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学者姓名：刘卫强
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摘要 ：
The oil-based Nd-Fe-B sludge waste was directly recycled to single-phase Nd2Fe14B powders via the combination of purification and modified Ca-reduction reaction method. The impurities and organics in the purified Nd-Fe-B sludge waste were greatly reduced, reducing calcium consumption in the subsequent reduction and diffusion (RD) process, thereby reducing the cost. By further optimizing the Ca-reduction diffusion parameters, especially the mass ratio of CaCl2 and KCl, where the liquid CaCl2, along with the gaseous KCl provide conditions for sufficient and uniform Ca-reduction reaction, high-property Nd-Fe-B magnetic powders with good dispersion, uniform particle sizes, and excellent orientation, were successfully obtained. Using the mixed diffusion medium of CaCl2 and KCl with a mass ratio of 1:1, the room-temperature magnetization of the recycled Nd-Fe-B powders was increased to 157 emu/g at 3 T-magnetic field, which was about 28 % higher than that of the original sludge. The contents of carbon, hydrogen, and oxygen in the recycled magnetic powders were significantly reduced from 6.8, 1.8, and 5.9 wt% to 0.1, 0.19, and 0.56 wt%, respectively. In addition, the uniform grain size with X-50 = 3.6 mu m and good distribution greatly improved the orientation, which can be beneficial to the preparation of the bonded or sintered Nd-Fe-B based magnets. The reasons that CaCl2-KCl mixed diffusion medium can lead to well-dispersed, uniform recycled powder with high magnetization arise from a combination of factors for improving the liquid phase reaction environment and the gaseous KCl to prevent agglomeration and inhibit particles merging or growth.
关键词 ：
Ca-reduction reaction Ca-reduction reaction Nd-Fe-B sludge waste Nd-Fe-B sludge waste Purification Purification Recycling Recycling
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| GB/T 7714 | Xu, Haibo , Wang, Feng , Lu, Qingmei et al. Nd-Fe-B: From sludge waste to powders via purification and modified Ca-reduction reaction process [J]. | JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS , 2022 , 543 . |
| MLA | Xu, Haibo et al. "Nd-Fe-B: From sludge waste to powders via purification and modified Ca-reduction reaction process" . | JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS 543 (2022) . |
| APA | Xu, Haibo , Wang, Feng , Lu, Qingmei , Qiu, Yubing , Liu, Weiqiang , Chen, Jingwu et al. Nd-Fe-B: From sludge waste to powders via purification and modified Ca-reduction reaction process . | JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS , 2022 , 543 . |
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摘要 ：
With the development of bonded Nd-Fe-B magnets, modifying epoxy resin (EP) binder has become a key factor to improve the properties of bonded Nd-Fe-B magnets. In this work, the magnetic properties, compressive strength, and microstructure of the bonded Nd-Fe-B magnets with diaminodiphenylmethane (DDM)-cured EP binder were systematically investigated. The results show that adding 20 wt% DDM to EP monomer maintains excellent magnetic properties while obtaining optimal temperature resistance and high compressive strength for magnets. Because the molecular structure of the DDM curing agent contains rigid groups, it can enhance the heat resistance and mechanical properties of the EP binder. In addition, fracture surface morphology observation reveals the bonding mechanism of DDM-EP bonded magnets and confirms the advantageous nature of DDM-EP binder for bonded magnets. © 1965-2012 IEEE.
关键词 ：
Compressive strength Compressive strength Curing Curing Epoxy resins Epoxy resins Heat resistance Heat resistance Iron alloys Iron alloys Magnetic properties Magnetic properties Morphology Morphology Neodymium alloys Neodymium alloys Permanent magnets Permanent magnets Surface morphology Surface morphology
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| GB/T 7714 | Xi, Wang , Liu, Weiqiang , Yue, Ming et al. DDM Curing Enhancement for the Epoxy Resin Binder Bonded Nd-Fe-B Magnets [J]. | IEEE Transactions on Magnetics , 2021 , 57 (2) . |
| MLA | Xi, Wang et al. "DDM Curing Enhancement for the Epoxy Resin Binder Bonded Nd-Fe-B Magnets" . | IEEE Transactions on Magnetics 57 . 2 (2021) . |
| APA | Xi, Wang , Liu, Weiqiang , Yue, Ming , Zhang, Dongtao , Lu, Qingmei , Zhang, Hongguo et al. DDM Curing Enhancement for the Epoxy Resin Binder Bonded Nd-Fe-B Magnets . | IEEE Transactions on Magnetics , 2021 , 57 (2) . |
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摘要 ：
Phase and texture evolution of the hot-deformed Sm(Co,Fe,Cu,Zr)z magnet prepared by spark plasma sintering (SPS) have been investigated. The effects of hot deformation temperature and height reduction on the phase structure and magnetic properties of the magnet were studied. The results show that with 90% height reduction at 900 °C, the hot-deformed magnet with TbCu7 structure obtains an obvious c -axis texture. However, with increasing hot deformation temperature, some 1:7H phases decompose into 2:17R, 1:5H, and Zr-rich particle phases in the hot deformation process. The hot-deformed magnet with 85% height reduction possesses a remanence ( Mr ) of 6.9 kG, which is higher than that of the isotopic precursor. © 1965-2012 IEEE.
