Effects of Al/Cu co-doping on crystal structure and chemical composition of Nd-rich phases in Nd-Fe-B sintered magnet

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

doi:10.1016/j.actamat.2017.05.046

Effects of Al/Cu co-doping on crystal structure and chemical composition of Nd-rich phases in Nd-Fe-B sintered magnet

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

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

73 Citations (Scopus)

Abstract

We investigated the effects of Al/Cu co-doping on the magnetic and microstructural properties of a Nd-Fe-B sintered magnet. In particular, the structural and compositional changes of Cu-dissolved Nd-rich (Cu-rich) triple junction phase (TJP) and grain boundary phase (GBP) experienced upon Al/Cu co-doping were intensively analyzed. Al was selectively dissolved into the Cu^low-rich phases (B phase, 3–15 at.% Cu) other than the Cu^high-rich phases (A phase, 20–45 at.% Cu). The B phase with an h-Nd₂O₃ structure was transformed to the C phase (Al-dissolved Cu^low-rich phases) with a c-Nd₂O₃ structure upon Al dissolution. In addition, the continuity of C GBP was improved and the Fe content of C GBP was reduced (25 → 5 at.% Fe). As a result, the coercivity (H_c) of the Al/Cu co-doped magnet was higher than that of a Cu-doped magnet. The critical role played by Al in improving the magnetic properties and microstructure of the Al/Cu co-doped magnet was elucidated. The detailed mechanism for the H_c enhancement of the Al/Cu co-doped magnet was discussed based on the results.

Original language	English
Pages (from-to)	200-207
Number of pages	8
Journal	Acta Materialia
Volume	133
DOIs	https://doi.org/10.1016/j.actamat.2017.05.046
Publication status	Published - 2017 Jul

Bibliographical note

Funding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1B03931980) and the Technology Innovation Program funded by the Ministry of Knowledge Economy (MKE, Korea) (No. 10043780), Republic of Korea.

Publisher Copyright:
© 2017 Acta Materialia Inc.

Keywords

Coercivity
Grain boundaries
Metastable phases
Microstructures
Nd-Fe-B sintered magnet
Triple junctions

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Polymers and Plastics
Metals and Alloys

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10.1016/j.actamat.2017.05.046

Cite this

@article{2f6ebb209b0746b7bd40a65b86319b01,

title = "Effects of Al/Cu co-doping on crystal structure and chemical composition of Nd-rich phases in Nd-Fe-B sintered magnet",

abstract = "We investigated the effects of Al/Cu co-doping on the magnetic and microstructural properties of a Nd-Fe-B sintered magnet. In particular, the structural and compositional changes of Cu-dissolved Nd-rich (Cu-rich) triple junction phase (TJP) and grain boundary phase (GBP) experienced upon Al/Cu co-doping were intensively analyzed. Al was selectively dissolved into the Culow-rich phases (B phase, 3–15 at.\% Cu) other than the Cuhigh-rich phases (A phase, 20–45 at.\% Cu). The B phase with an h-Nd2O3 structure was transformed to the C phase (Al-dissolved Culow-rich phases) with a c-Nd2O3 structure upon Al dissolution. In addition, the continuity of C GBP was improved and the Fe content of C GBP was reduced (25 → 5 at.\% Fe). As a result, the coercivity (Hc) of the Al/Cu co-doped magnet was higher than that of a Cu-doped magnet. The critical role played by Al in improving the magnetic properties and microstructure of the Al/Cu co-doped magnet was elucidated. The detailed mechanism for the Hc enhancement of the Al/Cu co-doped magnet was discussed based on the results.",

keywords = "Coercivity, Grain boundaries, Metastable phases, Microstructures, Nd-Fe-B sintered magnet, Triple junctions",

author = "Kim, \{Tae Hoon\} and Lee, \{Seong Rae\} and Bae, \{Kyoung Hoon\} and Kim, \{Hyo Jun\} and Lee, \{Min Woo\} and Jang, \{Tae Suk\}",

note = "Funding Information: This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1B03931980) and the Technology Innovation Program funded by the Ministry of Knowledge Economy (MKE, Korea) (No. 10043780), Republic of Korea. Publisher Copyright: {\textcopyright} 2017 Acta Materialia Inc.",

year = "2017",

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doi = "10.1016/j.actamat.2017.05.046",

language = "English",

volume = "133",

pages = "200--207",

journal = "Acta Materialia",

issn = "1359-6454",

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TY - JOUR

T1 - Effects of Al/Cu co-doping on crystal structure and chemical composition of Nd-rich phases in Nd-Fe-B sintered magnet

