Low Core Loss of a bcc Fe86Zr7B6Cu1 Alloy with Nanoscale Grain Size

Akihisa Inoue, Tsuyoshi Masumoto, Akihiro Makino, Kiyonori Suzuki

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We have investigated the possible applications potential of a newly developed bcc-nanocrystalline Fe86Zr7B6CU1 alloy by determining the core loss, permeability μe, and magnetization B800 (at a field 800 kA/m). The above parameters have been studied as a function of annealing temperature Ta of the as-quenched amorphous alloy, maximum induction Bm, and frequency (up to 100 kHz). On transformation to the bcc-nanocrystalline state at 873 K with a 10 nm grain size, maximum values of μe=41000 and B800= 1.52 T are obtained. The determined core loss is found to achieve a minimum value of 66 mW/kg at 1 T, 50 Hz. This value is considerably smaller (45 and 95% respectively) than those reported for the amorphous Fe78Si9B13 and bcc Fe-3.5%Si alloys now in use as transformer core materials. The observed Bm and frequency dependences of the loss values for our new Fe-Zr-B-Cu alloy are consistently found to be superior as well. Thus, the bcc-nanocrystalline Fe-Zr-B-Cu alloy is quite promising for practical use as a core material in various transformers with the advantage of high Bm, high μe and low core loss.

Original languageEnglish
Pages (from-to)551-556
Number of pages6
JournalMaterials Transactions, JIM
Issue number6
Publication statusPublished - 1 Jan 1991
Externally publishedYes


  • bcc-nanocrystalline alloy
  • core loss
  • crystallization
  • electrical resistivity
  • iron-zirconium-boron system
  • nanoscale grain size
  • permeability
  • saturation magnetization
  • soft magnetic property

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