Bulk amorphous powder cores with low core loss by spark-plasma sintering Fe76Si9.6B8.4P6 amorphous powder with small amounts of SiO2

Fe76Si9.6B8.4P6 amorphous powder was produced by gas atomization. Next, bulk amorphous powder discs were prepared by pressing a mixture of Fe76Si9.6B8.4P6 amorphous powder and a small amount of SiO2 powder using the spark plasma sintering technique. The resulting bulk amorphous powder cores were obtained from the compacted discs using an electrical spark erosion machine. The powder core with 5 mass% SiO2 shows both high saturation magnetization of 1.41 T and good soft magnetic properties, 23 A/m for coercive force and 117 for effective permeability at 1 kHz. The core also exhibits much lower core loss than silicon steels or the powder core without SiO2, only 71 W/kg at a maximum magnetic induction of 0.2 T with a frequency of 10 kHz. The low core loss is due to a SiO2 insulator layer forming on the surface of the alloy powder that can effectively reduce the eddy current and consequently reduce the core loss. (C) 2015 Elsevier B.V. All rights reserved.