Structural and microwave absorption properties of CoFe2O4/residual carbon composites

Electromagnetic interference is of urgent concern in contemporary society, necessitating the swift advancement of substances with exceptional capabilities in absorbing electromagnetic waves. In this work, a direct hydrothermal method was utilized to create CoFe2O4/residual carbon from coal gasification fine slag (CFO/RC) composites. These composites encompass various mechanisms for microwave absorption, including conductive loss, natural resonance, interfacial dipole polarization, and magnetic flux loss. Consequently, compared with pure residual carbon materials this composite offers superior capabilities in microwave absorption. At 7.76 GHz, the CFO/RC-2 composite achieves an impressive minimum reflection loss (RLmin) of −43.99 dB with a thickness of 2.44 mm. Moreover, CFO/RC-3 demonstrates an effective absorption bandwidth (EAB) of up to 4.16 GHz, accompanied by a thickness of 1.18 mm. This study revealed the remarkable ability of the composite to diminish electromagnetic waves, providing a new method for generating microwave absorbing materials of superior quality.