Abstract: Metal nitrides exhibit excellent properties and application potential as electromagnetic wave (EMW) ab-sorbing materials. Their high conductivity and adjustable dielectric properties allow them to effectively attenuate EMW. However, the current research on the synergistic effect of metal nitrides is scarce and has limited applications in the field of EMW absorption. In this work, Co/Ni metal-nitride fiber composites with multiphase structures were constructed by electrostatic spinning and multiphase composite process. The synergistic loss mechanism of multiphase structure and N atomic modulation is explored by modu-lating the components and microstructure of the materials. By constructing the multiphase composites, the controllable tuning of non-homogeneous interfaces and the enhanced interfacial polarization loss ef-fect were achieved. Electrochemical impedance spectroscopy was used to analyze the charge transfer ca-pability at the interface of multiphase Co/Ni metal nitride fiber composites. Through the controllable reg-ulation of the multiphase structure, the Co/Ni bimetallic nitride fiber composite (Co5.47 N/Ni4 N/CF) exhib-ited the strongest polarization loss capability, achieving a minimum reflection loss (RLmin ) of-43.82 dB and a maximum effective absorption bandwidth (EABmax ) of 7.04 GHz. This study provides a valuable reference for multiphase composites in the field of EMW absorption by exploring the polarization loss mechanism of Co/Ni metal nitride multiphase materials.

Key words: Multiphase composite, Heterogeneous interface, Polarization loss, Electromagnetic wave absorption