AU - Kim, Tae Hoon

AU - Lee, Seong Rae

AU - Bae, Kyoung Hoon

AU - Kim, Hyo Jun

AU - Lee, Min Woo

AU - Jang, Tae Suk

N1 - Funding Information: This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2016R1D1A1B03931980) and the Technology Innovation Program funded by the Ministry of Knowledge Economy (MKE, Korea) (No. 10043780), Republic of Korea. Publisher Copyright: © 2017 Acta Materialia Inc.

PY - 2017/7

Y1 - 2017/7

N2 - We investigated the effects of Al/Cu co-doping on the magnetic and microstructural properties of a Nd-Fe-B sintered magnet. In particular, the structural and compositional changes of Cu-dissolved Nd-rich (Cu-rich) triple junction phase (TJP) and grain boundary phase (GBP) experienced upon Al/Cu co-doping were intensively analyzed. Al was selectively dissolved into the Culow-rich phases (B phase, 3–15 at.% Cu) other than the Cuhigh-rich phases (A phase, 20–45 at.% Cu). The B phase with an h-Nd2O3 structure was transformed to the C phase (Al-dissolved Culow-rich phases) with a c-Nd2O3 structure upon Al dissolution. In addition, the continuity of C GBP was improved and the Fe content of C GBP was reduced (25 → 5 at.% Fe). As a result, the coercivity (Hc) of the Al/Cu co-doped magnet was higher than that of a Cu-doped magnet. The critical role played by Al in improving the magnetic properties and microstructure of the Al/Cu co-doped magnet was elucidated. The detailed mechanism for the Hc enhancement of the Al/Cu co-doped magnet was discussed based on the results.

AB - We investigated the effects of Al/Cu co-doping on the magnetic and microstructural properties of a Nd-Fe-B sintered magnet. In particular, the structural and compositional changes of Cu-dissolved Nd-rich (Cu-rich) triple junction phase (TJP) and grain boundary phase (GBP) experienced upon Al/Cu co-doping were intensively analyzed. Al was selectively dissolved into the Culow-rich phases (B phase, 3–15 at.% Cu) other than the Cuhigh-rich phases (A phase, 20–45 at.% Cu). The B phase with an h-Nd2O3 structure was transformed to the C phase (Al-dissolved Culow-rich phases) with a c-Nd2O3 structure upon Al dissolution. In addition, the continuity of C GBP was improved and the Fe content of C GBP was reduced (25 → 5 at.% Fe). As a result, the coercivity (Hc) of the Al/Cu co-doped magnet was higher than that of a Cu-doped magnet. The critical role played by Al in improving the magnetic properties and microstructure of the Al/Cu co-doped magnet was elucidated. The detailed mechanism for the Hc enhancement of the Al/Cu co-doped magnet was discussed based on the results.

KW - Coercivity

KW - Grain boundaries

KW - Metastable phases

KW - Microstructures

KW - Nd-Fe-B sintered magnet

KW - Triple junctions

UR - https://www.scopus.com/pages/publications/85019954414

U2 - 10.1016/j.actamat.2017.05.046

DO - 10.1016/j.actamat.2017.05.046

M3 - Article

AN - SCOPUS:85019954414

SN - 1359-6454

VL - 133

SP - 200

EP - 207

JO - Acta Materialia

JF - Acta Materialia

ER -

Effects of Al/Cu co-doping on crystal structure and chemical composition of Nd-rich phases in Nd-Fe-B sintered magnet

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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