In situ observations of temperature- and pressure-induced phase transitions in TiH[subscript 2]: Angle-dispersive and synchrotron energy-dispersive X-ray diffraction studies

Journal Article · Thu Apr 09 04:00:00 EDT 2009 · J. Phys. Chem. Solids

DOI:https://doi.org/10.1016/j.jpcs.2008.04.023· OSTI ID:1006857

Kalita, Patricia E; Cornelius, Andrew L; Lipinska-Kalita, Kristina E; Gobin, Cedric L; Liermann, H Peter ^[1]

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1. UNLV

We investigated the behavior of the structure of titanium hydride (TiH{sub 2}), an important compound in hydrogen storage research, at elevated temperatures (0-120 C) and high pressures (1 bar-34 GPa). Temperature-induced changes of TiH{sub 2} as indicated in the alteration of the ambient X-ray demonstrated a cubic to tetragonal phase transition occurring at about 17 C. The main focus of this study was to identify any pressure-induced structural transformations, including possible phase transitions, in TiH{sub 2}. Synchrotron X-ray diffraction studies were carried out in situ (diamond anvil cell) in a compression sequence up to 34 GPa and in subsequent decompression to ambient pressure. The pressure evolution of the diffraction patterns revealed a cubic (Fm-3m) to tetragonal (I4/mmm) phase transition at 2.2 GPa. The high-pressure phase persisted up to 34 GPa. After decompression to ambient conditions the observed phase transition was completely reversible. A Birch-Murnaghan fit of the unit cell volume as a function of pressure yielded a zero-pressure bulk modulus K{sub 0} = 146(14) GPa, and its pressure derivative K{prime}{sub 0} = 6(1) for the high-pressure tetragonal phase of TiH{sub 2}.

• Research Organization: Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
• Sponsoring Organization: USDOE
• OSTI ID: 1006857
• Journal Information: J. Phys. Chem. Solids, Journal Name: J. Phys. Chem. Solids Journal Issue: (9) ; 09, 2008 Vol. 69; ISSN 0022-3697; ISSN JPCSAW
• Country of Publication: United States
• Language: ENGLISH

Related Subjects

08 HYDROGEN
COMPRESSION
DIFFRACTION
HYDROGEN STORAGE
SYNCHROTRONS
TITANIUM HYDRIDES
TRANSFORMATIONS
X-RAY DIFFRACTION