Microstructure, coercivity and thermal stability of nanostructured (Nd,Ce)-(Fe,Co)-B hot-compacted permanent magnets

Yuye Wu; Konstantin P. Skokov; Lukas Schäfer; Fernando Maccari; Alex Aubert; Hao Xu; Haichen Wu; Chengbao Jiang; Oliver Gutfleisch

doi:10.1016/j.actamat.2022.118062

Microstructure, coercivity and thermal stability of nanostructured (Nd,Ce)-(Fe,Co)-B hot-compacted permanent magnets

Yuye Wu^*
, Konstantin P. Skokov
, Lukas Schäfer
, Fernando Maccari
, Alex Aubert
, Hao Xu
, Haichen Wu
, Chengbao Jiang
, Oliver Gutfleisch

^*Corresponding author for this work

School of Materials Science and Engineering

Technische Universität Darmstadt
Beihang University
CAS - Ningbo Institute of Material Technology and Engineering

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

37 Scopus citations

Abstract

We report on microstructure, hard magnetic properties and thermal stability of nanocrystalline (Nd_0.85Ce_0.15)₁₅(Fe_1-_xCo_x)₇₈B₇ (x = 0 – 1) hot-compacted permanent magnets. At lower Co concentrations (x < 0.3), the substitution of Fe by Co changes the composition of grain boundary phase from non-magnetic (Nd,Ce)₂Fe₁ to magnetic (Nd,Ce)₁(Fe,Co)_2, leading to the degrading of the coercivity. At x ≥ 0.6, the grain boundary phase is no longer observed between the nanocrystalline grains, resulting in strong magnetic coupling of constituent phases. With the further increase of Co concentration (x>0.6), additional RE(Fe,Co)₂, RE(Fe,Co)₄B and RECo₅ phases are gradually formed in the magnets. A new type of microstructure with nanograins of RE₂(Fe,Co)₁₄B phase, RE(Fe,Co)₂ phase and RE(Fe,Co)₄B phase, with partial or without grain boundary phase shows good thermal stability (x = 0.4 and 0.6). In (Nd_0.85Ce_0.15)₁₅(Fe_0.4Co_0.6)₇₈B₇ magnets, the absolute values of temperature coefficient of coercivity |β| can reach 0.3 %/K within the temperature range of 300 K - 500 K, and it exceeds 0.23 %/K for the temperature range of 300 K - 650 K, indicating a promising method for designing highly thermal stable permanent magnets.

Original language	English
Article number	118062
Journal	Acta Materialia
Volume	235
DOIs	https://doi.org/10.1016/j.actamat.2022.118062
State	Published - 15 Aug 2022

Keywords

Coercivity
Micromagnetic simulation
Microstructure
Permanent magnets
Thermal stability

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10.1016/j.actamat.2022.118062

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@article{68edc397c02f47ddb2730c7b39ec56f4,

title = "Microstructure, coercivity and thermal stability of nanostructured (Nd,Ce)-(Fe,Co)-B hot-compacted permanent magnets",

abstract = "We report on microstructure, hard magnetic properties and thermal stability of nanocrystalline (Nd0.85Ce0.15)15(Fe1-xCox)78B7 (x = 0 – 1) hot-compacted permanent magnets. At lower Co concentrations (x < 0.3), the substitution of Fe by Co changes the composition of grain boundary phase from non-magnetic (Nd,Ce)2Fe1 to magnetic (Nd,Ce)1(Fe,Co)2, leading to the degrading of the coercivity. At x ≥ 0.6, the grain boundary phase is no longer observed between the nanocrystalline grains, resulting in strong magnetic coupling of constituent phases. With the further increase of Co concentration (x>0.6), additional RE(Fe,Co)2, RE(Fe,Co)4B and RECo5 phases are gradually formed in the magnets. A new type of microstructure with nanograins of RE2(Fe,Co)14B phase, RE(Fe,Co)2 phase and RE(Fe,Co)4B phase, with partial or without grain boundary phase shows good thermal stability (x = 0.4 and 0.6). In (Nd0.85Ce0.15)15(Fe0.4Co0.6)78B7 magnets, the absolute values of temperature coefficient of coercivity |β| can reach 0.3 \%/K within the temperature range of 300 K - 500 K, and it exceeds 0.23 \%/K for the temperature range of 300 K - 650 K, indicating a promising method for designing highly thermal stable permanent magnets.",

