Effect of diffusion annealing on the hysteretic properties of sintered Nd-Fe-B magnets

Попов, А. Г.; Vasilenko, D. Yu.; Puzanova, T. Z.; Шитов, А. В.; Vlasyuga, A. V.

doi:10.1134/s0031918x11040107

Cited by 19 publications

(3 citation statements)

References 3 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For solid state diffusion, the shells should form on both sides of GBs. Although there are several reports on the formation of the shell structure both in Dy or Tb GBDP sintered Nd-Fe-B magnets [5,[8][9][10][11][12][13][14][15][16][17][18], all previous investigations overlooked this asymmetric nature of the Dy-rich shell along GBs. A better understanding on the origin of the unique asymmetric feature of the Dy-rich shell should shed light on the mechanism of the microstructure evolution that contribute to the coercivity enhancement.…”

Section: Introductionmentioning

confidence: 94%

Faceted shell structure in grain boundary diffusion-processed sintered Nd–Fe–B magnets

Seelam

Ohkubo

Abe

et al. 2014

Journal of Alloys and Compounds

101

View full text Add to dashboard Cite

a b s t r a c tDysprosium enriched shell structure formed by the grain boundary diffusion process (GBDP) of a sintered Nd-Fe-B magnet was characterized by using scanning electron microscopy, electron back-scattered diffraction and transmission electron microscopy. Faceted core-shell interfaces with an abrupt change in Dy concentration suggest the Dy-rich shells are formed by the solidification of the liquid phase during cooling from the GBDP temperature. The Nd-rich phases are almost free from Dy, and their quantity near the surface of a bulk sample is much higher than that in the center, indicating that a higher fraction of a liquid phase exists near the surface during processing at 900°C. These microstructural features are explained on the basis of the phase equilibrium between Nd and Nd 2 Fe 14 B at the processing temperature and subsequent cooling. Based on the results, we discuss the coercivity enhancement by the GBDP using Dy vapor.

show abstract

Section: Introductionmentioning

confidence: 94%

Faceted shell structure in grain boundary diffusion-processed sintered Nd–Fe–B magnets

Seelam

Ohkubo

Abe

et al. 2014

Journal of Alloys and Compounds

101

View full text Add to dashboard Cite

show abstract

“…Various diffusion methods with different diffusion resources have been developed so far, such as dip coating with HREE in the form of oxides and fluorides or hydrides [11,[15][16][17], sputtering deposition [18][19][20] or evaporation deposition [21][22][23][24] of pure HREE metals, and electrodeposition of fluorides [25][26][27][28]. The dip coating method involves a simple process, however, the amount of source coating cannot be precisely controlled.…”

Section: Introductionmentioning

confidence: 99%

Coercivity Enhancement of Sintered Nd-Pr-Fe-B Magnets by Cost-Effective Grain Boundary Diffusion of Dy/Tb Films

Zhu,

Wang,

et al. 2023

Crystals

View full text Add to dashboard Cite

High-performance sintered Nd-Pr-Fe-B magnets were successfully prepared by depositing Dy/Tb films on the surface using magnetron sputtering, which resulted in superior grain boundary diffusion (GBD) under heat treatments. The course of the diffusion was assessed using an electron probe microanalyzer (EPMA) and inductively coupled plasma (ICP). The magnetic properties and thermal stability of the magnets before and after diffusion were investigated. The results show that, mainly due to the increased and optimized Nd-Pr-rich phases and the formation of the (Nd,Pr,Dy/Tb)2Fe14B shell structure surrounding the (Nd,Pr)2Fe14B grains, the coercivity of the Dy- and Tb-diffused magnets was enhanced from 16.7 kOe to 24.8 kOe and 28.4 kOe, respectively, while the corresponding maximum energy product (BHmax) was 48.1 MGOe and 48.5 MGOe, respectively. The consumption of Dy/Tb in this work (0.35 wt% Dy in the Dy-diffused magnet and 0.42 wt% Tb in the Tb-diffused magnet) is much lower than that of previously reported magnets with comparable coercivity. Furthermore, Dy- or Tb-diffused magnets exhibit better thermal stability than that of the original magnet, owing to the better resistance to thermal disturbances of the magnets with optimized microstructure. This work can provide useful guidance for preparing Nd-Fe-B magnets with low cost and high performance.

show abstract

“…In 2000, Park et al proposed a promising way of grain boundary diffusion (GBD) to enhance the coercivity of thin Nd-Fe-B sintered magnets [8]. Lately, [9][10][11][12][13][14][15][16][17][18]. By annealing Nd-Fe-B sintered magnets, coated with micron-size TbF 3 particles, Nakamura et al [9] achieved a coercivity enhancement from 0.9 to 1.7 MA/m in the magnets without sacrificing their remanence.…”

Section: Introductionmentioning

confidence: 99%

Magnetic domain switching in Nd–Fe–B sintered magnets with superior magnetic properties

Yue

Liu

et al. 2018

Materials Research Letters

View full text Add to dashboard Cite

Nd-Fe-B sintered magnets with a giant intrinsic coercivity of 47.1 kOe and a high maximum energy product of 38.5 MGOe have been prepared via a combination of conventional sintering techniques and novel grain boundary diffusion process. Microstructural observations show that the Nd 2 Fe 14 B main phase grains in the magnets exhibit a core/shell type rare-earth elements distribution, where Tb enriched (Nd,Tb) 2 Fe 14 B phases are formed in the surface regions of the grains. Magnetic domain observations indicate that these modified surface regions strongly restrain the nucleation process of reversed magnetic domains, leading to a remarkable enhancement of the coercivity and overall magnetic performance of the magnets. IMPACT STATEMENT Nd-Fe-B sintered magnets with an unprecedented overall magnetic property have been fabricated with a novel approach, and the origin of magnetic property enhancement was elaborated via magnetic domain observation.

show abstract

Effect of diffusion annealing on the hysteretic properties of sintered Nd-Fe-B magnets

Cited by 19 publications

References 3 publications

Faceted shell structure in grain boundary diffusion-processed sintered Nd–Fe–B magnets

Faceted shell structure in grain boundary diffusion-processed sintered Nd–Fe–B magnets

Coercivity Enhancement of Sintered Nd-Pr-Fe-B Magnets by Cost-Effective Grain Boundary Diffusion of Dy/Tb Films

Magnetic domain switching in Nd–Fe–B sintered magnets with superior magnetic properties

Contact Info

Product

Resources

About