Article
Chemistry, Physical
Xiang Li, Qing-Zheng Jiang, Sajjad Ur Rehman, Qing-Fang Huang, You-Wei Chen, Chuan-Jia Zhao, Zhen-Chen Zhong
Summary: The addition of Nd70Cu30 significantly improves the thermal stability and magnetic properties of Ce-Fe-B-based hot-deformed magnets. The microstructure analysis shows a decrease in the proportion of coarse grain region and an increase in the proportion of the liquid region after the addition of Nd70Cu30. This leads to improved nucleation sites of magnetization reversal and weakened intergranular exchange coupling, enhancing the overall magnetic properties of the magnets.
Article
Chemistry, Applied
Zhifeng Shang, Dongtao Zhang, Zhihong Xie, Yunqiao Wang, Muhammad Haseeb, Pengbiao Qiao, Weiqiang Liu, Ming Yue
Summary: The coercivity of Sm(Co,Fe,Cu,Zr)z magnets is sensitive to Zr content, with excessive Zr leading to Cu and Fe distribution heterogeneity. A high Cu content destroys the cell boundary phase and enlarges the cell size, resulting in decreased magnetic properties.
JOURNAL OF RARE EARTHS
(2021)
Article
Materials Science, Multidisciplinary
D. M. RajKumar, Mithun Palit, D. V. Sridhara Rao, N. V. Rama Rao, Vajinder Singh, C. V. S. Kiran, A. K. Singh, S. Kamat
Summary: Sm2Co17 type permanent magnets prepared by novel CIP technique showed higher remanence and energy product compared to those processed through conventional TP method, but lower intrinsic coercivity and knee field values.
MATERIALS CHARACTERIZATION
(2022)
Article
Chemistry, Physical
Xin Song, Yao Liu, Tao Yuan, Fang Wang, Jiuping Fan, Tianyu Ma
Summary: In the fabrication of 2:17-type Sm-Co-Fe-Cu-Zr magnets, slow cooling after solution treatment can lead to a better microstructure and magnetic properties, which is beneficial for improving the uniformity of magnets.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Physics, Condensed Matter
Jie Song, Qingzheng Jiang, Sajjad Ur Rehman, Lunke He, Xiang Li, Youwei Chen, Chuanjia Zhao, Zhenchen Zhong
Summary: The addition of Hf in Sm24.6Co50Fe17.4Cu5.7Zr2.3-xHfx ribbons and magnets prepared by melt-spinning and SPS methods significantly improves their magnetic properties. The microstructural analysis reveals that Hf contributes to grain refinement and more uniform structure, leading to enhanced magnetic properties. Furthermore, the presence of a micro-twin structure in the 2:17R phase of SPSed magnets is also observed.
PHYSICA B-CONDENSED MATTER
(2021)
Article
Materials Science, Multidisciplinary
Bang Zhou, Wenbing Fan, Xuefeng Liao, Jiayi He, Zhongwu Liu
Summary: This study investigates the phase precipitation and magnetic properties of Gd10+xFe84-xB6 alloys. It is found that Gd-Fe-B alloys exhibit high remanence and maximum energy product, along with good magnetic stability and high temperature resistance.
Article
Chemistry, Physical
Sajjad Ur Rehman, Chen Wei, Ruibiao Zhang, Haihua Liu, Shaoxiong Li, Minglong Zhong, Munan Yang, Qingzheng Jiang, Jun Wang, Zhenchen Zhong
Summary: This paper investigates the development of spinodal structure in Alnico 8 alloys and its effects on magnetic properties. By varying the titanium content and using directional solidification, the magnetic properties of the magnets are significantly improved.
