Coercivity Improvement in Ce‐Containing (Nd,Pr)‐Fe‐B‐Based Sintered Magnets by Application of the 2‐Powder Method

The 2‐powder method is an effective strategy for enhancing the utilization efficiency of rare earth elements in Nd‐Fe‐B‐based magnets. It involves blending a main powder (MP) with a finer‐sized powder characterized by a higher anisotropy field (termed anisotropy powder, AP), producing magnets with core‐shell structures. This method overcomes the limitations of the grain boundary diffusion process on magnet dimensions and avoids processing costs associated with additional coating and heating. Herein, the 2‐powder method is applied to counteract coercivity and remanence loss in Ce‐containing (Nd,Pr)‐Fe‐B magnets, achieving sustainable gap magnets with reduced criticality. Two types of anisotropy powders: Nd ₂ Fe ₁₄ B‐based and (Nd,Pr,Dy) ₂ Fe ₁₄ B‐based, are each blended with the (Ce,Nd,Pr) ₂ Fe ₁₄ B‐based MP in a 3:7 weight ratio. The MP has a mean particle size of ≈4 μm and APs of around 2.5 μm. Compared to the magnet produced from the MP alone, incorporating Nd‐enriched and Dy‐enriched APs increased coercivity from 750 to 931 and 1362 kA m ⁻¹ , respectively. The significant improvements are attributable to the formation of core‐shell structures, where Nd and Dy are selectively enriched in the shell region of RE ₂ Fe ₁₄ B grains. These distribution trends underscore the efficient rare earth element utilization realized through the 2‐powder method.