Magnetic and Microstructural Characteristics of a DyF$_{3}$ Dip-Coated Nd-Fe-B Sintered Magnet

Coercivity enhancement of sintered Nd–Fe–B magnets by efficiently diffusing DyF3 based on electrophoretic deposition

“…Based on the Nd-O phase diagram, the fcc-NdO phase in the as-sintered state could be retained instead of the h-Nd 2 O 3 phase at a temperature of approximately 950°C [15]. Therefore, the diffusion temperature of 950°C may be too high to allow the formation of the C-Nd 2 O 3 phase during the low temperature annealing, which resulted in coercivity reduction [16].…”

Simultaneous application of Dy–X (X= F or H) powder doping and dip-coating processes to Nd–Fe–B sintered magnets

“…1(c). The microstructural modification of the magnets [i.e., enhancement of the uniformity and continuity of the Nd-rich grain boundary phase, stabilization of the meta-stable c-Nd 2 O 3 (Ia 3)] during the PSA improves the H c of the DyH 2 dip-coated un-doped magnet, F-magnet, and H-magnet because those magnets are optimally annealed [13][14][15]. In the case of grain boundary diffusion processed magnet, in addition to the above mentioned microstructural improvements, the changes in the core-shell microstructure and the grain boundary diffusion depth of Dy also affect the H c of the magnet additionally.…”

Faceted shell structure in grain boundary diffusion-processed sintered Nd–Fe–B magnets

“…For solid state diffusion, the shells should form on both sides of GBs. Although there are several reports on the formation of the shell structure both in Dy or Tb GBDP sintered Nd-Fe-B magnets [5,[8][9][10][11][12][13][14][15][16][17][18], all previous investigations overlooked this asymmetric nature of the Dy-rich shell along GBs. A better understanding on the origin of the unique asymmetric feature of the Dy-rich shell should shed light on the mechanism of the microstructure evolution that contribute to the coercivity enhancement.…”