Influence of Aluminum and Hydrogen on the Properties of Sm_2Fe_(17)

摘要

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 $$overline{3}$$ 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.