Microstructure and Magnetic Properties of Bulk FeCo Alloys Fabricated from Mechanically Alloying and Chemically Synthesized Powders

Three different methods of fabrication of FeCo soft magnetic material using ferromagnetic powders are compared: (i) simple sintering of elemental powders of Fe and Co, (ii) sintering of mechanically alloying FeCo powder, and (iii) sintering of chemically synthesized FeCo powder. The microstructure of ferromagnetic powders and bulk sintered alloys is characterized using scanning electron microscopy and energy-dispersive X-ray spectroscopy analysis. The best magnetic properties with high saturation magnetization, Ms = 211.3 emu/g, are obtained for bulk FeCo alloy sintered from chemically synthesized powder. It consists of nearly spherical FeCo particles with diameters from 5 to 15 μ m. The mean particle size of chemically synthesized FeCo powder can be controlled by changing the melt composition, temperature, and process duration. The relatively large size of FeCo particles reduces the influence of surface oxidation on the particle magnetic properties. The low-cost chemical technology developed is promising for a large-scale production of small FeCo magnetic components of arbitrary shapes with high-dimensional precision.