• 제목/요약/키워드: Nanocrystalline Fe

검색결과 209건 처리시간 0.019초

$Fe_{73}Si_{16}B_7Nb_3Cu_1$ 나노결정합금 분말코아의 자기적 특성에 미치는 분말입도 및 볼밀링 시간의 영향 (Effects of Powder Size and Ball-milling Time on the Magnetic Properties of $Fe_{73}Si_{16}B_7Nb_3Cu_1$ Nanocrystalline Alloy Powder Cores)

  • 문병기;강성찬;박원욱;손근용
    • 연구논문집
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    • 통권34호
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    • pp.121-129
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    • 2004

  • The influence of powder size and ball-milling time on the magnetic properties of $Fe_{73}Si_{16}B_7Nb_3Cu_1$ nanocrystalline alloy powder was investigated. Flake-shaped powders were produced by pulverizing the ribbons annealed at $550^\circC$ for 1 hour. The powders were classified and consolidated into core shapes at a pressure of 18ton/$cm^2$. The initial permeability at 100kHz of the inductor core produced using $53-75\mum$ powders showed the highest value although its consolidated density showed the lowest one. The reason for the result is due to the cracking of the particles larger than $75\mum$ during the consolidation process. The ball-milling of powders for 2-4 hours improved the consolidation density and the initial permeability of the cores. The intrinsic coercivity of the powder decreased as well, resulting from the stress relief of the powder by a short-time milling.

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초미세결정립과 비정질이 공존하는 $Fe_{73.9}$$Cu_{1.0}$$Nb_{3.5}$$Si_{14.0}$$B_{7.6}$ 합금의 자기장 중 열처리 (Heat Treatment Effects of $Fe_{73.0}Cu{1.0}Nb_{3.5}Si_{14.0}B_{7.6}$Alloy with Imbedded Nanocrystalline Phase under Magnetic Field)

  • 양재석;손대락;조육
    • 한국자기학회지
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    • 제8권1호
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    • pp.13-20
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    • 1998

  • 초미세결정립과 비정질을 동시에 포함하는 리본형 Fe73.9Cu1.0Nb3.5Si14.0B7.6 합금을 자기장 중 열처리한 시편의 결정？적 특성 및 고주파 연기자 특성을 인가 자기장과 열처리 온도에 따라하여 조사아였다. 제조된 리본의 표면에 석출된 Fe-Si 초미세결정립은 (400) 우선방위를 나타내는 동시에 리본길이방향으로 [011] 결정측이 형성되어 있음을 확인하엿다. 자기장을 인가하지 않거나 길이방향으로 자기장을 인가하여 열처리할 때 45$0^{\circ}C$에소 Fe-Si 초미세결정립이 석출되다, 폭방향의 자기장을 인가한 경우 초미세결정립의 석출은 지연되어 55$0^{\circ}C$에서 나타남을 확인하였다. 길이방향으로 자기장을 인가할 때 시편의 결정화 정도는 외부 자기장을 인가하지 않은 경우에 비해 조금 증가하였다. 그러나, 시편의 각도를 기울여 측정된 X-선 회절패턴으로부터 시편내부는 표면과 달리 결정화가 진행되고 있음을 확인하였다. 열처리한 시편의 포화자기유도는 1.3T로 비슷하였다. 열처리전 리본의 보자력의 크기는 1.06A/츠이었으나, 열처리한 시편은 열처리 온도가 40$0^{\circ}C$에서 55$0^{\circ}C$로 증가함에 따라 0.56A/cm에서 0.1A/cm로 감소하였다. 폭방향의 자기장을 인가한 경우 각형비는 자기장을 인가하지 않거나 길이방향으로 자기장을 인가하여 열처리한 시편의 각형비보다 작았다.

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스퍼터링 방법으로 성장한 코발트크롬철망간니켈 고엔트로피 질산화물 박막의 구조특성 (Structural Characterization of CoCrFeMnNi High Entropy Alloy Oxynitride Thin Film Grown by Sputtering)

  • 이정국;홍순구
    • 한국재료학회지
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    • 제28권10호
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    • pp.595-600
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    • 2018

  • This study investigates the microstructural properties of CoCrFeMnNi high entropy alloy (HEA) oxynitride thin film. The HEA oxynitride thin film is grown by the magnetron sputtering method using nitrogen and oxygen gases. The grown CoCrFeMnNi HEA film shows a microstructure with nanocrystalline regions of 5~20 nm in the amorphous region, which is confirmed by high-resolution transmission electron microscopy (HR-TEM). From the TEM electron diffraction pattern analysis crystal structure is determined to be a face centered cubic (FCC) structure with a lattice constant of 0.491 nm, which is larger than that of CoCrFeMnNi HEA. The HEA oxynitride film shows a single phase in which constituting elements are distributed homogeneously as confirmed by element mapping using a Cs-corrected scanning TEM (STEM). Mechanical properties of the CoCrFeMnNi HEA oxynitride thin film are addressed by a nano indentation method, and a hardness of 8.13 GPa and a Young's modulus of 157.3 GPa are obtained. The observed high hardness value is thought to be the result of hardening due to the nanocrystalline microstructure.

  • https://doi.org/10.3740/MRSK.2018.28.10.595 인용 PDF KSCI

MSR (Mechanically induced Self-sustaining Reaction)이 억제된 반응성 밀링에 의해 제조된 분산강화 페라이트의 미세조직과 기계적 특성 (Microstructure and Mechanical Properties of ODS Ferrite Produced by Reactive Milling for the MSR Suppression)

  • 황승준
    • 열처리공학회지
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    • 제26권6호
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    • pp.279-287
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    • 2013

  • Oxide Dispersion Strengthened (ODS) Fe with $Al_2O_3$ dispersoid was successfully produced by reactive milling with a mixture of Fe, $Fe_3O_4$ (Magnetite), $Fe_2O_3$ (Hematite) and Al reactants at cryogenic temperature. The milled powders were consolidated by Vacuum Hot Press (HP) at 1323 K, and the consolidated materials were characterized by Transmission Electron Microscopy (TEM), Scanning Transmission Electron Microscopy (STEM), and Energy Dispersive Spectroscopy (EDS); the yield strength and the hardness of the consolidated materials were determined by compressive test and Vickers hardness test at room temperature. The grain size of the materials was estimated by X-ray Diffraction technique using the scherrer's formula. The TEM observations showed that the microstructure was comprised with a mixture of nanocrystalline Fe matrix and $Al_2O_3$ nano-dispersoids with a bimodal size distribution; the 0.2% off-set yield strength of the materials was as high as $758{\pm}29$ MPa and the Vickers hardness was $358{\pm}2$. The effect of the cryogenic milling and addition of extra Fe powder was discussed on the suppression of MSR (Mechanically induced Self-sustaining Reaction) for the desired microstructural evolution of ODS alloys.

  • https://doi.org/10.12656/jksht.2013.26.6.279 인용 PDF KSCI