| 摘要 |
PROBLEM TO BE SOLVED: To improve battery characteristics such as electrode capacity, life characteristics and high rate dischargeability by using an alloy having a specified compsn. and a crystal structure as the material for the negative pole of a battery. SOLUTION: The compsn. of an alloy is expressed by the general formula of X2 Y1 Z3 (where X denotes at least one kind of element selected from rare earth elements, Y denotes one kind of element selected from Fe, Co, Ni, Cu and Mn and Z denotes one kind selected from Al, Ga, In, Si, Ge, Sn, Pb, Bi, Sb, Zn and B). Simultaneously, as for its crystal structure, the main phases are composed of hexagonal crystals. The average grain size preferably lies in the range of 5 to 100μm. As for the method for producing this hydrogen storage alloy, it is not particularly limited so long as it is the method for uniformizing the alloy compsn. and capable of preventing segregation, but preferably, it is melted by an ordinary vacuum casting method, is thereafter subjected to rapid cooling by a gas atomizing method, a rotary disk method, a centrifugal atomizing method, a roll method or the like and is thereafter subjected to homogenizing heat treatment at 500 to 1200 deg.C for 1hr to 1 week. |
