Inhibiting the abnormal grain growth for grain boundary diffused Nd-Fe-B magnets through Tb3O4 grain boundary construction
Source abstract
Abstract
The grain boundary diffusion (GBD) process has been widely applied to effectively improve the coercivity of sintered Nd-Fe-B magnets. However, the abnormal grain growth and shallow diffusion depth were not conducive to coercivity enhancement. In this work, 0.2 wt% of Tb 3O 4 powder addition during the sintering process was applied to inhibit the abnormal grain growth and increase the continuous GB phase, and thus a superior coercivity of 26.22 kOe was achieved after Tb GBD by comparing with that of 24.15 kOe for the GBD magnet without Tb 3O 4 powder addition. Correlated with the electron probe microanalyzer (EPMA) and transmission electron microscopy (TEM) characterizations, a deeper diffusion depth, a thicker Tb-rich shell, and finer Nd 2Fe 14B phase grains make synergetic contributions to this coercivity enhancement. Furthermore, the Nd 6Fe 13Ga phase is formed surrounding the Tb 3O 4 intergranular phase, which is conductive to reduce magnetic coupling. The relationships among the coercivity, grain size, and core-shell structure are further confirmed by micromagnetic simulation. This work provides a dependable approach to further coercivity enhancement by grain boundary regulation.
Source: expertdata · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Magnetic Properties of Alloys · Magnetic properties of thin films · Magnetic Properties and Applications
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
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