Preparation of Anisotropic ${\rm Sm}_{2}{\rm Fe}_{17}{\rm N}_{\rm X}$ Magnetic Materials by Strip Casting Technique

Strip casting technique was used to prepare anisotropic Sm₂Fe₁₇N_X compounds. It was found that single phase Sm₂Fe₁₇ compound could be obtained by this technique without postannealing treatment. The microstructure studies of the Sm₂Fe₁₇ strips showed that not only the grain size in the strips was small, but also the size distribution of the grains was narrow as compared to those of conventionally cast ingots. Single phase Sm₂Fe₁₇N_X interstitial compounds and anisotropic Sm₂Fe₁₇N_X magnetic powders with B_r=1.42 T , _iH_c=12.5 kOe and BH_max=316 kJ/m³ (39.5 MGOe) could be obtained by optimizing the nitrogenation process. The magnetic hardening mechanism of the anisotropic powders is mainly controlled by the domain nucleation.