Hydrogen Absorption of Oxide Composite Materials Prepared from Melt-Spun Zr-Pd-Ni Alloys

摘要

Melt-spun Zr_(65)Pd_(35-x)Ni_x(x = 035) amorphous alloys were produced by the single-roller melt-spinning technique and then oxidized at 553 K (x = 0) or 673 K (x = 5-35) in air. Hydrogen absorption of those oxide specimens was measured at 323 K by the conventional volumetric technique (Sieverts method). There was a tendency that the plateau of Pd disappeared and the maximum hydrogen absorption content (at about 5 MPa) decreased with increasing Ni (decreasing Pd) content in the starting alloys in the composition range of precursors, x = 0-25 as shown in the P-C-T curves. However hydrogen absorption content of the oxidized specimen prepared from precursors of x=27.5-35 peculiarly increased and the oxidized specimen prepared from the precursors of x = 32.5 showed the largest hydrogen absorption of about 1.8 mass percent H among the series of specimens used in this study. Moreover, comparing XRD patterns of these oxidized specimens obtained before and after hydrogen absorption, it can be known that the mixed microstructure of ZrO_2 and PdO appears before hydrogen absorption in the oxidized specimens prepared from Zr_(65)Pd_(35-x)Ni_x(x = 0-25) precursors. On the contrary, in the oxidized specimen prepared from Zr_(65)Pd_5Ni_(30) precursor, Zr_3NiO and NiO oxides appear before hydrogen absorption and their peaks move to lower angle after hydrogen absorption due to the lattice expansion by hydrogenation while ZrO_2 phase did not appear so much. The significant behavior of the oxidized specimen prepared from Zr_(65)Pd_(35-x)Ni_x (x = 27.5-35) alloy precursors is related to the outstandingly different microstructure produced in this specimen. The authors expect these specimens to be used not only as hydrogen storage materials but also as catalysts in future.