检索结果-南通市图书馆

Journal of Rare Earths 2024年第7期42卷 1282-1288,I0003页

作者： Yikuan Hu Jiajie Li Shengyu Sun Shuwei Zhong Munan Yang Xiaoqiang Yu sajjad ur rehman Xi Yu Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices College of Rare EarthsJiangxi University of Science and TechnologyGanzhou341000 National Rare Earth Functional Materials Innovation Center Ganzhou341000China Ganzhou Fortune Electronic Ltd. Ganzhou341000China

It is still a challenge to simultaneously enhance coercivity(H_(cj))and remanence(J_(r))of hot-deformed Nd-Fe-B magnet due to the coercivity-remanence trade-off ***,we achieved this balance between H_(cj)and Jr by flake Cu powder assisted DyF_(3)interflake *** Hcj increases from 1218 to 1496 kA/m and Jr increases from 1.32 to 1.34 T compared with the original *** show that the width of coarse grain layers reduces because of the introduction of flake Cu,which increases the contact areas of the adjacent grains at ribbon interfaces and suppresses the excessive growth of *** stronger degree of texture and higher density compared with the original magnet should take the responsibility for the increase of J_(r).Additionally,the aggregation regions of rare earth rich(RE-rich)phase reduce and the betterment of the microstructure is another reason for the enhancement of Jr in the flake Cu aided DyF_(3)hot-deformed *** strategy of using flake powder additives provides a promising method for optimizing microstructure and enhancing magnetic properties of hot-deformed Nd-Fe-B magnets.

关键词： Rare earths Nd-Fe-B Hot-deformed magnet Flake powder Interflake addition Remanence

Fabrication and application prospects of Pr-Fe-B/Alnico nanocomposite alloys

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第9期42卷 1717-1723页

作者： Hui Liang sajjad ur rehman Ruibiao Zhang Yongqiang Deng Haihua Liu Munan Yang National Rare Earth Functional Materials Innovation Center College of Rare EarthsJiangxi University of Science and Technology Zhejiang Tiantong Electronic Information Materials Research Institute Co. Ltd.

The potentials of rare earth-based nanocomposite alloys have never been realized due to strict microstructural *** to the easy demagnetization it is challenging to increase the soft magnetic phase *** avoid the easy demagnetization,Pr-Fe-B/Alnico magnets were fabricated and reported in this *** content of the Alnico phase is increased from 0 to 25 wt%,while the content of Pr element is reduced to below the sub-stoichiometry of the 2:14:1 main *** maximum magnetic energy product,which is the figure-of-merit for permanent magnets,is increased from 122 kJ/m3for the standard alloy to 146 kJ/m3for the alloy with 15 wt% Alnico which shows a significant improvement considering the fact that the Curie point of the magnet is also increased by～66 *** special microstructure contains distinctly and heterogeneously distributed 2:14:1 and Alnico *** dimensions of neither the 2:14:1 nor the Alnico phases meet the dimensional requirements of the nanocomposite magnets,but still the smooth demagnetization curves are noted for the *** behavior of effective anisotropy,the performance of the magnets in applied magnetic field and the magnetic interactions among the various constituent grains were quantitatively studied by reversible susceptibility,irreversible susceptibility and re coil loop *** study may provide some guiding principles for the development of nanocomposite magnetic alloys with excellent magnetic properties by using much less RE elements.

关键词： Composite alloys High performance magnets Magnetic properties Alnico alloys Rare earth magnets

Effect of La-Y co-substitution on magnetic properties and microstructure of NdFeB alloy ribbons

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2022年第12期40卷 1894-1898,I0003页

作者： Chuanjia Zhao Qingzheng Jiang sajjad ur rehman Xiang Li Youwei Chen Jie Song Zhenchen Zhong Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices&College of Rare Earths Jiangxi University of Science and TechnologyGanzhou 341000China Fujian Key Laboratory for Rare Earth Functional Materials Longyan 366300China

