Nd-Fe-B nanocomposite permanent magnets

Hirosawa, Rainer

doi:10.1201/9781420033816.ch20

Cited by 3 publications

(3 citation statements)

References 23 publications

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“…The (BH) max grew reaching maximum values for 4 at.% of Mo and Ti and 5 at.% of Nb. The highest (BH) max of 99 kJ/m 3 was obtained for 4 at.% Ti, which is consistent with the results reported by Hirosawa et al [8].…”

Section: Resultssupporting

confidence: 94%

“…In recent years addition of refractory metals has been used for the improvement of the properties of low Nd rapidly solidified nanocomposite magnets, which due to the high volume fraction of soft magnetic phases suffer from coercivity deterioration. Hirosawa reported that addition of a few percent of Ti retards formation and growth of the Fe primary grains, promoting crystallization of the hard magnetic Nd 2 Fe 14 B phase [8]. Microstructural studies showed that additional introduction of a small amount of carbon leads to further grain refinement giving rise to 300% increase of the coercivity ( J H c = 1 MA/m J r = 0,8 T).…”

Section: Introductionmentioning

confidence: 97%

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Improvement of the Properties of Hard Magnetic NdFeb/Fe Nanocomposites by Minor Addition of Refractory Metals

Leonowicz¹,

Spyra²,

Jezierska³

2011

Mechanics of Advanced Materials and Structures

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The effect of the addition of selected refractory metals on structure and magnetic properties was studied for the nanocomposite Nd 9 Fe 77−x B 14 M x (M=Ti, Mo, Nb) system, consisting of hard magnetic Nd 2 Fe 14 B phase, and soft magnetic phases (Fe, Fe 3 B). It was found that 2-5 at % of Ti, Mo or Nb addition leads to a substantial increase of the coercivity and maximum energy product of the nanocomposite magnets maintaining the remanence unchanged. The highest properties were obtained for the alloys containing 4-5 at% of the refractory metals. The hysteresis loops for the alloys containing additional elements are smooth and characteristic of single phase alloys. The initial magnetization curve indicates the change of the coercivity mechanisms giving rise for pinning of domain walls, which is caused by the reduction of the crystallite size.

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Section: Resultssupporting

confidence: 94%

Section: Introductionmentioning

confidence: 97%

Improvement of the Properties of Hard Magnetic NdFeb/Fe Nanocomposites by Minor Addition of Refractory Metals

Leonowicz¹,

Spyra²,

Jezierska³

2011

Mechanics of Advanced Materials and Structures

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“…Refractory metals has been added into the alloy to improve the properties of RE-lean nanocomposite magnets, which are suffering from coercivity deterioration because of the high volume fraction of soft magnetic phases [10]. Hirosawa et al reported that the addition of Ti could promote the crystallization of Nd 2 Fe 14 B phase [11], Li et al pointed that Nb could improve the grain refinement and promoted the c-axis texture formation during hot-deformation, thus a enhancement of magnetic properties of RE-lean magnets was obtained [12].…”

Section: Introductionmentioning

confidence: 99%

Effects of Co, Zr Additions on the Magnetic Properties of Nanocomposite Nd<sub>2</sub>Fe<sub>14</sub>B/α-Fe Magnets

Long

et al. 2017

MSF

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The effects of the additions of Co, Zr on microstructure and magnetic properties were studied for hot-deformed (HD) nanocomposite Nd11.5Fe81.5-xNb1CoxB6 (x=0, 2, 4, 8) and Nd11.5Fe82.5-xZrxB6 (x=0, 1) magnets, respectively. The remanence of hot-pressed (HP) magnets increased with increasing Co content firstly, but decreased when Co content was more than 2 at. % for HD magnets. Also the intrinsic coercivity (Hci) and maximum energy product ((BH)m) of HD alloys increased firstly, and then decreased with further increasing Co content. The maximum (BH)m of 24 MGOe was obtained at 2 at.% Co addition. Zr addition can improve significantly the c-axis alignment and magnetic properties of HD nanocomposite magnets, and HD Nd11.5Fe81.5Zr1B6 magnet with 1.5 wt.% Zn addition showed enhanced properties with Hci of 7100 Oe and remanent magnetization (Mr) of 1.06 T. The alloys have the structure of plate-like grains, but there are still many coarse grains, which may result from the un-uniform composition in the alloy.

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