Super‐High Coercivity Sintered NdFeB Magnets Enabled by High‐Rate Dy/Tb Grain Boundary Synergistic Diffusion
- 1Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education School of Materials Science and Engineering of Shanxi Normal University Taiyuan China
- 2Shanxi Key Laboratory of Advanced Magnetic Materials and Devices Research Institute of Materials Science Shanxi Normal University Taiyuan China
- 3Institute of Advanced Magnetic Materials Hangzhou Dianzi University Hangzhou China
Abstract
The surging demand for high‐performance NdFeB magnets has made it essential to achieve ultrahigh coercivity while minimizing the consumption of heavy rare earths. To tackle this challenge, this study proposes a Dy/Tb bilayer grain boundary diffusion strategy and systematically investigates the co‐diffusion behavior of Dy and Tb. Benefiting from Dy/Tb co‐diffusion, the diffused magnet (N50/Dy 3μm /Tb 11μm , using 3 μm Dy and 11 μm Tb as diffusion sources) achieves a super‐high coercivity of 22.66 kOe representing a 10.10 kOe increase over the pristine N50 magnet (12.56 kOe). Notably, the remanence and maximum magnetic energy product remain largely preserved ( B r = 14.21 kGs ( BH ) max = 50.47 MGOe), showing only marginal reductions (1.73% and 1.45%, respectively), approaching the performance of commercial G52 SHB super‐high coercivity NdFeB magnets. This coercivity enhancement is primarily attributed to the markedly increased grain boundary diffusion coefficients of Dy and Tb. Specifically, the Dy diffusion rate increases from (6.68 ± 0.41) × 10 −8 to (1.28 ± 0.32) × 10 −6 mm 2 s −1 , whereas the Tb diffusion rate rises from (2.73 ± 0.34) × 10 −7 to (7.31 ± 1.34) × 10 −7 mm 2 s −1 . The accelerated HRE transport promotes the formation of continuous (Nd,Dy,Tb) 2 Fe 14 B core–shell structures, and their widespread distribution throughout the magnet is identified as the key microstructural origin of the enhanced coercivity. These findings offer clear guidance for the design of diffusion sources in next‐generation high‐performance sintered NdFeB magnets.
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BibTeX
@article{chang2026superhigh,
title = {{Super‐High Coercivity Sintered NdFeB Magnets Enabled by High‐Rate Dy/Tb Grain Boundary Synergistic Diffusion}},
author = {Rui Chang and Guangzhu Bai and Peiyuan Ping and Zihao Nie and Xiaolian Liu and Lizhong Zhao and Fang Wang and X X Xu},
journal = {Rare Metals},
year = {2026},
month = jun,
doi = {10.1002/rar2.70238},
url = {https://doi.org/10.1002/rar2.70238},
note = {CC BY},
}
RIS
TY - JOUR
TI - Super‐High Coercivity Sintered NdFeB Magnets Enabled by High‐Rate Dy/Tb Grain Boundary Synergistic Diffusion
AU - Rui Chang
AU - Guangzhu Bai
AU - Peiyuan Ping
AU - Zihao Nie
AU - Xiaolian Liu
AU - Lizhong Zhao
AU - Fang Wang
AU - X X Xu
PY - 2026
DA - 2026/06/01
JO - Rare Metals
DO - 10.1002/rar2.70238
UR - https://doi.org/10.1002/rar2.70238
AB - The surging demand for high‐performance NdFeB magnets has made it essential to achieve ultrahigh coercivity while minimizing the consumption of heavy rare earths. To tackle this challenge, this study proposes a Dy/Tb bilayer grain boundary diffusion strategy and systematically investigates the co‐diffusion behavior of Dy and Tb. Benefiting from Dy/Tb co‐diffusion, the diffused magnet (N50/Dy 3μm /Tb 11μm , using 3 μm Dy and 11 μm Tb as diffusion sources) achieves a super‐high coercivity of 22.66 kOe representing a 10.10 kOe increase over the pristine N50 magnet (12.56 kOe). Notably, the remanence and maximum magnetic energy product remain largely preserved ( B r = 14.21 kGs ( BH ) max = 50.47 MGOe), showing only marginal reductions (1.73% and 1.45%, respectively), approaching the performance of commercial G52 SHB super‐high coercivity NdFeB magnets. This coercivity enhancement is primarily attributed to the markedly increased grain boundary diffusion coefficients of Dy and Tb. Specifically, the Dy diffusion rate increases from (6.68 ± 0.41) × 10 −8 to (1.28 ± 0.32) × 10 −6 mm 2 s −1 , whereas the Tb diffusion rate rises from (2.73 ± 0.34) × 10 −7 to (7.31 ± 1.34) × 10 −7 mm 2 s −1 . The accelerated HRE transport promotes the formation of continuous (Nd,Dy,Tb) 2 Fe 14 B core–shell structures, and their widespread distribution throughout the magnet is identified as the key microstructural origin of the enhanced coercivity. These findings offer clear guidance for the design of diffusion sources in next‐generation high‐performance sintered NdFeB magnets.
SN - 1001-0521
SN - 1867-7185
ER -