关键词 ：
Binary alloys Binary alloys Copper alloys Copper alloys Deformation Deformation Grain size and shape Grain size and shape Magnets Magnets Spark plasma sintering Spark plasma sintering Terbium alloys Terbium alloys Textures Textures Zirconium compounds Zirconium compounds
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| GB/T 7714 | Yang, Y.Q. , Zhang, D.T. , Li, Y.Q. et al. Phase and Texture Evolution of Hot-Deformed Sm(Co,Fe,Cu,Zr)zMagnet [J]. | IEEE Transactions on Magnetics , 2021 , 57 (2) . |
| MLA | Yang, Y.Q. et al. "Phase and Texture Evolution of Hot-Deformed Sm(Co,Fe,Cu,Zr)zMagnet" . | IEEE Transactions on Magnetics 57 . 2 (2021) . |
| APA | Yang, Y.Q. , Zhang, D.T. , Li, Y.Q. , Zhang, H.G. , Liu, W.Q. , Yue, M. . Phase and Texture Evolution of Hot-Deformed Sm(Co,Fe,Cu,Zr)zMagnet . | IEEE Transactions on Magnetics , 2021 , 57 (2) . |
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摘要 ：
一种Pr‑Fe‑(C, B)稀土永磁材料及其制备方法，涉及永磁材料技术领域，Pr‑Fe‑(C, B)稀土永磁材料，由具有按原子百分比计组成的物质组成Pr15Fe79(C1‑x, Bx)6，0.2＜x≤0.8；制备工艺包括配料、熔炼、熔体快淬、退火，其中，熔体快淬是采用铜辊转速30≤V≤40m/s的真空快淬炉在保护气氛下进行，退火是在保护气氛下在600‑950℃的退火炉中进行。在本发明利用Nd2Fe14B相的高稳定性，B原子的原子尺寸与C原子相似的特性，用B原子部分替代Pr2Fe14C中的C原子，大幅提升了Pr2Fe14(C, B)稳定性，提高了Pr2Fe14(C, B)相含量，使矫顽力大大提高。
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| GB/T 7714 | 岳明 , 姚辉 , 张红国 et al. 一种Pr-Fe-(C, B)稀土永磁材料及其制备方法 : CN202110166224.X[P]. | 2021-02-05 . |
| MLA | 岳明 et al. "一种Pr-Fe-(C, B)稀土永磁材料及其制备方法" : CN202110166224.X. | 2021-02-05 . |
| APA | 岳明 , 姚辉 , 张红国 , 刘卫强 , 张东涛 , 路清梅 . 一种Pr-Fe-(C, B)稀土永磁材料及其制备方法 : CN202110166224.X. | 2021-02-05 . |
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摘要 ：
The main difficulty for the recovery of Nd-Fe-B bonded magnet wastes is how to completely remove the epoxy resins. In this study, chemical reaction and physical dissolution were combined to remove the epoxy resins by adding ammonia-water and mixed organic solvents. Ammonia-water can react with the epoxy functional group of epoxy resin to generate polyols. Mixed organic solvents of alcohol, dimethyl formamide (DMF), and tetrahydrofuran (THF) can dissolve the generated polyols and residual epoxy resins. Under the optimum processing conditions, the epoxy resins in the waste magnetic powders are substantially removed. The oxygen and carbon contents in the recycled magnetic powder are reduced from 13500 x 10(-6) to 1600 x 10(-6) and from 19500 x 10(-6) to 2100 x 10(-6) with the reduction ratio of 88.1% and 89.2%, respectively. The recycled magnetic powder presents improved magnetic properties with Ms of 1.306 x 10(-1) A.m(2)/g, Mr of 0.926 x 10(-1) A.m(2)/g, Hcj of 1.170 T, and (BH) max of 125.732 kJ/m(3), which reach 99.8%, 99.4%, 95.9%, and 96.9% of the original magnetic powders, respectively. (C) 2021 The Authors. Published by Elsevier B.V.
