Magnetically hard Sm2Fe17Nx prepared by nitriding melt-spun ribbons

Abstract
We have obtained magnetically hard Sm‐Fe‐N ribbons with a room‐temperature intrinsic coercivity Hci=23 kOe by nitriding melt‐spun Sm‐Fe precursor ribbons. Best results are obtained by grinding the ribbons to a 2 gas at 450–480 °C. X‐ray diffraction shows that the primary phase is rhombohedral Sm2Fe17Nx, or possibly the disordered hexagonal modification of this phase having the TbCu7 structure. Higher coercivities will be obtainable if the volume fraction of soft magnetic impurity phases, such as α‐Fe, can be reduced by optimizing the composition and processing.