Hydrogen Reaction with SmCo Compounds: Literature Review

Eldosouky, Anas; Škulj, Irena

doi:10.1007/s40831-018-0195-z

Cited by 9 publications

(4 citation statements)

References 48 publications

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“…The biggest promises of exchange-coupled nanocomposites are miniaturization (due to the increased (BH) max ) and sustainability by the reduction of the rare earth mass fraction (10–20% reduction) and efficiency increase. In this work, we explore the possibility of improving on the sustainability aspect by creating exchange-coupled nanocomposites from recycled SmCo 5 magnets [ 21 , 22 , 23 ] (90 wt%) and a cheap and available 3d metal (Fe, 10 wt%). While most of the recent work in this area is on Nd 2 Fe 14 B+Fe nanocomposites [ 24 , 25 , 26 , 27 , 28 ], the choice of recycled SmCo 5 was made due to the relative purity of these industrial magnets compared with other compositions [ 2 , 3 ].…”

Section: Introductionmentioning

confidence: 99%

Magnetic Properties of SmCo5 + 10 wt% Fe Exchange-Coupled Nanocomposites Produced from Recycled SmCo5

et al. 2020

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Nanostructured alloy powders of SmCo5 + 10 wt% Fe obtained using recycled material were studied for the first time. The SmCo5 precursor was obtained from commercial magnets recycled by hydrogen decrepitation. The results were compared with identically processed samples obtained using virgin SmCo5 raw material. The samples were synthesized by dry high-energy ball-milling and subsequent heat treatment. Robust soft/hard exchange coupling was observed—with large coercivity, which is essential for commercial permanent magnets. The obtained energy products for the recycled material fall between 80% and 95% of those obtained when using virgin SmCo5, depending on milling and annealing times. These results further offer viability of recycling and sustainability in production. These powders and processes are therefore candidates for the next generation of specialized and nanostructured exchange-coupled bulk industrial magnets.

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Section: Introductionmentioning

confidence: 99%

Magnetic Properties of SmCo5 + 10 wt% Fe Exchange-Coupled Nanocomposites Produced from Recycled SmCo5

et al. 2020

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“…The analysis with X-ray diffraction is shown in a mixture of Sm 2 Co 17 (rhombohedral, space group R-3m) and SmCo 5 (hexagonal, space group P6/mmm), which fits well to the observations in literature. [6,21,22] Figure 2 shows the diffraction patterns of both sintered magnets at different H 2 exposure parameters. An increase in H 2 pressure (Figure 2a), temperature (Figure 2b), or time (Figure 2c) leads to a shift of diffraction reflections to lower angles, which indirectly indicates the lattice expansion.…”

Section: Microstructurementioning

confidence: 99%

“…The reaction behavior of different Sm–Co magnets under hydrogen atmosphere has been reported by various authors. [ 6 ] Evans et al found that an activation temperature of 120 °C is necessary to absorb hydrogen. At lower temperatures, even at high pressures of 12 atm (12.2 bar), no absorption was detectable.…”

Section: Introductionmentioning

confidence: 99%

“…It was shown that a higher Sm or Fe content increases the ability for hydrogen absorption. [ 6,10 ] In the same way, a reduction of Fe content and increase of Co, Cu, and Zr strongly improves the thermal stability and high‐temperature properties of SmCo magnets. [ 11–13 ] The third parameter which will influence the hydrogen reaction is the hydrogen pressure.…”

Section: Introductionmentioning

confidence: 99%

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Chemical Stability and Hydrogen Reaction Behavior of SmCo 2:17‐Type Permanent Magnets

Schönfeldt

Opelt

Betz³

et al. 2023

Adv Eng Mater

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Herein, the reaction behavior and chemical stability of two commercially available SmCo 2:17‐type sintered magnets with nominal composition of Sm23.75Co48.67FebalCu4.91Zr2.37 and Sm24.95Co48.80FebalCu4.46Zr2.68 (wt%) are investigated. The magnets are placed in a hydrogen atmosphere with systematically varied pressure, exposure time, and temperature ranging from 1–11 bar, 2–10 d, and 25–500 °C, respectively. Hydrogen content, magnetic properties, microstructure, and lattice constants are characterized in detail. It is found that for short exposure times like 2 d an activation temperature of 120 °C is necessary to initiate the reaction and to increase the amount of hydrogen in the Sm–Co material. Hydrogen absorption starts at lower temperatures with longer exposure times. An increase in exposure time, temperature, or pressure leads to a higher hydrogen content and a decrease in remanence Br, energy product (BH)max, and coercivity HcB. Lattice expansion, estimated by X‐ray diffraction analysis, correlates with the increasing amount of hydrogen in the Sm–Co magnets. With respect to all varied parameters under investigation, the exposure temperature has the highest impact on the observed property changes followed by reaction time and H2 pressure.

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