Simultaneous enhancement of the coercivity and remanence at high temperatures in a sintered Nd-Fe-B magnet after grain boundary diffusion with Dy60Co40 alloy

Chen, Fugang; Zhang, Lanting; Jin, Yunxue; Cheng, Ye

doi:10.1016/j.matchar.2018.08.012

Cited by 36 publications

(4 citation statements)

References 24 publications

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“…As shown in Figure 1 and Table 1, all of the magnets' magnetic properties decrease as temperature increases. Both the coercivity and remanence of magnets decrease with increasing temperatures, but the temperature sensibility of the coercivity is much larger than that of the remanence, which is consistent with previous reports [31,32]. The magnets after GBD with Dy/Tb possess much higher coercivity than that of the original magnet at 20 • C, 100 • C, and 150 • C, and the corresponding remanence as well as maximum magnetic energy product are slightly lower than those of the original magnet.…”

Section: Magnetic Propertiessupporting

confidence: 90%

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

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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.

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Section: Magnetic Propertiessupporting

confidence: 90%

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

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“…The above observation hence points to a trade-off between B r @150 °C and H cj @150 °C. Hence, it is unlikely that simultaneous enhancement of B r and H cj could be achieved through doping with the investigated species in this work, although it can be achieved with a grain boundary diffusion process 80 or through an annealing process. 81…”

Section: Post-hoc Interpretationmentioning

confidence: 98%

Accelerated discovery of cost-effective Nd–Fe–B magnets through adaptive learning

Chen¹,

Liu²,

Zhang³

et al. 2023

J. Mater. Chem. A

Self Cite

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“…The GBDP was originally developed for the sintered Nd-Fe-B magnets. In early studies, the GBDP which utilized HRE fluorides [ 46 , 47 ], HRE hydrides [ 17 , 48 ], or HRE alloys [ 49 , 50 ] has been proven successful in improving the coercivity of sintered magnets through the formation of HRE-enriched shells. However, this process requires high temperatures of about 900 °C, making it unsuitable for the nanosized HD magnets due to the significant grain coarsening.…”

Section: Two Routes For High-coercivity Hot-deformed Magnetsmentioning

confidence: 99%

Significant Progress for Hot-Deformed Nd-Fe-B Magnets: A Review

et al. 2023

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High-performance Nd-Fe-B-based rare-earth permanent magnets play a crucial role in the application of traction motors equipped in new energy automobiles. In particular, the anisotropic hot-deformed (HD) Nd-Fe-B magnets prepared by the hot-press and hot-deformation process show great potential in achieving high coercivity due to their fine grain sizes of 200–400 nm, which are smaller by more than an order of magnitude compared to the traditional sintered Nd-Fe-B magnets. However, the current available coercivity of HD magnets is not as high as expected according to an empirical correlation between coercivity and grain size, only occupying about 25% of its full potential of the anisotropy field of the Nd2Fe14B phase. For the sake of achieving high-coercivity HD magnets, two major routes have been developed, namely the grain boundary diffusion process (GBDP) and the dual alloy diffusion process (DADP). In this review, the fundamentals and development of the HD Nd-Fe-B magnets are comprehensively summarized and discussed based on worldwide scientific research. The advances in the GBDP and DADP are investigated and summarized based on the latest progress and results. Additionally, the mechanisms of coercivity enhancement are discussed based on the numerous results of micromagnetic simulations to understand the structure–property relationships of the HD Nd-Fe-B magnets. Lastly, the magnetization reversal behaviors, based on the observation of magneto-optic Kerr effect microscopy, are analyzed to pinpoint the weak regions in the microstructure of the HD Nd-Fe-B magnets.

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Simultaneous enhancement of the coercivity and remanence at high temperatures in a sintered Nd-Fe-B magnet after grain boundary diffusion with Dy60Co40 alloy

Cited by 36 publications

References 24 publications

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

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

Accelerated discovery of cost-effective Nd–Fe–B magnets through adaptive learning

Significant Progress for Hot-Deformed Nd-Fe-B Magnets: A Review

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