Enhanced anti-corrosion and microwave absorption performance with carbonyl iron modified by organic fluorinated chemicals

Magnetic absorbing materials suffer from corrosion and aging in harsh environments such as ocean and acid, which limits their practical applications. Therefore, it is important to design a material with excellent corrosion resistance and microwave absorption properties. Herein, perfluorooctyltriethoxysilane (PFOTES) modified carbonyl iron (CI) with tunable PFOTES content was prepared by the sol-gel method. The presence of PFOTES layer improved the corrosion resistance and microwave absorption of CI. The good hydrophobicity of PFOTES layer with the static contact angle of 129.73 degrees hindered the contact of corrosive medium with CI core. The corrosion current of CI@PFOTES composite decreased significantly, and the corrosion rate was reduced by three orders of magnitude. The surface coating not only affected the electromagnetic parameters of carbonyl iron, but also improved the impedance matching of materials. Electromagnetic performance test results demonstrated that the microwave absorption performance of CI@PFOTES composite was better than that of carbonyl iron, and its minimum reflection loss was -40.45 dB at 4.08 GHz with a matching thickness of 3.5 mm. Our work provides a new perspective for preparing composites with good microwave absorption and corrosion resistance in practical applications.