keywords = "Coercivity, Micromagnetic simulation, Microstructure, Permanent magnets, Thermal stability",

author = "Yuye Wu and Skokov, \{Konstantin P.\} and Lukas Sch{\"a}fer and Fernando Maccari and Alex Aubert and Hao Xu and Haichen Wu and Chengbao Jiang and Oliver Gutfleisch",

note = "Publisher Copyright: {\textcopyright} 2022 Acta Materialia Inc.",

year = "2022",

month = aug,

day = "15",

doi = "10.1016/j.actamat.2022.118062",

language = "英语",

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TY - JOUR

T1 - Microstructure, coercivity and thermal stability of nanostructured (Nd,Ce)-(Fe,Co)-B hot-compacted permanent magnets

AU - Wu, Yuye

AU - Skokov, Konstantin P.

AU - Schäfer, Lukas

AU - Maccari, Fernando

AU - Aubert, Alex

AU - Xu, Hao

AU - Wu, Haichen

AU - Jiang, Chengbao

AU - Gutfleisch, Oliver

PY - 2022/8/15

Y1 - 2022/8/15

N2 - We report on microstructure, hard magnetic properties and thermal stability of nanocrystalline (Nd0.85Ce0.15)15(Fe1-xCox)78B7 (x = 0 – 1) hot-compacted permanent magnets. At lower Co concentrations (x < 0.3), the substitution of Fe by Co changes the composition of grain boundary phase from non-magnetic (Nd,Ce)2Fe1 to magnetic (Nd,Ce)1(Fe,Co)2, leading to the degrading of the coercivity. At x ≥ 0.6, the grain boundary phase is no longer observed between the nanocrystalline grains, resulting in strong magnetic coupling of constituent phases. With the further increase of Co concentration (x>0.6), additional RE(Fe,Co)2, RE(Fe,Co)4B and RECo5 phases are gradually formed in the magnets. A new type of microstructure with nanograins of RE2(Fe,Co)14B phase, RE(Fe,Co)2 phase and RE(Fe,Co)4B phase, with partial or without grain boundary phase shows good thermal stability (x = 0.4 and 0.6). In (Nd0.85Ce0.15)15(Fe0.4Co0.6)78B7 magnets, the absolute values of temperature coefficient of coercivity |β| can reach 0.3 %/K within the temperature range of 300 K - 500 K, and it exceeds 0.23 %/K for the temperature range of 300 K - 650 K, indicating a promising method for designing highly thermal stable permanent magnets.

AB - We report on microstructure, hard magnetic properties and thermal stability of nanocrystalline (Nd0.85Ce0.15)15(Fe1-xCox)78B7 (x = 0 – 1) hot-compacted permanent magnets. At lower Co concentrations (x < 0.3), the substitution of Fe by Co changes the composition of grain boundary phase from non-magnetic (Nd,Ce)2Fe1 to magnetic (Nd,Ce)1(Fe,Co)2, leading to the degrading of the coercivity. At x ≥ 0.6, the grain boundary phase is no longer observed between the nanocrystalline grains, resulting in strong magnetic coupling of constituent phases. With the further increase of Co concentration (x>0.6), additional RE(Fe,Co)2, RE(Fe,Co)4B and RECo5 phases are gradually formed in the magnets. A new type of microstructure with nanograins of RE2(Fe,Co)14B phase, RE(Fe,Co)2 phase and RE(Fe,Co)4B phase, with partial or without grain boundary phase shows good thermal stability (x = 0.4 and 0.6). In (Nd0.85Ce0.15)15(Fe0.4Co0.6)78B7 magnets, the absolute values of temperature coefficient of coercivity |β| can reach 0.3 %/K within the temperature range of 300 K - 500 K, and it exceeds 0.23 %/K for the temperature range of 300 K - 650 K, indicating a promising method for designing highly thermal stable permanent magnets.

KW - Coercivity

KW - Micromagnetic simulation

KW - Microstructure

KW - Permanent magnets

KW - Thermal stability

UR - https://www.scopus.com/pages/publications/85131412176

U2 - 10.1016/j.actamat.2022.118062

DO - 10.1016/j.actamat.2022.118062

M3 - 文章

AN - SCOPUS:85131412176

SN - 1359-6454

VL - 235

JO - Acta Materialia

JF - Acta Materialia

M1 - 118062

ER -

Microstructure, coercivity and thermal stability of nanostructured (Nd,Ce)-(Fe,Co)-B hot-compacted permanent magnets

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