关键词 ：
Epoxy resin Epoxy resin Nd-Fe-B bonded magnet wastes Nd-Fe-B bonded magnet wastes Open-loop reaction Open-loop reaction Physical dissolution Physical dissolution Rare earths Rare earths Recycled magnetic powders Recycled magnetic powders
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| GB/T 7714 | Liu, Min , Cui, Haiyuan , Li, Qingyan et al. Magnetic property recovery in Nd-Fe-B bonded magnet wastes with chemical reaction and physical dissolution [J]. | JOURNAL OF RARE EARTHS , 2021 , 39 (11) : 1396-1401 . |
| MLA | Liu, Min et al. "Magnetic property recovery in Nd-Fe-B bonded magnet wastes with chemical reaction and physical dissolution" . | JOURNAL OF RARE EARTHS 39 . 11 (2021) : 1396-1401 . |
| APA | Liu, Min , Cui, Haiyuan , Li, Qingyan , Zhu, Peihong , Liu, Weiqiang , Lu, Qingmei et al. Magnetic property recovery in Nd-Fe-B bonded magnet wastes with chemical reaction and physical dissolution . | JOURNAL OF RARE EARTHS , 2021 , 39 (11) , 1396-1401 . |
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摘要 ：
The effect of doping Cu on the mechanical properties and magnetic properties of Sm(Co0.71Fe0.15Cu0.07Zr0.03)7.6 magnets was studied systematically. The results show that the Cu-lean grain boundaries and bending strength of the magnet can be improved by increasing of doping Cu content. The optimal magnetic properties of magnet with 1.0 wt% Cu doping are $B_{\mathrm {r}} =9.9$ kG, $H_{\mathrm {cj}} =23.0$ kOe, and (BH) $_{\mathrm {max}} = 22.2$ MGOe. With the doping content of Cu powders, the bending strength first reaches a peak value of 143.0 MPa at 1.0 wt% and then drops. The bending strength of the magnet with 1.0 wt% Cu doping is about 51.8% higher than that of the magnet with 0 wt% Cu doping. The coercivity and bending strength of the magnet are improved. © 1965-2012 IEEE.
关键词 ：
Bending strength Bending strength Copper Copper Grain boundaries Grain boundaries Magnetic properties Magnetic properties Magnetism Magnetism Magnets Magnets Powders Powders
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| GB/T 7714 | Qiao, P.B. , Zhang, D.T. , Wu, S. et al. The Effect of Doping Cu Powders on Mechanical Properties and Magnetic Properties of Sm(CoFeCuZr)zSintered Magnets [J]. | IEEE Transactions on Magnetics , 2021 , 57 (2) . |
| MLA | Qiao, P.B. et al. "The Effect of Doping Cu Powders on Mechanical Properties and Magnetic Properties of Sm(CoFeCuZr)zSintered Magnets" . | IEEE Transactions on Magnetics 57 . 2 (2021) . |
| APA | Qiao, P.B. , Zhang, D.T. , Wu, S. , Shang, Z.F. , Xie, Z.H. , Liu, W.Q. et al. The Effect of Doping Cu Powders on Mechanical Properties and Magnetic Properties of Sm(CoFeCuZr)zSintered Magnets . | IEEE Transactions on Magnetics , 2021 , 57 (2) . |
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摘要 ：
The correlation between crystallographic orientation textures (including orientation textures of grain and grain boundary plane) and magnetic properties of (Sm,Pr)(2)Co-7 phase (short as 2:7 phase later) in high-performance commercial (Sm,Pr)Co-5 sintered magnet has been investigated. The Rietveld analysis shows that there is about 6.9 wt% of 2:7 phase in the magnet. EBSD results indicate that the grains are strongly textured and the {0001} orientation texture are remarkably preferred. Moreover, the grain boundary planes are also textured. However, the 100011 orientation texture of 2:7 phase is slightly worse than that of (Sm,Pr)Co-5 phase (short as 1:5 phase later). Moreover, the distribution of grain boundary plane has been calculated by the grain orientation texture in the magnet. The most preferential plane distribution locates at 100011 position, and the normal line of the phase boundary plane between the 2:7 phase and 1:5 phase is perpendicular to the easy axis of the magnetization of the magnet. There is difference in crystallographic orientation textures of 2:7 phase and 1:5 phase, which specifies that the orientation degree of phases is different. Furthermore, the orientation degree in turn affects the remanence, suggesting the presence of 2:7 phase will slightly reduce it. Meanwhile, magnetooptical Kerr optical microscope observation shows that the domain widths of 2:7 phase and 1:5 phase are almost the same, and there is no obvious difference in the reversal sequence of magnetic domain. The results proved that 2:7 phase has no significant negative effect on the coercivity. Therefore, the magnet has a crystallographic-orientation-dependent magnetic property. Besides, the study suggests that the anisotropy of crystal plane energy may become a new method to characterize the performance of permanent magnets in the future.
