Microstructure of hot-pressed and die-upset NdFeB magnets

Transmission electron microscopy was used to establish densification, alignment, and magnetization reversal mechanisms in hot-pressed and die-upset NdFeB magnets. Microstructures of these materials reveal two principal phases: Nd2Fe14B grains and a grain boundary phase of approximate composition Nd7Fe3. The grains in the hot-pressed material are polygonal and isotropic, while those in the die-upset material are flat platelets. The alignment of …