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Journal of rare earths 2024年第10期42卷 1937-1942页

作者： Weijun Zhao Meng Zhang Liyan Xue Kaixian Wang Fan Yang Jiuping Zhong Heng Chen School of materials Sun Yat-sen University Xiamen Institute of rare earth materials Haixi InstituteChinese Academy of Sciences Xiamen Key Laboratory of rare earth Photoelectric functional materials Xiamen Institute of Rare Earth MaterialsHaixi InstituteChinese Academy of Sciences Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China Advanced Energy Science and Technology Guangdong Laboratory Sichuan Jcc rare earth Metals New material Co. Ltd.

The electrical properties of high-entropy ceramics（HECs） have been extensively studied in recent years due to their unique structural characteristics and fascinating functional properties induced by entropy *** high-entropy(Sm0.2Eu0.2Gd0.2Ho0.2Yb0.2)CrO3（HE-RECrO3） nanofibers were prepared by electro *** work demonstrates that HE-RECrO3nanofibe rs were successfully synthesized at a low temperature（800℃）,which is approximately 400 ℃ lower than the temperatures at which chromate ceramics were synthesized via the sol-gel method and the solid-state reaction *** resistivity of HE-RECrO3nanofibers decreases exponentially with increasing temperature from 25 to600℃.The logarithm of the resistivity is linearly related to the inverse of the temperature,confirming the negative temperature coefficient property of *** B25/50value of the HERECrO3nanofibers reaches 4072 *** conclusion,HE-RECrO3nanofibers are expected to be potential candidates for negative-temperature-coefficient（NTC） thermistors.

关键词： Ceramic fiber materials High-entropy ceramics Negative temperature coefficient thermistors rare earths

Effect of phase transition during roasting of Mountain Pass rare earth concentrate on leaching efficiency of rare earths

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Journal of rare earths 2024年第2期42卷 409-414,I0006页

作者： Yanyan Zhao Xu Sun Deliang Meng Xiangsheng Liu Qiang Zhong Zongyu Feng National Engineering research Center for rare earth Grirem Advanced Materials Co.Ltd.Beijing0088China rare earth functional materials(Xiong'an)Innovation Center Co. Ltd.Xiongan071700China General research Institute for Nonferrous Metals Beijing100088China

To find a greener and more economical approach for treating the Mountain Pass rare earth concentrate(MPREC),a novel "Combination Method",including the processes of oxidizing roasting,HCI leaching and sulfuric acid roasting,is proposed in this *** this paper,the effect of phase transition behavior in hydrochloric acid leaching during oxidative roasting at 450-600℃ was *** roasting,the bastnasite in MPREC is decomposed into CeLa_(2)O_(3)F_(3) and(Ce_(0.33),La_(0.33),Ca_(0.33))O_(1.5).As the CeLa_(2)O_(3)F_(3) phase has the fluorine-fixation effect,the generated CeLa_(2)O_(3)F_(3) phase can not be dissolved by HCI after roasting at 500 and 550℃,but it can be decomposed by HCI after roasting at over 600℃,resulting in the improvement of the leaching rate of total F *** maximum leaching efficiency of rare earth elements(REEs) can reach 70.32 wt% at the roasting temperature of 550℃.After roasting at over 600℃,some F^-ions in the solution combined with RE^(3+) to form REF_(3) precipitate and enter the leaching residue,and the others are in the form of [CeF_(3)]^+ in the leaching solution during leaching,therefore,the leaching efficiency of non-ce rium REEs decreases while that of cerium element *** work provides basic research for optimizing the actual production process of MPREC.

关键词： Mountain pass rare earth mine Roasting Phase change rare earths

Hydrogen storage thermodynamics and kinetics of as-cast Ce-Mg-Ni-based alloy

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Journal of Iron and Steel research International 2024年第3期31卷 752-766页

作者： Yan Qi Xin Zhang Jun Li Dong-liang Zhao Shi-hai Guo Yang-huan Zhang Department of functional material research Central Iron and Steel Research InstituteBeijing 100081China China rare earth New material(Weishan)Co..Ltd. Jining 277600ShandongChina Collaborative Innovation Center of Integrated Exploitation of Bayan Obo Multi-Metal Resources Inner Mongolia University of Science and TechnologyBaotou 014010Inner MongoliaChina

