Improvement of co-frequency synergy between dielectric and magnetic losses of core-shell Fe3O4@C composites for enhancing their microwave absorption properties

Core-shell Fe3O4@C composite with nano and submicron Fe3O4 core structures was prepared by vacuum heat treatment of Fe2O3@phenolic resin (Fe2O3@PR) precursor. The multi-scale core structures confer the composite with improved electromagnetic synergy. As a result, the composite exhibits optimized impedance matching, strong attenuation capability, and excellent microwave absorption properties. In the high-frequency (10-18 GHz) band, its minimum reflection loss (RL, RL value below - 10 dB represents above 90% microwave absorption) is - 54.45 dB and effective absorption bandwidth (EAB, frequency range of RL < - 10 dB) is 6.34 GHz. In the low-frequency (2-10 GHz) band, the obtained minimum RL and EAB are - 53.57 dB and 3.38 GHz, respectively. These results suggest that the multi-scale core structures can effectively enhance the microwave absorption properties of core-shell Fe3O4@C composites and it may be an effective idea for the design of high-performance microwave absorption materials.

Automated summary

A core-shell Fe3O4@C composite with nano and submicron Fe3O4 core structures was prepared by vacuum heat treatment. The multi-scale core structures improved the electromagnetic synergy of the composite, resulting in optimized impedance matching, strong attenuation capability, and excellent microwave absorption properties. The composite exhibited minimum reflection loss of -54.45 dB and effective absorption bandwidth of 6.34 GHz in the high-frequency band (10-18 GHz), and minimum reflection loss of -53.57 dB and effective absorption bandwidth of 3.38 GHz in the low-frequency band (2-10 GHz). These results suggest that the multi-scale core structures effectively enhance the microwave absorption properties of core-shell Fe3O4@C composites and provide a potential design strategy for high-performance microwave absorption materials.