Enhanced barrier properties of epoxy coating containing CaCO3 microparticles modified with cerium nitrate

In this study, the protective properties of epoxy coatings containing pH-sensitive calcium carbonate (CaCO3) microparticles modified with cerium nitrate (Ce(NO3)(3)) have been investigated in 3.5 wt. % NaCl solution via electrochemical impedance spectroscopy (EIS) and salt spray tests. Modifying the CaCO3 microparticles with Ce (NO3)(3) was conducted via spontaneous precipitation method. The modified CaCO3 microparticles were added to epoxy resin, applied on mild steel substrates. Scanning electron microscope (SEM), X-ray powder diffraction (XRD) and inductively coupled plasma (ICP) tests were performed to evaluate the characteristics of the synthesized CaCO3 microparticles. Results showed that the modification process changed the morphology of the particles and loaded them with Ce(III). EIS and salt spray test results showed that the incorporation of the modified CaCO3 microparticles into epoxy coatings can enhance their corrosion protection. The corrosion performance of the coating was affected by the amount of incorporated microparticles so that increasing the amount of modified CaCO3 microparticles led to higher corrosion protection of the epoxy coating. Increasing the Ce(III) ions content stored in the CaCO3 microparticles led to similar behavior.