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Preparation and magnetic hardening of low Ti content(Sm,Zr)(Fe,Co,Ti)_(12) magnets by rapid solidification non-equilibrium method
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作者 Xing-Feng zhang Li-Bin Liu +3 位作者 Yu-Qing Li dong-tao zhang Wei-Qiang Liu Ming Yue 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第9期576-580,共5页
The Sm–Zr–Fe–Co–Ti quinary-alloys with ThMn12 structure has attracted wide attention for ultra-high intrinsic magnetic properties,showing potentiality to be developed into rare-earth permanent magnets.The Ti eleme... The Sm–Zr–Fe–Co–Ti quinary-alloys with ThMn12 structure has attracted wide attention for ultra-high intrinsic magnetic properties,showing potentiality to be developed into rare-earth permanent magnets.The Ti element in alloys is crucial for phase stability and magnetic properties,and lower Ti content can increase intrinsic magnetic properties but reduce phase stability.In this study,the 1:12 single-phase melt-spun ribbons with low Ti content was successfully prepared using a rapid solidification non-equilibrium method for the Sm1.1Zr_(0.2)Fe_(9.2)Co_(2.3)Ti_(0.5) quinary-alloy.However,this non-equilibrium ribbon did not achieve good magnetic hardening due to the uneven microstructure and microstrain.Then,annealing was carried out to eliminate micro-strain and homogenize microstructure,therefore,remanence and coercivity were significantly improved even the precipitation of a small amount of a-Fe phase which were not conducive to coercivity.The remanence of 86.1 emu/g and coercivity of 151 kA/m was achieved when annealing at 850℃ for 45 min.After hot pressing,under the action of high temperature and pressure,a small portion of ThMn12 phases in the magnet decompose into Sm-rich phases and a-Fe,while remanence of 4.02 kGs(1 Gs=10^(-4) T),and coercivity of 1.12 kOe(1 Oe=79.5775 A·m^(-1))were still acquired.Our findings can provide reference for exploring practical permanent magnets made of 1:12 type quinary-alloys. 展开更多
关键词 magnetic materials (Sm Zr)(Fe CO Ti)_(12) magnets nanocrystalline magnet microstructure
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Coercivity,microstructure,and thermal stability of sintered Nd-Fe-B magnets by grain boundary diffusion with TbH3 nanoparticles 被引量:19
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作者 Wei-Qiang Liu Cheng Chang +4 位作者 Ming Yue Jing-Shan Yang dong-tao zhang Jiu-Xing zhang Yan-Qin Liu 《Rare Metals》 SCIE EI CAS CSCD 2017年第9期718-722,共5页
Grain boundary diffusion technique with TbH3 nanoparticles was applied to fabricate Tb-less sintered NdFe-B permanent magnets with high coercivity. The magnetic properties and microstructure of magnets were systematic... Grain boundary diffusion technique with TbH3 nanoparticles was applied to fabricate Tb-less sintered NdFe-B permanent magnets with high coercivity. The magnetic properties and microstructure of magnets were systematically studied. The coercivity and remanence of grain boundary diffusion magnet are improved by 112% and reduced by 26% compared with those of the original magnet, respectively. Meanwhile, both the remanence temperature coefficient(α) and the coercivity temperature coefficient(β) of the magnets are improved after diffusion treatment. Microstructure shows that Tb element enriches in the surface region of Nd2Fe(14)B grains and is expected to exist as(Nd,Tb)2Fe(14)B phase. Thus, the magneto-crystalline anisotropy field of the magnet improves remarkably. As a result, the sintered Nd-FeB magnets by grain boundary diffusion with TbH3 nanoparticles exhibit enhanced coercivity. 展开更多
关键词 Grain boundary diffusion TbH3 nanoparticles COERCIVITY Thermal stability
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Enhancement of corrosion resistance in sintered Nd-Fe-B permanent magnet doping with different CuZn5 contents 被引量:7
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作者 Zhuang Wang Wei-Qiang Liu +3 位作者 dong-tao zhang Ming Yue Xiu-Lian Huang Xu-Liang Li 《Rare Metals》 SCIE EI CAS CSCD 2017年第10期812-815,共4页
