Facile synthesis and enhanced electromagnetic wave absorption of thorny-like Fe–Ni alloy/ordered mesoporous carbon composite

• Thorny-like Fe–Ni alloy/OMC composites are successfully synthesized.
• The morphology, chemical composition, and crystalline structure are characterized.
• The μ″μ″ values of Fe–Ni(0.2)/OMC are very negative from ∼7 to 18 GHz (−0.7).
• Its effective absorption bandwidth (<−10 dB) can reach up to 4.8 GHz (2.00 mm).

Ordered mesoporous carbon (OMC) coated with thorny-like Fe–Ni alloy composites have been successfully synthesized. The electromagnetic (EM) parameters of Fe–Ni alloy/OMC/paraffin wax composites were measured. Interestingly, the μ″μ″ values of Fe–Ni(0.2)/OMC were very negative from ∼7 to 18 GHz and the minimum value was −0.7, which are mainly caused by the eddy current. The reflection loss (RL) values were calculated with the measured EM parameters based on the transmission line theory. Results showed that the effective absorption bandwidth (<−10 dB) of Fe–Ni(0.2)/OMC/paraffin wax composites with the thickness of 2.00 mm could reach up to 4.8 GHz. The enhanced EM wave-absorbing properties of the composites could be attributed to well impedance matching between the absorber and air. Moreover, the enhanced dielectric loss and magnetic loss induced by Fe–Ni alloy also played a crucial role in the EM wave-absorbing process.

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