ZnFe₂O₄@SiO₂/C Composites Synthesized by High-Temperature Mechanochemical Technology for Efficient Electromagnetic Wave Absorption in the X-Band

Constructing a reasonable dielectric-magnetic synergistic effect is an effective way to prepare high-performance electromagnetic wave absorbers. In this paper, ZnFe 2 O 4 @SiO 2 /C composites with a close-packed structure were successfully synthesized by an efficient condensation reaction of a silane coupling agent and high-temperature mechanochemical technology. The silane coupling agent can effectively adjust the occurrence state of ZnFe 2 O 4 and the graphite interlayer compound, so as to realize the adjustable electromagnetic parameters. When the ratio of silane coupling agent, deionized water, and anhydrous ethanol is 1:1:1, ZnFe 2 O 4 @SiO 2 /C composites achieve a minimum reflection loss value (RL min ) of −52.5 dB at a thickness of 1.87 mm and a maximum effective absorption bandwidth (EAB max ) of 4.16 GHz at a thickness of 2.07 mm. In addition, the EAB covers 8–12 GHz at a thickness of 1.97 mm, achieving efficient absorption of X-band electromagnetic waves. Through the optimization of structure and composition, the problems of large thickness and limited electromagnetic wave performance of ZnFe 2 O 4 /C composites are effectively improved, which provides a way for the design and large-scale preparation of ZnFe 2 O 4 -based absorbers with high electromagnetic wave absorption performance in the X-band.