Effective corrosion protection of magnetic microwave absorber with designed macromolecular network barrier

Carbonyl iron (CI) particles as magnetic microwave absorption material often suffer from serious corrosion under corrosive environment which leads to performance deterioration. In this study, fluorin-containing acrylate type polymer network layers with thickness ranging from tens of nanometers to around one hundred nanometers were formed continuously around CI. The crosslinked coating layer (named FT) effectively increases CI’s thermal decomposition temperature by at least 34%. The FT-coated CI (named CI-FT) was able to resist both inorganic and organic corrosive media attacking efficiently compared with bare CI. The surface polymer network could also help CI withstand organic medium dissolution which proved the firmness of coating. Cyclic voltammetry (CV) test revealed that the coating layer could significantly reduce maximum oxidation current density of CI by more than 45 times. Tafel polarization study during CV tests also confirmed that thicker FT coating layer could help CI sample stabilize corrosion current density. Meanwhile, the surface coating also enhanced the impedance matching properties of CI as microwave absorber and the CI-FT samples demonstrated improved microwave absorption properties which degenerated little after corrosive medium soaking compared with that of CI.