Transmission electron microscopy study on Nd-rich phase and grain boundary structure of Nd-Fe-B sintered magnets

The crystal structure and morphology of the Nd-rich phase in postannealed sintered Nd-Fe-B hard magnets using transmission electron microscopy (TEM) was investigated. The results stated that the intragrain Nd-rich precipitates frequently disrupt magnetic domain wall arrangements, and that the magnetic interactions across thin amorphous Nd-rich phase are dominated by a simple dipole interaction.