New excellent soft magnetic fesibpcu nanocrystallized alloys with high Bs of 1.9 T from nanohetero-amorphous phase

Akihiro Makino, He Men, Takeshi Kubota, Kunio Yubuta, Akihisa Inoue

Research output: Contribution to journalArticlepeer-review

90 Citations (Scopus)


The melt-spun Fe83.3-84.3Si4 B8 P 3-4 Cu0.7 (at%) alloys have heterogeneous amorphous structures including a large amount of α -Fe clusters with less than 3 nm in size after rapid solidification, due to the unusual effect of the simultaneous addition of the small amounts of P and Cu. A homogeneous nanocrystalline structure composed of α -Fe grains with a size of about less than 20 nm can be realized by crystallizing the heteroamorphous alloys. The Fe83.3-84.3Si4 B8 P3-4 Cu 0.7 nanocrystalline alloys show significantly high saturation magnetic flux density of 1.88-1.94 T almost comparable to the commercial silicon steel. The Fe83.3-84.3Si4 B8 P3-4 Cu0.7 alloys exhibit excellent magnetic softness; low coercivity of 7-10 A/m, relatively high effective permeability of 16 000-25 000 at 1 kHz due to the simultaneous realization of the uniform nanostructure composed by fine α-Fe grains and a small magnetostriction of 2 - 3 × 10-6 The nanocrystalline alloys also exhibit much smaller W than the silicon steel over the Bm range up to 1.7 T due to significantly higher B s and excellent magnetic softness. Therefore, the Fe-Si-B-P-Cu alloys have a great advantage for engineering and industry, and, thus, should make a contribution to energy saving and conservation of earth's resources and environment.

Original languageEnglish
Article number5257379
Pages (from-to)4302-4305
Number of pages4
JournalIEEE Transactions on Magnetics
Issue number10
Publication statusPublished - 2009 Oct


  • Hetero-amorphous alloy
  • High magnetic flux density
  • Nanocrystalline alloy
  • Soft magnetic material

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering


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