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Start Over Author "Mi Yan" Publisher institute of electrical and electronics engineers (ieee)
47 results on '"Mi Yan"'

9. Effects of (Nd, Pr)H x Intergranular Addition on the Mechanical Properties of Nd–Pr–Ce–Fe–B Sintered Magnets

Author

Yongsheng Liu, Guohua Bai, Mi Yan, Jiaying Jin, Zeyu Qian, and Baixing Peng

Subjects
010302 applied physics, Materials science, Hydrogen, Analytical chemistry, chemistry.chemical_element, Sintering, 02 engineering and technology, Intergranular corrosion, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Electronic, Optical and Magnetic Materials, Fracture toughness, chemistry, Phase (matter), 0103 physical sciences, Volume fraction, Grain boundary, Electrical and Electronic Engineering, 0210 nano-technology
Abstract

Influences of (Nd, Pr)H x additives on the microstructure and mechanical properties of Nd–Pr–Ce–Fe–B sintered magnets have been investigated. The results show that both the fracture toughness and bending strength exhibit a monotonically increasing trend with raised (Nd, Pr)H x incorporation. The (Nd, Pr)H x powders transform into metallic Nd/Pr with high reactivity upon dehydrogenation, increasing the volume fraction of rare earth-rich intergranular phase, and promoting the formation of thick and continuous grain boundary (GB) layer surrounding the RE2Fe14B matrix phase grains. Besides, the hydrogen desorption behavior also demonstrates that the excessive hydrogen introduced by (Nd, Pr)H x additives can be completely released upon high-temperature sintering. As a result, the crack propagation along the thick GBs is suppressed, giving rise to the substantially enhanced mechanical performance of bulk magnets. This paper suggests that the Nd–Pr–Ce–Fe–B permanent magnet with (Nd, Pr)H x incorporation satisfies the constraints of cost, magnetic, and mechanical properties simultaneously, thereby possessing competitive advantages for mass production.

Published
2018

10. Mechanical Properties of La–Ce-Substituted Nd–Fe–B Magnets

Author

Mi Yan, Jiaying Jin, Tianyu Ma, and Yujing Zhang

Subjects
010302 applied physics, Materials science, Modulus, Fracture mechanics, 02 engineering and technology, Bending, Intergranular corrosion, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, Electronic, Optical and Magnetic Materials, Grain growth, Phase (matter), Magnet, 0103 physical sciences, Electrical and Electronic Engineering, Composite material, 0210 nano-technology
Abstract

Influences of La–Ce substitution on the microstructure and mechanical properties of R2Fe14B-type (R: rare earth) permanent magnets have been investigated. The results show that the optimum compressive and bending strengths of 1137.8 and 339.9 MPa, respectively, are achieved at 18 wt.% La–Ce substitution for Pr–Nd. La–Ce substitution is found to enhance the micro-hardness and Young’s modulus of 2:14:1 matrix phase gradually, strengthening the main phase grains. The irregular grain growth together with weakened R-rich intergranular phase in higher La/Ce-containing magnets, however, leads to easier crack propagation, hence deteriorating the mechanical properties. Consequently, R–Fe–B permanent magnet with a proper La–Ce content satisfies the constraints of cost, and magnetic and mechanical properties simultaneously, thereby exhibiting competitive advantages for mass production.

Published
2016

18. Fe-Based Soft Magnetic Composites With High <tex-math notation='LaTeX'>${B}_{s}$ </tex-math> and Low Core Loss by Acidic Bluing Coating

Author

Chen Wu, Mi Yan, and Guoliang Zhao

Subjects
Materials science, Annealing (metallurgy), Iron oxide, engineering.material, Bluing, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, Coating, chemistry, Electrical resistivity and conductivity, engineering, Fe based, Electrical and Electronic Engineering, Composite material
Abstract

Fe-based soft magnetic composites (SMCs) with high $B_{s}$ and low core loss were fabricated by acidic bluing coating. Effects of reaction time and annealing temperature on the magnetic properties of the SMCs have been investigated. The Fe3O4 grows as the coating layer of the Fe powders and converts to Fe2O3 with increased reaction time. The iron oxide coating layer gives rise to highly normalized saturation magnetization (0.954–0.928) and low core loss due to its high electrical resistivity. The lowest core loss (785.1 mW/cm3 measured at 50 mT and 100 kHz) of the Fe SMCs can be achieved with the reaction time of 30 min and annealing temperature of 550 °C.

Published
2015

24. Anomalous Magnetization Behavior of Fe-N Films Deposited by Reactive Pulsed Laser Deposition

Author

Yinzhu Jiang, Mi Yan, Deren Yang, Jing Li, and Tianyu Ma

Subjects
Materials science, Analytical chemistry, chemistry.chemical_element, Coercivity, Nitrogen, Electronic, Optical and Magnetic Materials, Pulsed laser deposition, Magnetization, Nuclear magnetic resonance, Lattice constant, chemistry, Conversion electron mössbauer spectroscopy, Remanence, Phase (matter), Electrical and Electronic Engineering
Abstract

A series of Fe-N films with thickness of 200 nm have been prepared by reactive pulsed laser deposition (PLD) at 25°C and at 150°C in various nitrogen pressures. Both series of samples consist of mixtures of γ'-Fe 4N and α-Fe phase. The amount of α-Fe decreases with the increase of nitrogen pressure. Higher remnant ratio and lower coercivity are observed for the films deposited at 150°C compared to the films deposited at 25°C. An anomalously large magnetization is observed for both series of films deposited at a nitrogen pressure of 8 mTorr. The average magnetization is as high as or even larger than that of α-Fe. Conversion electron Mossbauer spectroscopy demonstrated that the highest-magnetization film consists mixtures of γ'-Fe4N and α-Fe phase at a mole ratio of 1:6. The origin of this intriguing high moment is ascribed to a certain lattice constant of the α-Fe which is in a heterogeneous state with γ'-Fe4N for films deposited at a certain nitrogen pressure.

Published
2012

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