Multi-phase EBSD mapping and local texture analysis in NdFeB sintered magnets

A combination of electron backscatter diffraction and energy-dispersive X-ray spectroscopy has been used to identify the crystal structure and composition of all the phases present in commercially available NdFeB sintered magnets and to map their spatial distribution. The Nd2Fe14B and NdO grains were shown to have low defect densities. The fcc Nd-rich and Nd2O3 grains had intra-grain misorientation angles of up to 14°, which was shown to be due to defects. Large numbers (∼100) of data points for each phase were used to study texture in the NdO, Nd2O3 and Nd2Fe14B phases. The Nd2Fe14B grains exhibited a 〈0 0 1〉 fibre texture. The Nd oxide phases showed no strong texture, which implied that no strongly preferred orientation relationships between those phases and Nd2Fe14B exist. The result was shown to be valid for optimally annealed samples exhibiting high coercivity and as-sintered samples exhibiting low coercivity.