Enhanced microwave absorption and corrosion resistance of carbonyl iron encapsulated by silicone modified epoxy resin

Abstract

The novel silicone modified epoxy resin (ER) was synthesized and used to encapsulate the carbonyl iron powders (CIP) with core–shell structure by in-situ polymerization method. The silicone modified epoxy resin coating was introduced to enhance both microwave absorption and corrosion resistance of carbonyl iron. Microstructure analysis demonstrated that CIP were densely covered with ER shell. Hydroxyl (–OH) and amino group (–NH2) present in silicone-modified epoxy resin, and chemically interact with the metal oxide layer on carbonyl iron to form covalent bonds or hydrogen bonds, improving interfacial adhesion and uniform dispersion of CIP. The ER shell effectively strengthens the microwave absorption ability and corrosion resistance of CIP. The reflection loss peak reached − 52.1 dB and effective absorption bandwidth achieved 7.8 GHz (10.2 GHz − 18 GHz). The epoxy resin coating significantly reduced the charge transfer resistance (Rct) and corrosion current density (Jcorr), indicating improved corrosion protection. Polarization resistance (Rp) and corrosion rate (CR) analysis further verified corrosion resistance. The epoxy resin-coated CIP exhibit excellent microwave absorption and corrosion resistance, indicating widespread application in anti-electromagnetic interference field.