The evolution of microstructure and magnetic properties of Fe–Si–Cr powders on ball-milling process

Flake-shaped particles were fabricated from crushing ingots with ball milling method. Scanning electron microscope (SEM), X-ray diffraction (XRD), vibrating samples magnetometer (VSM) and Mössbauer spectroscopy measurements were carried out to characterize the milled powders. The XRD results show that the DO3 ordered phase coexists with α-Fe(Si,Cr) matrix phase. Generally, grain size decreases with milling time, as internal strain increases. The fitting result of the Mössbauer spectra of the as-prepared powders reveals that the DO3 phase always exists, but the percentage of DO3 phase drops from 52% in the starting powder to 25% after 80 h milling. A planar anisotropy of the flake-shaped powders is also demonstrated by the Mössbauer spectra, and found to increase with milling time. The saturation magnetization Ms has a maximum value of 109 emu/g after milling of 8 h, and then remains at a steady value around 104 emu/g. The maximum complex permeability is obtained by 32 h milling.