A new study describes the barrier properties of epoxy coating containing CaCO3 microparticles modified with cerium nitrate.

In the study, the protective properties of epoxy coatings containing pH-sensitive calcium carbonate (CaCO3) microparticles modified with cerium nitrate (Ce (NO3)3), applied to mild steel substrates, were investigated in 3.5 wt. % NaCl solution, via electrochemical impedance spectroscopy (EIS) and salt spray testing. Scanning electron microscope (SEM), X-ray powder diffraction (XRD) and inductively coupled plasma (ICP) tests were performed to evaluate the characteristics of the synthesised CaCO3 microparticles.

Results showed that the modification process changed the morphology of the particles and loaded them with Ce(III). EIS and salt spray tests showed that the incorporation of the modified CaCO3 microparticles to epoxy coatings can enhance their corrosion protection.

The corrosion protection performance of the coating was affected by the amount of incorporated microparticles, in that increasing the amount of modified CaCO3 microparticles led to higher corrosion protection. Increasing the Ce(III) ions content of the CaCO3 microparticles led to similar behaviour.

The study was published in Progress in Organic Coatings, Volume 144, July 2020.