• Journal of the Korean Magnetics Society
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• v.21 no.4
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• pp.147-150
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• 2011

Since their discovery in the early 1980's, the market for bonded rare earth magnets has shown steady growth. Today these magnets are widely used for our daily life such as computer peripherals, automotive, consumer electronics, and office automation. However, the price increases of rare-earths started from the $2^{nd}$ half of 2010 became even worse in 2011. During $2^{nd}$ quarter of 2011, almost all of rare-earths showed unprecedented vertical price increases, and it brought significant impact to the related industry in terms of the price and supply. This will ask the fundamental change in the policy of the bonded rare earth industry to expand its market share, which has been highly dependent on the replacement of ferrite magnets via relatively higher performance compared to the price at certain applications. In order to achieve the sustainable growth of bonded rare-earth magnets in the future, it needs to change the current paradigm and setup the new business model. This article includes a brief summary of the rare earth price trend and the applications of the rare-earth bonded magnets. The efforts to improve the performance and diversify the applications for future growth have been also presented.

• Resources Recycling
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• v.22 no.4
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• pp.55-61
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• 2013

In this study, eco efficiency analysis is performed to analyze Neodymium (Nd) containing permanent magnet recycling process. Life cycle assessment (LCA) and life cycle costing (LCC) are used to apply eco efficiency analysis. In the environmental aspects, global warming potential (GWP) of 1kg permanent magnet is 1.25E + 00 kg $CO_2$ eq. and abiotic resource depletion potential (ADP) is 1.10E - 02 Sb eq. This recycling process costs about 2130 KWR. Environmental efficiency of GWP is at 6.43 and ADP is at 5.32 when compared with vigin metal. Economic efficiency is at 6.74. This study confirms that Nd containing permanent magnet recycling process is sustainable system because of environmental and economical improvement.

• Journal of the Korean Magnetics Society
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• v.22 no.3
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• pp.109-115
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• 2012

NeFeB anisotropy bonded magnet has proposed a new paradigm of weight reduction of small motors by replacing the conventional ferrite permanent magnets with its high magnetic property of 25 MGOe during last five years. It has also advanced by leaps and bounds in the field of motor industry for automobiles and electric power tools. And it has led a new innovation of fifty percent weight lightening compared to its current motors by correctly focusing on fuel performance improvement through weight lightening that automobile industry chased. There was, however, another price skyrocketing in 2011 after China had announced its export regulation in rare earth materials in July, 2010. And this price change has an extensive impact on the industries that consume rare earth magnets. This environmental change has caused technical challenge to improve the performance by using least amount of rare earth elements in NdFeB anisotropy bonded magnets, and led to make a new technical approach to a new applied field. In this article, we will show how each nation deals with this industrial issue, and introduce development trend and application of anisotropic NdFeB bonded magnets, so-called MAGFINE made by Aichi Steel Corp.

• Journal of the Korean Magnetics Society
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• v.12 no.1
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• pp.34-40
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• 2002

In order to improve the microstructure of the strip cast Nd-Fe-B alloys that are frequently used for production of high energy sintered magnets, influence of various strip casting conditions on the microstructure and phase formation and distribution were investigated. Nd-Fe-B strips consisting of microstructures suitable for preparation of high energy sintered magnets could be obtained when the wheel speed was below 5 m/s. The compositional limit that can avoid the crystallization of free iron in the as-cast state was estimated to be Nd$\_$14/Fe$\_$79/B$\_$7/. Regardless of the compositional variation, <001> preferred orientation of Nd$_2$Fe$\_$14/B normal to the strip surface was always occurred below 5 m/s, which would eventually enhance the grain alignment during pressing the powder under a magnetic field. While the coercivity of the strip cast alloys increased with the increase of the wheel speed, mainly due to the refinement of Nd$_2$Fe$\_$14/B grains, it decreased with the reduction of Nd content in the alloy composition as the formation of free iron increased.

• Proceedings of the Korean Magnestics Society Conference
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• 2012.11a
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• pp.85-85
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• 2012

• Korean Journal of Materials Research
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• v.3 no.2
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• pp.175-184
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• 1993

Abstract Co-and/or AI-added Nd-Fe-B-based magnetic alloys were fabricated by using vacuum induction melting frunace, and melt-spun ribbons were made of the magnetic alloys with single roll rapid quenching method. The variation of magnetic properties of the melt-spun ribbons as a function of Cuwheel velocity (Vs) were investigated. Bonded magnets were made of the optimally quenched ribbon fragments, and the magnetic properties of the melt-spun ribbons and the bonded magnets were studied, relating to the microstructure and crystalline structure. Cu-wheel surface velocity had a strong effect on the magnetic properties of the melt-spun ribbons, and the maximum properties were obtained around Vs =20m/sec. The optimally quenched ribbon had a cellura-type microstructure, in which fine N$d_2$F$e_14$B grains were surrounded by thin Nd-rich phase. In case of a 2.1at% AI-added melt-spun ribbon, the magnetic properties were as follows: iHc, Br, and (BH)max were 15.5KOe, 7.8KG and 8.5MGOe respectively. And resin bonded magnets were fabricated by mixing optimally quenched ribbon fragments with 2.5wt % polyamide resin, compacting and binding at room temperature. The iHc, Br and (BH)max of bonded magnet were lO.2KOe, 4.4KG and 3.3MGOe respectively. And hot-pressed magnets were made by pressing the overquenched ribbons at high temperature. The magnetic properties of hot-pressed magnets were better than those of bonded magnets, and when the holding time was 8 minutes, the iHc, Br, and (BH)max of the hot-pressed magnet were 1O.8KOe, 7.3KG and 8.0MGOe respectively. Domain structure was mainly maze pattern, which means that the easy magnetization axis could be aligned, and the domain width of the hot-pressed magnets was smaller than that of bonded magnets.

• Korean Journal of Materials Research
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• v.8 no.9
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• pp.819-824
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• 1998

The influence of casting cooling rate during the preparation of ingots on the grain size distribution and the magnetizing ability of $\textrm{Nd}_{16}\textrm{Fe}_{72}\textrm{V}_{4}\textrm{B}_{8}$ sintered magnets were investigated. Sintered magnets prepared from copper mold which allow a higher cooling rate, show a smaller grain size distribution and god magnetizing ability. The effects of adding bride forming elements, such as Cr, Mn, Nb, and W on the magnetic properties of Nd-Fe-B sintered magnets were also investigated. Both Cr and W addition increase coercivity and the resultant $\textrm{Nd}_{16}\textrm{Fe}_{72}\textrm{Cr}_{4}\textrm{B}_{9}$ alloy exhibits a similar magnetizing ability in comparison with $\textrm{Nd}_{16}\textrm{Fe}_{72}\textrm{V}_{4}\textrm{B}_{8}$ alloy.

• Proceedings of the Korean Magnestics Society Conference
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• 1998.05a
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• pp.86-87
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• 1998

• Proceedings of the Korean Magnestics Society Conference
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• 1994.10a
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• pp.50-51
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• 1994

• Proceedings of the Korean Magnestics Society Conference
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• 1994.10a
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• pp.52-53
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• 1994