Thermal and magnetic properties of Fe56Co7Ni7Zr10-xNbxB 20 amorphous alloys with wide supercooled liquid range

Akihisa Inoue, Hisato Koshiba, Tao Zhang, Akihiro Makino

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68 Citations (Scopus)


Amorphous alloys with a wide supercooled liquid region of 45 to 85 K were found to be formed in Fe56Co7Ni7Zr10-xNbxB 20 (x=0 to 10 at%) alloys by melt spinning. The glass transition temperature (Tg) and the crystallization temperature (Tx) increase by the dissolution of 2 to 4%Nb. The degree of increase is larger for Tx than Tg, leading to the maximum ΔTx(=Tx-Tg) of 85 K for the 2%Nb alloy. The ΔTx value is about 20 K larger than the largest value for the newly developed Fe-(Al, Ga)-(P, C, B, Si) amorphous alloys. The crystallization occurs through a single stage, amorphous→α-Fe+γ-Fe+Fe2Zr+Fe76Nb 6B18, for the alloys containing less than about 6%Nb and through two stages, amorphous→amorphous+γ-Fe→γ-Fe+Co3Nb 2B5+Ni8Nb, for the alloys containing more than 8%Nb. The change in the crystallization process for the Nb-rich alloys probably reflects the disappearance of Fe2(Nb, Zr) precipitates because of the weaker bonding of Fe-Nb pair as compared with Fe-Zr one. As the Nb content increases, the saturation magnetization (Is) and permeability (μe) of the annealed alloys decrease while the coercive force (Hc) remains almost unchanged. The good soft magnetic properties are obtained for the alloys containing less than 2%Nb subjected to annealing for 300 s at 800 K and the Is, Hc and μe at 1 kHz are 0.96 T, 2.0 A/m and 19100, respectively, for the 0%Nb alloy and 0.75 T, 1.1 A/m and 25000, respectively, for the 2%Nb alloy. The success of synthesizing the new amorphous alloys with a wide supercooled liquid region more than 80 K and with good soft magnetic properties is promising for future development as soft magnetic bulk amorphous alloys.

Original languageEnglish
Pages (from-to)577-582
Number of pages6
JournalMaterials Transactions, JIM
Issue number7
Publication statusPublished - 1997 Jul


  • Glass transition
  • Iron-based alloy system
  • Melt spinning
  • Single stage crystallization process
  • Soft magnetic amorphous alloy
  • Soft magnetic property
  • Wide supercooled liquid region

ASJC Scopus subject areas

  • Engineering(all)

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