Article
Materials Science, Multidisciplinary
Mario Schoenfeldt, Konrad Opelt, Stefan Betz, Christof Metzmacher, Songhak Yoon, Juergen Gassmann
Summary: The reaction behavior and chemical stability of two commercially available SmCo 2:17-type sintered magnets under a hydrogen atmosphere were investigated. It was found that a temperature of 120°C was necessary to initiate the reaction and increase the hydrogen content in the Sm-Co material for short exposure times. With longer exposure times or higher temperatures, a higher hydrogen content and decreased magnetic properties were observed. The lattice expansion of the Sm-Co magnets correlated with the increasing amount of hydrogen.
ADVANCED ENGINEERING MATERIALS
(2023)
Article
Chemistry, Physical
Qiqi Yang, Zhuang Liu, Xiaolei Gao, Haichen Wu, Chaoqun Zhu, Wenxin Cheng, Yilong Ma, Renjie Chen, Aru Yan
Summary: This research successfully regulates the ordering process in 2:17 type SmCo magnets by doping nano ZrO2, resulting in a prolonged presence of twin boundaries. The continuous migration of twin boundaries allows Cu to converge towards the cell boundary center, leading to an improved coercivity of the magnets.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Physics, Multidisciplinary
Xiao-Lei Gao, Zhuang Liu, Guang-Qing Wang, Chao-Qun Zhu, Wen-Xin Cheng, Ming-Xiao Zhang, Xin-Cai Liu, Ren-Jie Chen, A-Ru Yan
Summary: The effects of CeO2 doping on the magnetic properties and microstructure of 2:17 type SmCo magnets were investigated. The results showed that with the increase of CeO2 content from 0 wt.% to 3 wt.%, the coercivity of the magnets increased by more than 30%. The remanence and magnetic energy product remained almost constant when the doping content was lower than 1 wt.%, but decreased sharply with further increase in doping concentration. CeO2 doping significantly increased the oxide content in the magnets and led to a uniform distribution of Ce element. It also refined the magnetic domains and stabilized the magnetic domain wall, resulting in a significant increase in coercivity of the magnets.
Article
Physics, Multidisciplinary
Qi-Qi Yang, Zhuang Liu, Chao-Yue Zhang, Hai-Chen Wu, Xiao-Lei Gao, Yi-Long Ma, Ren-Jie Chen, A-Ru Yan
Summary: The study focused on doping ZrO2 to improve the resistivity and coercivity of permanent magnets, with results showing a decrease in resistive anisotropism and enhancement of magnetic properties. Excessive ZrO2 led to phase increase and deterioration of the cellular structure, reducing coercivity.
Article
Nanoscience & Nanotechnology
Jin Qian, Binglin Wang, Geng Wei, Shaolong Tang
Summary: This study successfully prepared anisotropic 2:17-type SmCo alloy spherical magnetic powder by combining the solid/liquid interface de-wetting effect and abnormal grain growth method. The study explored the formation mechanism and single crystal growth rule of the alloy powder, and investigated the impact of solution-aging magnetic hardening treatment on the permanent magnet properties. The resulting optimized powder exhibited great potential for applications in bonded magnets.
SCRIPTA MATERIALIA
(2023)
Article
Materials Science, Multidisciplinary
Donghui Liu, Qiaofa Lan, Xiaolin Zhang, Fei Niu, Youming Yang
Summary: A one-step method for preparing Sm (CobalFe0.08Cu0.1Zr0.03)(7.45) alloy through transition metal-induced SmF3 calciothermic reduction is presented. The alloy composition, crystal structure, element distribution, and chemical valence were characterized. The magnetic properties of the alloy were also investigated, showing good magnetization, coercivity, and energy product.
Article
Chemistry, Physical
Hulin Wu, Zhimei Long, Zhongsheng Li, Kaiqiang Song, Chaoqun Li, Dalong Cong, Bin Shao, Xiaowei Liu, Jianchun Sun, Yilong Ma
Summary: The oxidation of Sm(Co, Fe, Zr, Cu)(7.8) permanent magnets has a significant impact on their magnetic properties. Experimental results showed that the magnetic flux losses increased after low-temperature oxidation, but could be inhibited by using temperature cycling.
Article
Materials Science, Multidisciplinary
Xin Song, Dan Huang, Wentao Jia, Yao Liu, Jianrong Gao, Yang Ren, Tianyu Ma
Summary: The early-stage decomposition behavior of a Sm-Co-based permanent magnet was studied, and the formation of 1:5H precipitate and its effect on the magnetic properties were observed. The effective nucleation temperature of the 1:5H phase was determined to be -760 degrees C, which is much higher than the starting transformation temperature of the 2:17H phase. The results provide guidance for designing proper material processing towards high-performance magnets.
