| 摘要 |
PURPOSE: To improve corrosion resistance and prevent pulverization to provide a hydrogen storage alloy for battery capable of realizing a higher electrode capacity and a longer battery life by specifying the composition consisting of a rare earth element, Ni, Co and P. CONSTITUTION: In a hydrogen storage alloy for battery represented by the general formula RNia Mb Pc or RNia Mb Pc Bd (wherein R represents a rare earth element containing Y, M represents Co, Mn, Al, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Cu, Zn, Ga, In, Si, Ge, Sn, or Sb, 3.0<=a<=5.0 by atomic ratio, 0.5<=b<=2.0, 0.001<=c<=0.5, 0<=d<=0.5, 4.5<=a+b+c+d<=5.5), the formation of a passive state film excellent in corrosion resistance is accelerated by addition of P, B to provide excellent corrosion resistance. As this alloy, a one obtained by bringing the molten metal into contact with a cooling medium and quenching it at a cooling speed of 100 deg.C/sec or more, and having a flake form or spherical form having a roundness of 80% or more is preferably used. This alloy can be used for a negative electrode to provide an excellent nickel-hydrogen secondary battery. |
