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| 1 | Magnetic microstructure and coercivity mechanism of high performance Nd-Fe-B magnets显示文摘Magnetic microstructure of high performance Nd-Fe-B magnets was investigated by using magnetic force microscopy. The correlation between magnetic microstructure and coercivity for high performance Nd-Fe-B magnets was studied. It is found that the magnets with different coercivity mechanism take on different microstructures and magnetism. Moreover, the magnetic microstructures of high performance permanent magnets can be explained by the starting field theory model. | ZHU Minggang LIU Xingmin FANG Yikun LI Zhengbang LI Wei | 2006 | Rare Metals2006，25，z1： | 7 |
| 2 | Optimization of microstructures and magnetic properties of Sm(Co_(bal)Fe_(0.227)Cu_(0.07)Zr_(0.023))_(7.6) magnets by sintering treatment显示文摘Magnetic properties and microstructures of Sm(Co_(bal)Fe_(0.227)Cu_(0.07)Zr_(0.023_)_(7.6) sintered magnets were optimized by sintering treatment. Results show that the knee-point magnetic field, Hknee, is twofold up and the intrinsic coercivity Hcjincreases by 40%, ranging from 21.64 to 30.39 kOe at the cost of a little decrease of Brfrom 10.84 to 10.31 kGs with sintering temperature decreasing from 1488 to 1473 K. And the average domain width is narrower and more uniform for the specimen sintered at 1473 K than that of the specimen sintered at 1488 K. It is impressive that the density of lamellar phase increases from ~0.050 to ~0.058 nm^(-1) with the sintering temperature decreasing from 1488 to 1473 K. Moreover, the average cellular size is about ~84 nm for the magnets sintered at 1473 K, which is 80% of that of the magnets sintered at 1488 K(~97 nm). And the cell boundary width of the magnets sintered at 1473 K(~7 nm) is only half average width of the magnets sintered at 1488 K(~14 nm). It is found that the Cu content in the cell boundaries is much higher(~17 at%) in the magnets sintered at 1473 K compared to that of the magnets sintered at 1488 K(~10 at%). It can be concluded that smaller cells and narrower cell boundaries together with higher gradient of Cu content are key points for obtaining the optimum Hkneeand Hcj. | Kuikui Songa Wei Suna Yikun Fang Shuai Wang Nengjun Yu Meiling Zhang Minggang Zhu Wei Li | 2019 | Journal of Rare Earths2019，37，2： | 6 |
| 3 | Optimization of both coercivity and knee-point magnetic field of Sm2Co17-type magnets via solid solution process显示文摘It is confirmed that phase homogenization is very important for improving the magnetic properties of 2:17-type Sm-Co sintered magnets,In this work,the influence of solid solution process on microstructure and magnetic properties of the Sm(CobalFe0.233Cu0.073Zr0.024)7.6 sintered magnets was systematically studied.With the solid-solution treating duration(tS)increasing from 0 to 4 h,intrinsic coercivity(Hcj)increases from 12.83 to 36.54 kOe,magnetic field at knee-point(Hknee)increases from2.76 to 19.14 kOe,and the maximum energy product increases from 19.79 to 29.48 MGOe.The electron probe microanalyzer results reveal that there mainly exist gray and dark regions besides'white'rare earth-rich phase,and the conte nt of Sm,Fe and Cu elements for the two kinds of regions changes a lot for the specimens,Furthermore,with tS increasing up to 4 h,the elements content deviation between the gray and dark regions becomes small gradually from 3.94 at%to 0.27 at%,7.66 at%to 0.21 at%and 7.27 at%to 0.16 at%for Sm,Fe and Cu elements,respectively.Moreover,transmission electron microscopy results show that the distribution of cell size is much more concentrated for aged specimens when tS is 4 h.It is also found that the Cu concentration at cell boundaries for the 4 h solid-solution treatment case shows relatively higher values and greater concentration gradient(1.94 at%/nm).It is verified that sufficient solution treatment duration is prerequisite to form these homogeneous microstructural features,which are the key points for obtaining both high Hcj and Hknee. | Shuai Wang Yikun Fang Kuikui Song Xiaoyu Zhu Lei Wang Wei Sun Wei Pan Minggang Zhu Wei Li | 2020 | Journal of Rare Earths2020，38，11： | 5 |
