Magneto-electric adjustable Co/C porous layer coated flaky carbonyl iron composites with bifunctions of anti-corrosion and microwave absorption

Coating carbon materials on the surface of magnetic metal is an effective strategy to obtain lightweight high performance anticorrosive absorbers. Herein, the structure of the dense anticorrosive shell (Co/C porous layer) coated on the surface of the magnetic core (Flaky carbonyl iron, FCI) was successfully constructed. And the electromagnetic parameters of the composites can be precisely adjusted by controlling the mass reaction ratio of polydopamine/sodium dodecyl benzene sulfonate modified Co/C composites (Co/C@PDA-SDBS) and polydopamine/polyethyleneimine modified FCI (FCI@PDA-PEI). When the reaction ratio was 4:6 (FCI@Co/C-4/6), the sample exhibited excellent microwave absorption performance with suitable impedance matching and strong attenuation ability. The minimum reflection loss ( RL min ) value reached -72.6 dB at 14.8 GHz and the maximum effective absorption bandwidth (EAB) covered the Ku band (11.8-18 GHz) with a thickness of only 1.5 mm. Besides, the dense Co/C layer with effective isolation of FCI@Co/C-4/6 also represented the excellent corrosion resistance for its higher E corr (-0.193 V) and lower I corr (0.33 μA/cm 2 ). Therefore, our research provides a novel approach for reducing the application thickness of FCI and paves the way for commercial application of lightweight high performance anticorrosive microwave absorbents. • Controlled organic reaction process precisely realized magneto-electric tunability of composites. • A novel magnetic carbon-based core-shell structure exhibited suitable impedance matching and strong attenuation ability of composites. • The modified flaky carbonyl iron with thinner application thickness achieved excellent microwave absorption performance • The dense Co/C layers with effective isolation improved corrosion resistance of flaky carbonyl iron