Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Structural Properties of (Ti, Zr)(Mn, Cr)2M0.1 (M = None, Fe, Co, Ni, and Cu) Hydrogen Storage Alloys: Composition Distribution and Occupied Site of Doped Element
Tessui NakagawaDaichi HeshikiHiroki HigaJunko KawakamiRiki KobayashiNobuko HanadaKazutaka IkedaToshiya OtomoHironori OfuchiMasayoshi Ishida
Author information

2021 Volume 62 Issue 6 Pages 899-904


CO2 tolerance of hydrogen storage alloys of AB2-type (C14 Laves phase) Ti0.515Zr0.485Mn1.2Cr0.8M0.1 (AB2-M, M = none, Fe, Co, Ni, and Cu) depends on dopant M. Since our goal is to clarify this mechanism, we determined the elemental analysis using X-ray absorption spectroscopy (XAS), scanning electron microscope (SEM) coupled with energy dispersive X-ray spectroscopy (EDX), powder X-ray diffraction (XRD), and neutron powder diffraction (NPD) with Rietveld refinement in this study. As a result of XAS analysis, a strong evidence of all doped elements occupying B site in AB2 was obtained. SEM-EDX showed inhomogeneous composition with vacancy in B site and linear correlation of Ti/Zr and Mn/Cr ratio. The peak width in XRD patterns of AB2-M depends on the magnitude of homogeneity, therefore the Rietveld analysis using NPD patterns could not be well refined. Thus, homogeneity is not important but element of B site would be important for CO2 tolerance as well as AB5 type alloys.

Additive metal M occupies B site in AB2-type hydrogen storage alloys. Therefore, CO2 tolerance depends on B element. Fullsize Image
Content from these authors
© 2021 The Japan Institute of Metals and Materials
Previous article Next article