TY - JOUR
T1 - (Nd,La,Ce)-Fe-B hot-deformed magnets for application of variable-magnetic-force motors
AU - Tang, Xin
AU - Sepehri-Amin, H.
AU - Bolyachkin, A.
AU - Ohkubo, T.
AU - Hono, K.
N1 - Funding Information:
This work was supported by the Elements Strategy Initiative Center for Magnetic Materials (ESICMM), Grant Number JPMXP0112101004, through the Ministry of Education, Culture, Sports, Science and Technology (MEXT). We acknowledge Dr. Hirosawa for fruitful discussion and Xin Tang acknowledges ICYS for provision of ICYS fellowship.
Publisher Copyright:
© 2022
PY - 2022/4/15
Y1 - 2022/4/15
N2 - The recent development of variable-magnetic-force (VMF) motors has raised a new demand for permanent magnets with a moderate coercivity and magnetizing field (Hmag), flat first-order reversal curves (FORCs), and high magnetization. In this study, we explored the potential of low-cost (Nd,La,Ce)-Fe-B hot-deformed magnets for the VMF motor application. We showed that the coercivity can be tuned to a desirable value (∼0.15-0.65 T) using a combined effect of intrinsic and extrinsic factors. Unlike commercial Nd-Fe-B sintered magnets, FORCs of the (Nd,La,Ce)-Fe-B hot-deformed magnets are flat. Microstructure observation and magneto-optical Kerr effect (MOKE) microscopy showed the origin of the flat FORCs is the large volume fraction of the rare-earth-rich intergranular phase in the ultra-fine grained microstructure, which acts as pinning sites against magnetic domain wall propagation. Moreover, a relatively high remanent magnetization of 1.26 T for the (Nd,La,Ce)-Fe-B hot-deformed magnet is an additional merit compared to the previously proposed sintered magnets for the VMF motor application. This work demonstrates the (Nd,La,Ce)-Fe-B hot-deformed magnets are excellent candidates for VMF motor applications and thus widens the application spectrum for low-cost (Nd,La,Ce)-Fe-B magnets with a goal of well-balanced use of critical rare earth elements.
AB - The recent development of variable-magnetic-force (VMF) motors has raised a new demand for permanent magnets with a moderate coercivity and magnetizing field (Hmag), flat first-order reversal curves (FORCs), and high magnetization. In this study, we explored the potential of low-cost (Nd,La,Ce)-Fe-B hot-deformed magnets for the VMF motor application. We showed that the coercivity can be tuned to a desirable value (∼0.15-0.65 T) using a combined effect of intrinsic and extrinsic factors. Unlike commercial Nd-Fe-B sintered magnets, FORCs of the (Nd,La,Ce)-Fe-B hot-deformed magnets are flat. Microstructure observation and magneto-optical Kerr effect (MOKE) microscopy showed the origin of the flat FORCs is the large volume fraction of the rare-earth-rich intergranular phase in the ultra-fine grained microstructure, which acts as pinning sites against magnetic domain wall propagation. Moreover, a relatively high remanent magnetization of 1.26 T for the (Nd,La,Ce)-Fe-B hot-deformed magnet is an additional merit compared to the previously proposed sintered magnets for the VMF motor application. This work demonstrates the (Nd,La,Ce)-Fe-B hot-deformed magnets are excellent candidates for VMF motor applications and thus widens the application spectrum for low-cost (Nd,La,Ce)-Fe-B magnets with a goal of well-balanced use of critical rare earth elements.
KW - Coercivity
KW - First-order reversal curves
KW - Hot-deformed magnets
KW - Light rare earth
KW - Permanent magnet
KW - Variable-magnetic-force motor
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U2 - 10.1016/j.actamat.2022.117747
DO - 10.1016/j.actamat.2022.117747
M3 - Article
AN - SCOPUS:85126143843
SN - 1359-6454
VL - 228
JO - Acta Materialia
JF - Acta Materialia
M1 - 117747
ER -