The microstructural changes of Nd-rich interface phases during postsintering annealing were investigated. A mixture of very fine (about 2–3 nm) crystallites of hexagonal [formula omitted], cubic [formula omitted] [formula omitted], and amorphous phases were observed at the interface phase in the as-sintered magnet and after the first postsintering annealing process. The transformation from [formula omitted] to [formula omitted] occurred during the second postsintering annealing process, and the resulting [formula omitted] has the proper crystallographic relation with the main phase. The reduced lattice mismatch between the (110) plane of [formula omitted] interface phase and the (001) or (100) plane of Nd–Fe–B main phase after the second postsintering annealing process is the primary reason for the enhancement in the magnetic properties.
ASJC Scopus subject areas
- Physics and Astronomy(all)