Magnetic and Microstructural Characteristics of Nd-Fe-B Sintered Magnets Doped With Dy $_2$ O $_3$ and

Magnetic and microstructural properties of (Nd_26.06, Dy_6.51)-Fe_bal.-B_0.97-M_2.39 (wt.%) ( M = Cu, Al, Co, and Nb) sintered magnets doped with Dy₂O₃ and DyF₃ powders were studied. In the case of the Dy₂O₃-doped magnet, Dy was distributed along the near grain boundaries. In contrast, the DyF₃-doped magnet and the undoped magnet showed that Dy was distributed uniformly in the main phase. The coercivity and the remanence of the Dy₂O₃ and DyF₃-doped magnets were 33.2 kOe, 11.64 kG, and 34.5 kOe, 11.21 kG, respectively. The coercivity of the DyF₃-doped magnet was the largest but its remanence was the smallest among other magnets because the Dy was distributed throughout the main phase. Uniform distribution of the Dy in the DyF₃-dopedmagnet was probably due to their lower bonding energy and higher chemical potential for diffusion.