Characteristics of Fe-Si-B-P-Cu Nanocrystalline Soft Magnetic Alloy Powders With High Bs.

Nanocrystalline soft magnetic alloy powders produced by heat treating amorphous powders are expected to improve properties and miniaturize dust cores because of their low coercive force H_c and high saturation magnetic flux density B_s. By water atomization process, we successfully obtained quenched Fe-Si-B-P-Cu alloy powders with spherical particle shape. The obtained powders have different average particle sizes of 2.0, 3.0, 5.0, and 8.5 \mum. After annealing at 723 K, the as-quenched alloy powders are crystallized and B_s of the nanocrystalline alloy powders with Fe83.3Si4B8P4Cu0.7 and Fe84.8Si2B10P2Cu1.2 exhibit high B_s of 1.72 and 1.76 T, respectively. Core loss characteristics of the dust cores are found to be dependent on amorphous stability of the as-quenched powders. Thus, the Fe83.3Si4B8P4Cu0.7 nanocrystalline alloy powder with an average particle size of 3.0 \mum exhibits the best core loss of 1461 kW/m^3 (B_m=50\ mT, f=300\ kHz). [ABSTRACT FROM AUTHOR]