Study on the phase composition of Mg2-xMxNi (M=Al, Ti) alloys

X-ray powder diffraction structure analysis showed that the hydrogen storag e alloy Mg2-xMxNi (M=Al, Ti) is a multiphase system composed of Mg2Ni, Mg, TiNi3, MgO, AINi and Mg3MNi2 (M=Al, Ti) when the A component Mg in the A(2) B type alloy Mg2Ni is partially replaced by Al or Ti. Mg3MNi2 (M=Al, Ti) is a new type of compound with cubic structure, space group (S.G.), Fd3m (no. 227) and with 16 molecules per unit cell. The cell parameters are a=1.1547 4(2)nm for Mg(3)ALNi(2) and a=1.16178(2)nm for Mg3TiNi2. The 48 Mg atoms ar e located on the 48(S) sites, the 16 M (Ti, Al) atoms on the 16(d) sites an d the 32 Ni atoms on the 32(e) sites. (C) 2001 Elsevier Science B.V. All ri ghts reserved.