Intragranular glass/crystal conjugated particles in strip cast Nd-Fe-B flakes

Hansheng Chen, Wanqiang Xu, Chunguang Tang, Zibin Chen, Hongwei Liu, Pengju Bian, Yin Yao, Jiangtao Qu, Fan Yun, Derek Wong, Zhixiao Ye, Xingmo Zhang, Tiebin Yang, Xiaozhou Liao, Simon P. Ringer, Rongkun Zheng (Corresponding Author)

Research output: Journal article publicationJournal articleAcademic researchpeer-review

1 Citation (Scopus)

Abstract

Intragranular rare earth-rich phases play a vital role in affecting the intrinsic coercivity of sintered Nd-Fe-B permanent magnets. To explore the origin of these intragranular rare-earth-rich phases, the starting material-strip cast Nd-Fe-B flakes were characterized by a variety of high-end microscopy techniques. It was surprisingly found that the intragranular rare-earth-rich phase is spherical in a diameter of ~150–300 nm and consists of amorphous regions rich in additive elements (e.g., Cu, Co, and Ga) and crystalline regions which are a combination of hexagonal light-rare-earth-rich phases and body centered cubic phases rich in light and heavy rare earth, and oxygen. Amorphous interfacial layers between the glass/crystal particles and the crystalline matrix were observed, probably due to insufficient time to reach a crystalline equilibrium state. Based on the microstructural observation, we proposed a formation mechanism of these intragranular glass/crystal conjugated particles in strip cast Nd-Fe-B flakes, which may facilitate to minimize the volume of these detrimental intragranular phases during the strip casting process.

Original languageEnglish
Article number165863
JournalJournal of Magnetism and Magnetic Materials
Volume495
DOIs
Publication statusPublished - 1 Feb 2020
Externally publishedYes

Keywords

  • Atom probe microscopy
  • Intragranular glass/crystal rare-earth-rich particle
  • Magnetic force microscopy
  • Nd-Fe-B
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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