Enhancing the grain boundary diffusion efficiency of Tb for Nd-Fe-B magnets using dual-alloy diffusion source
Grain boundary diffusion is an effective approach to enhance coercivity for Nd-Fe-B magnets with reduced consumption of heavy rare earths (HRE). However, during diffusion treatment, the HRE tends to accumulate at the magnet surface, leading to an insufficient coercivity improvement and a decreased m...
| Main Authors: | , , , , , , , , , |
|---|---|
| Format: | Article |
| Language: | English |
| Published: |
Elsevier
2022-05-01
|
| Series: | Journal of Materials Research and Technology |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S2238785422003222 |
| _version_ | 1818338830813495296 |
|---|---|
| author | Wenyue Song Jiayi He Zhigao Yu Jiali Cao Xuefeng Liao Wenbing Fan Hongya Yu Huayun Mao Congyao Mao Zhongwu Liu |
| author_facet | Wenyue Song Jiayi He Zhigao Yu Jiali Cao Xuefeng Liao Wenbing Fan Hongya Yu Huayun Mao Congyao Mao Zhongwu Liu |
| author_sort | Wenyue Song |
| collection | DOAJ |
| description | Grain boundary diffusion is an effective approach to enhance coercivity for Nd-Fe-B magnets with reduced consumption of heavy rare earths (HRE). However, during diffusion treatment, the HRE tends to accumulate at the magnet surface, leading to an insufficient coercivity improvement and a decreased magnetic hysteresis loop squareness. Here, a Pr-Al-Cu/Tb-Al-Cu dual-alloy diffusion source is proposed to improve the diffusion of Tb element. During the GBD process, the low melting point Pr-Al-Cu alloy has higher diffusion rate than the Tb-Al-Cu alloy. The formation of continuous grain boundary phase by Pr-Al-Cu diffusion is beneficial to constructing effective channels for the subsequent diffusion of Tb. As a result, the dual-alloy diffusion enhances the coercivity of an initial magnet from 1040 to 1911 kA/m and a high loop squareness of 91.31% is also obtained. In comparison, the coercivity of the magnet treated by the Pr-Tb-Al-Cu single-alloy source was only enhanced to 1832 kA/m with loop squareness of 87.44%. The microstructure characterizations revealed that, by dual-alloy diffusion, both Pr and Tb can infiltrate deeply from the diffusion surface to the interior of the magnet. The formation of (Nd,Tb)2Fe14B phase with high anisotropy field and continuous grain boundary phase contribute to the coercivity enhancement. Using the dual-alloy diffusion source, the HRE resources can be efficiently utilized for increased infiltration depth by avoiding the formation of over-thick Tb-rich grain shells. This facile and flexible process is also attractive for industrial application. |
| first_indexed | 2024-12-13T15:17:21Z |
| format | Article |
| id | doaj.art-4c34cb30626f485f8dce83fc32f2abfb |
| institution | Directory Open Access Journal |
| issn | 2238-7854 |
| language | English |
| last_indexed | 2024-12-13T15:17:21Z |
| publishDate | 2022-05-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Materials Research and Technology |
| spelling | doaj.art-4c34cb30626f485f8dce83fc32f2abfb2022-12-21T23:40:40ZengElsevierJournal of Materials Research and Technology2238-78542022-05-0118841851Enhancing the grain boundary diffusion efficiency of Tb for Nd-Fe-B magnets using dual-alloy diffusion sourceWenyue Song0Jiayi He1Zhigao Yu2Jiali Cao3Xuefeng Liao4Wenbing Fan5Hongya Yu6Huayun Mao7Congyao Mao8Zhongwu Liu9School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, ChinaSchool of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, ChinaJL MAG Rare-Earth Co., Ltd., Ganzhou 341000, ChinaJL MAG Rare-Earth Co., Ltd., Ganzhou 341000, ChinaSchool of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China; Corresponding author.Grain boundary diffusion is an effective approach to enhance coercivity for Nd-Fe-B magnets with reduced consumption of heavy rare earths (HRE). However, during diffusion treatment, the HRE tends to accumulate at the magnet surface, leading to an insufficient coercivity improvement and a decreased magnetic hysteresis loop squareness. Here, a Pr-Al-Cu/Tb-Al-Cu dual-alloy diffusion source is proposed to improve the diffusion of Tb element. During the GBD process, the low melting point Pr-Al-Cu alloy has higher diffusion rate than the Tb-Al-Cu alloy. The formation of continuous grain boundary phase by Pr-Al-Cu diffusion is beneficial to constructing effective channels for the subsequent diffusion of Tb. As a result, the dual-alloy diffusion enhances the coercivity of an initial magnet from 1040 to 1911 kA/m and a high loop squareness of 91.31% is also obtained. In comparison, the coercivity of the magnet treated by the Pr-Tb-Al-Cu single-alloy source was only enhanced to 1832 kA/m with loop squareness of 87.44%. The microstructure characterizations revealed that, by dual-alloy diffusion, both Pr and Tb can infiltrate deeply from the diffusion surface to the interior of the magnet. The formation of (Nd,Tb)2Fe14B phase with high anisotropy field and continuous grain boundary phase contribute to the coercivity enhancement. Using the dual-alloy diffusion source, the HRE resources can be efficiently utilized for increased infiltration depth by avoiding the formation of over-thick Tb-rich grain shells. This facile and flexible process is also attractive for industrial application.http://www.sciencedirect.com/science/article/pii/S2238785422003222Nd-Fe-BGrain boundary diffusionCoercivityHeavy rare earthDual-alloy diffusion source |
| spellingShingle | Wenyue Song Jiayi He Zhigao Yu Jiali Cao Xuefeng Liao Wenbing Fan Hongya Yu Huayun Mao Congyao Mao Zhongwu Liu Enhancing the grain boundary diffusion efficiency of Tb for Nd-Fe-B magnets using dual-alloy diffusion source Journal of Materials Research and Technology Nd-Fe-B Grain boundary diffusion Coercivity Heavy rare earth Dual-alloy diffusion source |
| title | Enhancing the grain boundary diffusion efficiency of Tb for Nd-Fe-B magnets using dual-alloy diffusion source |
| title_full | Enhancing the grain boundary diffusion efficiency of Tb for Nd-Fe-B magnets using dual-alloy diffusion source |
| title_fullStr | Enhancing the grain boundary diffusion efficiency of Tb for Nd-Fe-B magnets using dual-alloy diffusion source |
| title_full_unstemmed | Enhancing the grain boundary diffusion efficiency of Tb for Nd-Fe-B magnets using dual-alloy diffusion source |
| title_short | Enhancing the grain boundary diffusion efficiency of Tb for Nd-Fe-B magnets using dual-alloy diffusion source |
| title_sort | enhancing the grain boundary diffusion efficiency of tb for nd fe b magnets using dual alloy diffusion source |
| topic | Nd-Fe-B Grain boundary diffusion Coercivity Heavy rare earth Dual-alloy diffusion source |
| url | http://www.sciencedirect.com/science/article/pii/S2238785422003222 |
| work_keys_str_mv | AT wenyuesong enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource AT jiayihe enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource AT zhigaoyu enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource AT jialicao enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource AT xuefengliao enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource AT wenbingfan enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource AT hongyayu enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource AT huayunmao enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource AT congyaomao enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource AT zhongwuliu enhancingthegrainboundarydiffusionefficiencyoftbforndfebmagnetsusingdualalloydiffusionsource |