| 4 | Microstructures and magnetic properties of Ce_(32.15)_Co_(49.36)Cu_(9.84)Fe_(9.65) magnet sintered at different temperatures显示文摘The microstructures and magnetic properties of Ce-32.15Co_49.36Cu_9.84Fe_9.65 magnet sintered at the temperatures ranging from 1005 to 1105 °C were investigated. The results on scanning electron microscopy and X-ray diffraction analysis indicate that the remanence B r of the magnets is mainly influenced by the degree of the easy-axis orientation when sintering temperature is less than 1085 °C, the rapidly increasing amount of the secondly phase (5:19 phase) gives rise to the deterioration of the magnetic properties of the magnet above 1085 °C. Moreover, it is found that intrinsic coercivity H ci is strongly related to the content of copper in the matrix of the sintered magnets. The optimal sintering temperature is located in 1025~1055 °C, the corresponding magnetic properties of the magnets are B_r =0.685T, H_(ci) =350kA·m^-1 , and maximum energy product (BH)_m =85.6 kJ·m 3 . | SUN Wei ZHU Minggang FANG Yikun PAN Wei LI Jiajie LI Yanfeng LI Wei | 2012 | Rare Metals2012，31，5： | 3 |
| 5 | Cellular microstructure modification and high temperature performance enhancement for Sm2Co17-based magnets with different Zr contents显示文摘Influence of Zr contents on high-temperature magnetic performance of Sm(CoFeCuZr)(x=0.025,0.03,0.035,0.04) magnets were investigated.As x increases from 0.025 to 0.04,the temperature coefficient of intrinsic coercivity(H) is optimized from-0.1673% K^(-1)to-0.1382% K^(-1)and the Hat 773 K gradually increases from 556.32 kA m^(-1)to 667 kA m^(-1).The microstructure and microchemistry of different Zr-content magnets were revealed by a transmission electron microscope equipped with EDS.The increasing Zr content induces that the average size of cells decreases from ~76 nm to ~56 nm and the weight fraction of 1:5 H cell boundary phase increases from ~25% to ~37% as well,resulting decreasing of the average Cu content at cell boundaries from 13.59 at% to ~8.52 at%.It is found that the Cu-lean characteristic at cell boundary phase is the reason that gives rise to higher magnetic properties at elevated temperatures for x=0.04 magnet. | Chao Wang Peng Shen Yikun Fang Shuai Wang Qiangfeng Li Lei Wang Wei Li Minggang Zhu | 2022 | Journal of Materials Science & Technology2022，，25： | 2 |
| 6 | Electrochemomechanical coupled behaviors of deformation and failure in electrode materials for lithium-ion batteries显示文摘The growing demands of lithium-ion batteries with high energy density motivate the development of high-capacity electrode materials. The critical issue in the commercial application of these electrodes is electrochemomechanical degradation accompanied with the large volume change, built-in stress, and fracture during lithiation and delithiation. The strong and complex couplings between mechanics and electrochemistry have been extensively studied in recent years. The multi-directional couplings, e.g.,(de)lithiation-induced effects and stress-regulated effects, require cooperation in the interdisciplinary fields and advance the theoretical and computational models. In this review, we focus on the recent work with topics in the electrochemomechanical couplings of deformation and fracture of conventional and alloying electrodes through experimental characterization, theoretical and computational models. Based on the point of view from mechanics, the strategies for alleviating the degradation are also discussed, with particular perspectives for component-interaction patterns in the composite electrodes. With interdisciplinary principles, comprehensive understanding of the electrochemomechanical coupled mechanism is expected to provide feasible solutions for low-cost, high-capacity, high-safety and durable electrodes for lithium-ion batteries. | LIANG HuanZi ZHANG XingYu YANG Le WU YiKun CHEN HaoSen SONG WeiLi FANG DaiNing | 2019 | Science China(Technological Sciences)2019，62，8： | 2 |
