• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1997.11a
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• pp.120-123
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• 1997

In this paper, we deal with the effect on magnetic properties when Nd is added to Sr ferrite bonded magnet. First, we choose SrO$_{n}$.Fe$_2$O$_3$(n=5.9), which is nonstoichiomatric composition, as specimen ferrite. Then, we add 5wt% polyvinyl alcohol and calcinate at 12$25^{\circ}C$ under $N_2$ environment for carbon coating on chemical compound specimen. After that we obtain 1.2${\mu}{\textrm}{m}$ single domain powder through grinding process for 18 hours. The single domain Sr ferrite Powder is well mixed with silage coupling and calcium stearate of 1wt% Then, it is kneaded by using polyamide12 as a binder and is pelleted. After adding Nd-Fe-B powder to the pelleted specimen, we injection-mould it under magnetic field by using anisotropic mould. Especially, when we add l3wt% Nd-Fe-B powder to the polyamide12, we obtain excellent magnetic propertiecs which are $_{B}$H$_{C}$=2.65KOe, Br=3.16KG and (BH)$_{max}$=2.61MGOeOeOeOeOe

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.412-415
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• 1995

By adding 1wt.% $HfB_{2}$ into $Nd_{3-4}Fe_{77-78.5}B_{18.5}$ alloys, the grain growth of $Fe_{3}B/Nd_{2}Fe_{14}B$ composite phases during annealing was found to be hindered by 40~50%. It is proposed that the addition of $HfB_{2}$ leads to the formation of fine dispersoids of $HfB_{2}$ in the $Fe_{3}B/Nd_{2}Fe_{14}B$ composite magnet. The maximum energy product($(B.H)_{max}$) as well as intrinsic coercivity($_{i}H_{c}$) for the $Nd_{3}Fe_{78.5}B_{18.5}\;+\;1wt.%\;HfB_{2}$ alloy were enhanced by more than 25% $(B.H)_{max}=10\;MGOe,\;_{i}H_{c}=2.5\;kOe)$ due to the addition of $HfB_{2}$ while remanent magntization($B_{r}$) was reduced slightly. Itis deduced that the formation of fine dispersoids will also play a role of magnetic domain pinning.

• Journal of the Korean Magnetics Society
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• v.5 no.5
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• pp.421-426
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• 1995

The magnetic properties of the hot-pressed magnets made from the Fe-Nd-B alloys, mechanically ground and subsequently blended with binary additives such as Al-Cu and Ag-Zn before hot pressing, were investigated. The coercivities of the magnets increased as the concentration of Al-Cu increased up to 1 wt.% or up to 3 wt.% in the case of Ag-Zn. At higher concentrations the coercivities decreased markedly. The maximum gain in coercivity by the addition was about 20 %. typical values of $_{i}H_{c}$ and $B_{r}$ of a hotpressed magnet containing 1 wt.% Al-Cu were 18 kOe and 7 kG, respectively. It was found that Cu, Ag, and Zn, which diffused into the magnet during hot pressing, were mostly concentrated on the Nd-rich grain boundary phase whereas Al was present not only in the grain boundary region but also in the matrix grains.

• Proceedings of the Korean Magnestics Society Conference
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• 2012.05a
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• pp.102-102
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• 2012

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.15-17
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• 2002

In this paper, we analyse the dynamic characteristic of 3-phase line start permanent magnet motor considering magnetization. Magnetization vector of NdFeB is obtained from the 2-D FEM magnetization analysis. And comparing the proposed analysis with conventional analysis method, we know that it is necessary to consider magnetization in dynamic analysis.

• Journal of the Korean Magnetics Society
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• v.6 no.2
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• pp.80-85
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• 1996

An externally applied magnetic field during annealing the $Nd_{2}Fe_{14}B/Fe_{3}B$ based spring magnet was found to enhance the exchange coupling between the hard and soft magnetic grains. More than 30 % increase in remanence values for melt-spun $Nd_{4}Fe_{73.5}Co_{3}(Hf_{1-x}-Ga_{x})B_{18.5}$(x=0, 0.5, 1.0) alloys was resulted from uniform distribution of $Fe_{3}B$, $\alpha$-Fe as well as $(Nd_{2}Fe_{14}B)$, and also from reduced grain size of those phases by 20 %. The result also showed that there is an optimum grain size exhibiting a high coercivity value which will be discussed in terms of previously simulated exchange coupling parameter.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.721-722
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• 2006

Industrialization and technique consequently in quick development the motor field small size and light weight, high efficiency and highly energy density in necessity. The permanent magnet motor small size and the research regarding the research of the torque and efficiency is coming to be active. From this paper the research regarding the quality permanent magnet motor and analysis and it was developed recently the NdFeB anisotropic bond magnet which is a high magnetic force material use, from the hazard which accomplishes power density it is high permanent magnet motor of small size and light weight it researched. The Finite Element Method it led and motor optimization. Also the experiment and analysis permanent magnet motor it is improved the motor and result it led and different it compared.

• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.308-311
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• 1998

Experiments and design efforts have been made to develope a hybrid-type magnet for magnetically levitated(MAGLEV) vehicle using NdFeB permanent magnet. The permanent magnet, which embedded in both poles of the magnet, has been designed, analyzed using FEM program. The model is manufactured and tested to verify its performance.

• Proceedings of the Korean Magnestics Society Conference
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• 2004.12a
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• pp.241-242
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• 2004

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2004.04a
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• pp.47-47
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• 2004