Crystallization of Nd2Fe17Bx from stoichiometric melt composition

Containerless solidification of gas-atomized Nd10Fe85B5 melt droplets was carried out using the drop tube technique. The phase constituents and microstructure of the solidified samples were investigated by means of powder X-ray diffraction analysis, thermomagnetic analysis, and scanning electron microscopy. Besides α-Fe and Nd2Fe14B, non-equilibrium phases such as Nd2Fe17Bx, ɛ-Nd, and Nd1.1Fe4B4 were identified. The microstructure of the samples was categorized into three types, including a quasi-single phase one that consists mainly of Nd2Fe17Bx dendrites. The lattice parameters and Curie temperature of Nd2Fe17Bx were determined, and compared with those of the same type phase crystallized in Nd-rich Nd–Fe–B melt compositions. The results were discussed with respect to the stoichiometry, formation as well as potential application of Nd2Fe17Bx.