Hydrophobic enhancement of flaky carbonyl iron for superior corrosion resistance in electromagnetic wave absorbing coatings

The rapid advancement of electromagnetic technologies and the growing threats of interference highlight the urgent need for the development of robust electromagnetic wave absorbing (EWA) coatings to safeguard critical systems and ensure environmental safety. However, their effectiveness is often limited by poor corrosion and aging resistance. To enhance the durability of these coatings, we developed an epoxy (EP)-based coating using fluorinated flaky carbonyl iron powder (F-FCI) as the absorbing filler. Hydrophobic F-FCI particles were synthesized using perfluoro-decyl trimethoxy-silane (PFDTMS) to effectively block corrosive ions. Electrochemical tests demonstrated that the fluorinated layer significantly improved the corrosion resistance while remained decent electromagnetic wave absorption properties of FCI. We further evaluated the performance of EP/FCI and EP/F-FCI coatings under salt spray corrosion tests, finding that the EP/F-FCI coating exhibited minimal structural changes and color differences while maintaining strong hydrophobic performance during aging. These results indicate that incorporating F-FCI particles substantially enhances the corrosion resistance and service stability of EWA coatings.