Article
Materials Science, Multidisciplinary
Jia Li, Shihui Li, Qingrong Yao, Weichao Huang, Jianqiu Deng, Jiang Wang, Guanghui Rao, Huaiying Zhou
Summary: The addition of Tb6Fe13Cu was found to significantly improve the intrinsic coercivity and corrosion resistance of Nd-Fe-B magnets, leading to the formation of a Tb-rich shell structure, optimization in distribution/morphology of intergranular phases, and stabilization of RE-rich phases.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2021)
Article
Chemistry, Physical
Shuwei Zhong, Munan Yang, Hang Wang, Sajjad Ur Rehman, Xi Yu, Sangen Luo, Longgui Li, Chao Li, Shuhua Xiong, Bin Yang
Summary: In this study, submicron Al, Sn, Zn metal powders were introduced into the precursor powder to improve the infiltration effect and enhance the grain boundary diffusion depth and efficiency of sintered Nd-Fe-B magnets. The addition of Al, Sn, and Zn elements decreased the transformation temperature of the Nd-rich phase and improved the microstructure, promoting the diffusion of Tb into the 2:14:1 phase. The intrinsic coercivity of Al-, Sn-, and Zn-added magnets also increased significantly.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Applied
Jia Li, Qingrong Yao, Weichao Huang, Jue Xie, Zhilin Mo, Jianqiu Deng, Jiang Wang, Guanghui Rao, Huaiying Zhou
Summary: The addition of low-melting-point eutectic Tb68Ni32 alloy powders can enhance the coercivity and slightly affect the remanence of Nd-Fe-B sintered magnets, while also improving their corrosion resistance.
JOURNAL OF RARE EARTHS
(2022)
Article
Materials Science, Multidisciplinary
Zhi Jia, Mingpeng Kou, Shuai Cao, Xintong Yang, Guangfei Ding, Shuai Guo, Xiaodong Fan, Bo Zheng, Renjie Chen, Aru Yan
Summary: The magnetic properties and microstructure of Nd-Ce-Y-Fe-B magnets with Nd-Co boundary additions were systematically investigated. It was found that appropriate Nd-Co addition could simultaneously improve the coercivity, remanence, and Curie temperature of the magnets. The coercivity enhancement was attributed to widened grain boundary width and reduced magnetic exchange coupling, while the remanence improvement was achieved through partial substitution. This study provides new insights into the preparation of high-abundance magnets.
RESULTS IN PHYSICS
(2022)
Article
Materials Science, Multidisciplinary
Zhi Li, Yu-Qing Li, Wei-Qiang Liu, Dan Wu, Hao Chen, Wei-Xing Xia, Ming Yue
Summary: The reduction in coercivity of high La-Ce-containing Nd-Fe-B sintered magnets is mainly due to the poor magnetic isolation of grain boundaries and a higher proportion of reversible portions in magnets with a large content of La-Ce, leading to decreased performance.
Article
Chemistry, Physical
Sangen Luo, Munan Yang, Zaiping Xu, Tongyun Zhao, Sajjad Ur Rehman, Xi Yu, Shuwei Zhong, Haitao Wang, Chaoxiang Jin, Qiang Ma, Bin Yang
Summary: This paper investigates the effect of grain size in the diffusion matrix on the grain boundary diffusion mechanism of Tb element. The results show that with only 0.75 wt. % TbF3 diffusion, the intrinsic coercivity increases significantly for the magnet with finer average grain size compared to the coarse-grain magnet. The increase in intrinsic coercivity is attributed to the increase in defect density and the higher grain orientation caused by grain refinement, which leads to improved diffusion efficiency and magnetic properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Physical
Shuhan Dong, Xiantao Li, Qingmei Lu, Weiqiang Liu, Yufeng Wu, Ming Yue
Summary: The efficient regeneration of sintered Nd-Fe-B rare earth magnets plays a crucial role in the recycling economy of rare earth resources. This study systematically investigated the mechanical properties of the original and recycled magnets and analyzed the chemical composition and microstructure to explain the mechanism. The main fracture mechanism of recycled magnets is intergranular fracture. The regenerated magnets have similar mechanical properties to the original magnets, fully meeting product requirements.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Chemistry, Applied
Shuwei Zhong, Munan Yang, Sajjad Ur Rehman, Sangen Luo, Longgui Li, Chao Li, Jiajie Li, Shuhua Xiong, Ihor Bulyk, Bin Yang
Summary: In order to solve the uneven distribution issue of the core-shell structure in sintered Nd-Fe-B magnets, this study suggests using high-melting-point and reactive element titanium (Ti) as an additive to enhance the diffusion of heavy rare earth elements along the grain boundary phase. The addition of Ti significantly increases the diffusion depth and intrinsic coercivity of the magnets. The formation of TiB2 phase improves the crystal structure arrangement and enhances the activity of the grain boundary phase, leading to improved diffusion and distribution in the magnets.
