Journal of the Korean Magnetics Society (한국자기학회지)

The Korean Magnetics Society (한국자기학회)
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The Effect of Magnetic Field on Enhancing the Anisotropy of Melt-spun Nd-Fe-Co(-Zr)-B Alloy

급속응고중 외부자장에 의한 Nd-Fe-Co(-Zr)-B계 합금의 자기이방성 향상

  • Lee, U-Yeong (Electromagnetic Materials Laboratory, Research Institute of Industrial Science and Technology) ;
  • Choe, Seung-Deok (Electromagnetic Materials Laboratory, Research Institute of Industrial Science and Technology) ;
  • Yang, Chung-Jin (Electromagnetic Materials Laboratory, Research Institute of Industrial Science and Technology)
  • 이우영 (산업과학기술연구소, 신소재부문 자성재료연구분야) ;
  • 최승덕 (산업과학기술연구소, 신소재부문 자성재료연구분야) ;
  • 양충진 (산업과학기술연구소, 신소재부문 자성재료연구분야)
  • Published : 1992.11.01
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Abstract

Melt-spun $Nd_{14}Fe_{76}Co_4B_6$ and $Nd_{10.5}Fe_{79}Co_2Zr_{1.5}B_7$ ribbons were prepared under an externally applied magnetic field. Magnetic properties in terms of anisotropy were evaluated by discussing the effect of textured structure of the ribbon samples as well as its powders. About 32 % increase in $(B{\cdot}H)_{max}$ and 18.8 % increase in $B_r$ were observed along the perpendicular direction of the ribbon plane which is more prominent for the Nd-Fe-Co-Zr-B than for the Nd-Fe-Co-B alloy. The enhancement of magnetic anisotropy was monitored by measuring the anisotropy constant of each alloy as a function of quenching rate of the ribbon. It was found that for the melt-spun ribbon quenched at slow rate(less than 7 m/s) the magnetic field effect was overwhelmed by the heat gradient effect through the ribbon thickness while the field effect was prominent at intermediate quenching rate (more than 7~11 m/s). The reproducible maximum energy product, $(B{\cdot}H)_{max}$=16.4 MGOe can be obtained from the Nd-Fe-Co-Zr-B alloy.

유도용해법으로 $Nd_{14}Fe_{76}Co_4B_6$합금 및 $Nd_{10.5}Fe_{79}Co_2Zr_{1.5}B_7$합금의 급냉리본을 제조하고, 냉각속도와 급냉중 외부자장력이 결정이방성과 자기특성에 미치는 영향을 조사하였다. 토크자력계로 측정한 두 합금의 결정자기 이방성은 냉각속도가 증가함에 따라 급격히 감소하였다. 가장 우수한 자기 특성은 두 합금 모두 냉각속도 $V_s$=11 m/s에서 얻어졌으며, 자장중 급냉한 합금의 결정자기이방성 상수가 자장없이 급냉한 합금보다 30~40 % 높게 측정되었다. 외부 자장하에서 급냉된 $Nd_{10.5}Fe_{79}Co_2Zr_{1.5}B_7$합금은 냉각속도 $V_s$=11 m/s에서 $B_r$=8.82 kG, $_iH_c$=9.85 kOe 및 $(B{\cdot}H)_{max}$=16.4 MGOe의 우수한 자기특성을 보인다.

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