Article ID Journal Published Year Pages File Type
1600764 Intermetallics 2011 11 Pages PDF
Abstract

The effect of Pd substitution on the crystal structure and hydrogenation properties of TiNi compound has been investigated. Ti(Ni,Pd) are pseudo-binary compounds. The unit-cell volumes of B2 (Austenite) and B19 (Martensite) structures linearly increase with Pd substitution in Ti1.04Ni0.96−xPdx samples. The hydrogenation properties of Pd-substituting Ti(Ni,Pd) compounds are not affected by the crystal structure of the parent compounds. For all samples, hydrogen absorption occurs without showing any clear plateau pressure in Pressure-Composition-Isotherm (PCI) curves. All hydrided samples crystallise in the tetragonal I 4/mmm space group. At 6 MPa of hydrogen pressure and T = 423 K, the hydrogenation capacity of Ti(Ni,Pd) compounds reaches 1.52 hydrogen atoms per formula unit (H/f.u.) for x = 0.1 and then gradually decreases with Pd content down to 0.93 H/f.u. for x = 0.5. Ti1.04Ni0.86Pd0.10 sample yields a discharge capacity of 148 mAh/g at C/5 regime when used as negative electrode in Ni-MH battery. The hydrogenation properties of Pd-substituting Ti(Ni,Pd) compounds are discussed in detail by comparison with previous studies on Zr substituting, (Ti,Zr)Ni compounds.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Ti(Ni,Pd) compounds behave as pseudo-binary compounds. ► Their hydrogenation properties are not affected by the martensitic transformation. ► All Ti(Ni,Pd) hydrides crystallize in I4/mmm tetragonal symmetry. ► Hydrogenation capacity decreases with Pd content in Ti(Ni,Pd) compounds. ► Electronic effects probably dictate the hydrogenation properties of Ti(Ni,Pd) compounds

Related Topics
Physical Sciences and Engineering Materials Science Metals and Alloys
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