Committed to obtaining cost-effective NdFeB based permanent magnets,Nd_(27-x)La_(3)Y_(x)Fe_(bal)Al_(0.1)Cu_(0.1)B_(1)(x=0-3)alloys were fabricated to detect the magnetic properties and *** x=1.8,coercivity of 1004 kA/m and the magnetic remanence of 0.75 T are obtained,which are close to those of the original Nd_(30)Fe_(bal)A_(l0.1)Cu_(0.1)B_(1)alloy *** temperature coefficient of coercivity(β)and the temperature coefficient of remanence(α)of the LaY-substituted alloys are better than those of the original *** research results manifest that La is mainly distributed in the grain boundary phases and plays the role of refining the main grains,optimizing the grain boundary phases and improving the wettability between the main phases and the grain boundary phases,while Y tends to enrich in the main phases and enhances the short-range exchange coupling.

关键词： Magnetic properties Microstructure Alloy ribbons Main phase Exchange coupling Rare earths

Enhancement of terbium efficiency by gallium and copper co-doping in(Pr,Nd)-Fe-B sintered magnets

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2023年第4期41卷 572-577页

作者： Qingfang Huang Qingzheng Jiang Yao Shi sajjad ur rehman Xing Wei Ruoshu Wang Yongjian Zhang Deqin Xu Dakun Chen Zhenchen Zhong Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices&College of Rare Earth Jiangxi University of Science and TechnologyGanzhou 341000China Institute of Rare Earth Magnetic Material Xiamen Tungsten Co.Ltd.Xiamen 361010China Fujian Key Laboratory for Rare Earth Functional Materials Longyan 366300China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China

It is well known that Tb substitution for(Pr,Nd)in(Pr,Nd)-Fe-B based sintered magnetic materials is an effective way to increase intrinsic coercivity,but it is not quite clear whether the increment depends on the different matrix phases with various doping ingredient or not,which is essential to develop high quality magnets with high coercivity more efficiently and effectively with economic consumption of expensive Tb and other costly heavy rare *** this paper,we investigated the efficiency of Tb substitution for magnetic property in(Pr,Nd)-Fe-B sintered permanent magnets by co-doping Ga and Cu *** is shown that Ga and Cu co-doping can effectively improve the efficiency of Tb substitution to increase the thermal stability and the *** intrinsic coercivity increases up to 549 and 987 kA/m respectively by 1.5 wt%and 3.0 wt%Tb substitution in Ga and Cu co-doped magnets while the intrinsic coercivity increases up to only 334 and 613 kA/m respectively by the same amounts of Tb substitution in non-Ga and low-Cu *** other words,it demonstrates that there is about 329-366 kA/m linear equivalent enhancement of intrinsic coercivity by 1.0 wt%Tb substitution for(Pr,Nd)in Ga and Cu co-doped *** temperature coefficients of both intrinsic coercivityβand remanenceαat 20-150℃by 3.0 wt%Tb substitution for the magnets with Ga and Cu co-doping are-0.47%/K and-0.109%/K respectively,and in contrast those values are-0.52%/K and 0.116%/K respectively for the non-Ga and low-Cu *** is the principal reason for more efficient enhancement of magnetic property by Tb substitution in the Ga and Cu co-doped magnets in which Tb atoms are expelled from triple junction phases(TJPs)to penetrate into the grain boundary phases(GB phases)and thus modify the grain *** is prospected that the efficiency of Tb substitution would rely on different matrix phases with various doping constituents.

关键词： (Pr Nd)-Fe-B magnet Magnetic properties Microstructure Efficiency of Tb substitution Ga and Cu co-doping Rare earths

Extraordinary simultaneous enhancement of the coercivity and remanence of dual alloy HRE-free Nd-Fe-B sintered magnets by post-sinter annealing

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第11期106卷 236-242页

作者： Qingfang Huang Qingzheng Jiang Jifan Hu sajjad ur rehman Gang Fu Qichen Quan Jixiang Huang Deqin Xu Dakun Chen Zhenchen Zhong Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices&College of Rare Earths Jiangxi University of Science and TechnologyGanzhou 341000China Fujian Key Laboratory for Rare Earth Functional Materials Longyan 366300China School of Materials Science and Engineering Taiyuan University of Science and TechnologyTaiyuan 030024China