The reaction kinetics of alloys based on magnesium are known to be greatly improved by the partial substitution of Mg with rare earths and transition metals,particularly *** enhanced superficial hydrogen dissociation rate,the weakened Mg-H bond and the lower activation energy following element replacement are thought to be related to the better *** experimental alloys Ce5Mg_(95-x)Ni_(x)(x=5,10,15)were smelted by the vacuum induction *** phase transformation and structural evolution of experimental alloys before and after reaction with hydrogen were char-acterized by X-ray diffraction,scanning electron microscopy and transmission electron *** cast specimens contain CeMg_(12),Mg and Mg_(2)Ni phases,and the increase in Ni content results in an obvious growth of Mg_(2)Ni *** isothermal and non-isothermal hydrogenation and dehydrogenation kinetics of the experimental specimens were investi-gated using the Sievert apparatus,differential scanning calorimetry and thermal gravimetric *** activation energy may be calculated using the Arrhenius and Kissinger *** experimental alloys have been shown to have good activation properties,with a reversible hydriding and dehydriding capacities of around 5.0 wt.%in the first *** initial dehydrogenation temperature of MgH_(2) decreases from 557.5 to 537.7 K with changing Ni content from 5 to 15 at.%.The dehydrogenation activation energy also reduces from 77.09 to 62.96 kJ/mol,which explains the improved hydrogen storage performance caused by Ni *** can be shown that the impact of Ni on the decomposition enthalpy of MgH_(2) is quite modest,with the absolute enthalpy(ΔHr)only decreasing from 78.48 to 76.15 kJ/mol.

关键词： Mg-based alloy Ni content Hydrogen storage kinetics Thermodynamic property Activation energy

Simultaneously enhancing coercivity and remanence of hot-deformed Nd-Fe-B magnets by flake copper powder assisted DyF_(3) interflake addition

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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

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Journal of rare earths 2024年第9期42卷 1717-1723,I0003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 TechnologyGanzhou341000China Zhejiang Tiantong Electronic Information materials research Institute Co. Ltd.Haining314400China

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/m^(3) for the standard alloy to 146 kJ/m^(3) for 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

Damping capacity of Fe_(83)Ga_(17) magnetostrictive alloy under magnetic field

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rare Metals 2024年第1期43卷 402-409页

作者： Shao-Wen Yan Xing Mu Bing-Jie Liu Li-Hong Xu Shi-Hai Guo Yan Qi Hong-Ping Zhang Department of functional material research Central Iron and Steel Research InstituteBeijing 100081China

The damping performance of Fe_(83)Ga_(17) alloys has been investigated in the static magnetic field (H). The results demonstrate that the damping peak value can be adjusted between 0.020 and 0.085 under the magnetic f... 详细信息

关键词： alloy magnetic alloys

A novel Ce_(0.485)Zr_(0.485)Y_(0.03)O_(2) composite oxide with surface doping of Y and its application in Pd-only three-way catalyst

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rare Metals 2024年第2期43卷 749-757页

作者： Zheng Zhao Wei-Xin Zhao Yong-Qi Zhang Mei-Sheng Cui Yong-Ke Hou Dong-Ming Chen Juan-Yu Yang Zong-Yu Feng Xiao-Wei Huang National Engineering research Center for rare earth Grirem Advanced Materials Co.Ltd.GRINM Group Corporation LimitedBeijing100088China Griem Hi-Tech Co.Ltd. Langfang065000China rare earth functional materials(Xiong’an)Innovation Venter Co.Ltd. Baoding071700China

The ceria-zirconia compound oxide-supported noble metal Pd(Pd@CZ)is widely used in three-way ***,the surface structure of CZ plays an important role in catalytic activity of ***,how to regulate the surface structure of CZ and clarify the structure–activity relationship is still a *** this paper,a strategy is proposed to develop high activity Pd@CZ nanocatalysts by tuning Y doping sites in *** precipitate-deposition method is developed to prepare the novel Ce_(0.485)Zr_(0.485)Y_(0.03)O_(2) composite with surface doping of Y(CZ-Y-S).In addition,the Pd@CZ-Y-S(Pd supported on CZ-Y-S)exhibits superior catalytic activity for HC,CO,and NO oxide,wherein,for CO and C_(3)H_(6) oxidation,the low-temperature activity of Pd@CZ-Y-S is still 20%higher than that of Pd@CZ-Y-B(Y bulk doping)and commercial Pd@CZ after 1000℃/4 h *** effect mechanism is further studied by density functional theory(DFT)*** with Pd@CZ-Y-B,Pd@CZ-Y-S shows the lower CO oxide reaction energy barriers due to the weaker adsorption strength of *** Y surface doping strategy could provide valuable insights for the development of highly efficient Pd@CZ catalyst with extensive applications.

关键词： rare earth Ceria-zirconia-supported Pd Surface doping Experiment and theory Catalytic application

High cerium content(Nd-Pr-Ce)_(2)Fe_(14)B melt-spun ribbons with high coercivity

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Journal of rare earths 2024年第4期42卷 690-695页

作者： Yujiang Zhong Junming Wang Zikai Yuan Ruijin Liu Minggang Zhu Zhe Liu Xin Chen Wei Li Zhaohui Guo Division of functional materials Central Iron and Steel Research InstituteBeijing100081China Ningbo Jinji Strong Magnetic material Co. Ltd.Ningbo315172China Jiangxi Jiangwu rare Metal New material Co. Ltd.Nanchang330013China

The effects of wheel speeds on the magnetic properties and microstructures of[(Nd,Pr)_(1-x)Ce_(x)]-Fe-B meltspun ribbons were *** to melt-spun ribbons with low cerium(Ce)content(x=0.2),amorphous formation can be suppressed at high wheel speed in the ribbons with a relatively high Ce content(x=0.8),and with the increase of the wheel speed,the magnetic properties of the ribbons with high Ce content raise *** high wheel speed,the coercivity mechanism of melt-spun ribbons is mainly pinning field,and the high wheel speed introduces a large number of defects into the matrix as pinning ***,ribbons with high Ce content form a fine and uniform grain structure,so the grain boundary area enlarges,which further hinders the movement of domain *** combined effects of the above factors enable ribbons with high Ce content to have excellent magnetic properties(Hcj=0.977 T,Mr=64 m^(2) A/kg)at the wheel speed of 35 m/s.

