Approach to Synthesizing Bulk, Fully Dense Anisotropic Nanocomposite Rare Earth Permanent Magnets

Liu, S.; Cui, Bai; Bauser, S.; Leese, R.; Hilton, J.; Yu, Ruozhou; Kramp, A.; Miles, Danny

doi:10.1002/chin.200311230

Cited by 7 publications

(4 citation statements)

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“…At present, the nanocomposite magnet materials reported to date are isotropic in nature and polymer binders are required to convert these nanocomposite powders into magnets. Converting the isotropic nature into anisotropic and/or identifying a means to compact these nanocomposites into fully dense magnets are challenges of scientific interest and of technology importance [7].…”

Section: Introductionmentioning

confidence: 99%

Hot-pressed and hot-deformed nanocomposite (Nd,Pr,Dy)/sub 2/Fe/sub 14/B/α-Fe-based magnets

et al. 2003

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Fully dense isotropic and anisotropic (Nd,Pr,Dy) 2 Fe 14 B/ -Fe nanocomposite magnets have been successfully prepared by a hot press and hot deformation technique using melt-spun precursors. For the fully dense, hot-deformed, anisotropic nanocomposite (Nd,Pr,Dy) 2 Fe 14 B/ -Fe-based magnets containing 4 vol% and 11 vol% -Fe, the maximum energy products have reached 31 and 24 MGOe, respectively. At the time of proofreading for this paper, 42 MGOe has been reached for the nanocomposite magnets with~4 vol% -Fe.

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Section: Introductionmentioning

confidence: 99%

Hot-pressed and hot-deformed nanocomposite (Nd,Pr,Dy)/sub 2/Fe/sub 14/B/α-Fe-based magnets

et al. 2003

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“…Since both Pr 2 Fe 14 B and PrCo 5 compounds have high uniaxial magnetocrystalline anisotropy, high coercivity would be readily obtained in Pr 2 Fe 14 B and PrCo 5 with nanograin structure. The University of Dayton has also developed the innovative techniques of rapid hot press and hot deformation and has successfully synthesized anisotropic nanocomposite Nd 2 Fe 14 B/α-Fe magnets with full density [5,6]. These techniques were utilized to synthesize anisotropic nanocrystalline Pr 2 (Fe,Co) 14 B and Pr(Co,Fe) 5 magnet materials.…”

Section: (B) Interdiffusion Between Two Different Types Of Materials mentioning

confidence: 99%

“…In an attempt to enhance magnetization of hybrid magnets, we tried to decrease the Pr content in the Pr 2 (Fe,Co) 14 B component from 14.1 at% to 13.6 at%. Figure 14 shows demagnetization curves of Pr 14.1 Fe 72.3 Co 5.1 Ga 0.5 B 8.1 /Pr(Co 0.8 Fe 0.2 ) 5 (80 wt%/20 wt%) and Pr 13.6 Fe 72.8 Co 5.1 Ga 0.5 B 8.1 /Pr(Co 0.8 Fe 0.2 )5 (80 wt%/20 wt%) magnets, respectively. It is obvious that the magnet with 13.6 at% Pr shows not only much lower M H c , but also lower B r and (BH) max than the magnet with 14.1 at% Pr.…”

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confidence: 99%

Hybrid R-Fe-B/R-Co Magnets with Improved Thermal Stability

Shen¹,

Higgins²,

Chen³

et al. 2009

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“…Among all known permanent magnets, the permanent magnets based on rare-earth metals (REM) exhibit the highest characteristics including, in particular, the coercive force, magnetization, and specific magnetic energy. According to the theoretical calculations [1,2], their properties can be improved by the formation of nanocrystalline states in these materials [3]. There are numerous technological approaches developed in this direction [4][5][6][7].…”

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confidence: 99%

Dependence of the Phase Composition of Nd16Fe73.9Zr2.1B8 Alloy on the Conditions of Milling in Hydrogen

Bulyk¹,

Trostyanchyn²,

Burkhovetskyi³

et al. 2015

Mater Sci

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We reveal the competitive influence of two factors in the process of "dry" milling of Nd 16 Fe 73.9 Zr 2.1 B 8 ferromagnetic alloy in hydrogen. As the rotation frequency of the mill chamber and the duration of the process increase, the range of particle sizes of the powder increases but particles become isotropic as a result of agglomeration. We indicate the possibility of application of a liquid medium (oleic acid) with an aim to prevent mechanical alloying of highly dispersed powder particles as a result of long highenergy milling. Highly dispersed anisotropic powders are obtained by milling of the alloy saturated with hydrogen in oleic acid at a rotation frequency of the mill chamber of 100-200 rpm for 12 h.The development of contemporary advanced technologies requires the uninterrupted improvement of permanent magnets. Among all known permanent magnets, the permanent magnets based on rare-earth metals (REM) exhibit the highest characteristics including, in particular, the coercive force, magnetization, and specific magnetic energy. According to the theoretical calculations [1, 2], their properties can be improved by the formation of nanocrystalline states in these materials [3]. There are numerous technological approaches developed in this direction [4][5][6][7]. As their common disadvantage, we can mention the difficulties connected with the appearance of anisotropy.For the formation of anisotropic structures with the help of hydrogen-vacuum thermal treatment by the method of hydrogenation, disproportionation, desorption, and recombination (HDDR), it is customary to use magnetic alloys of the Nd-Fe-B system [8]. There are several assumptions concerning the mechanism of formation of anisotropy after HDDR connected with the state of the material after the first stage of treatment, namely, after hydrogenation and disproportionation (HD). In particular, it is believed that anisotropy can be caused by the presence of residues of the nondisproportionated ferromagnetic phase among the products of HD, by a metastable phase of unknown nature, and by a certain ordering between the crystallographic directions of the phases in the intact material and in the disproportionated mixture.In the investigation of alloys of the Sm-Co system, it was established that anisotropy is attained if the HDDR procedure is realized for the values of parameters guaranteeing that an insignificant amount of ferromagnetic residues of the ferromagnetic phase remains in the alloy after disproportionation. These residues serve as crystallization centers in the course of desorption and recombination and play a decisive role in the formation of

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Approach to Synthesizing Bulk, Fully Dense Anisotropic Nanocomposite Rare Earth Permanent Magnets

Abstract: Inorganic chemistry Inorganic chemistry Z 0100Approach to Synthesizing Bulk, Fully Dense Anisotropic Nanocomposite Rare Earth Permanent Magnets -[9 refs.]. -(LIU, S.; CUI, B.; BAUSER, S.; LEESE, R.; HILTON, J. S.; YU, R. H.; KRAMP, A.; DENT, J.; MILES, D.; Rare Earth Magn.

Cited by 7 publications

References 0 publications

Hot-pressed and hot-deformed nanocomposite (Nd,Pr,Dy)/sub 2/Fe/sub 14/B/α-Fe-based magnets

Hot-pressed and hot-deformed nanocomposite (Nd,Pr,Dy)/sub 2/Fe/sub 14/B/α-Fe-based magnets

Hybrid R-Fe-B/R-Co Magnets with Improved Thermal Stability

Dependence of the Phase Composition of Nd16Fe73.9Zr2.1B8 Alloy on the Conditions of Milling in Hydrogen

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