Temperature dependence of magnetization reversal mechanism in misch-metal substituted Nd-Fe-B magnets sintered by dual alloy method

Liu, D.; Xiong, Jin; Wang, Lichen; Zheng, Xunhua; Peng, Fei; Xi, Mian; Zhao, Tongyun; Hu, Fengxia; Sun, J. R.; Shen, Baogen; Shen, Jun

doi:10.1016/j.actamat.2023.118710

Cited by 16 publications

(4 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…[ 76 ] Judging from comparable powder blend methods where CILFM (or solution/precipitation) could account for the Dy shell formation, a significant grain growth correlated to Dy incorporation should be observed on final magnets. [ 54,59 ] The fact that this is not the case here might exclude these mechanisms on magnet scale. However, the presence of sharp interfaces on anticore–shell recycled grains suggests that a fusion/precipitation of Dy‐poor shells [ 68 ] or CILFM is locally possible.…”

Section: Discussionmentioning

confidence: 87%

“…To avoid microstructural and compositional heterogeneities at a few grains scale, it is more convenient to use HRE-rich alloys having a composition close to a Nd-Fe-B magnet, also called Multi Main Phase (MMP) methods. [34,[51][52][53][54][55][56][57][58][59] Several authors report on the implementation of this process using recycled material as a source of HRE, [22,29,60] as well as the formation of core-shell-type structures. [22] The formation mechanism of Dy shells during GBDP or MMP is still a subject of scientific controversy and at least three different mechanisms have been proposed so far.…”

Section: Introductionmentioning

confidence: 99%

“…To avoid microstructural and compositional heterogeneities at a few grains scale, it is more convenient to use HRE‐rich alloys having a composition close to a Nd–Fe–B magnet, also called Multi Main Phase (MMP) methods. [ 34,51–59 ] Several authors report on the implementation of this process using recycled material as a source of HRE, [ 22,29,60 ] as well as the formation of core–shell‐type structures. [ 22 ]…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Toward the Improvement of the Short‐Loop Recycling of Dy‐Rich Nd–Fe–B Permanent Magnets: Experimental and Numerical Approaches

Bacchetta,

Luca,

Rado

et al. 2024

Adv Eng Mater

View full text Add to dashboard Cite

The method of short‐loop recycling of Nd‐Fe‐B magnets is implemented, with End of Life (EoL) magnets used as a source of Heavy Rare Earths (HRE). Partially recycled magnets are fabricated by co‐sintering of HRE‐free powders obtained from strip casted alloys, blended with HRE‐rich powders obtained from EoL magnets. The impact of several process parameters (blending ratio, sintering cycle and HRE‐rich recycled particle sizes) on the microstructure and magnetic properties are discussed. A coercivity gain up to 160 kA m‐1 per wt. % of Dy with respect to the HRE‐free magnets is reported, even though impurities are incorporated. Microstructural characterizations show a heterogeneous Dy localization in core‐shell/anti‐core‐shell structures, and thus a non‐optimal use of HRE. The experimental results are compared with finite elements simulations performed using existing data of bulk Dy diffusion coefficients. The simulation model consists of a network of square grains separated by a liquid phase, whose fraction is based on the ternary Nd‐Fe‐B phase diagram. Results show similarities with the observed microstructures, and point to the interest of reducing the Dy‐rich particle size with respect to the main powder. This study provides new insights into the Dy transport mechanisms at stake in an efficient short‐loop recycling of HRE.This article is protected by copyright. All rights reserved.

show abstract

Section: Discussionmentioning

confidence: 87%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Toward the Improvement of the Short‐Loop Recycling of Dy‐Rich Nd–Fe–B Permanent Magnets: Experimental and Numerical Approaches

Bacchetta,

Luca,

Rado

et al. 2024

Adv Eng Mater

View full text Add to dashboard Cite

show abstract

“…The degree of substitution in focus so far has rather been less than 40% of the total rare earth content. For the investigations, the dual-alloy process from two different starting alloys (Ce-rich, Ce-poor) was predominantly used [14][15][16]38]. Furthermore, the influence of grain boundary regulation/engineering and reconstruction was investigated [39][40][41][42][43].…”

