Stability and equation of state of a nanocrystalline Ga-Ge mullite in a vitroceramic composite: A synchrotron x-ray diffraction study
- UNLV
Synchrotron x-ray diffraction and diamond anvil cell techniques were used to characterize the phase transformations and to evaluate the structural stability at elevated pressures of a developed nanocrystalline composite. The optically transparent material was built of a germanium oxide-based amorphous host matrix with homogeneously dispersed 13{+-}3 nm Ga-Ge mullite-type nanocrystals, which had a structure similar to the conventional Al{sub 2}O{sub 3}-SiO{sub 2} mullite. The equation of state of the nanocrystals and the overall structural integrity of the nanocomposite were investigated in quasihydrostatic conditions on compression to 36 GPa and on the following decompression to ambient conditions. The overall pressure-induced changes of x-ray diffraction patterns evidenced that the structural integrity of the material is well preserved up to about 14-16 GPa. The nanocomposite decompressed from 36 GPa to ambient pressure showed a very limited reversibility of the pressure-driven changes. A Birch-Murnaghan fit of the unit cell volume as a function of pressure yielded a zero-pressure bulk modulus, K{sub 0}, for the nanocrystalline phase of 229(15) GPa which makes this material potentially interesting for structural applications at elevated pressures.
- Research Organization:
- Advanced Photon Source (APS), Argonne National Laboratory (ANL), Argonne, IL (US)
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 1006574
- Journal Information:
- Phys. Rev. B, Journal Name: Phys. Rev. B Journal Issue: 2008 Vol. 77; ISSN 1098-0121
- Country of Publication:
- United States
- Language:
- ENGLISH
Similar Records
In situ observations of temperature- and pressure-induced phase transitions in TiH[subscript 2]: Angle-dispersive and synchrotron energy-dispersive X-ray diffraction studies
Equation of state of TiH[subscript 2] up to 90 GPa: A synchrotron x-ray diffraction study and ab initio calculations