Magnetic Properties and Phase Constitution of the Nanocrystalline $(Nd_{10}Fe_{67}B_{23})_{100-x}Nb_{x}$ (where x=1, 2, 3, 4) Alloy Ribbons

In the present work the magnetic properties and phase constitution of $(Nd_{10}Fe_{67}B_{23})_{100-x}Nb_{x}$ (where x=1, 2, 3, 4) alloys in a form of ribbons were investigated. The ribbon samples were obtained by controlled atmosphere melt-spinning technique. In order to generate the nanocrystalline microstructure, ribbons were annealed at various temperatures (from 923 K to 1023 K) for 5 min. Subsequent annealing resulted in an evolution of the phase constitution accompanied by a change of their magnetic properties. The X-ray diffraction studies show presence of hard magnetic $Nd_{2}Fe_{14}B$, paramagnetic $Nd_{1+\epsilon}Fe_{4}B_{4}$ and ferromagnetic metastable $Nd_{2}Fe_{23}B_{3}$ phases. The best hard magnetic parameters were measure for annealed ribbons of the $(Nd_{10}Fe_{67}B_{23})_{96}Nb_{4}$ alloy.