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

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

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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

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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

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Densification and anticorrosion performances of vacuum evaporated aluminium coatings on NdFeB magnets

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Journal of Rare Earths 2021年第10期39卷 1238-1245,I0003页

作者： Jun Huang Qing Liu Zhenyu Yang Guangqing Xu pengjie zhang Jun Lv Wei Sun Bingshan Li Dongmei Wang Yucheng Wu School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China China International S&T Cooperation Base for Advanced Energy and Environmental Materials Hefei University of TechnologyHefei 230009China Key Laboratory of Advanced Functional Materials and Devices of Anhui Province Anhui Provincial International S&T Cooperation Base for Advanced Energy MaterialsHefei University of TechnologyHefei 230009China BGRIMM Technology Group Co. Ltd.Beijing 102600China National Engineering Research Center for Magnetic Materials Beijing 102600China

Al coated NdFeB magnets obtained by vacuum evaporation technique were densified by high energy ball milling *** surface morphology,metal composition and micro structure of the coatings were characterized by scanning electron microscopy,X-ray diffraction and X-ray photoelectron spectroscopy,*** anticorrosive properties were investigated by potentiodynamic polarization curves and neutral salt spray *** pores in the Al coatings of columnar crystals(Al) induced by the evaporation technique,were apparently filled in the following ball milling process,leading to the densification of Al coatings and the evident improvement of the anticorrosive *** treated with ball milling for 30 min,the sample achieves the best anticorrosive performances with the self-corrosion potential of-0.87 V,self-corrosion current density of 1.65 μA/cm^(2) and the neutral salt spray(NSS) time of 144 h(red rust).The improvement of the anticorro sive performances of vacuum evaporated Al coating mainly lies in the densification effect of the coating,which depends on different loading conditions of ball milling process.

关键词： Sintered NdFeB magnet Al coating Anticorrosive performances Vacuum evaporation Densification Rare earths

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Rare earth passivation and corrosion resistance of zinc coated NdFeB magnets

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Journal of Rare Earths 2022年第2期40卷 302-308,I0005页

作者： Jing Chen Hongyi Yang Guangqing Xu pengjie zhang Jun Lv Wei Sun Bingshan Lidi Jun Huang Dongmei Wang Xia Shu Yucheng Wu School of Materials Science and Engineering.Hefei University of Technology Hefei 230009China China International S&T Cooperation Base for Advanced Energy and Environmental Materials Hefei University of TechnologyHefei 230009China Key Laboratory of Advanced Functional Materials and Devices of Anhui Province Anhui Provincial International S&T Cooperation Base for Advanced Energy MaterialsHefei University of TechnologyHefei 230009China BGRIMM Technology Group Co. Ltd.Beijing 102600China National Engineering Research Center for Magnetic Materials Beijing 102600China

Rare earth passivation was conducted on Zn coated NdFeB magnets by chemical reaction to enhance the corrosion resistance ***,micro structures and compositions of different passivated coatings were studied by X-ray diffraction,field emission scanning electron microscopy,and X-ray photoelectron spectroscopy,*** corrosion behavior was evaluated by electrochemical measurement and neutral salt spray *** results show that the rare earth passivation can enhance the corrosion resistance of Zn coated NdFeB *** the concentration of cerium nitrate is 5 g/L,the passivated specimens can achieve the longest NSS time of 360 h,which is 144 h longer than that of the pristine Zn/NdFeB *** passivation layer on the Zn coating surface contributes to the enhancement of the magnets’corrosion resistance.

关键词： Sintered NdFeB magnets Rare earth passivation Zn coating Electroplating Corrosion resistance

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Testing Foundations of Modern Cosmology

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Bulletin of the Chinese Academy of Sciences 2011年第3期25卷 164-167页

作者： zhang pengjie Shanghai Astronomical Observatory CAS Shanghai 200030

1。我们宇宙的理解极大地在最后二十年和一个标准宇宙论范例被推进了的介绍是很好建立的现在。标准宇宙论在我们的宇宙统计上同类、各向同性的宇宙论的原则之上被基于。它也与非零在一般相关性之上被基于宇宙论的常数。在如此的一个框... 详细信息

1。我们宇宙的理解极大地在最后二十年和一个标准宇宙论范例被推进了的介绍是很好建立的现在。标准宇宙论在我们的宇宙统计上同类、各向同性的宇宙论的原则之上被基于。它也与非零在一般相关性之上被基于宇宙论的常数。在如此的一个框架，我们的宇宙由大约 4% 平常的事 baryonic 物质组成，

关键词：现代宇宙学基础测试广义相对论各向同性宇宙常数标准物质

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Anti-corrosion performance of Si-surface-alloying NdFeB magnets obtained with magnetron sputtering and thermal diffusion