| 7 | Correlation of mechanical anisotropy with fine grain strengthening for Sm_(2)Co_(17)-type sintered permanent magnets显示文摘The as-solution-treated Sm_(2)Co_(17)-type magnets exhibiting a single 1:7 H phase with different average grain sizes(D) were designed.Anisotropy of bending strength(R_(bb))and compressive strength(R_(mc)) of the magnets were investigated.Moreover,the R_(bb) increases from 86 to 173 MPa with D decreasing from~52 to~18 μm for group c//h samples.The Hall-Petch correlation was employed to reveal the effect of grain size on mechanical properties of the magnets,giving deep understanding of the mechanical anisotropy characteristics.The relatively high Hall-Petch coefficient K^(Rbb)(0.79 MPa·m^(1/2)) gives rise to the largest R_(bb)(173 MPa) for group c//h samples.The mechanical anisotropy of the samples is well explained based on crystal structure and grain size features(grain boundaries).Grain refinement is an effective way to enhance the mechanical properties of Sm_(2)Co_(17)-type sintered magnets. | Lei Wang Chao Wang Qiangfeng Li Youhao Liu Yikun Fang Xiaofei Yi Wei Li | 2022 | Journal of Rare Earths2022，40，10： | 1 |
| 8 | Study of Magnetic Micro- structures of Nd-Fe-B casting strips by using Magnetic force microscope显示文摘 | Zhu Minggang Fang Yikun | 2004 | Journal of Magnetism and Mag- netic Materials2004，282，： | 1 |
| 9 | Analysis of NdFeB multi-pole ring by SEM and MFM显示文摘Sintered multi-pole ring that is made in America and China was analysed by SEM and MFM. The results show that the average size of American multi-pole ring is much smaller than the Chinese one and has much better orientation degree. The magnetic field of American specimen is much higher than that of the Chinese one and its average value is about 500 Gs, and more uniform distribution of the Nd-rich phase has been obtained. | LIU Xingmin LI Xiumei FANG Yikun ZHU Minggang HAN Baoshan LI Wei | 2006 | Rare Metals2006，25，z1： | 1 |
| 10 | A chloride efflux transporter,BIG RICE GRAIN 1,is involved in mediating grain size and salt tolerance in rice显示文摘Grain size is determined by the size and number of cells in the grain.The regulation of grain size is crucial for improving crop yield;however,the genes and molecular mechanisms that control grain size remain elusive.Here,we report that a member of the detoxification efflux carrier/Multidrug and Toxic Compound Extrusion(DTX/MATE)family transporters,BIG RICE GRAIN 1(BIRG1),negatively influences grain size in rice(Oryza sativa L.).BIRG1 is highly expressed in reproductive organs and roots.In birg1 grain,the outer parenchyma layer cells of spikelet hulls are larger than in wild-type(WT)grains,but the cell number is unaltered.When expressed in Xenopus laevis oocytes,BIRG1 exhibits chloride efflux activity.Consistent with this role of BIRG1,the birg1 mutant shows reduced tolerance to salt stress at a toxic chloride level.Moreover,grains from birg1 plants contain a higher level of chloride than those of WT plants when grown under normal paddy field conditions,and the roots of birg1 accumulate more chloride than those of WT under saline conditions.Collectively,the data suggest that BIRG1 in rice functions as a chloride efflux transporter that is involved in mediating grain size and salt tolerance by controlling chloride homeostasis. | Zhijie Ren Fenglin Bai Jingwen Xu Li Wang Xiaohan Wang Qian Zhang Changxin Feng Qi Niu Liying Zhang Jiali Song Fang Bao Liangyu Liu Yikun He Ligeng Ma Wang Tian Congcong Hou Legong Li | 2021 | Journal of Integrative Plant Biology2021，63，12： | 1 |
| 11 | Purification,characterization and preliminary crystallographic studies of a PR-10 protein from Pachyrrhizus erosus seeds显示文摘 | Wu Fang Li Yikun Chang Shaojie | 2002 | Acta Cryst2002，58，： | 1 |
