Improving corrosion resistance of epoxy coating

The steel fiber textile overcomes mostly the shortcomings of traditional reinforcement materials. However, the poor corrosion resistance severely limits service life. In this study, based on the mechanism of stress corrosion and electrochemical corrosion, the epoxy resin anti-corrosion coating was designed and prepared. First, the von Mises stress distribution of lamellar and spherical fillers in epoxy resin was studied by finite element simulation, which confirmed that the stress distribution of spherical SiO₂ filler was more uniform when it was stressed. In addition, to optimise the dispersion of spherical SiO₂ in epoxy resin, the spherical polyaniline@SiO₂ (PANI@SiO2) composites with core-shell structure were produced with in situ polymerisation method.

Corrosion resistance

Ultrasonic C scanning results showed that the addition of PANI@SiO₂ nano-filler can effectively reduce the defects in epoxy resin. Compared with bare steel fiber, the composites coating of 2 wt% PANI@SiO₂/epoxy showed the most excellent resistance to stress corrosion and electrochemical corrosion. The capacitance diameter is two orders of magnitude higher, which has good stability in simulated concrete pore solution. This is due to the fact that the addition of PANI@SiO₂ nanomaterials improves the physical shielding properties of epoxy, creating a labyrinth effect, and that PANI can produce passivation on the metal surface.

The study has been published in Progress in Organic Coatings, Volume 179, June 2023.

Reading tip

The EC Tech Report Waterborne Protective Coatings gives you an extensive up-to-date bundle on protective coatings, focusing on water-borne solutions, with articles, videos and other content handpicked by the European Coatings Team. In addition to cutting-edge technical articles, the Tech Report is rounded off with valuable market insights and key fundamentals on water-borne protective coatings.