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Journal of Rare Earths 2023年第8期41卷 1203-1210,I0003页

作者： Jin Tao Bang Liu pengjie zhang Guangqing Xu Jun Lv Jun Huang Jian Yan Wei Sun Bingshan Li Dongmei Wang Yucheng Wu School of Materials Science and Engineering Hefei University of TechnologyHefei 230009China BGRIMM Technology Group Co. Ltd.Beijing 102600China National Engineering Research Center for Magnetic Materials Beijing 102600China Key Laboratory of Advanced Functional Materials and Devices of Anhui Province Anhui Provincial International S&T Cooperation Base for Advanced Energy MaterialsHefei University of TechnologyHefei 230009China

Si alloying in the surface layer of NdFeB magnets was realized by thermal diffusion combined with magnetron *** surface composition,phase structure and morphology of NdFeB(S-Si)specimens were characterized by an X-ray diffractometer,an X-ray photoelectron spectrometer and a field emission scanning electron microscope,*** corrosion resistance of bare NdFeB(S-Si)was analyzed by static full immersion corrosion test and electrochemical *** of sputtering and thermal diffusion on the microstructure and corrosion resistance of the surface layer were *** show that surface alloying layer can effectively improve the corrosion resistance of bare NdFeB with the optimized static total immersion corrosion test time in NdFeB(1S-Si)-800 of 36 h,which is much longer than that of the pristine NdFeB(less than 0.5 h).The E_(corr)of NdFeB(1S-Si)-800 positively shifts from-1.05 to-0.92 V,indicating that the corrosion tendency is obviously *** J_(corr)is1.45×10^(-6)A/cm^(2)which is 2 orders of magnitude lower than that of the pristine NdFeB(5.25×10^(-4)A/cm^(2)).The intergranular composite oxides existing in Nd-rich phase contribute to the enhancement of corrosion resistance of Si-surface-alloying NdFeB.

关键词： NdFeB magnets Si surface alloying Magnetron sputtering Thermal diffusion Corrosion resistance Rare earths

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DESI Legacy Imaging Surveys Data Release 9:Cosmological constraints from galaxy clustering and weak lensing using the minimal bias model

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Science China(Physics,Mechanics & Astronomy) 2023年第12期66卷 230-254页

作者： Haojie Xu Hekun Li Jun zhang Xiaohu Yang pengjie zhang Min He Yizhou Gu Jian Qin Zhaozhou Li Antonios Katsianis Ji Yao Zhaoyu Wang Yirong Wang Liping Fu Department of Astronomy Shanghai Jiao Tong UniversityShanghai 200240China Key Laboratory for Particle Astrophysics and Cosmology(MOE)/Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai 200240China Tsung-Dao Lee Institute Shanghai Jiao Tong UniversityShanghai 201210China CAS Key Laboratory of Optical Astronomy National Astronomical ObservatoriesChinese Academy of SciencesBeijing 100101China Centre for Astrophysics and Planetary Science Racah Institute of PhysicsThe Hebrew UniversityJerusalem 91904Israel Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China Shanghai Key Lab for Astrophysics Shanghai Normal UniversityShanghai 200234China

We present a tentative constraint on cosmological parameters Ω_(m) and σ_(8) from a joint analysis of galaxy clustering and galaxygalaxy lensing from DESI Legacy Imaging Surveys Data Release 9(DR9),covering approximately 10000 square degrees and spanning the redshift range of 0.1 to *** study the dependence of cosmological parameters on lens redshift,we divide lens galaxies into seven approximately volume-limited samples,each with an equal width in photometric *** retrieve the intrinsic projected correlation function w_(p)(r_(p))from the lens samples,we employ a novel method to account for redshift ***,we measured the galaxy-galaxy lensing signal ΔΣ(r_(p))for each lens sample,using source galaxies selected from the shear catalog by applying our Fourier Quad pipeline to DR9 *** model these observables within the flatΛCDM framework,employing the minimal bias *** ensure the reliability of the minimal bias model,we apply conservative scale cuts:r_(p)>8 and 12 h^(-1)Mpc,for w_(p)(r_(p))and ΔΣ(r_(p)),*** findings suggest a mild tendency that S_(8)=σ_(8)√Ω_(m)/0.3increases with lens redshift,although this trend is only marginally *** we combine low redshift samples,the value of S8is determined to be 0.84±0.02,consistent with the Planck results but significantly higher than the 3×2 pt analysis by 2-5σ.Despite the fact that further refinements in measurements and modeling could improve the accuracy of our results,the consistency with standard values demonstrates the potential of our method for more precise and accurate cosmology in the future.

