• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 춘계연구발표회 논문개요집
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• pp.142-143
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• 2002

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2002년도 춘계연구발표회 논문개요집
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• pp.144-145
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• 2002

• 한국자기학회:학술대회 개요집
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• 한국자기학회 1992년도 추계연구발표회 논문개요집
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• pp.66-67
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• 1992

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2001년도 춘계연구발표회 논문개요집
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• pp.74-75
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• 2001

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2002년도 춘계학술강연 및 발표대회
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• pp.26-27
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• 2002

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2001년도 추계연구발표회 논문개요집
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• pp.94-95
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• 2001

• 한국자기학회지
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• 제22권3호
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• pp.109-115
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• 2012

지난 5년간 NdFeB계 이방성 본드자석은 25 MGOe의 높은 자기특성을 강점으로 기존 페라이트 영구자석을 갈음하면서 모터의 경량화라는 새로운 패러다임을 주도했고 자동차용과 전동공구용 모터산업분야에서 두드러진 약진을 보였다. 또한 차체중량감소를 통한 연비향상이라는 자동차산업의 기술동향에 정확히 초점을 두고 기존모터의 50 % 경량화라는 새로운 변혁을 이끌어 냈다. 그러나 2010년 7월에 중국이 희토류원소의 수출규제를 발표함에 따라 2011년 희토류 원자재는 또 한 차례의 폭등을 기록하였고 그 여파는 전방 수요산업에 심각한 충격으로 던져지고 있다. 각 희토류 주요 소비국들은 자원 확보, 희토류 최소사용부품개발 및 희토류 대체 신기술개발 강화에 총력을 다하는 모습이다. 이러한 환경적 변화가 이방성 본드자석 분야에는 중희토류 원소인 Dy의 사용량을 줄이면서 보자력을 향상시키고자하는 기술적 도전을 유발하였고 모터고속화 응용분야에 탐색을 시도하게 하였다. 본 글에서는 희토류 자원문제에 대한 각국 희토류자석산업의 대응과 NdFeB 이방성 본드자석으로 대표되는 Aichi Steel사의 MAGFINE 자성분말에 대해 최근의 개발 동향 및 응용분야에 대해 소개하고자 한다.

• 한국분말재료학회지
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• 제18권1호
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• pp.29-34
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• 2011

In order to increase the coercivity of (Nd, Dy)-Fe-B sintered magnets without much reduction of remanence, small amount of Dy compounds such as $Dy_2O_3$ and $DyF_3$ was mixed with (Nd, Dy)-Fe-B powder. After mixing, the coercivity of (Nd, Dy)-Fe-B sintered magnets apparently increased with the increase of Dy compound in the mixture. Addition of $DyF_3$ was more effective than $Dy_2O_3$ for the improvement of coercivity. Reduction of the remanence by the addition of Dy compound, however, was larger than expected mostly due to unresolved coarse Dy compound in the magnet. EPMA analysis revealed that Dy was diffused throughout the grains in the magnet mixed with $DyF_3$ whereas Dy was rather concentrated around grain boundaries in the magnet mixed with $Dy_2O_3$.

• Journal of Magnetics
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• 제3권1호
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• pp.4-8
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• 1998

Two different compositions of melt spun magnetic alloys, $ Nd_4Fe_{80}B_{16} and Nd_4Fe_{76}Co}\_3Hf_{0.5}Ga_{0.5}B_{16},$ were characterized in terms of magnetic properties and thermal behaviors. It was found that the addition of Hf and Ga effectively slow down the crystallization rate of the nanocomposite $ Nd_2Fe_{14}B/Fe_3B$ magnet. Coercivity(iHc) changes only slightly with varying the post annealing conditions confirming that iHc is not a sensitive magnetic quantity as a function of grain size and exchange coupled interaction. The experimentally observed behaviors of Mr and Hc do not vary monotonously with in-creasing grain size which is not in agreement with the numerically calculated result near the critical grain size (dc). The plot of the grain size dependence for the remanence and coercivity in isotrop!c nanocomposite magnets has been revised in this study. The maxium energy product, $(B, H)_{max}$ =15.34 MGOe, and a reduced remanence, Mr/Ms=0.84 were obtained, respectively.

• 소성∙가공
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• 제8권2호
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• pp.135-142
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• 1999

Tube Process(TP) is one of the processes to produce permanent magnets. Advantage claimed for this process is that it can accmplish both densification and anisotropication in one step forming. This process is distinguished from other processes since it uses deformable tube for densification of powder magnets. TP has, however, difficulties in manufacturing permanent magnets from Nd-Fe-B green powder due to folding resulted from large height reduction and localized densification. Therefore, an adequate preform is necessary to reduce folding resulted from large height reduction and localized densification. Therefore, an adequate preform is necessary to reduce folding, lead magnets into almost desired final shape and get uniform densification. In this paper, preform design for TP is carried out without a deformable tube to investigate the behaviour of magnet sinter-forging. Preform design is accomplished to increase the effective magnet area with a near net shape and uniform densification.