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Journal of Rare Earths 2021年第6期39卷 682-688,I0003页

作者： Weiqiang Liu yi Li Dan Wu Ming Yue Zhanjia Wang Shanshun Zha Youhao Liu xiaofei yi yihui Du Key Lab of Advanced Functional Materials Ministry of EducationCollege of Materials Science and EngineeringBeijing University of TechnologyBeijing 100124China State Key Laboratory of Rare Earth Permanent Magnetic Materials.Hefei 231500 China Earth-Panda Advanced Magnetic Materials Co. Ltd.Hefei 231500China

The grain boundary diffusion(GBD) technology was used to prepare high performance Nd-Fe-B sintered magnets by NdH3 and TbH3 nanoparticle *** factors affecting the coercivity of GBD magnets include distribution of rare earth rich grain boundary phase and substitution of the heavy rare *** 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 *** 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.

关键词： Nd-Fe-B sintered magnet Heavy rare earth Coercivity Grain boundary diffusion Core-shell structure Magnetic domain reversal

Correlation of mechanical anisotropy with fine grain strengthening for Sm_(2)Co_(17)-type sintered permanent magnets

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Journal of Rare Earths 2022年第10期40卷 1584-1591页

作者： Lei Wang Chao Wang Qiangfeng Li Youhao Liu yikun Fang xiaofei yi Wei Li Division of Functional Materials Research Central Iron and Steel Research InstituteBejing 100081China State Key Laboratory of Rare Earth Permanent Magnetic Materials Hefei 231500China

The as-solution-treated Sm_(2)Co_(17)-type magnets exhibiting a single 1:7 H phase with different average grain sizes(D) were *** of bending strength(R_(bb))and compressive strength(R_(mc)) of the magnets were ***,the R_(bb) increases from 86 to 173 MPa with D decreasing from~52 to~18 μm for group c//h *** 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 *** 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 *** 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.

关键词： Sm_(2)Co_(17)-type permanent magnets Grain refinement Bending strength Compressive strength Anisotropy Rare earths

Improvement of coercivity and thermal stability of Nd-Fe-B sintered magnets by intergranular addition of Tb80Fe20 alloy

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Journal of Rare Earths 2022年第12期40卷 1899-1904,I0003页

作者： Ze Duan Haicheng Xuan Jincai Su Jingwu Chen xiaofei yi Youhao Liu Peide Han College of Materials Science and Engineering Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of Rare Earth Permanent Magnet Materials Hefei 231500China

To improve the coercivity and temperature stability of Nd-Fe-B sintered magnets for high-temperature applications,the eutectic Tb_(80)Fe_(20)(wt%)alloy powders were added into the Nd-Fe-B sintered magnets by intergranular method to enhance the coercivity(H_(cj))and thermal *** micro structure,magnetic properties and thermal stability of the Nd-Fe-B magnets with different Tb_(80)Fe_(20)contents were *** experimental results demonstrate that the coercivity(H_(cj))of the sintered Nd-Fe-B magnet is significantly enhanced from 14.12 to 27.78 kOe,and the remanence(Br)decreases not obviously by introducing 4 wt%Tb_(80)Fe_(20)***,the reversible tempe rature coefficients of coercivity(β)and remanence(α)of the Nd-Fe-B magnets are increased from-0.5634%/℃to-0.4506%/℃and-0.1276%/℃to-0.1199%/℃at 20-170℃,*** Curie temperature(TC)of the Nd-Fe-B magnet is slightly enhanced with the increase of Tb_(80)Fe_(20)***,the irreversible flux magnetic loss(hirr)is obviously reduced as Tb80Fe20addition *** analysis of the microstructure reveals that a modified microstructure,*** and continuous RE-rich grain boundary layer,is acquired in the sintered magnets by introducing Tb_(80)Fe_(20)*** associated mechanisms on improved coercivity and thermal stability were comprehensively researched.

