Formation of Disordered ${\rm Th}_{2}{\rm Zn}_{17}$ -Type ${\rm Sm}_{2}{\rm Fe}_{17}$ With T

Compounds with nominal compositions Sm₁₀Fe₉₀ and Sm₁₀Fe₉₀Ti₂B were prepared by strip casting method. Disordered Th₂Zn₁₇-type phase of Sm₁₀Fe₉₀Ti₂B was achieved. This disordered Th₂Zn₁₇ (space group R-3m) phase was formed by randomly replacing Sm(3a) with Fe(6c)-dumbbell ((3a) and (6c) are Wyckoff symbols)). Scanning electron microscopy image revealed that the disordered Sm₁₀Fe₉₀Ti₂B crystallized in micron-scaled grains, which is useful for the improvement of its hard magnetic properties. By annealing this disordered phase, it transformed into ordered rhombohedral Th₂Zn₁₇ structure. This derivative 2:17 type compound was further nitrided and then finely pulverized using surfactant-assisted grinding method. The final anisotropy powders showed excellent hard magnetic properties with coercivity of 12.4 kOe and (BH)_max ~ 37 MGOe.