Formation Of Disordered Th2zn17-Type With Ti And B Additions And Hard Magnetic Properties Of Their Nitrides

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) similar to 37 MGOe.