关键词： Tb80Fe20 alloy Coercivity Nd-Fe-B sintered magnet Thermal stability Rare earths

Corrosion resistance and mechanical properties of (Ho,Nd)FeB magnets

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Journal of Rare Earths 2021年第11期39卷 1409-1414,I0004页

作者： Yujie Cao Youhao Liu Pengjie Zhang Guangqing Xu Jiaqin Liu Jingwu Chen xiaofei yi Yucheng Wu School of Materials Science and Engineering.Hefei University of Technology Hefei 230009China State Key Laboratory of Rare Earth Permanent Magnet Materials Hefei 231500China BGRIMM Magnetic Materials and Technology(Fu Yang)Co. Ltd.Fuyang 236000China Key Laboratory of Advanced Functional Materials and Devices of Anhui Province Hefei 230009China Institute of Industry and Equipment Technology Hefei University of TechnologyHefei 230009China

(Ho,Nd)FeB magnets with different Ho contents were prepared by Ho substitution for part of Nd during the casting *** of Ho contents on the corrosion resistance and mechanical properties of(Ho,Nd)FeB magnets were analyzed by a highly accelerated aging tester,an electrochemical workstation,a microhardness tester,a bending tester,a scanning electron microscope and an X-ray *** show that the addition of Ho can change the main phase structure,optimize the distribution of rare-earth rich(RE-rich) phases in grain boundary,and improve the corrosion resistance and mechanical properties of NdFeB *** the content of Ho increases from 0 to 21.0 wt%,the weight loss of magnets decreases from 2.672 to 0.933 mg/cm^(2),and the microhardness and bending strength increase from 528.74 HV and 374.92 MPa to 633.84 HV and 459.80 MPa,respectively.

关键词： (Ho Nd)FeB magnets Corrosion resistance Mechanical property Microstructure Rare earths

Study on preparation and properties of CeO_2/epoxy resin composite coating on sintered NdFeB magnet

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Journal of Rare Earths 2018年第5期36卷 544-551页

作者： Pengjie Zhang Minggang Zhu Wei Li Guangqing Xu Xiulian Huang xiaofei yi Jingwu Chen Yucheng Wu School of Materials Science and Engineering Hefei University of Technology Hefei 230009 China Central 1ran and Steel Research institute Beijing 100081 China State Key Laboratory of Rare Earth Permanent Magnet Materials (Earth-Panda Advance Magnetic Material Co. Ltd.) Hefei 231500 China School of Mechanical Engineering Hefei University of Technology Hefei 230009 China

The CeO2/epoxy resin composite coating was deposited on NdFeB substrate by cathode electrophoresis method for enhancing the anticorrosion and anti-wear performances. The morphologies and structures were characterized by a scanning electron microscope and an X-ray diffractometer. The micro hardness of the composite coating was evaluated by a microhardness tester. The corrosive behaviors of the coatings were studied by potentiodynamic polarization curve, electrochemical impedance spectroscopy and neutral salt spray tests. The concentration of CeO2 nanoparticles（NPs） in the electrophoresis bath was optimized according to the coating structures and anticorrosion performances. The results show that CeO2 NPs can enhance the microhardness of the composite coatings. Moreover, the nanoparticles disperse uniformly in the matrix when the concentration is lower than 30 g/L. The microhardness of CeO2/epoxy resin（30 g/L） composite coating is about 63% higher than that of the blank epoxy resin coating. And the NSS time of the CeO2/epoxy resin（30 g/L） composite coated sample can reach 1248 ***, the composite coatings possess no deteriorate influence on the magnetic properties of NdFeB substrates. The anticorrosion mechanisms of the composite coatings on the NdFeB substrate are deeply discussed.

关键词： Sintered NdFeB Epoxy resin CeO2 nanoparticle Corrosion resistance Rare earths

Calcium hydride reduced high-quality Nd-Fe-B powder from Nd-Fe-B sintered magnet sludge

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Journal of Rare Earths 2022年第12期40卷 1905-1912,I0004页

作者： Haibo Xu Qingmei Lu Liying Cong Haowen Tian Weiqiang Liu Youhao Liu Yunqiao Wang Jingwu chen xiaofei yi Ming Yue Key Lab of Advanced Functional Materials Ministry of EducationFaculty of Materials and ManufacturingBeijing University of TechnologyBeijing 100124China State Key Laboratory of Rare Earth Permanent Magnetic Materials Hefei 231500China Earth–Panda Advanced Magnetic Materials Co. Ltd.Hefei 231500China Beijing Zhong Ke San Huan Research Beijing 102200China

