• 제목/요약/키워드: Nd-Fe-B alloy

검색결과 83건 처리시간 0.024초

Cu와 DyF3 분말의 혼합이 Nd-Fe-B 소결자석의 보자력에 미치는 영향 (Effect of Cu and DyF3 Powder Additions on the Coercivity of Sintered Nd-Fe-B Magnets)

  • 남궁석;이민우;;임태환;김태훈;이성래;장태석
    • 한국분말재료학회지
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    • 제19권4호
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    • pp.247-252
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    • 2012

  • Effect of Cu and $DyF_3$ powder mixing with Cu-free (Nd, Dy)-Fe-B jet-milled powder on the magnetic properties of sintered magnets was investigated. The coercivity of a magnet prepared from the Cu-free (Nd, Dy)-Fe-B powder was about 10 kOe even though the alloy powder already contained some Dy (3.5 wt%). When small copper powder was blended, however, the coercivity of the magnet increased almost 100%, exhibiting about 20 kOe. On the contrary, the coercivity enhancement was moderate, about 4 kOe, when dysprosium content in the sintered magnet was simply increased to 4.9 wt% by the addition of small $DyF_3$3 powder.

  • https://doi.org/10.4150/KPMI.2012.19.4.247 인용 PDF KSCI

기계적 분쇄한 Nd-Fe-B 합금의 다이업셋과 열처리가 자기적 특성에 미치는 영향 (The Effect of Die Upset and Heat Treatment on the Magnetic Properties of Mechanically Ground Nd-Fe-B Alloys)

  • 정원용;박정덕;곽창섭;양현수
    • 한국자기학회지
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    • 제4권3호
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    • pp.233-238
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    • 1994

  • 건식 기계적 분쇄법을 이용하여 $Nd_{16}Fe_{84-x}B_{x}(x\;=\;5,\;6,\;7,\;8)$ 합금에서 다이업셋과 열처리가 자기적 특성에 미치는 영향을 연구하였다. 기계적 분쇄 이후에 다이업셋하면 시편 전체적으로 압축방향과 평행한 stripe형 자구가 많이 나타나지만 자화용이축인 c축으로 완전하게 정렬되지 않고 있어 잔류자속밀도가 낮다. 다이업셋한 시편을 $1000^{\circ}C$, 5시간 열처리하면 결정립이 약 $20\mu\textrm{m}$으로 성장하여 잔류자속밀도와 보자력이 감소한다. 13시간 동안 기계적 분쇄하여 제조한 분말을 다이업셋$(T:750^{\circ}C,\;\dot{\varepsilon}:0.001/sec,\;{\varepsilon}:60%)$한 시편에서 가장 높은 자기적 특성$(_{i}H_{c}=14\;kOe,\;B_{r}=7.8\;kG)$을 얻을 수 있었다.

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이방성${(Nd_{0.8}Dy_{0.2})}_{12}Fe_{80}B_8$ 급속 응고리본의 미세조직 및 자기특성에 미치는 디스크 표면속도의 영향 (Effects of Disk Surface Velocity on the Microstructures and Magnetic Properties of Anisotropic ${(Nd_{0.8}Dy_{0.2})}_{12}Fe_{80}B_8$ Melt-spun Ribbons )

  • 신현철;김동환;김택기;김윤배
    • 한국자기학회지
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    • 제1권2호
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    • pp.69-73
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    • 1991

  • 단롤법 급속응고기술을 이용하여 제작한 ${(Nd_{0.8}Dy_{0.2})}_{12}Fe_{80}B_8$ 리본의 미세조직 및 자기특성에 미치는 디스크표면속도의 영향을 조사하였다. X-선 회절패턴으로 부터 $I_{410}/I_{006}$의 비를 계산한 결과, 리본의 이방화는 디스크표면속도($V_{s}$)가 느릴수록 우수하였다. 그러나, 리본을 분쇄하여 자장중에서 정렬시킨 분말의 잔류자속밀도는 디스크표면속도가 빨라짐에 따라 증가하여, $V_{s}=14.6m/s$에서 최대치를 나타낸후, 그 이상의 속도에서는 감소하였다. $V_{s}=14.6m/s$로 제작한 리본을 분쇄하여 자장중에서 정렬시킨 분말의 잔류자속밀도는 자장중에서 정렬시키지 않은 경우에 비해 약 10%높았으며, 이는 리본의 일부가 이방화되어 있기 때문인 것으로 사료된다.

