Synthesis and Study of Influence of Mechanical Activation Processing on the Structure and Magnetic Properties of Sm_2Fe_(17-x)Al_xN_y Nitride Powders

摘要

Sm_2Fe_(17-x)Al_x (x = 0.1, 0.2, 0.3 and 0.4) alloys and alloy-based nitrides were synthesized. The chemical and phase composition, microstructure of cast and homogenized alloys, and the hysteresis properties were studied by scanning electron microscopy, local microanalysis, and X-ray diffraction analysis. It was established that nitriding of pseudobinary Sm_2Fe_(17-x)Al_x compounds leads to the increase in lattice parameters and simultaneous increase in the specific saturation magnetization. Mechanical activation processing of the nitriding products revealed the different nature of their magnetic behavior depending on aluminum concentration in the alloys. Mechanical activation leads to the increase in coercive force and simultaneous decrease in the values of specific saturation magnetization and the average size of particles at small content of aluminum (18.6 at %). The coercive force of nitride also increases after mechanical activation at high aluminum content (38.3 at %); however, the specific saturation magnetization also increases. Generally, the increase in aluminum content in Sm-Fe-Al-N alloy leads to the decrease in their hysteresis characteristics after mechanical activation processing.