کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1517418 | 1511604 | 2008 | 5 صفحه PDF | دانلود رایگان |
![عکس صفحه اول مقاله: In situ observations of temperature- and pressure-induced phase transitions in TiH2: Angle-dispersive and synchrotron energy-dispersive X-ray diffraction studies In situ observations of temperature- and pressure-induced phase transitions in TiH2: Angle-dispersive and synchrotron energy-dispersive X-ray diffraction studies](/preview/png/1517418.png)
We investigated the behavior of the structure of titanium hydride (TiH2), an important compound in hydrogen storage research, at elevated temperatures (0–120 °C) and high pressures (1 bar–34 GPa). Temperature-induced changes of TiH2 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 TiH2. 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 K0=146(14) GPa, and its pressure derivative K′0=6(1) for the high-pressure tetragonal phase of TiH2.
Journal: Journal of Physics and Chemistry of Solids - Volume 69, Issue 9, September 2008, Pages 2240–2244