Anisotropic SmFe10V2 Bulk Magnets with Enhanced Coercivity via Ball Milling Process

Autor: Tian Hong Zhou, Baochao Zhang, Xing Zheng, Youngwoon Song, Pingzhan Si, Chul-Jin Choi, Young-Rae Cho, Jihoon Park
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Nanomaterials, Vol 14, Iss 16, p 1329 (2024)
Druh dokumentu: article
ISSN: 2079-4991
DOI: 10.3390/nano14161329
Popis: Anisotropic bulk magnets of ThMn12-type SmFe10V2 with a high coercivity (Hc) were successfully fabricated. Powders with varying particle sizes were prepared using the ball milling process, where the particle size was controlled with milling time. A decrease in Hc occurred in the heat-treated bulk pressed from large-sized powders, while heavy oxidation excessively occurred in small powders, leading to the decomposition of the SmFe10V2 (1–12) phase. The highest Hc of 8.9 kOe was achieved with powders ball-milled for 5 h due to the formation of the grain boundary phase. To improve the maximum energy product ((BH)max), which is only 2.15 MGOe in the isotropic bulk, anisotropic bulks were prepared using the same powders. The easy alignment direction, confirmed by XRD and EBSD measurements, was . Significant enhancements were observed, with saturation magnetization (Ms) increasing from 59 to 79 emu/g and a remanence ratio (Mr/Ms) of 83.7%. (BH)max reaching 7.85 MGOe. For further improvement of magnetic properties, controlling oxidation is essential to form a uniform grain boundary phase and achieve perfect alignment with small grain size.
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