Post-sinter annealing process plays an important role in the microstructures and magnetic properties of the Nd-Fe-B sintered *** this paper,systematically investigated are the magnetic properties and microstructures of the as-sintered and post-sinter annealed Nd-Fe-B magnets with Pr-Fe-Ga boundary *** choice consecutive annealing methods are adopted at high and low temperatures,namely the 1 st annealing at 880℃ for 2 h and then the 2^(nd) annealing at 440℃ for 3 *** is exceptional to find out that both the remanence and coercivity are improved after 2^(nd) annealing process for this type of *** coercivity is hugely increased from 10.09 kOe for the as-sintered sample to 17.19 kOe for the 2^(nd) annealed magnet,with a significant increment of 70.37%in *** extraordinary magnetic properties of B_(r)=14.44 kGs,H_(cj)=17.19 kOe and(BH)_(max)=51.08 MGOe are obtained for the designated Nd-Fe-B sintered magnets without heavy rare earth(HRE)elements manufactured by dual alloy *** Curie temperature is monotonically decreased from 634 K to 602 K while the c-axis alignment degree is optimized after *** observation and analysis indicate that the elemental distribution patterns are altered after the 2^(nd) *** diffusion of the aggregate(Pr,Nd,Cu,Ga)-rich phase from triple junctions into the grain boundary regions is ascribed to the formation of thin and continuous grain boundary layer,which is critical to improve the microstructures and magnetic properties.

关键词： Nd-Fe-B sintered magnets HRE-free Dual alloy method Post-sinter annealing Magnetic properties

Optimization of core-shell structure distribution in sintered Nd-Fe-B magnets by titanium addition

在线全文

学校读者我要写书评

暂无评论

Journal of Rare Earths 2023年第7期41卷 1068-1072,I0004页

作者： Shuwei Zhong Munan Yang sajjad ur rehman Sangen Luo Longgui Li Chao Li Jiajie Li Shuhua Xiong Ihor Bulyk Bin Yang Faculty of Materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Key Laboratory of Development and Application of Ionic Rare Earth Resources Ministry of EducationJiangxi University of Science and TechnologyGanzhou 341000China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China National Rare Earth Function Materials Innovation Center Ganzhou 341000China Ganzhou Dongci Rare Earth Co. Ltd.(DMEGC)Ganzhou 341000China Jiangxi Rare Earth Functional Materials Technology Co. Ltd.Ganzhou 341000China

In view of the uneven distribution of the core-shell structure of sintered Nd-Fe-B magnets after grain boundary diffusion,this study proposes to use high-melting-point and reactive element titanium(Ti)as an additive to increase the diffusion channels and to enhance the diffusion of heavy rare earth elements along the grain boundary *** adding Ti element,the diffusion depth and hence the intrinsic coercivity of magnets are increased *** addition of Ti increases the coercivity at two stages:initially from 16.07 to 16.29 kOe by addition effect,and then from 16.29 to 25.16 kOe by facilitating the diffusion of Tb *** formation of TiB_(2) phase improves the periodic arrangement of the crystal structure in the surroundings of the grain boundary phase and enhances its *** improved grain boundary diffusion and better core-shell structure distribution provide a theoretical guidance fo r solving the problem of diffusion depth in bulk magnets.

关键词： Sintered Nd-Fe-B magnets Grain boundary diffusion Core-shell structure TiB_(2)phase Rare earths

Enhanced magnetic properties and improved corrosion performance of nanocrystalline Pr-Nd-Y-Fe-B spark plasma sintered magnets

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第23期58卷 138-144页

作者： Qingzheng Jiang Jie Song Qingfang Huang sajjad ur rehman Lunke He Qingwen Zeng Zhenchen Zhong Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices&Institute for Rare Earth Magnetic Materials and Devices(IREMMD) Jiangxi University of Science and TechnologyGanzhou 341000China Fujian Changting Golden Dragon Rare-Earth Co.Ltd. Longyan 366300China