Section: Introductionmentioning

confidence: 99%

Exploring Sintered Fe-(Ce, Nd)-B with High Degree of Cerium Substitution as Potential Gap Magnet

Goll,

Loeffler,

Boettle

et al. 2024

Materials

View full text Add to dashboard Cite

The more effective use of readily available Ce in FeNdB sintered magnets is an important step towards more resource-efficient, sustainable, and cost-effective permanent magnets. These magnets have the potential to bridge the gap between high-performance FeNdB and hard ferrite magnets. However, for higher degrees of cerium substitution (>25%), the magnetic properties deteriorate due to the lower intrinsic magnetic properties of Fe14Ce2B and the formation of the Laves phase Fe2Ce in the grain boundaries. In this paper, sintered magnets with the composition Fe70.9-(CexNd1-x)18.8-B5.8-M4.5 (M = Co, Ti, Al, Ga, and Cu; with Ti, Al, Ga, and Cu less than 2.0 at% in total and Cobal; x = 0.5 and 0.75) were fabricated and analyzed. It was possible to obtain coercive fields for higher degrees of Ce substitution, which previous commercially available magnets have only shown for significantly lower degrees of Ce substitution. For x = 0.5, coercivity, remanence, and maximum energy product of µ0Hc = 1.29 T (Hc = 1026 kA/m), Jr = 1.02 T, and (BH)max = 176.5 kJ/m3 were achieved at room temperature for x = 0.75 µ0Hc = 0.72 T (Hc = 573 kA/m), Jr = 0.80 T, and (BH)max = 114.5 kJ/m3, respectively.

show abstract

High‐Cerium‐Content Fe–Ce–Nd–B Sintered Magnets with High Coercivity

Goll,

Boettle,

Buschbeck

et al. 2024

Physica Rapid Research Ltrs

View full text Add to dashboard Cite

Ce substitution of Nd in FeNdB sintered magnets is very interesting for reasons of resource efficiency, sustainability and costs. However, the magnetic properties of high Ce‐content magnets are poor. This is mainly due to the lower values of intrinsic magnetic properties of Fe14Ce2B compared to Fe14Nd2B as well as the Laves phase Fe2Ce, which is formed in the grain boundaries and forms flat aggregates for higher Ce‐content. In this paper, sintered magnets with 75 at% degree of substitution of the composition Fe70.9‐[(Ce1‐xLax)0.75Nd0.25]18.8‐B5.8‐M4.5 (M = Co, Ti, Al, Ga, Cu, 0 ≤ × ≤ 0.3) are produced and analyzed. It is shown that a new rare earth rich grain boundary phase is formed adding La and that the Laves phase fraction can be reduced by up to 85%. With increasing La content, the remanence and Curie temperature increase and the temperature coefficient of Hc improves. A coercivity, remanence and maximum energy density of up to µ0Hc = 0.74 T, Jr = 0.98 T and (BH)max = 139.9 kJ/m3 have been achieved.This article is protected by copyright. All rights reserved.

show abstract

Temperature dependence of magnetization reversal mechanism in misch-metal substituted Nd-Fe-B magnets sintered by dual alloy method

Cited by 16 publications

References 34 publications

Toward the Improvement of the Short‐Loop Recycling of Dy‐Rich Nd–Fe–B Permanent Magnets: Experimental and Numerical Approaches

Toward the Improvement of the Short‐Loop Recycling of Dy‐Rich Nd–Fe–B Permanent Magnets: Experimental and Numerical Approaches

Exploring Sintered Fe-(Ce, Nd)-B with High Degree of Cerium Substitution as Potential Gap Magnet

High‐Cerium‐Content Fe–Ce–Nd–B Sintered Magnets with High Coercivity

Contact Info

Product

Resources

About