Hydrothermal synthesis of FeCo alloys with excellent microwave Absorption: Effect of reaction time

The hydrothermal method was used to prepare FeCo alloys with varying reaction times. The results show that the reaction time has a significant impact on the microstructure and microwave absorption properties of FeCo alloys. By varying the reaction time (8 h, 10 h, and 12 h), the alloy phase becomes increasingly purer, and the particle size and saturation magnetization (MS) of the alloys increase, but the coercive force (Hc) decreases. At the same time, the morphology of FeCo alloys gradually changed from irregular small particles to hexagonal star-shaped large particles. When the reaction time is 10 h, the FeCo alloys shows the highest attenuation coefficient (α), excellent impedance matching performance, and microwave absorption performance. When the matching thickness is 1.95 mm, the minimum reflection loss (RLmin) value at 11.12 GHz is −49.88 dB. When the matching thickness is 1.56 mm, the maximum effective absorption bandwidth (EABmax) is 6.8 GHz (11.2–18 GHz).