Abstract: A hydrogen storage alloy suitable for a negative electrode of an on-board alkaline storage battery, and an alkaline storage battery using the alloy, which has an AB3-type crystal structure as a main phase, represented by: (SmxLayRz)1?a?bMgaTbNicCodMe. (R is selected from Pr, Nd; T is selected from Ti, Zr, Hf; M is selected from V, Nb, Ta, Cr, Mo, W, Mn, Fe, Cu, Al, Si, P, B; the following conditions are met: 0<x<1.0, 0<y<1.0, 0.8?x+y?1.0, x+y+z=1.0; 0.93?(x?y)·(1?a?b)+4.5(a+b)?1.62, 0<a?0.45, 0?b?0.05, 0?d?0.7, 0?e?0.15, 2.85?c+d+e?3.15 and 0.01?d+e).

Abstract: Magnesium-based hydrogen storage alloys having metallic magnesium (Mg) and a magnesium-containing intermetallic compound (MgxMy wherein y is 1?x) and containing not less than 60 mass-% of magnesium in total, and having a phase of a primarily crystallized magnesium-containing intermetallic compound in its solidification structure.

Abstract: In a method for producing an alloy containing a metal of a low melting point, a low boiling point and a high vapor pressure such as Mg, Ca, Li, Zn, Mn, Sr or the like, a helium containing gas is used as an atmosphere gas for the melting. As a result, the alloy containing the above metal can be produced as an alloy having a targeted chemical composition precisely and safely at a low cost without causing the risk of firing, contamination or the like by active metal fine powder being vaporized. Furthermore, by using the helium containing gas as the atmosphere gas, the quench-solidification of the molten metal can be conducted due to a high thermal conductivity inherent to the helium gas, so that a special alloy can be produced even by the usual melting apparatus.

Abstract: Magnesium-based hydrogen storage alloys comprise metallic magnesium (Mg) and a magnesium-containing intermetallic compound (MgxMy wherein y is 1-x) and contain not less than 60 mass-% of magnesium in total, and have a phase of a primarily crystallized magnesium-containing intermetallic compound in its solidification structure.

Abstract: Magnesium-based hydrogen storage alloys comprise a metallic magnesium (Mg) and a magnesium-containing intermetallic compound (MgxMy wherein y is 1-x) and contain not less than 60 mass % of magnesium in total, and have a phase of a primarily crystallized magnesium-containing intermetallic compound in its solidification structure.