Nd-Fe-B permanent magnets doped with CuZn5 powders were prepared via conventional sintered method. The effects of CuZn5 contents on magnetic properties and corrosion resistance of the magnets were sys- tematically stu... Nd-Fe-B permanent magnets doped with CuZn5 powders were prepared via conventional sintered method. The effects of CuZn5 contents on magnetic properties and corrosion resistance of the magnets were sys- tematically studied. It shows that the remanence, coercivity, and maximum energy product decrease gradually with the increase in CuZn5 doping content. The magnet's corrosion kinetics in autoclaves environment and its electrochemical properties in electrolytes were also examined. It is interesting to see that the weight loss of 3.5 wt% and 4.5 wt% CuZn5 powders doping magnets is only 1 and 0 mg.cm^-2 after autoclaves test at 121 ℃, 2 × 10^5 Pa for 500 h, respectively, which is much lower than that of the magnets without CuZn5 doping. Electrochemical results show that the CuZn5 powders doping magnets display more positive corrosion potential (Eoorr) and lower corrosion current density (Icorr) than those of the original magnets without CuZn5 doping in sulphuric acid electrolyte and distilled water. It is, therefore, concluded that doping CuZn5 powders is a promising way to enhance the corrosion resistance of sintered Nd-Fe-B magnets. 展开更多
关键词 Sintered Nd-Fe-B magnet Corrosion resistance CuZn5 powders AUTOCLAVE Polarization characteristics
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In-situ observation of magnetization reversal process of Sm(Co,Cu,Fe,Zr)_z magnets with different Fe contents 被引量:3
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作者 Shuo Wu dong-tao zhang +4 位作者 Ming Yue Yun-Qiao Wang Zhi-Feng Shang Dan Wu Jing-Ming Liang 《Rare Metals》 SCIE EI CAS CSCD 2020年第3期250-255,共6页
Sm(Co,Cu,Fe,Zr)z magnets have drawn much attention for high-temperature applications due to their high Curie temperature,strong corrosion resistance and thermal stability.The effect of increasing Fe content on the dis... Sm(Co,Cu,Fe,Zr)z magnets have drawn much attention for high-temperature applications due to their high Curie temperature,strong corrosion resistance and thermal stability.The effect of increasing Fe content on the distribution of elements and squareness(Sr)of demagnetization curves were investigated for two kinds of magnets with different nominal compositions of Sm(CobalFe0.15-Cu0.07Zr0.03)7.8 and Sm(CobalFe0.28Cu0.07Zr0.03)6.6 in this work.The magnetic properties of the magnets with higher Fe content fluctuate greatly after different solution treatments,indicating that they are more sensitive to the process temperature.The increase in Fe content can obviously enhance the cellular phase size.Meanwhile,inhomogeneous Cu distribution is observed in the Sm(CobalFe0.28-Cu0.07Zr0.03)6.6 magnet,resulting in the different cellular structures and corresponding magnetic domain patterns in different regions in the inner grains.Furthermore,the lower Cu content regions are responsible for the wider magnetic domain,which have weaker resistance to applied magnetic field.As a result,Sr of demagnetization curve decreases with the increase in Fe content due to the inhomogeneous Cu distribution,which was confirmed by in-situ observation of electron probe micro-analyzer(EPMA)and magneto-optical Kerr optical microscope(MOKE). 展开更多
关键词 Sm(Co Cu Fe Zr)_z MAGNETS CU distribution Microstructure MAGNETIC properties MAGNETIC domain Squareness
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High-temperature magnetic properties of anisotropic Mn Bi/Nd Fe B hybrid bonded magnets 被引量:4
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作者 dong-tao zhang Peng-Fan Wang +4 位作者 Ming Yue Wei-Qiang Liu Jiu-Xing zhang Jennifer Anand Sundararajan You Qiang 《Rare Metals》 SCIE EI CAS CSCD 2016年第6期471-474,共4页
Anisotropic MnBi/NdFeB (MnBi contents of 0 wt%, 20 wt%, 40 wt%, 60 wt%, 80 wt%, and 100 wt%) hybrid bonded magnets were prepared by molding compression using MnBi powders and commercial hydro-genation disproportiona... Anisotropic MnBi/NdFeB (MnBi contents of 0 wt%, 20 wt%, 40 wt%, 60 wt%, 80 wt%, and 100 wt%) hybrid bonded magnets were prepared by molding compression using MnBi powders and commercial hydro-genation disproportionation desorption and recombination (HDDR) NdFeB powders. Magnetic measurements at room temperature show that with MnBi content increasing, the magnetic properties of the MnBi/NdFeB hybrid bonded magnets all decrease gradually, while the density of the hybrid magnets improves almost linearly. In a temperature range of 293-398 K, the coercivity temperature coefficient of the hybrid magnets improves gradually from -0.59 %.K^-1 for the pure NdFeB bonded magnet to -0.32 %.K^-1 for the hybrid bonded magnet with 80 wt% MnBi, and the pure MnBi bonded magnet exhibits a positive coercivity temperature coefficient of 0.61%-K^-1. 展开更多
