Rapid-annealing effect on the microstructure and magnetic properties of the Fe-rich nanocomposite magnets

Akinori Kojima, Akihiro Makino, Akihisa Inoue

Research output: Contribution to journalConference article

24 Citations (Scopus)

Abstract

The rapid-annealing effect on the microstructure and magnetic properties of the nanocomposite Fe93-x-yCoxNb2(Nd, Pr)yB5 (x = 0-20, y = 5-7 at. %) alloys produced by crystallization of an amorphous phase have been investigated. The melt-spun ribbons consist of an amorphous phase in the as-quenched state and the amorphous phase changes to a nanocomposite structure consisting mainly of bcc-(Fe, Co), (Nd, Pr)2(Fe, Co)14B and residual amorphous phases after annealing at temperatures of 973-1023 K. The nanocomposite alloys exhibit improved values of remanence (Jr), coercive force (HcJ), and maximum energy product [(BH)max] upon annealing at a higher heating rate (α) in the temperature range corresponding to the primary crystallization temperature of bcc-Fe phase. As α increases, the grain sizes of each phase decrease, especially for the Nd2Fe14B phase, and the ratio of total surface area of the Nd2Fe14B to bcc-Fe phases (Shard/Ssoft), which are evaluated assuming each grain is a sphere, becomes close to 1 for the Fe88Nb2Nd5B5 alloy. This result indicates that the homogeneity of soft and hard magnetic phases is improved by rapid annealing, and it causes the improvement of hard magnetic properties of the Fe-rich nanocomposite alloys.

Original languageEnglish
Pages (from-to)6576-6578
Number of pages3
JournalJournal of Applied Physics
Volume87
Issue number9 III
DOIs
Publication statusPublished - 2000 May 1
Event44th Annual Conference on Magnetism and Magnetic Materials - San Jose, CA, United States
Duration: 1999 Nov 151999 Nov 18

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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