The hydrogen storage alloy powder, its manufacturing method and a negative electrode for a nickel h

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A hydrogen storage alloy which has a composition represented by the formula (1) : RNiaCobAlcMndMe ---- (1) wherein R represents a rare earth element including Y, or the like, M represents Mg, Fe or the like, and 3.50 <= a <= 4.95, 0.10 <= b <= 0.50, 0.35 <= c <= 0.55, 0.10 <= d <= 0.45 and 0 <= e <= 0.10, provided that 5.10 <= a+b+c+d+e <= 5.50, and has a particle diameter of 10 mum or less and, at a grain boundary and within a grain of the base phase constituting the alloy, a second phase having a Al content and a Mn content greater than those of the base phase. The hydrogen storage alloy is useful as an electrode material for a secondary cell has achieved the reduction of a cobalt content, and also offers a good balance of a level of activities such as initial activity and discharge characteristics, corrosion resistance, and life characteristics, and further is excellent in recyclability.