Article
Nanoscience & Nanotechnology
Chengpeng Zhu, Genshen Peng, Y. C. Lin, Xiao-Yong Zhang, Chaoqiang Liu, Kechao Zhou
Summary: The study investigated the effects of molybdenum and chromium content on the microstructure, mechanical properties, and deformation mechanisms of novel titanium alloys. Molybdenum notably influenced grain refinement during quenching, while the ductility of the alloys was mainly affected by the deformation ability of the alpha phase.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2021)
Article
Chemistry, Physical
Ondrej Zivotsky, Lucie Gembalova, Yvonna Jiraskova, Ivo Szurman, Tomas Cegan, Ondrej Malina, Jan Kuriplach, Jakub Cizek
Summary: The microstructural and magnetic properties of Mn2FeSi and Mn2FeAl alloys prepared in the bulk form were investigated. Si and Al were found to have different effects on the alloys' microstructural and magnetic properties. Mn2FeAl alloys exhibited a single-phase structure before and after annealing, while Mn2FeSi alloys showed a two-phase behavior in the as-quenched state. From a magnetic viewpoint, all samples were paramagnetic at room temperature and transformed into an antiferromagnetic state at specific temperatures. Mn2FeSi alloys contained a high concentration of vacancies, while Mn2FeAl alloys had a very low concentration of vacancies.
JOURNAL OF ALLOYS AND COMPOUNDS
(2023)
Article
Nanoscience & Nanotechnology
Hui-Dong Qian, Jung Tae Lim, Jong-Woo Kim, Yang Yang, Kyung Mox Cho, Jihoon Park, Chul-Jin Choi
Summary: This study successfully produced high density sintered Sm(Fe0.8Co0.2)(11)Ti bulk magnets using a newly developed high pressure pressing method. The purity of the hard magnetic ThMn12 phase in the bulk magnet was over 97 wt.%. The phase transformation behavior from amorphous to ThMn12 phase during heat treatment was systematically investigated, achieving high remanent magnetization and maximum energy product. The achieved maximum energy product in the bulk magnet is the highest reported among all SmFe12-based bulk magnets.
SCRIPTA MATERIALIA
(2021)
Article
Physics, Condensed Matter
Shu Wang, Ji-Bing Sun, Zhi-Xia Xiao, Ming-Xu Yang, Wei-Dong Shi
Summary: Doping 1 wt% Al89.5Cu9.7Fe0.8 alloy promotes the phase separation and microstructure evolution of Nd13.53Fe74.89Co5.54B6.04 alloy. Low-temperature annealing improves the disorder degree, reduces composition difference between phases, and results in the formation of small particles or nanoparticles.
PHYSICA B-CONDENSED MATTER
(2022)
Article
Materials Science, Multidisciplinary
Qin Zou, Xihui Ye, Yanguo Li, Wenqi Luo, Yongan Luo
Summary: Fe-Mn-Si-Cr-Ni shape memory alloys (SMAs) were prepared by mechanical alloying and discharge plasma sintering. The effects of milling time on the microstructure evolution, mechanical properties, superelasticity, and corrosion resistance of Fe-Mn-Si-Cr-Ni SMAs were investigated. The increase in milling time promoted the phase transition during the sintering process and affected the superelasticity and corrosion resistance of the alloy.
JOURNAL OF MATERIALS SCIENCE
(2023)
Article
Materials Science, Ceramics
Haoran Peng, Peijie Yang, Pao Yang, Hongbin Qi
Summary: Multicomponent co-doping is used to balance the magnetic properties of ferrite ceramics. In this study, novel (Ni,Cr,Zr)-co-doped M-type barium hexaferrites were synthesized. The sintering behavior and densification temperature of the ceramics were found to be similar regardless of the composition x, and all the fabricated ceramics exhibited pure-phase M-type barium ferrite.
CERAMICS INTERNATIONAL
(2023)
Article
Chemistry, Physical
R. Kabilan, M. Ashokkumar
Summary: Cu and Cr co-doped ZnO nanopowder was synthesized and annealed at different temperatures. Sample S2 exhibited the best crystallization with the least defects, while samples S1 and S3 showed impurities and lattice distortion. The nanopowders displayed wide absorption and emission bands in UV/violet, blue, and green regions, with room-temperature ferromagnetism observed in all samples.
