| Sm₂Fe_(17)N_x compounded powders, where the x was found to be 2.9, were prepared from parent alloys of Sm₂Fe_(17) made by both the arc melting and rapid solidification processes. The cast Sm₂Fe_(17) compound contained mixed phases of SmFe₃and α-Fe, and correspondingly formed less amount of Sm₂Fe_(17)N_(x3) , with rather a large amount of residual α-Fe after nitrogenation. The melt-spun Sm₂Fe_(17), however, was single phase and exhibited negligible amount of residual α-Fe after nitrogenation. The residual amount of free iron was found to increase as a function of milling time and impede promising permanent magnetic properties. The melt-spun Sm₂Fe_(17)N_x compound powders exhibited a coercivity value(_iH_c) of 5 kOe, which is double that of the as-cast Sm₂Fe_(17)N_x powders and a high remanence, B_r=60emu/g. The average magnetic moment of Fe atoms in the crystal is estimated to be 2.29μ_B and the Fe atom in the 6c site shows the highest magnetic moment of 2.65μ_B. The expansion in c-axial direction of the nitrogenated crystal was mainly due to extension of Sm(6c)-Fe(6c) and Fe(18f)-Fe(18f) distances. |
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