ABSTRACT The development of Fe‐rich 2:17‐type SmCo permanent magnets is crucial for achieving high performance, yet it has been persistently plagued by an inescapable performance trade‐off. The high degree of order in the Fe‐rich solid solution severely impedes the disordering phase transition and subsequent Cu segregation, leading to defective cellular structures and poor squareness and magnetic energy product. Herein, a novel cyclic heat treatment strategy is introduced that overturns the conventional paradigm of simply prolonging the solid solution time. By utilizing the existing nanoscale cellular structure as a precursor for secondary solution treatment, this strategy ingeniously engineers a rapid and complete boundary‐initiated disordering pathway. Driven by Sm diffusion, the process rapidly consumes the ordered intracellular, leading to significant reduction in the degree of order within the solid solution. This optimized precursor enables the formation of a highly continuous and uniform cellular architecture with ideal Cu distribution during aging. Consequently, the magnet exhibits an ultra‐high squareness of 87.8%, ultimately resulting in a recorded magnetic energy product of 282.9 kJ/m 3 and intrinsic coercivity of 1846.7 kA/m. This work provides a new insight into regulating phase transition kinetics and paves the way for the development of permanent magnets with higher performance.
Li et al. (Fri,) studied this question.