关键词： Wheel speed Cecontent Microstructure Magnetic properties rare earths

Oxygen self-doping pyrolyzed polyacrylic acid as sulfur host with physical/chemical adsorption dual function for lithium-sulfur batteries

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Chinese Chemical Letters 2024年第7期35卷 473-479页

作者： Yan Wang Huixin Chen Fuda Yu Shanyue Wei Jinhui Song Qianfeng He Yiming Xie Miaoliang Huang Canzhong Lu Engineering research Center of Environment-Friendly functional materials Ministry of EducationInstitute of Materials Physical ChemistryHuaqiao UniversityXiamen 361021China CAS Key Laboratory of Design and Assembly of functional Nanostructures and Fujian Provincial Key Laboratory of NanomaterialsFujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou 350002China Xiamen Key Laboratory of rare earth Photoelectric functional materials Xiamen Institute of Rare Earth MaterialsHaixi InstitutesChinese Academy of SciencesXiamen 361021China

Lithium-sulfur(Li-S)batteries with high theoretical capacity and energy density need to solve problems such as the high decomposition energy barrier of Li_(2)S and large volume change of sulfur in the charging process caused by the shuttle effect before practical ***,a green synthesis method is used to prepare polyacrylic acid(PAA)superabsorbent material,and then the pyrolyzed PAA(P/PAA)material is obtained as the positive electrode of Li-S *** functional calculation reveals that the oxygen self-doping pyrolyzed polyacrylic acid(P/PAA)delivered stronger binding energy toward Li2S species in carbonyl C=O than that of graphite powder(GP)which are-1.58 eV and-1.02 eV,*** with the distribution of relaxation time analysis and the in-situ electrochemical impedance approach,it is further demonstrated that the designed P/PAA as sulfur host plays a physical/chemical adsorption dual function in maintaining the stability and rate performance of *** an initial discharge capacity of 1258 mAh/g at 0.1 C and a minimal capacity decline of 0.05%per cycle even after 800 cycles at 0.5 C,the produced cathode demonstrated outstanding electrochemical *** average Coulombic efficiency is nearly 100%.The P/PAA electrodes may typically retain 96%of their capacity while declining on average only 0.033%per cycle after 130 cycles at 3 *** effort provides a new method for the future development of heteroatomic self-doping superabsorbent with promising adsorption properties for polysulfides as cathode materials of Li-S batteries.

关键词： Polyacrylic acid Oxygen self-doping Green synthetic Pore mesh polymer cathodes Lithium-sulfur batteries

Circularly polarized luminescence switch based on a photochromic europium(Ⅲ) helicate derived coordination polymer

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Chinese Chemical Letters 2024年第2期35卷 272-277页

作者： Mei Li Yanyan Zhou Jingya Li Wenru Huang Zhiwei Yao Yuying Li Ting Gao Pengfei Yan Hongfeng Li Key Laboratory of functional Inorganic material Chemistry Ministry of EducationSchool of Chemistry and Materials ScienceHeilongjiang UniversityHarbin 150080China State Key Laboratory of Baiyunobo rare earth Resource researches and Comprehensive Utilization Institution Baotou 014030China

Chiroptical switches based on circularly polarized luminescence(CPL)have shown the promising applications in advanced information ***,a pair of lanthanide coordination polymer enantiomers[Eu_(2)(L^(R))_(3)(BTFPO)_(2)]_(n) and[Eu_(2)(L^(S))_(3)(BTFPO)_(2)]_(n) with light-regulated CPL property are designed,which are assembled by a chiral binuclear triple-stranded Eu^(3+) helicates[Eu_(2)(L^(R/S))_(3)]coordinated with two photochromic triphenylphosphine oxides(BTFPO).Upon the alternative UV and 526 nm light irradiation,the complexes show the reversible photochromism,PL and CPL ***,the luminescence dissymmetry factor,g lum of ^(5)D_(0)→^(7)F_(1)(591 nm)transition shows an obvious increase from 0.19 to 0.29 before and after 275 nm light ***,the emission from Eu^(3+) center is not completely quenched in closed-ring state due to the low photocyclization(Ф_(o-c))quantum yield of the *** partial maintenance of emissive intensity is of essential importance for the monitor of CPL *** importantly,the CPL photo-switching property of the complexes in solid hybrid film is maintained,and still displays the enhanced CPL emission in photostationary ***,the potential applications of the doping film in logic gate and anti-counterfeiting were investigated.

关键词： Chiroptical switches Coordination polymer CPL Anti-counterfeiting Logic gate