TY - JOUR
T1 - Structural properties of (Ti, Zr)(Mn, Cr)2M0.1(M = none, Fe, Co, Ni, and Cu) hydrogen storage alloys
T2 - Composition distribution and occupied site of doped element
AU - Nakagawa, Tessui
AU - Heshiki, Daichi
AU - Higa, Hiroki
AU - Kawakami, Junko
AU - Kobayashi, Riki
AU - Hanada, Nobuko
AU - Ikeda, Kazutaka
AU - Otomo, Toshiya
AU - Ofuchi, Hironori
AU - Ishida, Masayoshi
N1 - Funding Information:
XAS measurement in this study was performed in SPring-8 (Proposal No. 2015B1776) with funding support from the Foundation for high energy accelerator science, Japan. This work was partially supported by the Neutron Scattering Program Advisory Committee of IMSS, KEK (Proposal No. 2014S06). The authors thank Itsuki Miyazato from the University of the Ryukyus (master student at this time) for XAS measurement. Figure 1 and 2 are from his master thesis.
Publisher Copyright:
©2021 The Japan Institute of Metals and Materials.
PY - 2021
Y1 - 2021
N2 - 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.
AB - 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.
KW - Energy dispersive X-ray spectroscopy
KW - Hydrogen storage alloys
KW - Neutron diffraction
KW - X-ray absorption spectroscopy
KW - X-ray diffraction
UR - http://www.scopus.com/inward/record.url?scp=85106550068&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85106550068&partnerID=8YFLogxK
U2 - 10.2320/matertrans.MT-M2021004
DO - 10.2320/matertrans.MT-M2021004
M3 - Article
AN - SCOPUS:85106550068
SN - 1345-9678
VL - 62
SP - 899
EP - 904
JO - Materials Transactions
JF - Materials Transactions
IS - 6
ER -