Recently it is a hot topic to make full use of high abundant Y element in Nd_(2)Fe_(14)B-type permanent *** contrast to Pr and Nd elements,Y shows different metallurgical behaviors during preparation *** this paper,we have explored the magnetic properties,microstructures and corrosion performance of Pr-Nd-Y-Fe-B magnets fabricated by spark plasma sintering(SPS)technique from the ribbons of nanocrystalline and amorphous precursors,*** coercivity and maximum energy product were improved for the magnets prepared from amorphous precursor materials(denoted as SPS-A hereafter)compared with the magnets prepared from crystalline precursor materials(denoted as SPS-C hereafter).Magnetic properties of Jr=0.79 T,Hci=864 k A/m,and(BH)_(max)=102 k J/m^(3)were obtained for SPS-A *** contrast with SPS-C magnets,the magnetic properties of SPS-A magnets are not so sensitive to the preparation conditions,which is quite beneficial to the homogeneity of microstructure and enhancement of coercivity for large-scale production of the designated ***(Pr,Nd,Y)-rich phase was found out in SPS-C *** and Nd elements are rich at grain boundary while Y is distributed uniformly at main phase and grain boundary *** strip grains and equiaxed grains exist in SPS-C and SPS-A magnets,*** enhanced magnetic properties for SPS-A magnets are accredited to the uniform distribution of rare-earth-rich phase and low demagnetization *** is revealed by electrochemical test and dipping test that the corrosion potential is more positive and the corrosion rate is slower for the SPS-A magnets in 3.5 wt.%Na Cl *** work is also expected to shed light on developing the nanocrystalline Pr-Nd-Y-Fe-B SPSed high-performance magnets in industry.

关键词： Pr-Nd-Y-Fe-B magnets Spark plasma sintering(SPS) Magnetic properties Corrosion performance Microstructure and homogeneity

An Efficient Medium Access Control Mechanism for Flying Ad-hoc Networks

在线全文

学校读者我要写书评

暂无评论

Computer Systems Science & Engineering 2021年第7期38卷 47-63页

作者： Muhammad Asghar Khan Fazal Noor Insaf Ullah sajjad ur rehman Shibli Nisar Mohaira Ahmad Department of Electronic Engineering ISRA UniversityIslamabad44000Pakistan Department of Computer Science and Information Systems Islamic University of MadinahMadinah400411Saudi Arabia Hamdard Institute of Engineering&Technology Islamabad44000Pakistan Department of Electrical Engineering Namal InstituteMianwali42200Pakistan Department of Electrical Engineering National University of Sciences and Technology(NUST)Islamabad44000Pakistan

The Flying Ad-hoc Networks(FANETs)is characterized by the transition from a single large Unmanned Aerial Vehicle(UAV)to multiple small UAVs connected in an ad-hoc *** high mobility is the core feature of such networks,they are prone to route breaks within the *** issue of connectivity loss can be coped with,to some extent,by making use of omnidirectional *** modification,however,curtails Quality-of-Service(QoS)requirements of networks in terms of bandwidth,media access delay,coverage and ***,directional antennas have advantages over omnidirectional antennas such as improved transmission range,spatial reuse and high ***,its introduction raises location-dependent issues to the Medium Access Control(MAC)*** calls for an efficient MAC protocol that can cater to new directional antenna models and,at the same time,can counter the constraints associated with the dynamic ***,in this article,we consider a UAV interconnection mechanism that lets the UAVs execute the communication tasks using the directional MAC *** technique is advantageous as compared to the approach of utilizing the MAC protocol using omnidirectional *** scheme is being implemented as a case study for Industry 4.0 inventory and traceability applications in the *** modeling and simulation purposes,we use the Optimized Network Engineering Tool(OPNET)and aim to seek an evaluation with respect to throughput,media access delay,retransmission attempts and data *** results obtained demonstrate the effectiveness of the proposed scheme.

