Influence mechanism of Fe content on the magnetic properties of Sm2Co17-type sintered magnets: Microstructure and Microchemistry

Yu, Nengjun; Gao, Wuyi; Pan, Minxiang; Yang, Hangfu; Wu, Qiong; Zhang, Pengyue; Ge, Hongliang

doi:10.1016/j.jallcom.2019.152908

Cited by 42 publications

(8 citation statements)

References 23 publications

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“…The HR-TEM image shown in Figure 4 a revealed that the cell boundary was free of 1:5H precipitates but was aggregated with defects. Therefore, the majority of the dark contrasts observed in Figure 3 c should belong to DACBs, which act as the nucleation sites of 1:5H precipitates [ 18 ]. In the grain interiors, the average cell size was ~29.1 nm for the solution-treated magnets.…”

Section: Resultsmentioning

confidence: 99%

“…It has been stated that Cu-enriched 1:5H cell boundary precipitates can provide a strong pinning force to hinder the motion of magnetic domain walls (DWs), giving rise to a large coercivity [3,5,[12][13][14][15][16][17][18][19]]. An ideal microstructure configuration for achieving strong hard magnetic properties is that all the 2:17R nanocells should be surrounded by continuous 1:5H precipitates.…”

Section: Introductionmentioning

confidence: 99%

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Grain Boundary Evolution of Cellular Nanostructured Sm-Co Permanent Magnets

et al. 2021

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Grain boundaries are thought to be the primary demagnetization sites of precipitate-hardening 2:17-type Sm-Co-Fe-Cu-Zr permanent magnets with a unique cellular nanostructure, leading to a poor squareness factor as well as a much lower than ideal energy product. In this work, we investigated the grain boundary microstructure evolution of a model magnet Sm25Co46.9Fe19.5Cu5.6Zr3.0 (wt. %) during the aging process. The transmission electron microscopy (TEM) investigations showed that the grain boundary region contains undecomposed 2:17H, partially ordered 2:17R, 1:5H nano-precipitates, and a Smn+1Co5n-1 (n = 2, 1:3R; n = 3, 2:7R; n = 4, 5:19R) phase mixture at the solution-treated state. After short-term aging, further decomposition of 2:17H occurs, characterized by the gradual ordering of 2:17R, the precipitation of the 1:5H phase, and the gradual growth of Smn+1Co5n−1 compounds. Due to the lack of a defect-aggregated cell boundary near the grain boundary, the 1:5H precipitates are constrained between the 2:17R and the Smn+1Co5n-1 nano-sheets. When further aging the magnet, the grain boundary 1:5H precipitates transform into Smn+1Co5n-1 compounds. As the Smn+1Co5n-1 compounds are magnetically softer than the 1:5H precipitates, the grain boundaries then act as the primary demagnetization sites. Our work adds important insights toward the understanding of the grain boundary effect of 2:17-type Sm-Co-Fe-Cu-Zr magnets.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Grain Boundary Evolution of Cellular Nanostructured Sm-Co Permanent Magnets

et al. 2021

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“…[ 8–13 ] However, B r tends to be constant when the Fe content is greater than 23 wt%, in contrast to the increase linearly of that before Fe contents reach 23 wt%, as illustrated in Figure a. [ 7,14–20 ]…”

Section: Introductionmentioning

confidence: 99%

“…Data are from refs. [7,14–20]. Insets show comparison of microstructure of Fe‐rich magnet before and after synergistic process optimization in this article.…”

Section: Introductionmentioning

confidence: 99%

High‐Remanence Fe‐Rich 2:17‐Type Sm–Co Sintered Magnets Mediated via Multiscale Microstructure

Xi,

Zhang,

et al. 2024

Adv Eng Mater

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Realizing high remanence in Fe‐rich 2:17‐type Sm‐Co sintered magnets remains a challenge when Fe content exceeds 23 wt.%. Here, a record remanence of 12.42 kGs has been obtained by multi‐scale microstructure regulation strategy, based on co‐optimization from pulverizing treatment to solid solution and aging treatment. The density of sintered magnet is significantly enhanced by refining magnetic powders using the ball milling to reduce the porosity. Grain boundary precipitation phase has been eliminated via prolonging solid solution time, together with reduced Fe concentration in the cell boundaries, due to increased proportion of defected 1:3R planar Z phase. Furthermore, the proportion of 1:3R planar Z phase has been increased by greatly reducing the 2:17R’ phase during appropriately isothermal aging temperature to reduce Fe concentration in cell boundaries and increases the remanence of the magnet. Our studies deepen the understanding of the correlation among process, microstructure, and remanence, guiding the preparation of Fe‐rich 2:17‐type Sm‐Co sintered magnets with high magnetic performance.This article is protected by copyright. All rights reserved.

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“…The role of grain boundaries in pinning-type magnets may be understood if they can be modified separately from the grain interior, in conjunction with measuring the associated coercivity change. Traditional processing approaches, such as heat treatments 13 , plastic deformation 16 and alloying 9,17 , can dramatically change the coercivity. However, these approaches often induce irreversible modification (or destruction) of the microstructure both in grain boundaries and grain interior, obscuring the assessment of their respective impact on coercivity.…”

Section: Introductionmentioning

confidence: 99%

Magnetoelectric Tuning of Pinning‐Type Permanent Magnets through Atomic‐Scale Engineering of Grain Boundaries

Yan

Schäfer

et al. 2020

Advanced Materials

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a diameter less than ≈100 nm. After that, a cleaning of the specimen at 5 kV was performed to remove the beam-damaged surface regions. The prepared tips were transferred into the load-lock chamber of APT, waited ≈2 h until the vacuum reached ≈10 −8 Pa (LEAP 3000 XHR), and then transferred into analysis chamber (≈10 −11 Pa) at 70 K. Data on Cameca LEAP 5000XR were also acquired, and only waited for half an hour before transferring the sample from APT load-lock to analysis chamber. The APT experiments were conducted using high-voltage mode with a pulse fraction of 15% at a base temperature of 70 K, a pulse frequency of 200 kHz, and an evaporation rate of 0.5. Atom probe data reconstruction and analysis were performed using CAMECA IVAS 3.8.4 software.

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Influence mechanism of Fe content on the magnetic properties of Sm2Co17-type sintered magnets: Microstructure and Microchemistry

Cited by 42 publications

References 23 publications

Grain Boundary Evolution of Cellular Nanostructured Sm-Co Permanent Magnets

Grain Boundary Evolution of Cellular Nanostructured Sm-Co Permanent Magnets

High‐Remanence Fe‐Rich 2:17‐Type Sm–Co Sintered Magnets Mediated via Multiscale Microstructure

Magnetoelectric Tuning of Pinning‐Type Permanent Magnets through Atomic‐Scale Engineering of Grain Boundaries

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