Kouji Sakaki1, Hyunjeong Kim1, Akihiko Machida2, Tetsu Watanuki2 and Yumiko Nakamura1
1Hydrogen Energy Technology Group, Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8565
Compositional dependence of hydrogenation properties in Ti1+y(Fe1-xMnx)1-y were investigated. The annealed alloys mainly showed B2 structure (CsCl) and some of them contained a small amount of secondary phase. The lattice constant of B2 phase increased and their equilibrium pressures decreased with increasing Mn or Ti content. Ti50Fe40Mn10 and Ti50Fe35Mn15 showed two distinct flat plateaus on pressure-composition isotherms. Ti52Fe28Mn20 and Ti53Fe25Mn22 also showed two distinct flat plateaus below certain temperatures. Above those temperatures, however, only their first plateau became slant without hysteresis keeping the second plateau flat. In addition, the first plateau was slanted without hysteresis even at room temperature in Ti54Fe23Mn23. These results suggest that Ti1+y(Fe1-xMnx)1-y have critical temperatures for the first phase transformation from the α -solid solution phase to the β -Ti1+y(Fe1-xMnx)1-yH∼1 and they decreased with increasing Mn or Ti content. [doi:10.2320/jinstmet.JC201404]
hydrogen storage, compositional dependence, phase transformation, critical temperature
Please do not copy without permission.