Synthesis, structure, and magnetic properties of Nd-Y-Fe-Mo-B bulk nanocomposite magnets

NdxY6−xFe68Mo4B22 (x = 1–5) nanocomposites were prepared directly by the devitrification of amorphous rods. The effects of Y doping on the glass-forming ability, microstructure, and magnetic properties of the alloys were also investigated. GFA of the alloys was found to get enhanced through substituting Nd with Y and to increase with the growth of Y contents. Results also showed that the best glass former was Nd1Y5Fe68Mo4B22 with a critical diameter of 4 mm. The coercivity first increased after subsequent crystallization and then decreased with the reduction of Y content, which was closely related to the phase transition during the crystallization. The devitrified Nd3Y3Fe68Mo4B22 exhibited a maximal coercivity of 364.1 kA/m, resulting from strong exchange coupling between the hard and the soft phases.