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Your search keyword '"Lee, Don"' showing total 20 results
Start Over Author "Lee, Don" Journal ieee transactions on magnetics
20 results on '"Lee, Don"'

1. Fully dense bulk nanocomposites of [([Sm.sub.1-x][Gd.sub.x]).sub.2][([Co.sub.1-Y][Fe.sub.v]).sub.17]+(Co, Fe) with high coercivity and high curie temperature

Author

Chen, Christina H., Lee, Don, Liu, Sam, Walmer, Michael H., Zhang, Yong, and Hadjipanayis, George C.

Subjects
Magnets, Permanent -- Research, Electromagnetism -- Research, Nanotechnology, Business, Electronics, Electronics and electrical industries
Abstract

Fully dense nanocomposites of [([Sm.sub.1-x][Gd.sub.x]).sub.2] [([Co.syb.1-y] [Fe.sub.y]).sub.2:17] phase + Co/Fe were obtained by hot pressing the amorphous powders at 740[degrees]-760[degrees]C. Amorphous powders were made by mechanical alloying. Up to 14 kOe of Coercivity was obtained for these Cu and Zr free nanocomposites. X-ray diffraction patterns confirm the status of amorphous powder and crystallized structure after annealing at 750-825[degrees]C. Transmission electron microscopy image shows that the sizes of crystals were in the range of several nm to 100 nm. These fully dense nanocomposites have Curie temperatures higher than 900[degrees]C and lower temperature coefficient of magnetization, which would make them ideal candidates for temperature compensated permanent magnets. Index Terms--Curie temperature, full density, nanocomposites magnets, Sm-Co rare earth magnets, temperature coefficient.

Published
2004

19. Mechanism Analysis of Coercivity Enhancement of Hot Deformed Nd-Fe-B Magnets by DyF3 Diffusion.

Author

Tang, Xu, Chen, Renjie, Yin, Wenzong, Lin, Min, Lee, Don, and Yan, Aru

Subjects
COERCIVE fields (Electronics), NEODYMIUM compounds, DIFFUSION, PERPENDICULAR magnetic anisotropy, MAGNETIC resonance imaging, NANOCRYSTALS, DYSPROSIUM
Abstract

Isotropic and anisotropic Nd-Fe-B magnets with 2 wt% DyF3 addition are successfully prepared. With the addition of 2 wt% DyF3, the coercivity of the hot-pressed magnets increases from 20.52 kOe to 23.13 kOe by increasing the hot-pressed temperature. BSEM results show that most of the DyF3 additions exist in triple junctions and on the surface of ribbons even though the hot-pressed temperature is as high as 983 K. The coercivity of the die-upset magnets increases from 15.18 kOe to 19.14 kOe when 2 wt% DyF3 added. The BSEM results of the hot-deformed magnets show that the content of the DyF3 between ribbons in the die-upset magnets is reduced which indicates that most DyF3 decomposes into Dy and F elements. The Dy atoms penetrate into the Nd2Fe14B phases and (Nd,Dy)2Fe14B phases are formed. The improvement of coercivity of the die-upset magnets is caused by the higher magnetocrystalline anisotropy of (Nd,Dy)2Fe14B. [ABSTRACT FROM AUTHOR]

Published
2013
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20. Fully Dense Bulk Nanocomposites of (Sm1-xGDx)2 With High Coercivity and High Curie Temperature.

Author

Chen, Christina H., Lee, Don, Liu, Sam, Walmer, Michael H., Yong Zhang, and Hadjipanayis, George C.

Subjects
*CURIE temperature, *METALLIC composites, *AMORPHOUS substances, *METAL powders, *MECHANICAL alloying, *MAGNETIC properties of metals
Abstract

Fully dense nanocomposites of (Sm1-xGdx)2(Co1-yFey)2:17 phase + Co/Fe were obtained by hot pressing the amorphous powders at 740 °-760 °C. Amorphous powders were made by mechanical alloying. Up to 14 kOe of Coercivity was obtained for these Cu and Zr free nanocomposites. X-ray diffraction patterns confirm the status of amorphous powder and crystallized structure after annealing at 750-825 °C. Transmission electron microscopy image shows that the sizes of crystals were in the range of several nm to 100 nm. These fully dense nanocomposites have Curie temperatures higher than 900 °C and lower temperature coefficient of magnetization, which would make them ideal candidates for temperature compensated permanent magnets. [ABSTRACT FROM AUTHOR]

Published
2004
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