Prolonged ordering process induced higher segregation of copper in 2:17 type SmCo magnets

The segregation of Cu is crucial for the magnetic properties of 2:17 type SmCo magnets, which is firstly affected by the ordering process during aging treatment. In this research, the ordering process is successfully regulated by doping nano ZrO2, which achieves a prolonged ordering process and an increased duration of twin boundaries in 2:17 type SmCo magnets. The continuous migration of twin boundaries in a longer period drives extra Cu to converge towards the cell boundary center, resulting in about 10.52 kOe coercivity only by isothermal aging treatment. The precipitation sequence of the lamellar phase and the cell boundary phase is exchanged. A new understanding of Cu segregation contributes to the development of high performance 2:17 type SmCo magnets. [Display omitted] •The ordering porcess was significantly prolonged with ~17 h in 2:17 type SmCo magnets.•The coercivity with over 1 T was achieved without slow cooling treatment.•The higher efficient of Cu segregation was achieved.