The structural and magnetic properties were studied for recycling Nd-Fe-B powders from Nd-Fe-B sintered magnets sludge via reduction diffusion(RD)with calcium hydride(CaH_(2))*** comparison,traditional reducing agent calcium granules were applied to prepare recycled Nd-Fe-B *** particle size and better size distribution as well as lower impurity content are achieved by using CaH_(2)instead of *** detail,the average particle size of the recycled Nd-Fe-B powder is reduced from 4.66 to 3.43μm,and the bimodal distribution ***,the residual calcium content and oxygen content are reduced to about 0.080 wt%and 0.32 wt%.As a consequence,the roomtemperature magnetization of the CaH_(2)-recycled Nd-Fe-B powder is increased to 146.30 emu/g,6.8%and 33%,respectively,higher than that of Ca-reduced powder and the initial *** analysis indicates that CaH_(2)is able to reduce the sludge at lower tempe rature to fabricate well-dispersed,unifo rm recycled powder with high magnetization arising from a combination factors of its low melting point,low thermodynamic behavior,and the release of hydrogen during the reaction.

关键词： Recycled Nd-Fe-B powders Magnetic properties Microstructure Reducing agent Reduction diffusion Rare earths

Effects of bias voltage on coating structures and anticorrosion performances of PA-PVD Al coated NdFeB magnets

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Journal of Rare Earths 2021年第6期39卷 703-711,I0004页

作者： Yujie Cao Pengjie Zhang Wei Sun Weifeng Zhang Hanzhong Wei Jiquan Wang Bingshan Li xiaofei yi Guangqing Xu Yucheng Wu School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China State Key Laboratory of Rare Earth Permanent Magnet Materials Earth-Panda Advance Magnetic Material Co.Ltd.Hefei 231500China BGRIMM Magnetic Materials and Technology(Fu Yang)Co. Ltd.Fuyang 236000China BGRIMM Technology Group Co. Ltd.Beijing 102600China

Al coated NdFeB magnets were prepared by plasma-assisted-physical-vapor-deposition(PA-PVD)method fo r enhancing the corro sion *** rphologies and structures were characterized by an Xray diffractometer and a scanning electron *** behaviors of the samples with different bias voltages were studied by electrochemical methods and neutral salt spray test,*** bias voltage during the deposition process was optimized according to the coating structures and corrosion *** density and flatness of Al coating increase with increasing the bias voltage,and at the same time the thickness *** coating density and thickness turn to be stable when bias voltage is 1800 ***,the corrosion behaviors of PA-PVD Al coatings in different media,such as NaOH,HNO_(3) and NaCl solutions,were *** self-corrosion potentials(E_(corr)) of PA-PVD Al coatings almost keep constant in NaOH and HNO_(3) solutions with diffe rent ***,the self-corrosion current densities(J_(corr)) decrease with the increasing concentrations.E_(corr) shifts to negative potential and J_(corr)decreases gradually when increasing the concentration of NaCl *** corrosion mechanisms of Al coatings are discussed based on the corrosion behaviors in different media.

关键词： Physical vapor deposition Plasma assistance Al coating Sintered NdFeB Corrosion behavior Rare earths

Two birds with one stone:Functionalized wood composites for efficient photocatalytic hydrogen production and solar water evaporation

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Chinese Chemical Letters 2024年第9期35卷 392-397页

作者： Deqi Fan yicheng Tang Yemei Liao Yan Mi yi Lu xiaofei Yang College of Chemical Engineering Nanjing Forestry UniversityNanjing 210037China Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources International Innovation Center for Forest Chemicals and MaterialsCollege of ScienceNanjing Forestry UniversityNanjing 210037China Key Laboratory of Chemistry and Engineering of Forest Products State Ethnic Affairs CommissionGuangxi Key Laboratory of Chemistry and Engineering of Forest ProductsGuangxi Minzu UniversityNanning 530006China

Maximizing solar energy utilization is a persistent challenge in photo catalysis,which determines sustainable solar-driven photocatalytic *** thermal-coupled photo catalysis is considered as a promising solution to tackle the issues of sustainable energy scarcity and environmental pollution by harvesting the full-spectrum solar ***,a highly efficient photo thermal-accelerated photo catalysis system is elaborately established,in which the assembled carbonized stick/Nb_(2)C MXene evaporator can heat water into vapor and the integrated g-C_(3)N_(4)photocatalyst further enables high-efficiency photocatalytic hydrogen *** designed hyperboloid wood-based architecture possesses a multiphase interface of water steam/catalyst/hydrogen to reduce the transport resistance of hydrogen gas in liquid and ultimately maximize the output of hydrogen ***,this coupled photothermal-photocatalytic system achieves a stable solar evaporation rate of 2.16 kg m^(-1)h^(-1)under one sun irradiation and highly efficient hydrogen-evolving rate of 3096μmol g^(-1)h^(-1).This work paves a way to explore the improvement of photocatalytic hydrogen production by synergic photothermal effect for potential applications in renewable solar energy utilization and hydrogen production.