Review
Materials Science, Multidisciplinary
Chao Wang, Ming-Gang Zhu
Summary: Sm-Co permanent magnets are widely used due to their excellent magnetic properties at high temperatures, with the capability to reliably operate at temperatures up to 500 degrees C being their biggest advantage. However, achieving reliable high-temperature magnetic properties depends greatly on alloy composition and technique processes. This review emphasizes the importance of appropriate composition and technique processes for good high-temperature magnetic properties in Sm-Co magnets.
Article
Chemistry, Physical
Xin Song, Yao Liu, Wentao Jia, Jian Li, Xiaolian Liu, Lizhong Zhao, Tao Yuan, Tianyu Ma
Summary: In this study, a comparative investigation was conducted on TEM specimens prepared under different ion milling conditions in a commercial magnet. It was found that low-energy ion milling preferentially damages the 1:5H cell boundaries and causes structural transformations. Additionally, the elemental distribution within the damaged cell boundaries becomes discontinuous. These findings highlight the importance of carefully preparing TEM specimens to avoid structural damage and artificial deficiencies when studying the microstructure of Sm-Co based magnets.
Article
Chemistry, Physical
Xin Song, Yao Liu, Tao Yuan, Fang Wang, Jiuping Fan, Tianyu Ma
Summary: In the fabrication of 2:17-type Sm-Co-Fe-Cu-Zr magnets, slow cooling after solution treatment can lead to a better microstructure and magnetic properties, which is beneficial for improving the uniformity of magnets.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Physics, Multidisciplinary
Chao-Zhong Wang, Lei Liu, Ying-Li Sun, Jiang-Tao Zhao, Bo Zhou, Si-Si Tu, Chun-Guo Wang, Yong Ding, A-Ru Yan
Summary: The effects of Nd doping on the microstructures and magnetic properties of Sm1-x Nd x (Co0.695Fe0.2Cu0.08Zr0.025)(7.2) permanent magnets were studied. It was found that with the increase of Nd content, the distribution of elements became inhomogeneous and miscellaneous phase was generated. The magnets with x = 0.3, 0.5, and 0.7 showed positive temperature coefficient of coercivity (beta) and had corresponding positive beta temperatures in specific ranges. Thermomagnetic analysis revealed that spin-reorientation-transition (SRT) of the cell boundary phase was responsible for this phenomenon. Based on this discovery, a Sm0.7Nd0.3 (Co0.695Fe0.2Cu0.08Zr0.025)(7.2) magnet with thermal stability and a beta value of approximately -0.002 %/K in the temperature range of 150 K-200 K was obtained.
Article
Chemistry, Multidisciplinary
Fabian Paschke, Tobias Birk, Vivien Enenkel, Fupin Liu, Vladyslav Romankov, Jan Dreiser, Alexey A. Popov, Mikhail Fonin
Summary: Single-molecule magnets (SMMs) show promise for future magnetic data storage or quantum computing applications due to their magnetic bistability and long magnetic relaxation times. Research has demonstrated that sub-monolayers of Dy-2@C-80(CH2Ph) dimetallofullerenes on graphene exhibit magnetic behavior comparable to the bulk, with stable magnetic moments at low temperatures, potentially advancing the development of SMM-based spintronic units.
ADVANCED MATERIALS
(2021)
Article
Engineering, Electrical & Electronic
J. H. Jia, D. T. Zhang, J. J. Yang, Z. H. Xie, Y. Q. Li, H. G. Zhang, W. Q. Liu, M. Yue
Summary: The effect of Fe-rich content on the microstructure, phase structure, elements distribution, and magnetic properties of Sm(Co0.91-xFexCu0.07Zr0.02) 7.6 (x = 0.22, 0.30, and 0.35) magnets has been investigated systematically. It was found that the increase of Fe content affects the phase structure of the solid solution and leads to changes in the cellular structure and element distribution, thus affecting the magnetic properties.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Chemistry, Physical
Tuhin Ghosh, Jonathan Marbey, Wolfgang Wernsdorfer, Stephen Hill, Khalil A. Abboud, George Christou
Summary: A covalently-linked dimer of two single-molecule magnets has been synthesized, exhibiting hysteresis loops with positive exchange bias of the quantum tunnelling of magnetization (QTM) steps.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2021)
