Microstructural modification of grain boundary area in WS2/Al co-doped Nd-Fe-B sintered magnet

Kyoung Hoon Bae, Seong Rae Lee, Hyo Jun Kim, Min Woo Lee, Tae Suk Jang

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

We investigated the effect of microstructural modification of grain boundary area and WS2 powder size on the magnetic properties of WS2/Al-doped Nd-Fe-B sintered magnet. Grain growth inhibition (7.6 → 6.4 μm) in optimally doped magnet with Dy-rich core-shell microstructure was effectively improved the magnetic properties compared with only doped magnet. In the case of only doped magnet, the lattice misfit between the (002) WFeB precipitates and (110) Nd2Fe14B interfaces was about 9.9%, which caused the strong strain fields at the grain boundaries. However, the doped magnet with Dy-rich core-shell exhibited a decreased lattice misfit (9.9 → 3.4%) owing to the formation of the high anisotropic Dy-rich (Nd,Dy)2Fe14B phase around the GB area, thus suppressing reverse-domain nucleation at the grain boundaries. As a result, the coercivity increments in the optimally doped magnets with Dy-rich core-shell (6.5%) was larger than that of only doped magnets (3.9%) compared with each corresponding undoped magnet. When the particle size of WS2-doped powders was reduced (∼2.0 → ∼0.6 μm), the coercivity further increased owing to the improved inhibition of grain growth although the doping content of WS2 was reduced from 0.6 to 0.4 wt%.

Original languageEnglish
Pages (from-to)93-100
Number of pages8
JournalIntermetallics
Volume92
DOIs
Publication statusPublished - 2018 Jan 1

Fingerprint

Magnets
Grain boundaries
Coercive force
Grain growth
Powders
Magnetic properties
Precipitates
Nucleation
Particle size
Doping (additives)
Microstructure

Keywords

  • Coercivity
  • Core-shell microstructure
  • Grain growth inhibition
  • Nd-Fe-B sintered magnet

ASJC Scopus subject areas

  • Chemistry(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Metals and Alloys
  • Materials Chemistry

Cite this

Microstructural modification of grain boundary area in WS2/Al co-doped Nd-Fe-B sintered magnet. / Bae, Kyoung Hoon; Lee, Seong Rae; Kim, Hyo Jun; Lee, Min Woo; Jang, Tae Suk.

In: Intermetallics, Vol. 92, 01.01.2018, p. 93-100.

Research output: Contribution to journalArticle

Bae, Kyoung Hoon ; Lee, Seong Rae ; Kim, Hyo Jun ; Lee, Min Woo ; Jang, Tae Suk. / Microstructural modification of grain boundary area in WS2/Al co-doped Nd-Fe-B sintered magnet. In: Intermetallics. 2018 ; Vol. 92. pp. 93-100.
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AB - We investigated the effect of microstructural modification of grain boundary area and WS2 powder size on the magnetic properties of WS2/Al-doped Nd-Fe-B sintered magnet. Grain growth inhibition (7.6 → 6.4 μm) in optimally doped magnet with Dy-rich core-shell microstructure was effectively improved the magnetic properties compared with only doped magnet. In the case of only doped magnet, the lattice misfit between the (002) WFeB precipitates and (110) Nd2Fe14B interfaces was about 9.9%, which caused the strong strain fields at the grain boundaries. However, the doped magnet with Dy-rich core-shell exhibited a decreased lattice misfit (9.9 → 3.4%) owing to the formation of the high anisotropic Dy-rich (Nd,Dy)2Fe14B phase around the GB area, thus suppressing reverse-domain nucleation at the grain boundaries. As a result, the coercivity increments in the optimally doped magnets with Dy-rich core-shell (6.5%) was larger than that of only doped magnets (3.9%) compared with each corresponding undoped magnet. When the particle size of WS2-doped powders was reduced (∼2.0 → ∼0.6 μm), the coercivity further increased owing to the improved inhibition of grain growth although the doping content of WS2 was reduced from 0.6 to 0.4 wt%.

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