关键词 ：
2:7 phase 2:7 phase Crystallographic orientation texture Crystallographic orientation texture EBSD EBSD Magnetic domain Magnetic domain Magnetic property Magnetic property SmCo5 sintered magnet SmCo5 sintered magnet
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| GB/T 7714 | Yang, Jianjun , Zhang, Dongtao , Zhu, Rongchun et al. Effect of (Sm,Pr)(2)Co-7 phase on magnetic properties of high-performance (Sm,Pr)Co-5 magnet based on EBSD analysis and magnetic domain observation [J]. | MATERIALS CHARACTERIZATION , 2021 , 181 . |
| MLA | Yang, Jianjun et al. "Effect of (Sm,Pr)(2)Co-7 phase on magnetic properties of high-performance (Sm,Pr)Co-5 magnet based on EBSD analysis and magnetic domain observation" . | MATERIALS CHARACTERIZATION 181 (2021) . |
| APA | Yang, Jianjun , Zhang, Dongtao , Zhu, Rongchun , Xu, Xiaochang , Wu, Dan , Li, Yuqing et al. Effect of (Sm,Pr)(2)Co-7 phase on magnetic properties of high-performance (Sm,Pr)Co-5 magnet based on EBSD analysis and magnetic domain observation . | MATERIALS CHARACTERIZATION , 2021 , 181 . |
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摘要 ：
In this paper, microstructure, micromagnetic structure, texture, together with magnetic properties of the hot-deformed (HD) Nd-Fe-B magnets were systematically studied to understand the deformation process and the formation mechanism of c-axis texture. The results show that the platelet grains are formed in the fine-grain regions at the initial stage of the deformation. As the amount of deformation increases, the proportion of platelet grains increases and arranges gradually, causing the formation of c-axis texture, till the grain merging occurres when the deformation is excessive. It should be noted that the rare earth-rich phase in the fine-grained region slowly diffuses to the coarse-grained region where only grain growth can be observed during deformation. The deformation mechanism and formation of c-axis texture in HD Nd-Fe-B magnets can be deduced to be accomplished by the processes of dissolution-precipitation diffusion, grain rotation and grain arrangement, based on the characterization of microstructure and texture evolution. Also, approaches to optimize the preparation process and magnetic properties of the hot-deformed Nd-Fe-B magnets were discussed. © 2021
关键词 ：
Deformation Deformation Grain growth Grain growth Iron alloys Iron alloys Magnetic properties Magnetic properties Magnets Magnets Neodymium alloys Neodymium alloys Platelets Platelets Rare earths Rare earths Textures Textures
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| GB/T 7714 | Tang, Yuyang , Li, Yuqing , Xu, Xiaochang et al. Analysis on deformation and texture formation mechanism of hot-deformed Nd-Fe-B magnets based on heterogeneous structure evolution [J]. | Journal of Materials Science and Technology , 2021 , 80 : 28-35 . |
| MLA | Tang, Yuyang et al. "Analysis on deformation and texture formation mechanism of hot-deformed Nd-Fe-B magnets based on heterogeneous structure evolution" . | Journal of Materials Science and Technology 80 (2021) : 28-35 . |
| APA | Tang, Yuyang , Li, Yuqing , Xu, Xiaochang , Yue, Ming , Liu, Weiqiang , Zhang, Hongguo et al. Analysis on deformation and texture formation mechanism of hot-deformed Nd-Fe-B magnets based on heterogeneous structure evolution . | Journal of Materials Science and Technology , 2021 , 80 , 28-35 . |
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摘要 ：
The high-temperature oxidation resistance is a critical evaluation index for the practical applications of Nd-Fe-B sintered magnets. In this paper, the high temperature (> 523 K) oxidation behavior of the recycled Nd-Fe-B sintered magnets was investigated and compared with the original magnets. The results show that both magnets exhibit similar high-temperature oxidation characteristics. The recycled magnets oxidized after 300 h at 673 K possesses remanence (B-r) of 1.189 T, coercivity (H-ci) of 1688 kA/m, and maximum energy product [(BH)(max)] of 268 kJ/m(3). Compared with the recycled magnet before oxidizing, the oxidized recycled magnets retain 96.0% of B-r, 85.2% of H-ci, and 92.2% of (BH)(max), respectively. The recycled magnets negatively influence the high-temperature oxidation resistance compared with the original magnets, demonstrating the recycled magnets' applicability. (C) 2021 Published by Elsevier B.V.