JOURNAL OF MOLECULAR STRUCTURE
(2022)
Article
Chemistry, Physical
Sihan Cheng, Jiaqi Wang, Yunsheng Wu, Xuezhi Qin, Lanzhang Zhou
Summary: The effects of Fe content on the microstructure, thermal stability, and tensile properties of a Ni-Fe-Cr based superalloy used in advanced ultra-supercritical power plants were investigated. It was found that Fe content influenced the precipitation behavior and morphology of different phases in the alloy. Fe content improved the ductility but slightly reduced the strength of the alloy. Long-term thermal exposure resulted in a phase transformation of gamma ' phase from spherical to cubic shape in the alloy with 35% Fe content. The coarsening rate of gamma ' phase decreased with increasing Fe content due to the restricted diffusion of Fe atoms. The change in yield strength with particle size was explained by dislocation shearing and Orowan bowing models. Precipitation of harmful Laves phase at intermediate stage of thermal exposure led to a more rapid reduction in yield strength when Fe content was 35%.
Article
Materials Science, Multidisciplinary
H. W. Chang, S. U. Jen, D. H. Tseng, C. R. Wang, W. C. Cheng, W. C. Chang
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2020)
Article
Chemistry, Physical
H. W. Chang, S. U. Jen, D. H. Tseng, Y. H. Liao, H. Y. Hsieh, W. C. Chang
JOURNAL OF ALLOYS AND COMPOUNDS
(2020)
Article
Chemistry, Physical
T. K. Lin, H. W. Chang, C. R. Wang, D. H. Wei, C. S. Tu
JOURNAL OF ALLOYS AND COMPOUNDS
(2020)
Article
Engineering, Multidisciplinary
H. C. Fan, Fu-Te Yuan, H. W. Chang, Chi-Yang Shen
Summary: An optical method has been proposed to monitor the order transformation of FePt thin films in real-time, with the onset temperature determined accurately by measuring surface reflection amplitude. The experimentally measured kinetic ordering temperatures for different compositions of FePt thin films are in good agreement with published DSC data, confirming the effectiveness of the optical method in tracking order transformation.
JOURNAL OF THE CHINESE INSTITUTE OF ENGINEERS
(2021)
Article
Materials Science, Multidisciplinary
H. W. Chang, S. U. Jen, D. H. Tseng, Y. H. Liao, H. Y. Hsieh, C. R. Wang, W. C. Chang
MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS
(2020)
Article
Nanoscience & Nanotechnology
H. W. Chang, G. T. Lin, Y. J. Wong, W. M. Huang, W. C. Chang
Summary: Significant enhancement in coercivity for hot deformed NdFeB magnets is achieved by doping R80Al20 (R= La, Ce, Dy, Tb) alloy powders. Microstructure analysis shows that Ce or La tends to distribute at grain boundary, while Dy or Tb and Al are located at grain boundary and surface. Magnetic isolation due to R-rich phase containing Nd, Ce or La, Al at the grain boundary contributes to coercivity enhancement, while strengthening magnetic anisotropy field of 2:14:1 phase due to Tb or Dy, and slight Al substitutions gives rise to significant coercivity enhancement.
Article
Nanoscience & Nanotechnology
Y. J. Wong, W. C. Hsu, H. W. Chang, Y. Lee, W. C. Chang, C. H. Chiu, C. C. Mo
Summary: Enhancement of coercivity in sintered NdFeB magnets through grain boundary diffusion (GBD) with Tb70Cu30 powders prepared by different milling methods was compared. Results showed that powders prepared by low-energy ball milling (LEBM) provided a wider contact area, leading to higher diffusion efficiency and coercivity increment.
Article
Chemistry, Multidisciplinary
Da-Hua Wei, Tei-Kai Lin, Yuan-Chang Liang, Huang-Wei Chang
Summary: Monodispersed FePt core and FePt-Au core-shell nanoparticles were chemically synthesized with controllable surface-functional properties. The size of the nanoparticles could be tuned by the initial concentration of gold acetate, and FePt-Au NPs showed a red shift in surface plasmon resonance compared to pure Au NPs. Surface modification using mercaptoacetic acid gave the NPs hydrophilic properties and potential applications in biomedical engineering research.