关键词 Hybrid bonded magnet NDFEB MnBi Coercivity temperature coefficient
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Microstructure and magnetic properties of SmCo_(5) sintered magnets 被引量:4
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作者 dong-tao zhang Rong-Chun Zhu +1 位作者 Ming Yue Wei-Qiang Liu 《Rare Metals》 SCIE EI CAS CSCD 2020年第11期1295-1299,共5页
SmCo_(5)sintered magnets with good thermal stability are mainly used in high-temperature field.In this study,two types of SmCo_(5) powders with different nominal z values were mixed and synthesized into SmCo_(5) magne... SmCo_(5)sintered magnets with good thermal stability are mainly used in high-temperature field.In this study,two types of SmCo_(5) powders with different nominal z values were mixed and synthesized into SmCo_(5) magnets by the traditional powder metallurgy method.The magnetic properties of the SmCo_(5) sintered magnet are maximum energy product of(BH)_(max)=172.29 kJ·m^(-3),remanence of B_(r)=7.47×10^(5)A·m^(-1)and coercivity of H_(ci)=2.42 T.The results show that there are three coexisting phases in the magnet,which are SmCo_(5)phase,Sm_(2)Co_(7)phase and Sm_(2)O_(3)phase.The microstructural observation indicates that the average grain size in the magnet is about 8μm,and the high coercivity of this magnet is attributed to these fine grains.X-ray diffraction(XRD)and electron backscatter diffraction(EBSD)results indicate that the magnet has a well-aligned(00l)orientation texture. 展开更多
关键词 SmCo_(5) Sintered magnets Magnetic properties
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Numerical simulation of single roller melt spinning for NdFeB alloy based on finite element method 被引量:2
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作者 Xu-Chao Wang Ming Yue +2 位作者 dong-tao zhang Wei-Qiang Liu Ming-Gang Zhu 《Rare Metals》 SCIE EI CAS CSCD 2020年第10期1145-1150,共6页
The numerical simulation model of single roller melt spinning for rapid quenching process of NdFeB alloy was built,and the vacuum chamber,cooling roller and sample were taken into account as a system.The existing matu... The numerical simulation model of single roller melt spinning for rapid quenching process of NdFeB alloy was built,and the vacuum chamber,cooling roller and sample were taken into account as a system.The existing mature technology was in order to verify the correctness of simulation.The rapid quenching ribbons with different roll speeds were used as the simulation objects.The results of the numerical simulation and experiments show that the validity of the model has been testified and the reasons of the formation of complete quenching ribbons and by-product have been explained.The experimental thickness of the ribbons is proportional to the theoretical thickness.In the same spray condition,with the roll speed increasing,the thickness decreases linearly.At the speed range of25-30 m·s^(-1),the simulated calculation date is close to the experimental date,which can be considered as an ideal technological parameter. 展开更多
关键词 NDFEB Melt spinning Finite element method Numerical simulation
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Low-cost Sm0.7Y0.3Co5 sintered magnet produced by traditional powder metallurgical techniques 被引量:1
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作者 dong-tao zhang Nai-Xing Cai +2 位作者 Rong-Chun Zhu Wei-Qiang Liu Ming Yue 《Rare Metals》 SCIE EI CAS CSCD 2020年第4期421-428,共8页
RCo5(R=rare earth)sintered magnets have good temperature stability,so it is still widely used in high temperature field.In this paper,by the method of adding liquid phase SmCo1.7 to the main phase,Sm0.7Y0.3Co5 magnet ... RCo5(R=rare earth)sintered magnets have good temperature stability,so it is still widely used in high temperature field.In this paper,by the method of adding liquid phase SmCo1.7 to the main phase,Sm0.7Y0.3Co5 magnet was prepared by traditional powder metallurgical process.The results show the presence of a main phase RCo5,a minor phase R2 Co7,and a R-rich phase in the magnet.Contrasting the results of the XRD(X-ray diffraction)in random and oriented directions,the magnet has a well-aligned(00l)orientated texture,which is consistent with the result of the electron backscattered diffraction(EBSD).The Sm0.7Y0.3Co5 sintered magnet has good magnetic properties as remanence(Br)is 0.96 T,the coercivity(Hcj)is 1201.96 kA·m-1,and maximum magnetic energy product((BH)max)is 175.16 kJ m-3. 展开更多