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Novel Properties of Boron Added Amorphous Rare Earth-transition Metal Alloys for Giant Magnetostrictive and Magneto-optical Recording Materials

  • Jai-Young Kim
    • Journal of Magnetics
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    • 제3권3호
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    • pp.78-81
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    • 1998

  • Large magneto crystalline anisotropy energy and demagnetization energy of rare earth-transition metal (RF-TM) alloys play roles of bottlenecks towards their commercial applications for giant magnetostrictive and blue wavelength magneto optical recording materials, respectively. To solve the above problems, boron is added into amorphous RE-TM alloys to produce its electron transferring. The boron added amorphous RE-TM alloys show novel magnetic and magneto-optical properties as follows; 1) an amorphous $(Sm_{33}Fe_{76})$97B3 alloy obtains the magnetostriction of$ -550{times}10^{-6}$ at 400 Oe compared with saturation magnetostriction of$ -60{\times}10^{-6}$ in conventional Ni based alloys, 2) an amorphous$ (Nd_{33}Fe_{67})_{95}B_5$ alloy increases effective magnetic anisotropy to$ -0.5{\times}10^{-6} ergs/cm^3 from -3.5{\times}10^6 ergs/cm^3$ without boron, which correspond to the polar Kerr rotation angles of 0.52$^{\circ}$and 0.33$^{\circ}$, respectively. These results attribute to selective 2p-3d electron orbits exchange coupling (SEC).

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가공온도에 따라 다이업셋한 Nd-Fe-B-Cu 합금의 응력과 결정에 관한 연구 (A Study on the Stress and Crystal in Die-Upsetted Nd-Fe-B-Cu Alloys as a Function of Working Temperature)

  • 박정덕;양현수;곽창섭;정원용
    • 열처리공학회지
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    • 제7권1호
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    • pp.61-71
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    • 1994

  • This study is to investigate the stress distributions, crystal orientations and magnetic properties during die-upsetting according to working temperature of Nd-Fe-B-Cu alloys. The stress distributions in the specimens during compressing process were calculated by a finite element method program(SPID). The calculated stresses were effective stress (${\sigma}_{eff}$), compression stress(${\sigma}_z$), radial direction stress(${\sigma}_r$) rotational direction stress(${\sigma}_e$) and shear stress(${\tau}_{rz}$). The stress distributions of ${\sigma}_z$, obtained by a computer simulation showed that the stress components causing the magnetic alignment during die-upsetting of the cast magnets were very high at the center-part of a specimen, and decreased toward the periphery-part of a specimen. In view of the above results the magnetic properties should be better at the center-part of a specimen than any other parts. But the measured magnetic properties were better at the mid-part. These results should be due to the fact that the specimens were casted. Normally the magnetic properties are affected by the casting process as well as by the stress levels. ${\sigma}_r$, ${\sigma}_e$ are thought to affect the liquid phase flowing and domain patterns, respectively. The influence of ${\tau}_{rz}$ was trivial, ${\sigma}_{eff}$ distributed similar throughout the specimen. The Nd-rich phase appeared at the peripheral of the specimen where the stress level of ${\sigma}_r$, ${\sigma}_z$, was low or the stress level of ${\sigma}_e$ was high. The Nd-rich phase was squeezed out during die-upsetting. This phase had an effect on the crystal orientation and grain growth. The stress distributions of alloy were irregular at the parts of the specimen where the die contacted with specimen.

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