关键词： spatial distribution of galaxies statistical and correlative studies of properties observational cosmology

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宇宙是由什么构成的?

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科学通报 2016年第16期61卷 1754-1757页

作者：张鹏杰上海交通大学物理与天文系

通过星系、星系团,乃至宇宙整体的动力学行为,天文学家发现宇宙中绝大部分物质是不发光的,即暗的.其中暗物质占宇宙中总物质和能量的27%,暗能量占68%,而普通物质(即粒子物理标准模型粒子)只占5%.暗物质和暗能量是当代天文学和物理学的... 详细信息

通过星系、星系团,乃至宇宙整体的动力学行为,天文学家发现宇宙中绝大部分物质是不发光的,即暗的.其中暗物质占宇宙中总物质和能量的27%,暗能量占68%,而普通物质(即粒子物理标准模型粒子)只占5%.暗物质和暗能量是当代天文学和物理学的重大发现,是主要研究前沿.我们回顾暗物质和暗能量的发现历史、已知属性和待解决的问题.

关键词：暗物质暗能量宇宙学

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Forecasts on CMB lensing observations with AliCPT-1

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Science China(Physics,Mechanics & Astronomy) 2022年第10期65卷 115-129页

作者： Jinyi Liu Zeyang Sun Jiakang Han Julien Carron Jacques Delabrouille Siyu Li Yang Liu Jing Jin Shamik Ghosh Bin Yue pengjie zhang Chang Feng Zhi-Qi Huang Hao Liu Yi-Wen Wu Le zhang Zi-Rui zhang Wen Zhao Bin Hu Hong Li Xinmin zhang Department of Astronomy Beijing Normal UniversityBeijing 100875China Department of Astronomy School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China Shanghai Key Laboratory for Particle Physics and Cosmology Shanghai 200240China Division of Astronomy and Astrophysics Tsung-Dao Lee InstituteShanghai Jiao Tong UniversityShanghai 200240China D´epartement de Physique Th´eorique et CAP Universit´e de Gen`eveGen`eve CH-1211Switzerland CNRS-UCB International Research Laboratory Centre Pierre Bin´etruyCPB-IN2P3Berkeley IRL2007USA Key Laboratory of Particle Astrophysics Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China CAS Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of ChinaChinese Academy of SciencesHefei 230026China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China National Astronomical Observatories Chinese Academy of SciencesBeijing 100101China School of Physics and Optoelectronics Engineering Anhui UniversityHefei 230039China School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China CSST Science Center for the Guangdong-Hong Kong-Macao Greater Bay Area Zhuhai 519082China Peng Cheng Laboratory Shenzhen 518000China Theoretical devision Institute of High Energy PhysicsChinese Academy of SciencesBeijing 100049China University of Chinese Academy of Sciences Beijing 100049China

Ali CPT-1 is the first Chinese cosmic microwave background(CMB) experiment aiming for the high-precision measurement of CMB B-mode polarization. The telescope, currently under deployment in Tibet, will observe in two frequency bands centered at 90 and 150 GHz. We forecast the CMB lensing reconstruction, lensing-galaxy, and lensing-cosmic infrared background(CIB) cross-correlation signal-to-noise ratio(SNR) for Ali CPT-1. We consider two stages with different integrated observation times, namely “4 module*yr”(first stage) and “48 module*yr”(final stage). For lensing reconstruction, we use three different quadratic estimators, namely temperature-only, polarization-only and minimum-variance(MV) estimators, using curved sky geometry. We take into account the impacts of inhomogeneous hit counts and mean-field bias due to incomplete sky *** the first stage, our results show that the 150 GHz channel can measure the lensing signals at 15σ significance with the MV estimator. In the final stage, the measurement significance will increase to 31σ. We also combine the two frequency data in the harmonic domain to optimize the SNR. Our results show that the coadding procedure can significantly reduce the reconstruction bias in the high multiple range. Owning to the high quality of the polarization data in the final stage of Ali CPT-1, the EB estimator will dominate the lensing reconstruction in this stage. We also estimate the SNR of cross-correlations between Ali CPT-1 CMB lensing and other tracers of the large scale structure of the universe. For its cross-correlation with Dark Energy Spectroscopic Instrument(DESI) galaxies/quasars, we report the cross-correlation SNR = 10-20 for the four redshift bins at 0.05 < z < 2.1. In the first stage, the total SNR is approximately 32. In the final stage, the lensing-galaxy cross-correlation can reach SNR = 52. For lensing-CIB cross-correlation, in the first stage, the cross-correlations between Ali CPT-1 lensing and Planck CIB 353

关键词： background radiation cosmic cosmology gravitational lenses and luminous ares

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