关键词 Sm0.7Y0.3Co5 Sintered magnets LOW-COST Magnetic properties RCo5
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Coercivity enhancement mechanism of Tb-diffusion Nd-Fe-B sintered magnets studied by magneto-optical Kerr optical microscope 被引量:1
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作者 Dan Wu Wei-Qiang Liu +5 位作者 Ming Yue Qiong Wu dong-tao zhang Qing-Mei Lu Xu-Liang Li Jing-Wu Chen 《Rare Metals》 SCIE EI CAS CSCD 2021年第3期570-574,共5页
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.Compared to the original magne... 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.Compared to the original magnet,the coercivity(Hci) of the GBDP magnets improved from 1702 to 2374 kA·m^(-1) with few remanence reduced from 1.338 to 1.281 T.Electron probe microanalysis(EPMA) analysis showed that Tb diffused along grain boundary,mainly concentrated in the boundary layer of the main phase,and formed a core-shell structure.Magneto-optical Kerr optical microscope(MOKE) analysis showed that there were two types of magnetic domain reversal in one grain:gradual reversal(GR) and abrupt reversal(AR).When the applied field decreased from saturated magnetic field,the reversal magnetic domain nucleated and then spread over the whole grain gradually,which was called GR.However,some grains kept the single domain state until Hh which was a value of reverse direction applied field in second quadrant in hysteresis loops.When the applied field increased above Hh,reversed magnetic domain would suddenly appear and occupy most of the area of the grain,which was called AR.That is because AR grains have higher reversed magnetic domain nucleation field(HRN2) than GR grains(HRN1).After GBDP,the area of AR region increased obviously and GR region decreased accordingly,indicating that the core-shell structure could change GR grain into AR grain.The coreshell structure could suppress flipping of the magnetization of the grains due to the large magnetic anisotropy of Tbrich shell.Therefore,large AR area led to high coercivity. 展开更多
关键词 Coercivity enhancement mechanism Magnetic domain Grain boundary diffusion Nd-Fe-B sintered magnets
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Structure, magnetic properties, and thermal stability of Sm(1-x)Tm_xCo_5compounds
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作者 Jian-Hua Zuo Ming Yue +5 位作者 Qing-Mei Lu dong-tao zhang Xue-Xu Gao Jiu-Xing zhang Zhao-Hui Guo Wei Li 《Rare Metals》 SCIE EI CAS CSCD 2014年第2期176-179,共4页
Structure, magnetic properties, and thermal stability of ternary Sm1-xTmxCo5 compounds were studied via X-ray diffraction(XRD), thermal magnetic analysis(TMA), and magnetic measurements. XRD results show that all ... Structure, magnetic properties, and thermal stability of ternary Sm1-xTmxCo5 compounds were studied via X-ray diffraction(XRD), thermal magnetic analysis(TMA), and magnetic measurements. XRD results show that all the compounds have a main phase of hexagonal CaCu5-type crystal structure with small amount of impurity phases; increasing Tm content is associated with contraction of the hexagonal unit cell in the direction of the c axis and expansion of the a and b parameters. TMA results indicate that the Curie temperature(TC) of Sm1-xTmxCo5 compounds gets higher with the increase in Tm content.Magnetic measurements show that both the magnetic anisotropy field(HA) and the magnetization at an applied field of 7 T(M7 T) decrease with the increase of Tm content. However, the thermal stability of both the HAand M7 Tof all the Tm doped compounds is remarkably improved compared with that of the pure SmCo5 compound, leading to the result that both the M7 Tand HAof Sm0.8Tm0.2Co5 .2are higher than those of SmCo5 compound at 473 K, which indicates the good potential of Tm doped compound in the practical applications at elevated temperature. 展开更多
关键词 Sm1-xTmxCo5 compounds Crystal structure Intrinsic magnetic property Thermal stability
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