JOURNAL OF RARE EARTHS
(2023)
Article
Materials Science, Multidisciplinary
Jia Li, Qingrong Yao, Zhao Lu, Weichao Huang, Dongwen Chen, Jianqiu Deng, Jiang Wang, Guanghui Rao, Huaiying Zhou
Summary: Adding low melting point Tb62.5Co37.5 alloy powders to NdFeB sintered magnets can significantly improve the coercivity and corrosion resistance of the magnets, with changes in microstructure and composition playing a crucial role in enhancing magnetic properties.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2021)
Article
Chemistry, Physical
Shuwei Zhong, Munan Yang, Sangeng Luo, Tong Chen, Sajjad Ur Rehman, Liuyimei Yang, Jiajie Li, Zhenggang Zou, Qiang Ma, Bin Yang
Summary: Cu nano powder is added to the grain boundary of sintered NdFe-B magnet to improve the diffusion of Tb element and form a (Nd,Tb)2Fe14B shell layer structure with high anisotropy, resulting in increased intrinsic coercivity of the magnet.
Article
Chemistry, Applied
Xiaodong Fan, Shuai Guo, Guangfei Ding, Sining Fan, Zhehuan Jin, Renjie Chen, Shukai Zhang, Aru Yan
Summary: In this study, partial Y substituted NdY-Fe-B magnets were successfully fabricated and their magnetic properties and service performances were systematically investigated. The phase constituents of the magnets remained unchanged with different Y contents, while a core-shell structure was formed with Y gathering in the core and Nd mainly distributing in the shell. Compared with pure Nd-Fe-B magnets, the magnetic performances of Y substituted magnets slightly decreased, but the 20% Y magnet still exhibited relatively high M-0(r) and (BH)(max) values, approaching the performances of commercial N45-grade magnet. The service performances of Y substituted magnets were relatively good, providing a balanced utilization of rare earth resources.
JOURNAL OF RARE EARTHS
(2023)
Article
Chemistry, Applied
Xiaodong Fan, Shuai Guo, Guangfei Ding, Sining Fan, Zhehuan Jin, Renjie Chen, Shukai Zhang, Aru Yan
Summary: We successfully fabricated partial Y substituted NdY-Fe-B magnets and investigated their magnetic properties and service performances. The phase constituents of the magnets remained consistent throughout the range of Y content, with a core-shell structure where Y gathered in the core and Nd distributed in the shell. Although the magnetic performances of Y substituted magnets slightly decreased compared to pure Nd-Fe-B magnets, the 20 at% Y magnet still exhibited high levels of A0Mr, A0Hcj, and (BH)max, approaching the performances of commercial N45-grade magnet. The service performances of Y substituted magnets remained relatively good, indicating their potential for medium-grade NdY-Fe-B magnets.
JOURNAL OF RARE EARTHS
(2023)
Article
Chemistry, Physical
Fugang Chen, Hechang Han, Tieqiao Zhang, Yong Zhao, Xiaoli Wang, Wenqiang Zhao
Summary: Grain boundary diffusion process (GBDP) can improve the coercivity and remanence of sintered Nd-Ce-Fe-B magnets. Ce substitution promotes the diffusion process, but excessive Ce content leads to the formation of abnormally large grains on the magnet surface.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Applied
Jinhao Zhu, Guangfei Ding, Lei Jin, Zhehuan Jin, Bo Zheng, Shuai Guo, Renjie Chen, Aru Yan
Summary: This study proposes a grain boundary modification approach using Nd-Ga addition to significantly enhance the coercivity of B-lean Nd-Fe-B sintered magnets. The coercivity is increased from 1.51 to 2.04 T by optimizing the microstructure and adjusting the phase composition of the grain boundary phase. The addition of Nd-Ga forms a continuous thin grain boundary phase and intermetallic Nd6Fe13Ga phases, resulting in improved magnetic properties.
JOURNAL OF RARE EARTHS
(2022)
Article
Materials Science, Multidisciplinary
Dan Wu, Wei-Qiang Liu, Ming Yue, Qiong Wu, Dong-Tao Zhang, Qing-Mei Lu, Xu-Liang Li, Jing-Wu Chen
Summary: The coercivity, microstructure, and magnetic domain structure of Nd-Fe-B sintered magnets by grain boundary diffusion process (GBDP) with TbH3 nanoparticles were systematically investigated. The analysis showed that a core-shell structure can increase coercivity and identified the presence of both GR and AR through magnetic domain structure analysis.
