High coercivity SmCo5 synthesized with assistance of colloidal SiO2

Hao, Tang; Mamakhel, Aref; Christensen, Mogens

doi:10.1038/s41598-021-83826-5

Cited by 2 publications

(2 citation statements)

References 31 publications

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“…SmCo 5 was chosen as a filler due to the great attention paid to it in modern science and practice [ 56 , 57 ], namely due to its high coercive force, as well as resistance to corrosion and oxidation, which allows the use of composites based on it in humid and aggressive environments. It was found that SmCo 5 /HEMA-gr-PVP composites possessed magnetic properties after band magnetization using profile inductors.…”

Section: Resultsmentioning

confidence: 99%

New Materials Based on Polyvinylpyrrolidone-Containing Copolymers with Ferromagnetic Fillers

et al. 2022

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The article investigates the peculiarities of the effect of ferromagnetic fillers (FMFs) of various natures (Ni, Co, Fe, FeCo, SmCo5) on the formation of the structure and properties of 2-hydroxyethylmethacrylate (HEMA) with polyvinylpyrrolidone (PVP) copolymers. The composites were characterized using FTIR-spectroscopy, SEM, DMTA, magnetometry of vibrating samples, specific electrical resistivity studies, and mechanical and thermophysical studies. The formation of a grafted spatially crosslinked copolymer (pHEMA-gr-PVP) was confirmed and it was established that the FMF introduction of only 10 wt.% into the copolymer formulation increased the degree of crosslinking of the polymer network by three times. The surface hardness of composites increased by 20–25%. However, the water content decreased by 16–18% and lay within 42–43 wt.%, which is a relatively high number. The heat resistance of dry composites was characterized by Vicat softening temperature, which was 39–42 °C higher compared to the unfilled material. It was established that the obtained composites were characterized by a coercive force of 200 kA × m−1 and induction of a magnetic field at the poles of 4–5 mT and 10–15 mT, respectively. The introduction of FMF particles into pHEMA-gr-PVP copolymers, which, in the dry state, are dielectrics, provides them with electrical conductivity, which was evaluated by the specific volume resistance. Depending on the FMF nature and content, as well as their orientation in the magnetic field, the resistance of filled materials could be regulated within 102–106 Ohm·m. Therefore, the modification of HEMA with PVP copolymers by ferromagnetic fillers of various natures provides the possibility of obtaining materials with unique predicted properties and expands the fields of their use, for instance as magnetic sorbents for various applications, as well as the possibilities associated with their being electrically conductive materials that can respond by changing of electrical conductivity, depending on various factors.

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Section: Resultsmentioning

confidence: 99%

New Materials Based on Polyvinylpyrrolidone-Containing Copolymers with Ferromagnetic Fillers

et al. 2022

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“…Particle size dependency of coercivity of SmCo 5 powder (Dong Y. et al, 2019;Li C. et al, 2018;Ma Z.-H. et al, 2017;Ma Z. et al, 2019a;Ma Z. et al, 2019b;Ma Z. et al, 2015;Shen B. et al, 2019;Tang H. et al, 2020a;Tang H. et al, 2021;Tang H. et al, 2020b;Wu Q. et al, 2020a;Zhang H. et al, 2011b). Tang (2020b) Ma ( 2015) Ma ( 2017) Tang ( 2021) Shen ( 2019) Dong ( 2019) Ma (2019a) Li ( 2018) Wu ( 2020) Ma (2019b) Zhang ( 2011) Tang (2020a) are free of the particle surface contamination which is a drawback of the chemical synthesis processes described in Section 2.1.2.…”

Section: Figmentioning

confidence: 99%

Recent Research Trend in Powder Process Technology for High-Performance Rare-Earth Permanent Magnets

Takagi

Hirayama

Okada

et al. 2023

KONA

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Higher performance is constantly required in rare earth permanent magnets, which are an indispensable component of the motors of electric vehicles. When producing sintered magnets, advanced structural control is necessary in the powder metallurgy process in order to achieve high performance. Especially in recent years, it has become important to develop processes for Sm-Fe-N magnets and metastable phase magnets as next-generation magnets to replace the Nd-Fe-B magnets. Because the crystal grain refinement of sintered magnets is most effective for improving coercivity, production methods for raw powders have evolved from the traditional pulverization to chemical synthesis approaches, and as a result, a submicron-sized Sm-Fe-N powder with huge coercivity has been developed. State-ofthe-art physical synthesis methods have also been applied successfully to the synthesis of nanopowders. Since control of the grain boundary is very effective in Nd-Fe-B magnets, this approach has also been evolved to Sm-Fe-N magnets by nano coating. On the other hand, since technologies for crystalline orientation control and high-density sintering are indispensable for improvement of remanence, new low-thermal load consolidation techniques such as spark plasma sintering are being developed for Sm-Fe-N magnets and metastable phase magnets in order to overcome the inherent low thermal stability of these materials.

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High coercivity SmCo5 synthesized with assistance of colloidal SiO2

Cited by 2 publications

References 31 publications

New Materials Based on Polyvinylpyrrolidone-Containing Copolymers with Ferromagnetic Fillers

New Materials Based on Polyvinylpyrrolidone-Containing Copolymers with Ferromagnetic Fillers

Recent Research Trend in Powder Process Technology for High-Performance Rare-Earth Permanent Magnets

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