| 摘要 |
PROBLEM TO BE SOLVED: To obtain a hydrogen storage alloy capable of satisfying the characteristics of a long service life and high rate dischargeability as the material for the negative pole of a battery by composing the alloy of elements essentially consisting of Ti, Zr, Hf and Fe and allowing fine crystal phases having crystal grains of specified value or below to precipitate into at least a part of the alloy structure. SOLUTION: This alloy has a compositional compsn. shown by the general formula, (T1-a Fea )100-b-c-d Lab Mc M'd . In the formula, T denoted at least one kind of element selected from among Ti, Zr and Hf, M denotes at least one kind of element selected from among V, Nb, Ta, Cr, Mo and W, and M' denotes at least one kind of element selected from among Mn, Co, Ni, Cu, Zn, B, Al, Ge and Sn. (a) satisfied, by atomic ratio, 0.45<=a<=0.55, and as for (b), (c) and (d), by atomic %, 0.01<=b<=10, 0<=c<=20 and 0<=d<=30 are satisfied. Fine phases having <=10 μm grain size are precipitated into at least a part of the alloy structure. The average grain size is preferably regulated to 1mm to 5 μm. |
