High-performance anisotropic SmCo-based magnet with novel microstructure

Abstract

A novel microstructure of magnetically anisotropic SmCo-based magnet with high-performance is reported. The magnet consists of SmCo7-H (TbCu7-hexagonal type), Sm2Co17–H (Th2Ni17-hexagonal type) and SmCo3-R (SmCo3-rhombohedral type) phases. The maximum magnetic energy product of the magnet is 231.69 kJ/m3, and the intrinsic coercivity is 1005.47 kA/m. An outstanding intrinsic coercivity temperature coefficient (β) of −0.125%/K between 298 and 773 K is obtained, which is very close to the β of commercial high-temperature Sm2Co17-based sintered magnets. The initial magnetization curve indicates that the coercivity mechanism is controlled by a domain wall pinning mechanism. The SmCo3-R lamellar phase may be a potential pinning center or self-pinning center. The microstructure of the magnet is different from that of any previous SmCo-based magnets. These findings provide a new idea for preparing high-performance SmCo-based permanent magnets.