Structural and magnetic engineering of (Nd, Pr, Dy, Tb)–Fe–B sintered magnets with Tb3Co0.6Cu0.4H  composition in the powder mixture

Skotnicová, Kateřina; Бурханов, Г. С.; Kolchugina, N. B.; Kursa, Miroslav; Čegan, Tomáš; Lukin, A. A.; Životský, Ondřej; Prokofev, Pavel A.; Juřica, Jan; Liu, Ying

doi:10.1016/j.jmmm.2019.166220

Cited by 15 publications

(9 citation statements)

References 33 publications

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“…The mass of the Nd-Fe-B magnet was 17.66 g and 2.88 g for the desktop-computer and laptopcomputer HDDs, respectively. The composition of leachates obtained after leaching of Nd-Fe-B magnets is given in Table 3 are in line with data reported in the literature [8,49].…”

Section: Composition Of Nd-fe-b Permanent Magnetssupporting

confidence: 88%

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Recovery of rare earth elements from electronic waste by diffusion dialysis

Hammache

Bensaadi

Berbar

et al. 2021

Separation and Purification Technology

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Recycling rare earth elements (REEs) contained in electronic waste is of utmost importance due to their ever-increasing use in the high-tech sector. In this context, the use of non-polluting techniques represents a real challenge for scientists. In this work, we demonstrated that a clean and energy-efficient process, diffusion dialysis, has great potential for the recovery of neodymium (Nd) and praseodymium (Pr), contained in the Nd-Fe-B magnets of end-of-life computer hard disk drives (HDDs). Four kinds of polymer membranes were prepared by blending cellulose triacetate (CTA) and polyethylenimine (PEI) with the addition of di-(2ethylhexyl) phosphoric acid (D2EHPA), tridodecylamine (TDDA), trioctylamine (TOA) or trioctylphosphine oxide (TOPO). The membranes were first characterized by several techniques such as water uptake, contact angle, ATR-FTIR, SEM, XRD and zeta potential. They were further implemented in diffusion dialysis experiments in which diluted HDDs leachates were used as feed solutions. The relevance of the diffusion dialysis process for the recovery of REEs was demonstrated as it was possible to extract up to 15% of the boron by spontaneous diffusion through the CTA / PEI / TOA membrane in 6 hours with a lab-scale cell operating in batch mode. All membranes were positively charged under the operating conditions and then, REEs (present mainly in the form of trivalent cations Nd 3+ and Pr 3+) were strongly rejected. A fairly good correlation was found between the membrane water uptake and boron transfer, with boric acid molecules passing more easily through the more hydrated membranes. The selectivity factor between boron and REEs resulted from the interplay between the membrane structure, its water uptake ability and surface charge. It was also found to be dependent on the leachate composition. The CTA / PEI / TDDA membrane was found to exhibit the greatest B / REE selectivity factors, with values reaching up to 3706 and 140 for Nd and Pr, respectively. The lower selectivity towards Pr was explained by the weaker Gibbs energy of hydration of Pr 3+ cations compared with Nd 3+ .

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Section: Composition Of Nd-fe-b Permanent Magnetssupporting

confidence: 88%

“…% REEs. Besides Nd, several other REEs, such as Pr, Dy, Tb, Gd and Ho, may be found in Nd-Fe-B magnets [8,9].…”

Section: Introductionmentioning

confidence: 99%

Recovery of rare earth elements from electronic waste by diffusion dialysis

Hammache

Bensaadi

Berbar

et al. 2021

Separation and Purification Technology

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“…It is evident from Figures 6 and 7 that Co evinced the tendency to incorporate the 2:14:1 phase grains, while the Cu enriched triple junction phases. The role of Cu in the grain-boundary restructuring and positive effects of Co on the coercivities of Nd-Fe-B magnets were reported in our previous work [22] and were also considered in [23][24][25][26][27][28][29][30][31].…”

Section: Microstructure and Electron Microprobe Analysis Of Sintered mentioning

confidence: 81%

Application of a Dy3Co0.6Cu0.4Hx Addition for Controlling the Microstructure and Magnetic Properties of Sintered Nd-Fe-B Magnets

et al. 2019

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The focus of new technologies on the formation of inhomogeneous distributions of heavy rare-earth metals (REMs) in hard magnetic Nd–Fe–B materials is of scientific importance to increase their functional properties, along with preserving existing sources of heavy REMs. This paper focused on the coercivity enhancement of Nd2Fe14B-based magnets by optimizing the microstructure, which includes the processes of grain boundary structuring via the application of a Dy3Co0.6Cu0.4Hx alloy added to the initial Nd–Fe–B-based powder mixtures in the course of their mechanical activation. We have studied the role of alloying elements in the formation of phase composition, microstructure, the fine structure of grains, and the hysteretic properties of hard magnetic Nd(R)2Fe14B-based materials. It was shown that the Dy introduction via the two-component blending process (the hydrogenated Dy3Co0.6Cu0.4 compound is added to a powder mixture) resulted in the formation of the core-shell structure of 2–14–1 phase grains. The efficient improvement of the coercivity of Nd(RE)–Fe–B magnets, with a slight sacrifice of remanence, was demonstrated.

