Tunable Electromagnetic and Microwave Absorption Properties of Magnetic FeNi₃ Alloys

Magnetic materials have a very broad application prospect in the field of microwave absorption, among which soft magnetic materials become the focus of magnetic materials research because of their high saturation magnetization and low coercivity. FeNi₃ alloy has been widely used in soft magnetic materials because of its excellent ferromagnetism and electrical conductivity. In this work, FeNi₃ alloy was prepared by the liquid reduction method. The effect of the filling ratio of FeNi₃ alloy on the electromagnetic properties of absorbing materials was studied. It is found that the impedance matching ability of FeNi₃ alloy is better when the filling ratio is 70 wt% than that of other samples with different filling ratios (30-60 wt%), showing better microwave absorption characteristics. When the matching thickness is 2.35 mm, the minimum reflection loss (RL) of FeNi₃ alloy with a 70 wt% filling ratio reaches -40.33 dB, and the effective absorption bandwidth is 5.5 GHz. When the matching thickness is between 2 and 3 mm, the effective absorption bandwidth ranges from 7.21 GHz to 17.81 GHz, almost covering the whole X and Ku bands (8-18 GHz). The results show that FeNi₃ alloy has adjustable electromagnetic properties and microwave absorption properties with different filling ratios, which is conducive to selecting excellent microwave absorption materials.