• Title/Summary/Keyword: Nanocrystalline Fe

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Nanocrystalline structure of electroformed Fe-Ni alloy thin foil (전주성형한 Fe-Ni 합금 극박재의 나노결정질 조직에 관한 연구)

  • Im, Tae-Hong;Lee, Heung-Ryeol;Gu, Seung-Hyeon
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2007.04a
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    • pp.27-28
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    • 2007
  • 전주는 표면코팅을 목적으로 하기보다 금속제품을 제조하기 위해 사용하는, 도금법과 유사한 기술이다. 다양한 조성의 Fe-Ni 합금들을 전주성형하여 극박형상으로 제조하였다. 2원계 Fe-Ni 합금의 결정립 크기는 10 nm 정도였으며 P 첨가에 의해 결정립 크기를 더욱 미세하게 할 수 있다. 전주한 2원계 Fe-Ni 합금들의 비저항은 전형적인 나노결정질 소재의 특성을 나타낸다.

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Effect of Annealing Temperature on the Permeability and Magneto-Impedance Behaviors of Fe68.5Mn5Si13.5B9Nb3Cu1 Amorphous Alloy

  • Le Anh-Than;Ha, Nguyen Duy;Kim, Chong-Oh;Rhee, Jang-Roh;Chau Nguyen;Hoa Nguyen Quang;Tho Nguyen Due;Lee, Hee-Bok
    • Journal of Magnetics
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    • v.11 no.1
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    • pp.55-59
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    • 2006
  • The effect of annealing temperature on the permeability and giant magneto-impedance (GMI) behaviors of $Fe_{68.5}Mn_{5}Si_{13.5}B_9Nb_3Cu_1$ amorphous alloy has been systematically investigated. The nanocrystalline $Fe_{68.5}Mn_{5}Si_{13.5}B_9Nb_3Cu_1$ alloys consisting of ultra-fine $(Fe,Mn)_3Si$ grains embedded in an amorphous matrix were obtained by annealing their precursor alloy at the temperature range from $500^{\circ}C\;to\;600^{\circ}C$ for 1 hour in vacuum. The permeability and GMI profiles were measured as a function of external magnetic field. It was found that the increase of both the permeability and the GMI effect with increasing annealing temperature up to $535^{\circ}C$ was observed and ascribed to the ultrasoft magnetic properties in the sample, whereas an opposite tendency was found when annealed at $600^{\circ}C$ which is due to the microstructural changes caused by high-temperature annealing. The study of temperature dependence on the permeability and GMI effect showed some insights into the nature of the magnetic exchange coupling between nanocrystallized grains through the amorphous boundaries in nanocrystalline magnetic materials.

Electromagnetic Wave Absorption Properties of Fe-based Nanocrystalline P/M sheets with Al2O3 additive (Al2O3 첨가에 따른 Fe계 나노결정립 P/M시트의 전자파 흡수특성)

  • Woo, S.J.;Cho, E.K.;Cho, H.J.;Lee, J.J.;Sohn, K.Y.;Park, W.W.
    • Journal of Powder Materials
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    • v.14 no.4
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    • pp.265-271
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    • 2007
  • Electromagnetic wave absorbing materials have been developed to reduce electromagnetic interference (EMI) for electronic devices in recent years. In this study, Fe-Si-B-Nb-Cu base amorphous strip was pulverized using a jet mill and an attritor and heat-treated to get flake-shaped nanocrystalline powders, and then the powders were mixed, cast and dried with dielectric $Al_{2}O_{3}$ powders and binders. As a result, the addition of $Al_{2}O_{3}$ powders improved the absorbing properties of the sheets noticeably compared with those of the sheets without dielectric materials. The sheet mixed with 2 wt% $Al_{2}O_{3}$ powder showed the best electromagnetic wave absorption, which was caused by the increase of the permittivity and the electric resistance due to the dielectric materials finely dispersed on the Fe-based powder.