Preparation of Fe-Pt Powders from Ingot by a Simple and Cost-Effective Spark Erosion Device

FePt powders with 1 µm average particle size have been synthesized from bulk ingot with no need for cryogenic temperatures or conventional powder processing. This is achieved with a compact, cost-effective spark erosion device which is simple to assemble, with no need of a mechanical workshop. The as-synthesized powders show a disordered A1 phase with curie temperature, T_c = 300 °C. The effect of annealing on the transition from the disordered to the ordered phase and on the magnetic properties are investigated in situ by magnetic susceptibility measurements. The phase transition to the L1₀ phase (T_c = 445 °C) is complete at 630 °C where the coercivity increases from 0 to 0.3 T. A urther increase of the heating temperature has no effect on the magnetic and crystallographic properties.