High performance RE–Fe–B sintered magnets with high-content misch metal by double main phase process

Double main phase process is applied to fabricate (Pr, Nd)_{1 – x}MM_x13.8Fe_balM_1.5B_5.9 (x = 0.5 and 0.7; M = Cu, Al, Co, and Nb) sintered magnets with high misch metal (MM) content. In comparison to the magnets by single main phase process, the enhanced magnetic properties have been achieved. For magnets of x = 0.7, H_cj increases to 371.9 kA/m by 60.5%, and (BH)_max is significantly enhanced to 253.3 kJ/m³ by 56.9%, compared with those of the single main phase magnets of the same nominal composition. In combination with minor loops and magnetic recoil curves, the property improvement of magnets with double main phase method is well explained. As a result, it is demonstrated that double main phase technology is an effective approach to improve the permanent magnetic properties of MM based sintered magnets.