| 12 | Study of Magnetic Micro Structures of Nd-Fe-B Casting Strips by Using Magnetic Force Microscope 显示文摘 | Zhu Minggang Fang Yikun Guo Yongquan | 2004 | J Magn Magn Mater2004，282，： | 1 |
| 13 | Magnetic properties,crystalline and magnetic microstructures of dual-main-phase(Nd,Ce)-Fe-B sintered magnets显示文摘The(Nd,Ce)-Fe-B sintered magnets were prepared by a dual-main-phase(DMP)process under the same conditions using different combinations of Nd-Fe-B with Ce-Fe-B and(Nd,Ce)-Fe-B strips.The crystalline and magnetic microstructures of DMP(Nd,Ce)-Fe-B magnets with the remanence of 11.92-12.68 kGs,the intrinsic coercivity of 3.97-5.31 kOe,and the maximum energy product of 23.08-32.99 MGOe have been investigated.Magnetic force microscope(MFM)investigations reveal that the DMP(Nd,Ce)-Fe-B magnets show maze-like patterns,which are like that of standard anisotropy Nd-Fe-B sintered magnets by and large.However,much finer domain structures mixing with coarse ones can be observed obviously in DMP(Nd,Ce)-Fe-B sintered magnets.The size distribution of the domain width of the DMP(Nd,Ce)-Fe-B magnet is not uniform obviously.The average domain width is W=0.912μm,and the fine domain width has only 0.216μm.The smaller domain width and more branch domain patterns exist in poorer coercivity DMP magnets.This is caused by the non-uniform Ce composition of poorer property DMP magnets and the grain boundary microstructure that is not conducive to improving the coercivity.Furthermore,it is found that some domains of rare-earth-rich grain boundary phases exhibit the characteristics of plate-like patterns rather than no-contrast by using MFM,indicating their ferromagnetism.Obvious correlations between the crystalline microstructure,chemical composition of phases,and magnetic structure were demonstrated for the DMP magnets. | Yifei Xiao Lele Zhang Tao Liu Xiaolong Song Qisong Sun Yikun Fang Minggang Zhu Wei Li | 2023 | Journal of Materials Science & Technology2023，，31： | 0 |
| 14 | Superior corrosion resistance and corrosion mechanism of dual-main-phase (Ce_(15)Nd_(85))_(30)Fe_(bal)B_(1)M magnets in different solutions显示文摘The electrochemical corrosion behavior of both (Ce_(15)Nd_(85))_(30)Fe_(bal)B_(1)M sintered magnets prepared with dual-main-phase method and N45-type magnets was studied in 3.5 wt% NaCl,1.1 wt% NaH_(2)PO_(4),and 2.5 wt% NaOH solutions,respectively.The (Ce_(15)Nd_(85))_(30)Fe_(bal)B_(1)M sintered magnets perform superior corrosion resistance than N45-type magnets in the tested solutions.In general,two kinds of magnets exhibit the best corrosion resistance property in 2.5 wt% NaOH solution,while the worst in 3.5 wt% NaCl solution.Microstructures of samples before and after corrosion were investigated.With the addition of Ce by means of dual-main-phase method,which is conducive to facilitating low-temperature sintering and grain refinement,uniform grain size and(Nd,Ce)-rich phase distribution form,give rise to narrow and thin corrosion channels.Moreover,the corrosion rate of the(Nd,Ce)-rich phase is lower than that of Nd-rich one.Acco rdingly,corro sion re sistance of (Ce_(15)Nd_(85))_(30)Fe_(bal)B_(1)M sintered magnet is superior when compared with the commercial N45-type magnet which has comparable magnetic properties. | Yaping Wu Minggang Zhu Qisong Sun Lele Zhang Peng Shen Yikun Fang Wei Li | 2023 | Journal of Rare Earths2023，41，1： | 0 |
| 15 | Preparation of FePt magnetic nanodot arrays by nanosphere lithography显示文摘Magnetic FePt nanodot arrays are promising candidates for making quantum magnetic recording disk. Here we introduce a hybrid method of FePt nanodot array fabrication through nanosphere lithography. This method combines the advantages of both top-down and bottom-up approaches and does not re- quire expensive equipment nor complicated processing steps.The size of magnetic FePt nanodots prepared can be as small as 40 nm. | wu PeiWen FANG YiKun TUO XinLin WANG XiaoGong HAN BaoShan YUAN Jun | 2007 | Chinese Science Bulletin2007，52，8： | 0 |
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