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“…2). Cobalt cannot be observed in the alloy structure by SEM since, as it was shown in [12,13], the hydrogenolysis of the R3Co compounds (with R = Tb, Dy) leads to their decomposition with the formation of fine Co and Cu particles. The other components will improve the grain boundary structure via enhanced wettability between the Nd2Fe14B-based grains and the Nd-rich phase and decreasing exchange coupling between Nd2Fe14B-based grains [14,15].…”

Section: Study Of the Structure And Phase Composition Of Pr3(co06cu04)hxmentioning

confidence: 99%

“…The other components will improve the grain boundary structure via enhanced wettability between the Nd2Fe14B-based grains and the Nd-rich phase and decreasing exchange coupling between Nd2Fe14B-based grains [14,15]. According to [12], cobalt, in using Tb3Co0.6Cu0.4Hx addition, forms core/shell microstructure, which favors the improved thermal stability of coercive force [16].…”

Section: Study Of the Structure And Phase Composition Of Pr3(co06cu04)hxmentioning

confidence: 99%

Sintered permanent magnets prepared from hydrogenated (Nd-Fe-b strip-cast alloy + pr3(Co,cu) compound) mixture

Prokofev

Kolchugina

Skotnicová

et al. 2020

METAL 2020 Conference Proeedings

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The application of powder blending procedure shows promise in manufacturing Nd-Fe-B magnets; in this case, hydrides, oxides, intermetallic compounds, etc. are used as one of the mixture components. The application of these additions allows one to increase the hysteretic characteristics of Nd-Fe-B magnets at the expense of realized grain-boundary diffusion and grain-boundary structuring processes since these characteristics of the magnets are highly sensitive to their microstructure, composition of phases, and distribution of alloy components as well. This study is focused on the possibility of using the Pr3Co0.6Cu0.4Hx composition as the addition to the powder mixture for manufacturing Nd-Fe-B magnets and on the processes occurred during hydrogen treatment of the addition. The base alloy having the composition Nd-24.0, Pr-6.5, Dy-0.5, B-1.0, Al-0.2, Fe-balance was prepared by strip-casting and subjected to hydrogen decrepitation at 270 °C for 1 h. The Pr3Co0.6Cu0.4 alloy was prepared by arc melting in an argon atmosphere and subjected to homogenizing annealing at 600 °C for 90 h and subsequent hydrogenation under the conditions used for the strip-cast alloy. The phase composition of Pr3Co0.6Cu0.4Hx was studied by X-ray diffraction analysis, DTA, scanning electron microscopy, and electron microprobe analysis. The Pr3Co0.6Cu0.4Hx composition was shown to undergo the hydrogenolysis with the formation of PrHx hydride (or hydrogen solid solution in Pr), Co+Cu fine mixture, and PrCu compound. The behavior of the additions in manufacturing sintered permanent magnets is analyzed from the viewpoint of the grain-boundary structuring effect of the addition. The sintered magnet prepared from the hydrogenated mixture Nd-Fe-B strip-cast alloy + Pr3(Co,Cu) compound exhibits the following hysteretic parameters: Br = 1.35 T, jHc = 1008 kA/m, and (BH)max = 349 kJ/m 3 .

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Structural and magnetic engineering of (Nd, Pr, Dy, Tb)–Fe–B sintered magnets with Tb3Co0.6Cu0.4H composition in the powder mixture

Cited by 15 publications

References 33 publications

Recovery of rare earth elements from electronic waste by diffusion dialysis

Recovery of rare earth elements from electronic waste by diffusion dialysis

Application of a Dy3Co0.6Cu0.4Hx Addition for Controlling the Microstructure and Magnetic Properties of Sintered Nd-Fe-B Magnets

Sintered permanent magnets prepared from hydrogenated (Nd-Fe-b strip-cast alloy + pr3(Co,cu) compound) mixture

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