Influence of Aluminum and Hydrogen on the Properties of Sm2Fe17

Cast, homogenized, and hydrogenated alloys based on intermetallic compound Sm 2 Fe 17 with replacement of iron by aluminum to concentrations of 8.9, 17.9, 26.8, and 35.8 at % Al are investigated by the methods of X-ray fluorescence, X-ray diffraction analysis, and scanning electron microscopy. The alloys are hydrogenated at a temperature of 180°C and a pressure of 25–30 atm. It is established that all the hydrides of the nominal compositions Sm 2 Fe 14.9 Al 2.1 H 3.6 , Sm 2 Fe 13.3 Al 3.8 H 2.1 , Sm 2 Fe 10.7 Al 6.3 Н 2 , and Sm 2 Fe 9.9 Al 7.1 H 1.8 , like Sm 2 Fe 17 , are crystallized in the rhombohedral Th 2 Zn 17 type of structure (space group R m ). The partial replacement of Fe in Sm 2 Fe 17 by Al is accompanied by a monotonic increase in the lattice periods and a simultaneous decrease in the specific saturation magnetization of the studied alloys. A similar trend is also established for the hydride phases.