enhancement mechanism can be attributed to the synergistic effect of BN nanosheets extending the corrosion medium diffusion pathway and CeO2 acting as a corrosion inhibitor to block the contact of corrosion ions with the metal substrate. This study provides a new way for the development of h-BN-based anti-corrosion materials.