FRONTIERS IN CHEMISTRY
(2021)
Article
Materials Science, Multidisciplinary
Ting-Kai Lin, Huang-Wei Chang, Wan-Chi Chou, Chang-Ren Wang, Da-Hua Wei, Chi-Shun Tu, Pin-Yi Chen
Summary: In this work, we used pulsed laser deposition (PLD) with a Nd:YAG laser to fabricate Bi1-xGdxFeO3 (BGFO) films on glass substrates. The study found that with increasing Gd content, there is a gradual decrease in crystallite size and surface roughness in the BGFO films, and the magnetic properties are significantly enhanced due to Gd substitution.
Article
Physics, Applied
H. W. Chang, F. T. Yuan, D. Y. Lin, D. H. Tseng, W. C. Chang, Y. S. Chen, J. G. Lin
Summary: Large in-plane magnetic uniaxial anisotropy was achieved in Fe60Co20B20 thin films prepared by rotational sputtering, exhibiting outstanding thermal stability up to 350°C. These stress-induced anisotropy films were used as free layers in synthetic spin valves, showing a linear resistance change against external field and reduced coercivity, providing a simple synthesis route to induce magnetic anisotropy for spintronic device design.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Electrical & Electronic
Y. J. Wong, H. W. Chang, Y. Lee, W. C. Chang, C. H. Chiu, C. C. Mo
Summary: This study demonstrates the modification of magnetic properties and enhancement of coercivity of NdFeB sintered magnets using dual-alloy (DA) sintering and grain boundary diffusion (GBD) treatment. Addition of CeAl powders increases the coercivity, while incorporating TbCu powders through GBD further enhances the coercivity and achieves different levels of NdFeB magnets.
IEEE TRANSACTIONS ON MAGNETICS
(2022)
Article
Chemistry, Physical
H. W. Chang, S. U. Jen, Y. Y. Shen, D. H. Tseng
Summary: The saturation magnetostriction of sputter-prepared Fe71Co10Ga19 films on Si(100) substrates is mainly influenced by the amount of m-D0(3) phase and can be controlled by adjusting sputtering parameters. The thickness dependence of magnetostriction shows an increase in lambda s as thickness decreases in the range of 200 nm to 50 nm, while a decrease is observed in the range of 50 nm to 30 nm.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Chemistry, Physical
H. W. Chang, S. U. Jen, Y. H. Liao, D. H. Tseng, H. Y. Hsieh, W. C. Chang, C. H. Chiu, J. Cifre, D. G. Chubov, I. S. Golovin
Summary: Enhancement of magneto-mechanical properties in Fe80Al20 alloys by doping Tb has been demonstrated, showing improved magnetostriction and sensitivity. The increased magnetostriction with Tb content is related to the degree of (110) texture. However, higher Tb content may lead to degradation of magneto-mechanical properties.
JOURNAL OF ALLOYS AND COMPOUNDS
(2022)
Article
Materials Science, Multidisciplinary
H. W. Chang, Y. M. Guo, Y. H. Fang, W. C. Chang, C. C. Shaw
Summary: The magnetic properties of melt spun LaCo5-based ribbons can be significantly improved by modifying the phases and refining the grains, resulting in reduced coercivity and enhanced squareness of the demagnetization curve. Substitution of elements M (M = Ti, Zr, Hf) for Co and R (R = Ce, Pr, Nd, Sm, Y) for La in the compositions also contributes to the enhancement of magnetic properties.
JOURNAL OF MATERIALS SCIENCE
(2022)
Article
Materials Science, Coatings & Films
T. K. Lin, H. W. Chang, C. R. Wang, D. H. Wei, C. S. Tu, P. Y. Chen
Summary: This study investigated the phase constitutions, ferroelectric, magnetic, and nanomechanical characteristics of BiFeO3 films with Dy substitution. The results showed that the BDFO films exhibited desired ferroelectric and ferromagnetic properties, and the hardness of the films was controlled mainly by the impeded propagation of dislocation by grain boundary. The findings suggest that the radius and magnetic moment of the Dy3+ ions play a critical role in the structural evolution and enhanced properties of the BDFO films.
SURFACE & COATINGS TECHNOLOGY
(2022)
