The influence of milling modes on the structure and magnetic properties of (Sm,Ho)$_{2}$Fe$_{17}$N$_{x}$ ($x$ = 0, 2.4) powder materials

The composition, structure, topology of the surface of a cast, homogenized, and nitrogenated alloy based on the Sm$_{2}$Fe$_{17}$ intermetallic compound by Ho substitution for Sm have been investigated by means of X-ray fluorescence, X-ray diffraction, and scanning electron microscopy using BSE/EDS detectors. Magnetic properties are presented for initial Sm$_{1.2}$Но$_{0.8}$Fe$_{17}$ compound, Sm$_{1.2}$Но$_{0.8}$Fe$_{17}$N$_{2.4}$ nitride and its milled powders. It has been established that the partial substitution of Sm by Ho in the rare-earth sublattice in combination with the effect of introduction of nitrogen into the lattice of initial compound lead to an increase of such magnetic characteristics as specific magnetization and coercive force. Comparative analysis of the magnetic hysteresis properties of powder samples showed that an increase of the milling time Sm–Ho–Fe–N powders using high-energy ball milling (15, 30, 45 and 60 min) improves the main magnetic characteristics. The functional characteristics of Sm–Ho–Fe–N powders prepared by milling are an important for the development of new high-coercive permanent magnets based on them.