| 摘要 |
PROBLEM TO BE SOLVED: To increase an amount of occlusion/release of hydrogen and to improve plateau characteristic by providing a structure in which a main phase of body-centered cubic structure containing V, Zr, Ti, and Ni and a network grain boundary phase composed of two or more phases are present and the grain boundary phase contains a C14 Laves phase and a phase containing specific amounts of Zr and also regulating the volume percentage of the grain boundary phase to a value in a specific range. SOLUTION: In this hydrogen storage alloy, the volume percentage of the grain boundary phase is regulated to 25-50%. This grain boundary phase contains a C14 Laves phase and a phase containing >=35 atomic% Zr. Accordingly, the total composition of this alloy contains, by atom, >75.0-85.0% V, 2.0-15.0% Zr, 2.0-15.0% Ti, and 2.0-15.0% Ni. By casting a molten alloy of this composition and then carrying out annealing, plateau characteristic can be improved to a greater extent. As to annealing conditions, it is preferable to perform annealing at 800-1,300 deg.C for 0.5-100 hr. |
