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
Hc
and high saturation magnetic flux density
Bs
. 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 μm. After annealing at 723 K, the as-quenched alloy powders are crystallized and
Bs
of the nanocrystalline alloy powders with Fe
_83.3
Si
₄
B
₈
P
₄
Cu
_0.7
and Fe
_84.8
Si
₂
B
₁₀
P
₂
Cu
_1.2
exhibit high
Bs
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 Fe
_83.3
Si
₄
B
₈
P
₄
Cu
_0.7
nanocrystalline alloy powder with an average particle size of 3.0 μm exhibits the best core loss of 1461 kW/m
³
(
Bm
= 50 mT,
f
=300 kHz).