关键词： FANETs QoS Industry 4.0 IEEE 802.11 MAC OPNET mobility models directional antenna

Magnetic-field-driven reverse martensitic transformation with multiple magneto-responsive effects by manipulating magnetic ordering in Fe-doped Co-V-Ga Heusler alloys

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2020年第23期58卷 145-154页

作者： Kai Liu Shengcan Ma Yuxi Zhang Hai Zeng Guang Yu Xiaohua Luo Changcai Chen sajjad ur rehman Yongfeng Hu Zhenchen Zhong Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices/Institute for Rare Earth Magnetic Materials and Devices(IREMMD) Jiangxi University of Science and TechnologyGanzhou 341000China School of Materials Science and Engineering Jiangxi University of Science and TechnologyGanzhou 341000China Canadian Light Source University of SaskatchewanSaskatoonSaskatchewan S7N 2V3Canada

Nowadays,searching for the materials with multiple magneto-functional properties and good mechanical properties is vital in various fields,such as solid-state refrigeration,magnetic actuators,magnetic sensors and intelligent/smart *** this work,the magnetic-field-induced metamagnetic reverse martensitic transformation(MFIRMT)from paramagnetic martensite to ferromagnetic austenite with multiple magneto-responsive effects is realized in Fe-doped Co-V-Ga Heusler alloys by manipulating the magnetic *** martensitic transformation temperature Tmreduces quasi-linearly with increasing *** strikingly contrast with the Fe-free alloys,the magnetization difference(M')across martensitic transformation increases by three orders of magnitude for Fe-doped *** increased M'should be ascribed to the reduction of Tm,almost unchanged Curie temperature of austenite and the increased magnetic moment in the samples with higher *** large M'provides strong driving force to realize the MFIRMT and accordingly multiple magneto-responsive effects,such as magnetocaloric,magnetoresistance and magnetostriction ***,giant Vickers hardness of 518 HV and compressive strength of 1423 MPa are *** magneto-responsive effects with exceptional mechanical properties make these alloys great potential candidates for applications in many fields.

关键词： Magneto-functional properties Mechanical properties Ferromagnetic ordering Reverse martensitic transformation Multiple magneto-responsive effects Co-based Heusler alloys

Large magnetocaloric effect and magnetoresistance in ErNi single crystal

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2021年第27期86卷 56-63页

作者： Xuanwei Zhao Xianming Zheng Xiaohua Luo Fei Gaod Hai Zeng Guang Yu sajjad ur rehman Changcai Chen Shengcan Ma Weijun Ren Zhenchen Zhong Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices College of Rare earthsJiangxi University of Science and TechnologyGanzhou 341000People’s Republic of China Ganzhou Key Laboratory for Rare Earth Magnetic Functional Materials and Physics College of Rare earthsJiangxi University of Science and TechnologyGanzhou 341000People’s Republic of China School of Materials Science and Engineering Faculty of Materials Metallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou 341000People’s Republic of China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016People’s Republic of China Key Laboratory of Electromagnetic Processing of Materials Northeastern UniversityShenyang110819People’s Republic of China

The magnetic properties,magnetocaloric effect and magnetoresistance in Er Ni single crystal have been investigated in *** decreasing temperature,Er Ni single crystal undergoes two successive magnetic transitions:a paramagnetic to ferromagnetic transition at T_(C)=11 K and a spin-reorientation transition at TS_(R)=5 ***,a sharp field-induced metamagnetic transition is observed below the T_(C)along the a *** Ni single crystal possesses a giant magnetocaloric effect around T_(C).The maximum magnetic entropy change is-36.1 J(kg K)^(-1)along the a axis under the field change of 0-50 k *** particular,the rotating magnetocaloric effect in Er Ni single crystal reaches its maximum under a relatively low field,and the maximum rotating entropy change with a value of 9.3 J(kg K)^(-1)is obtained by rotating the applied field from the[011]to[100]directions under 13 k *** results suggest that Er Ni could be a promising candidate for magnetic refrigeration working at liquid-helium temperature ***,a complicated transport behavior is uncovered in Er Ni single crystal,which is attributed to the complex magnetic states and magnetic polaronic *** positive and negative magnetoresistance are observed.A considerable large magnetoresistance with the value of-34.5%is acquired at 8 K under50 k Oe when the field is along the[100]direction.

关键词： Rare-earth transition-metal intermetallics Magnetic refrigeration Magnetocaloric effect Magnetocrystalline anisotropy Magnetoresistance