Synthesis and Magnetic Properties of MnBi(LTP) Magnets With High-Energy Product

Author

Ki Woong Moon ; Kwang-Won Jeon ; Min Kang ; Min-Kyu Kang ; Yangwoo Byun ; Jin Bae Kim ; Hwijun Kim ; Jongryoul Kim

Author_Institution

Dept. of Metall. & Mater. Eng., Hanyang Univ., Ansan, South Korea

Volume

50

Issue

11

fYear

2014

fDate

Nov. 2014

Firstpage

1

Lastpage

4

Abstract

MnBi magnets were prepared by melt-spinning, annealing, ball-milling, magnetic alignment, and subsequent hot compaction process. Mn-Bi melt-spun ribbons contained mainly unreacted Mn and Bi phases, including the low-temperature phase of MnBi. To increase the amount of this MnBi phase, these melt-spun ribbons were annealed under an oxygen-controlled atmosphere. As a result, a maximum saturation magnetization value of 57.90 emu/g was obtained when the melt-spun ribbons were annealed at 300 °C for 12 h. Bulk magnets fabricated by magnetic alignment and hot compaction processes showed a density of 8.71 g/cm³, a M_r/M_s ratio of 0.79, and a (BH)_max value of 6.7 MGOe at room temperature. With the temperature increasing, the coercivity changed from 6387 Oe at room temperature to 18540 Oe at 150 °C and a (BH)_max measured 5.5 MGOe at 150 °C.

Keywords

annealing; ball milling; bismuth alloys; coercive force; compaction; manganese alloys; melt spinning; permanent magnets; MnBi; annealing; ball-milling; coercivity; low-temperature phase magnets; magnetic alignment; melt-spinning; oxygen-controlled atmosphere; permanent magnets; saturation magnetization; subsequent hot compaction process; temperature 150 degC; temperature 293 K to 298 K; temperature 300 degC; time 12 h; Magnetic hysteresis; Magnetic resonance imaging; Perpendicular magnetic anisotropy; Powders; Saturation magnetization; Temperature measurement; (BH) (_{max }); LTP; MnBi; melt spinning; permanent magnets;

fLanguage

English

Journal_Title

Magnetics, IEEE Transactions on

Publisher

ieee

ISSN

0018-9464

Type

jour

DOI

10.1109/TMAG.2014.2329555

Filename

6971761