title: Synthesis of new compound Gd5Ni19 with a superlattice structure and hydrogen absorption properties.
abstract: We successfully synthesized the new intermetallic compound Gd(5)Ni(19) and determined its crystal structure by X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). The structure is a Sm(5)Co(19)-type superlattice structure (2H, space group P6(3)/mmc), and the lattice parameters were determined as a = 0.4950(1) nm and c = 3.2161(5) nm by X-ray Rietveld refinement. The XRD results agreed with the STEM analysis results. The P-C isotherm of Gd(5)Ni(19) was measured at 233 K. In the first absorption cycle, the maximum hydrogen capacity reached 1.07 H/M at 2.0 MPa. The sloping plateau was observed in the first absorption-desorption cycle. The maximum hydrogen capacity decreased by 0.87 H/M in the second absorption cycle, implying that hydrogen in the amount of H/M = 0.20 remained in the alloy before the second absorption-desorption cycle.
authors: Frontier Research Center for Applied Atomic Sciences, Ibaraki University, 162-1 Shirakata, Tokai, Naka, Ibaraki 319-1106, Japan. fbiwase@mx.ibaraki.ac.jp
authors: Kenji
authors: K
authors: Iwase
authors: Kazuhiro
authors: K
authors: Mori
authors: Akinori
authors: A
authors: Hoshikawa
authors: Toru
authors: T
authors: Ishigaki