Micron-scale 1:5H-based precipitated phase with the lamellar structure of sintered Sm2Co17-based magnets and its potential application

Abstract

The excellent thermal stability of magnetic properties of Sm2Co17-based magnets is their most important feature. However, this stability is reduced when the maximum energy product of Sm2Co17-based magnets is improved, which is mainly determined by the Fe/Cu distribution of the 2:17R cell and 1:5H cell boundary phases. During the demagnetization process, the Cu-rich 1:5H cell boundary phase with a width of 2–15 nm obstructs the motion of the domain walls, yielding coercivity. Herein, we report a micron-scale Cu/Zr-rich and Fe-lean 1:5H-based precipitated phase with a lamellar structure, probably induced by Sm2O3 doping. This structure enables the separate regulation of Fe and Cu distribution for Sm2Co17-based magnets with Fe-rich 2:17R cell phases and Cu-rich 1:5H cell boundary phases, considerably optimizing the thermal stability of magnetic properties. This discovery can be further developed to produce Sm2Co17-based magnets with high performance and excellent thermal stability of magnetic properties.