Structure and magnetic properties of Fe-based powders prepared by mechanical alloying

FeSiAlCr alloy powders were prepared by mechanical alloying, the milling time were 20 h, 40 h, 60 h and 80 h, respectively. Powders morphology was studied by SEM. Microstructure of powders milled for various times were analyzed by XRD. The complex permittivity and complex permeability of four powders were tested in the frequency range from 0.5 to 18 GHz, and their microwave absorption properties were analyzed. It was found that the particle size of powders milled for 80 h was less than 2 μm. Silicon and aluminum atoms were dissolved into the crystal lattice of iron, and chromium atoms can form alloy with iron atoms. The minimum peak value of reflectivity can reach to -11.3 dB at the frequency of 4.3 GHz for 80 h milling powders, and the other one was ?6 dB at 16.5 GHz.