关键词： Photocatalysis Photothermal Nb_(2)C MXene g-C_(3)N_(4) Wood

A facile process to optimize performance of regenerated Nd-Fe-B sintered magnets:Chemo-selective dissolution washing

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Journal of Rare Earths 2023年第12期41卷 1976-1983,I0006页

作者： Haibo Xu Qingmei Lu Lichao Yu Liying Cong Haowen Tian Weiqiang Liu Youhao Liu Yunqiao Wang Jingwu Chen xiaofei yi Qiong Wu Ming Yue College of Materials Science&Engineering Key Lab of Advanced Functional MaterialsBeijing University of TechnologyBeijing100124China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou341119China State Key Laboratory of Rare Earth Permanent Magnetic Materials Hefei231500China Earth-Panda Advanced Magnetic Materials Co. Ltd.Hefei231500China Beijing Zhong Ke San Huan Research Beijing102200China

In this work,the recycled Nd-Fe-B powders and regenerated Nd-Fe-B sintered magnets with low impurity content were successfully prepared from Nd-Fe-B magnet sludge via reduction diffusion(RD)method followed by a chemo-selective dissolution washing proc *** chemo-selective dissolution effect of various solution(deionized water,dilute acetic acid solution,NH_(4)Cl-methanol solution) was evaluated by impurity content and magnetic properties of the recycled Nd-Fe-B *** NH_(4)Cl-methanol solution can selectively remove impurities with minimal damage to the magnetic ***,the optimal NH_(4)Cl concentration and liquid-to-solid ratio were *** a consequence,the contents of Ca,O,and H after optimal washing process are reduced to 0.07 wt%,0.31 wt% and 0.22 wt%,***,M_(3) Tis increased to 146.72 emu/g,which is 33% higher than that of the initial ***,the regenerated Nd-Fe-B sintered magnets with properties of B_(r)=11.66 kG,H_(cj)=16.49 kOe,and(BH)_(m)=31.78 MGOe were successfully prepared by mixing with 40 wt% Nd4Fe14B alloy *** with the corresponding regenerated magnets washed with deionized water,the remanence and coercivity are increased by 18% and 59%,respectively.

关键词： Recycling Nd-Fe-B magnet Sludge Chemo-selective dissolution Washing process Magnetic properties Reduction diffusion Rare earths

3-D observations of a red tide event in the offshore water along the western Guangdong coast

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Acta Oceanologica Sinica 2015年第1期34卷 159-161页

作者： XIE Lingling CHEN Qingxiang HU Jianyu ZHANG Shuwen yi xiaofei CHEN Fajin DENG Rui DENG Xiaodong WANG Jing QI yiquan Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction Technologies Guangdong Ocean University State Key Laboratory of Marine Environmental Science Xiamen University Guangdong Key Laboratory for Urbanization and Geo-simulation School of Geography and PlanningSun Yat-sen University State Key Laboratory of Tropic Oceanography South China Sea Institute of OceanologyChinese Academy of Sciences

From November 24 to 26, 2014, a red tide event occurred in the offshore water off the Hailing Island located at the western Guangdong coast. The red tide appeared as pink strips distributed within 3 km in the offshore water and extended for about 10 km along the shoreline. During the flood tide, the pink seawater rushed to the beach with breaking waves, forming foam strips on the beach. Guangdong Province Key Laboratory for Coastal Ocean Variation and Disaster Prediction Technologies, Guangdong Ocean University, emergently responded to the event and organized three-dimensional observations from the air, onboard and on beach. The preliminary analyses of the cruise data and water samples indicate that the event was induced by non- toxic Noctiluca scintillans, of which the concentration reaches as high as 4 200 cells/L near the surface and 2600 cells/L at the bottom.

关键词： red tide Noctiluca scintillans marine pollution Hailing Island South China Sea