关键词 ：
High-temperature oxidation High-temperature oxidation Oxidation mechanism Oxidation mechanism Oxidation rate Oxidation rate Recycled Nd-Fe-B sintered magnets Recycled Nd-Fe-B sintered magnets
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| GB/T 7714 | Li, X. T. , Liu, W. Q. , Yue, M. et al. The evaluation of high-temperature oxidation for the original and recycled Nd-Fe-B sintered magnets [J]. | JOURNAL OF ALLOYS AND COMPOUNDS , 2021 , 884 . |
| MLA | Li, X. T. et al. "The evaluation of high-temperature oxidation for the original and recycled Nd-Fe-B sintered magnets" . | JOURNAL OF ALLOYS AND COMPOUNDS 884 (2021) . |
| APA | Li, X. T. , Liu, W. Q. , Yue, M. , Liu, Y. H. , Zha, S. S. , Yi, X. F. et al. The evaluation of high-temperature oxidation for the original and recycled Nd-Fe-B sintered magnets . | JOURNAL OF ALLOYS AND COMPOUNDS , 2021 , 884 . |
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摘要 ：
The grain boundary diffusion (GBD) technology was used to prepare high performance Nd-Fe-B sintered magnets by NdH3 and TbH3 nanoparticle diffusion. The factors affecting the coercivity of GBD magnets include distribution of rare earth rich grain boundary phase and substitution of the heavy rare earth. In order to distinguish the influence of various factors on the coercivity, the microstructure and magnetic domain evolution of the original, reference, Nd-diffused, and Tb-diffused magnets were analyzed. The core-shell structure formed by heavy rare earth substitution is the main factor of coercivity enhancement, and it can transform the magnetic domain reversal mode from easy-nucleation (EN) to difficultnucleation (DN). With increasing the diffusion depth, the shell of the core-shell structure gradually becomes thinner, DN grains gradually decrease while the EN grains gradually increase, indicating that the magnetic domain reversal mode is directly related to the core-shell structure. 0 2020 Chinese Society of Rare Earths. Published by Elsevier B.V. All rights reserved.
关键词 ：
Coercivity Coercivity Core-shell structure Core-shell structure Grain boundary diffusion Grain boundary diffusion Heavy rare earth Heavy rare earth Magnetic domain reversal Magnetic domain reversal Nd-Fe-B sintered magnet Nd-Fe-B sintered magnet
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| GB/T 7714 | Liu, Weiqiang , Li, Yi , Wu, Dan et al. Coercivity enhancement mechanism of grain boundary diffused Nd-Fe-B sintered magnets by magnetic domain evolution observation [J]. | JOURNAL OF RARE EARTHS , 2021 , 39 (6) : 682-688 . |
| MLA | Liu, Weiqiang et al. "Coercivity enhancement mechanism of grain boundary diffused Nd-Fe-B sintered magnets by magnetic domain evolution observation" . | JOURNAL OF RARE EARTHS 39 . 6 (2021) : 682-688 . |
| APA | Liu, Weiqiang , Li, Yi , Wu, Dan , Yue, Ming , Wang, Zhanjia , Zha, Shanshun et al. Coercivity enhancement mechanism of grain boundary diffused Nd-Fe-B sintered magnets by magnetic domain evolution observation . | JOURNAL OF RARE EARTHS , 2021 , 39 (6) , 682-688 . |
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