Hard magnetic bulk amorphous nd-fe-ai alloys of 12 mm in diameter made by suction casting

Akihisa Inoue, Tao Zhang, Akira Takeuchi, Wei Zhang

Research output: Contribution to journalArticlepeer-review

128 Citations (Scopus)

Abstract

Bulk amorphous Nd70Fe20Al10 Nd60Fe30Alu) and Nd60Fe30Al10 alloys with hard magnetic properties were produced in a cylindrical form with a diameter of 12 mm and a length of 70 mm by sucking their molten alloys into a copper mold. The sucking force was generated from the rapid movement (5.0 m/s) of piston with a diameter of 12 mm which was set at the center of the copper mold. The casting velocity was evaluated to be as high as 3.5 kg/s. Neither cavity nor hole is seen on the outer surface of the bulk amorphous alloy and the crystallization temperature (7,) and melting temperature (Tm) are 761 and 866 K, respectively, for the bulk amorphous Nd,0Fe2oAlIO alloy. Consequently, the temperature interval of supercooled liquid denned by the difference between Tm and Tx ATm(= Tx ΔTf) is as small as 105 K and the reduced crystallization temperature (Tx/ Tm) is as high as 0.88. The small Δ Tm and high Tx/Tm values are presumed to be the origin for the achievement of the large glass-forming ability for the Nd-Fe-Al alloys. The bulk amorphous Nd70Fe20Al10, Nd65Fe25Al10 and Nd60Fe30Al10 cylinders exhibit hard magnetic properties of 0.076 to 0.086 T for remanence, 291 to 321 kA/m for intrinsic coercive field and 13 to 16 kJ/m3 for maximum energy product at 298 K which are nearly the same as those for the corresponding bulk amorphous cylinders with diameters of 1 to 5 mm prepared by conventional casting. The hard magnetic properties for the Nd-Fe-Al amorphous alloys with large glass-forming ability are promising for future progress as a new type of hard magnetic materials.

Original languageEnglish
Pages (from-to)636-640
Number of pages5
JournalMaterials Transactions, JIM
Volume37
Issue number4
DOIs
Publication statusPublished - 1996

Keywords

  • Bulk amorphous alloy
  • Hard magnetic amorphous alloy
  • Hard magnetism
  • Large coercive field
  • Large glass-forming ability
  • Large reduced crystallization temperature
  • Neodymium-iron-aluminutn alloy
  • Suction casting process

ASJC Scopus subject areas

  • Engineering(all)

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