Synergistic regulation and optimization of microstructure, coercivity, and thermal stability in sintered NdFeB magnets through grain boundary diffusion of Dy and Al elements
The grain boundary diffusion process (GBDP) is a well-established method for producing high-performance NdFeB magnets. However, the limited diffusion ability of heavy rare earth (HRE) elements, which are only attached to the surface of the magnet, has been a major concern in the industry. In this st...
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2025-01-01
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| Series: | Journal of Materials Research and Technology |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785424030382 |
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| author | Rui Chang Guangzhu Bai Yaping Li Zhi Yan Xiufang Qin Jingdong Guo Fang Wang Xiaohong Xu |
| author_facet | Rui Chang Guangzhu Bai Yaping Li Zhi Yan Xiufang Qin Jingdong Guo Fang Wang Xiaohong Xu |
| author_sort | Rui Chang |
| collection | DOAJ |
| description | The grain boundary diffusion process (GBDP) is a well-established method for producing high-performance NdFeB magnets. However, the limited diffusion ability of heavy rare earth (HRE) elements, which are only attached to the surface of the magnet, has been a major concern in the industry. In this study, we utilize the GBDP method to diffuse low-melting-point DyAl alloy into magnets, resulting in the formation of continuous Dy-, Al-, and Nd-rich thin grain boundary phases and (Nd,Dy)2Fe14B shells with diffusion depths over 1500 μm. These results suggest that the presence of continuous Dy-, Al-, and Nd-rich thin grain boundary phases is crucial in promoting the diffusion of Dy elements in magnets. Furthermore, these thin and continuous grain boundary phases effectively isolate the Nd2Fe14B grains, preventing the simultaneous reversal of adjacent grains. As a result, the coercivity of the N42-DyAl magnet increases from 12.07 kOe to 19.95 kOe at room temperature and from 5.17 kOe to 10.76 kOe at high temperature (120 °C). The N42-DyAl magnets also exhibit a large coercivity temperature coefficient of −0.485%/°C and excellent thermal stability. This optimized effect of synergistic multi-element grain boundary diffusion creates an extensive core-shell structure, enhancing the anisotropy field and increasing the coercivity. |
| format | Article |
| id | doaj-art-89aa383d47e54880a06935773639d253 |
| institution | Kabale University |
| issn | 2238-7854 |
| language | English |
| publishDate | 2025-01-01 |
| publisher | Elsevier |
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| series | Journal of Materials Research and Technology |
| spelling | doaj-art-89aa383d47e54880a06935773639d2532025-01-19T06:25:55ZengElsevierJournal of Materials Research and Technology2238-78542025-01-013421832192Synergistic regulation and optimization of microstructure, coercivity, and thermal stability in sintered NdFeB magnets through grain boundary diffusion of Dy and Al elementsRui Chang0Guangzhu Bai1Yaping Li2Zhi Yan3Xiufang Qin4Jingdong Guo5Fang Wang6Xiaohong Xu7School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030031, People's Republic of ChinaSchool of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030031, People's Republic of ChinaSchool of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030031, People's Republic of China; Research Institute of Materials Science of Shanxi Normal University & Shanxi Key Laboratory of Advanced Magnetic Materials and Devices, Taiyuan, 030031, People's Republic of ChinaSchool of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030031, People's Republic of ChinaSchool of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030031, People's Republic of ChinaShanxi Jinshan Magnetic Materials Co., Taiyuan, 030008, People's Republic of ChinaSchool of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030031, People's Republic of China; Research Institute of Materials Science of Shanxi Normal University & Shanxi Key Laboratory of Advanced Magnetic Materials and Devices, Taiyuan, 030031, People's Republic of China; Corresponding author. School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030031, People's Republic of China.School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030031, People's Republic of China; Research Institute of Materials Science of Shanxi Normal University & Shanxi Key Laboratory of Advanced Magnetic Materials and Devices, Taiyuan, 030031, People's Republic of China; Corresponding author. School of Chemistry and Materials Science of Shanxi Normal University & Key Laboratory of Magnetic Molecules and Magnetic Information Materials of Ministry of Education, Taiyuan, 030031, People's Republic of China.The grain boundary diffusion process (GBDP) is a well-established method for producing high-performance NdFeB magnets. However, the limited diffusion ability of heavy rare earth (HRE) elements, which are only attached to the surface of the magnet, has been a major concern in the industry. In this study, we utilize the GBDP method to diffuse low-melting-point DyAl alloy into magnets, resulting in the formation of continuous Dy-, Al-, and Nd-rich thin grain boundary phases and (Nd,Dy)2Fe14B shells with diffusion depths over 1500 μm. These results suggest that the presence of continuous Dy-, Al-, and Nd-rich thin grain boundary phases is crucial in promoting the diffusion of Dy elements in magnets. Furthermore, these thin and continuous grain boundary phases effectively isolate the Nd2Fe14B grains, preventing the simultaneous reversal of adjacent grains. As a result, the coercivity of the N42-DyAl magnet increases from 12.07 kOe to 19.95 kOe at room temperature and from 5.17 kOe to 10.76 kOe at high temperature (120 °C). The N42-DyAl magnets also exhibit a large coercivity temperature coefficient of −0.485%/°C and excellent thermal stability. This optimized effect of synergistic multi-element grain boundary diffusion creates an extensive core-shell structure, enhancing the anisotropy field and increasing the coercivity.http://www.sciencedirect.com/science/article/pii/S2238785424030382Sintered NdFeB magnetCoercivityDyAl alloyGrain boundary diffusion process |
| spellingShingle | Rui Chang Guangzhu Bai Yaping Li Zhi Yan Xiufang Qin Jingdong Guo Fang Wang Xiaohong Xu Synergistic regulation and optimization of microstructure, coercivity, and thermal stability in sintered NdFeB magnets through grain boundary diffusion of Dy and Al elements Journal of Materials Research and Technology Sintered NdFeB magnet Coercivity DyAl alloy Grain boundary diffusion process |
| title | Synergistic regulation and optimization of microstructure, coercivity, and thermal stability in sintered NdFeB magnets through grain boundary diffusion of Dy and Al elements |
| title_full | Synergistic regulation and optimization of microstructure, coercivity, and thermal stability in sintered NdFeB magnets through grain boundary diffusion of Dy and Al elements |
| title_fullStr | Synergistic regulation and optimization of microstructure, coercivity, and thermal stability in sintered NdFeB magnets through grain boundary diffusion of Dy and Al elements |
| title_full_unstemmed | Synergistic regulation and optimization of microstructure, coercivity, and thermal stability in sintered NdFeB magnets through grain boundary diffusion of Dy and Al elements |
| title_short | Synergistic regulation and optimization of microstructure, coercivity, and thermal stability in sintered NdFeB magnets through grain boundary diffusion of Dy and Al elements |
| title_sort | synergistic regulation and optimization of microstructure coercivity and thermal stability in sintered ndfeb magnets through grain boundary diffusion of dy and al elements |
| topic | Sintered NdFeB magnet Coercivity DyAl alloy Grain boundary diffusion process |
| url | http://www.sciencedirect.com/science/article/pii/S2238785424030382 |
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