Enhanced microwave absorption properties of spherical Fe 4 N derived from spherical Fe

Advanced microwave-absorbing materials are technologically significant with extensive utilization of electronic communication equipment. Due to its good chemical stability, high-specific saturation magnetization, and high snoek’s limit, Fe 4 N has attracted widespread attention as a microwave-absorbing material. In this work, we transferred the spherical Fe into spherical Fe 4 N by the gas-nitriding process. The obtained spherical Fe 4 N exhibit an enhanced microwave absorption ability than spherical Fe. When the matching thickness is only 1.5 mm, the minimum reflection loss ( RL min ) runs up to − 22.3 dB. And the effective absorption bandwidth achieves 4.5 GHz when the matching thickness rises to 2 mm. Through the characterization of crystal structure, microscopic morphology, magnetic properties, and absorbing properties, we explored the mechanisms for improved microwave absorption performance in spherical Fe 4 N. Improved dielectric loss mechanisms, such as interface polarization and conductive loss, were discovered for spherical Fe 4 N. The microwave absorption performance also heavily relies on the magnetic loss mechanisms of eddy current loss, natural resonance, exchange resonance, and hysteresis loss. Meanwhile, the formation of Fe 4 N in SFN improves attenuation constant and optimizes impedance matching which take advantages of the synergy of dielectric loss and magnetic loss. Additionally, the 1/4 λ interference cancellation theory’s destructive interference occurs in microwave absorption process of spherical Fe 4 N. This research not only provides a new high-performance microwave absorber but also supplies experience for the preparation of Fe 4 N-based composite microwave absorbers.