Recent progress in high B s Fe-based nanocrystalline soft magnetic alloys

• Published in: Journal of physics. D, Applied physics Applied physics, 2011-02, Vol.44 (6), p.64004
• Main Authors: Ohta, M, Yoshizawa, Y
• Format: Article
• Language: English
• ISSN: 0022-3727; 1361-6463
• DOI: 10.1088/0022-3727/44/6/064004

High saturation magnetic flux density (high- B s ) alloy has been developed in an Fe-based nanocrystalline alloy system. A nanocrystalline phase with an average grain size of about 20 nm is obtained by annealing Cu-substituted and/or Cu-and-Si-complex-substituted Fe–B amorphous alloys. The alloy exhibits low coercivity of less than 7 A m −1 and a high B s of more than 1.8 T. The iron loss at 50 Hz and 1.6 T for a toroidal core made of Fe 80.5 Cu 1.5 Si 4 B 14 nanocrystalline alloy is 0.46 W kg −1 , which is about 2/3 of that of grain-oriented Si steel. Moreover, the iron loss at 10 kHz and 0.2 T for a wound core made of this alloy is 7.5 W kg −1 , which is about 25% of that of non-grain-oriented Si steel and about 60% of that of an Fe-based amorphous alloy. In addition, the cut cores made of the alloy show good superimposed dc-current characteristics and appear promising in applications such as power choke coils (at the high-frequency region).