Crystal Structures of La&ndash;Mg&ndash;Ni<I><SUB>x</SUB></I> (<I>x</I>=3&ndash;4) System Hydrogen Storage Alloys

Abstract

The new alloys of the La-Mg-Ni (Ni=ðLa þ MgÞ ¼ 3{4) system absorb and desorb hydrogen at room temperature, and their hydrogen storage capacities are greater than those of conventional AB 5 -type alloys. We investigated the crystal structures of the

Microstructures of Pd<SUB>47.5</SUB>Ag<SUB>47.5</SUB>La<SUB>5</SUB> Alloy Studied by Transmission Electron Microscopy

“…It is well known that many polytype phases exist in La-Ni (-Mg) alloy system, as reported by Komura,15) Yamamoto et al 16) and Hayakawa et al 17) Figure 4 shows a schematic illustration of atomic arrangements of LaNi 3 (PuNi [110] seen in Fig. 4(a).…”

Electron Diffraction study of Layer Structures in La-Mg-Ni Hydrogen Absorption Alloys

“…3.1 Layer structures in the La 0:8 Mg 0:2 Ni 3:4Àx Co 0:3 -(MnAl) x (0 < x < 0:4) alloys and description of the crystal structure As mentioned in the previous section, several intermetallic compounds, have been reported in the La-Ni or La-Mg-Ni alloy system, such as LaNi 2 (meta-stable, cF24-MgCu 2 , cubic Laves phase: 1,2,16) ), LaMgNi 4 (cF24-MgSnCu 4 , cubic ordered Laves phase 14,15) ), LaNi 3 (hR36-PuNi 3 , 1:3R-structure 1) ), LaMg 2 Ni 9 (hR36-PuNi 3 , 1:3R-structure 13) ), La 2 Ni 7 (hP36-Ce 2 Ni 7 , 2:7H-structure 1) ), La 17) ), and LaNi 5 (hP6-CaCu 5…”

“…[12][13][14][15][16][17] In order to improve farther the hydrogen properties of the La-Mg-Ni alloys, appropriate amounts of Ni were replaced by some elemental atoms, Mn, Co and Al. Then alloys of La 0:8 Mg 0:2 Ni 3:4Àx Co 0:3 (MnAl) x (0 < x < 0:4) were synthesized and studied.…”

Hydrogen induced amorphization behaviors of multiphase La0.8Mg0.2Ni3.5 alloy

“…Similarly, the reversible discharge capacity of La 5 Ni 19 is only 50 mAh g À1 which is much lower than the theoretical value of the gasesolid capacity [7]. It has been well described that AB 3 , A 2 B 7 and A 5 B 19 -type layered structures could be treated as composed of CaCu 5 -type ([AB 5 ]) and MgZn 2 -type ([A 2 B 4 ]) units stacking along the caxis [8,9]. Structural studies on hydrides of the LaNi 3 .…”