Anisotropic Nanocomposite $\hbox{Nd}_{2}\hbox{Fe}_{14}\hbox{B}/\alpha$–$\hbox{Fe}$ Magnets Prepared by Spark Plasma Sintering

Ma, Yi; Liu, Y.; Li, J.; Du, Hao; Gao, Jing

doi:10.1109/tmag.2009.2018911

Cited by 17 publications

(7 citation statements)

References 8 publications

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“…It has been employed to fabricate nanocrystalline materials [7], composites [8][9][10], and functionally graded materials [11][12][13], etc. The SPS for NdFeB based magnets has also been studied by many groups [5,[14][15][16] and good properties have been obtained. However, most work focused on the processing and properties, the evolution of the microstructure has not been very much emphasized.…”

Section: Introductionmentioning

confidence: 99%

Isotropic and Anisotropic Nanocrystalline NdFeB-Based Magnets Prepared by Spark Plasma Sintering and Hot Deformation

Liu

Huang

et al. 2012

KEM

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Isotropic and anisotropic NdFeB permanent magnets were prepared by Spark Plasma Sintering (SPS) and SPS followed hot deformation (HD), respectively, using melt spun NdFeB ribbons with various compositions as starting materials. It is found that, based on RE-rich composition, SPSed magnets sintered at low temperatures (<700 C) almost maintained the uniform fine grain structure inherited from rapid quenching. At higher temperatures, a distinct two-zone (coarse grain and fine grain zones) structure was formed in the SPSed magnets. The SPS temperature and pressure have important effects on the grain structure, which led to the variations in the magnetic properties. By employing low SPS temperature and high pressure, high-density magnets with negligible coarse grain zone and an excellent combination of magnetic properties can be obtained. For single phase NdFeB alloy, because of the deficiency of Nd-rich phases, it is relatively difficult to consolidate micro-sized melt spun powders into high density bulk magnet, but generally a larger particle size is beneficial to achieve better magnetic properties. Anisotropic magnets with a maximum energy product of ~38 MGOe were produced by the SPS+HD process. HD did not lead to obvious grain growth and the two-zone structure still existed in the hot deformed magnets. The results indicated that nanocrystalline NdFeB magnets without significant grain growth and with excellent properties could be obtained by SPS and HD processes.

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Section: Introductionmentioning

confidence: 99%

Isotropic and Anisotropic Nanocrystalline NdFeB-Based Magnets Prepared by Spark Plasma Sintering and Hot Deformation

Liu

Huang

et al. 2012

KEM

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“…4(a), the elements of Nd, Fe and Zn enriched at the particle interface. From previous studies, it is known that Zn powder can react with Nd-Fe-B in hot-pressing process to generate some new phases, such as Nd-Fe, Zn-Fe and α-Fe [10,11]. Therefore, according to the EDS results the white area is Nd-rich phase and the dark grey area is Zn, Fe-rich phases at the particle interface.…”

Section: Resultsmentioning

confidence: 99%

“…In our previous works, the anisotropic Nd-lean Nd-Fe-B magnets could be obtained by the addition of Zn powder combined with hot-deformation technology [10]. Moreover, the effects of adding Zn and other elements on the magnetic properties were also studied [11,12].…”

Section: Introductionmentioning

confidence: 99%

Preparation of Anisotropic Nd-Lean Nd-Fe-B Magnets with Improved Coercivity

Long

Yin

et al. 2017

MSF

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Anisotropic bulk nanocrystal Nd-lean Nd-Fe-B magnets were prepared by hot-pressing the mixture of Nd11.5Fe81.5Nb1B6 melt-spun ribbons and pure Zn powder and subsequent hot-deforming. The effects of deformation on the magnetic properties and microstructure were also studied. The magnetic properties increased significantly for hot-deformed (HD) samples due to the formation of good c-axis texture with increasing deformation. The remanence Mr and maximal energy product (BH)m increased and reached their maximal values at 65% deformation due to the increasing orientation. On the other hand, the grains increased and were elongated normal to the press direction gradually with increasing deformation. The variation trend was similar to that of traditional Nd-Fe-B magnets. However, there was an obvious improvement for coercivity in the initial stage of hot-deformation resulting from the adequate Zn diffusion into grain-boundary. When the deformation was larger than 65%, the magnetic properties were deteriorated due to abnormal grain growth. In order to improve further the coercivity Hci, the samples with Dy addition were prepared. The coercivity of 12300 Oe could be obtained for anisotropic bulk Nd9.5Dy2Fe81.5Nb1B6.

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“…Using the SPS method, powder can be easily consolidated at relatively lower temperatures in a short consolidation time. This method has been used in several studies to consolidate Nd-Fe-B powders [11][12][13][14][15][16] , and may also be applicable to the production of hot-deformed magnets 17) . It is known that the magnetic properties of Nd-Fe-B magnets depend on the degree of crystallographic alignment of the tetragonal Nd 2 Fe 14 B magnetic phase.…”

Section: Introductionmentioning

confidence: 99%

Magnetic Properties of Nd-Fe-B Anisotropic Magnets Prepared by Spark Plasma Sintering Method

Saito

Sajima

2016

J. Jpn. Soc. Powder Powder Metallurgy

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Nd-Fe-B hot-deformed magnets were produced by the spark plasma sintering (SPS) method from bulk materials prepared by the SPS method. The bulk materials, prepared by the SPS method from commercially available Nd-Fe-B melt-spun ribbon (MQ powder), consisted of the Nd 2 Fe 14 B phase and were magnetically isotropic. The subsequent hot deformation induced magnetic anisotropy in the Nd-Fe-B magnets. The optimally hot-deformed magnet showed a high remanence of 1.39 T with a maximum energy product of 240 kJm −3

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Anisotropic Nanocomposite $\hbox{Nd}_{2}\hbox{Fe}_{14}\hbox{B}/\alpha$–$\hbox{Fe}$ Magnets Prepared by Spark Plasma Sintering

Cited by 17 publications

References 8 publications

Isotropic and Anisotropic Nanocrystalline NdFeB-Based Magnets Prepared by Spark Plasma Sintering and Hot Deformation

Isotropic and Anisotropic Nanocrystalline NdFeB-Based Magnets Prepared by Spark Plasma Sintering and Hot Deformation

Preparation of Anisotropic Nd-Lean Nd-Fe-B Magnets with Improved Coercivity

Magnetic Properties of Nd-Fe-B Anisotropic Magnets Prepared by Spark Plasma Sintering Method

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