Grain size modulation to optimize the wave-absorbing properties of FeSiCr alloy micropowder

In this paper, the ball-milled flake FeSiCr alloy is subjected to a vacuum annealing temperature between 300 and 500 °C. The results show that the appropriate heat treatment temperature increases the average grain size of the material, eliminates defects and internal stresses, and improves the complex permeability of the material. The optimum wave-absorbing performance of the material is achieved when the heat treatment temperature is 400 °C with the minimum reflectivity RL min reaching −56.33 dB at a frequency f of 3.97 GHz, corresponding to the thickness of the wave-absorbing coating, d = 4.0 mm. This work provides an important reference value for application of FeSi-based alloy micropowder soft magnetic materials in the field of microwave absorption. At 400 °C corresponds to RL min = −56.33 dB at f = 3.97 GHz, d = 4.0 mm. Vacuum annealing can balance the electromagnetic wave attenuation ability of the materials and impedance matching, resulting in improved wave-absorbing properties.