Journal ArticleDOI
On the thermal expansion of β-cristobalite
TLDR
In this article, the authors measured the temperature dependence of the cell parameter of cubic β-cristobalite up to 1300°C by high-precision X-ray powder diffraction.Abstract:
We have measured the temperature dependence of the cell parameter of cubic β-cristobalite up to 1300° C by high-precision X-ray powder diffraction. The thermal expansion coefficient decreases on heating, until above 1000° C the cell parameter is virtually constant in value. We discuss this change in the thermal expansion with reference to the behaviour of low-frequency rigid unit modes and fluctuations associated with the α-β phase transition.read more
Citations
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Compressibility, Phase Transitions, and Oxygen Migration in Zirconium Tungstate, ZrW2O8
TL;DR: In situ neutron diffraction experiments show that at pressures above 2 kilobars, cubic zirconium tungstate (ZrW2O8) undergoes a quenchable phase transition to an orthorhombic phase, the structure of which has been solved from powder diffraction data.
Journal ArticleDOI
Negative thermal expansion and associated anomalous physical properties: review of the lattice dynamics theoretical foundation.
Martin T. Dove,Hong Fang +1 more
TL;DR: This paper identifies a number of different cases of vibrational mechanisms of NTE, some of which involve a small number of phonons that can be described as involving rotations of rigid polyhedral groups of atoms, others where there are large bands of phonon involved, and some where the transverse acoustic modes provide the main contribution to NTE.
Journal ArticleDOI
Silicon Carbide Oxidation in Steam up to 2 MPa
Kurt A. Terrani,Bruce A. Pint,Chad M. Parish,Chinthaka M. Silva,Lance Lewis Snead,Yutai Katoh +5 more
Journal ArticleDOI
Silica on Silicon Carbide
Volker Presser,Klaus G. Nickel +1 more
TL;DR: In this paper, a review of state-of-the-art information about the structural aspects of silicon carbide, silica, and SiC-SiO 2 interfaces is presented.
Journal ArticleDOI
Geometrical Origin and Theory of Negative Thermal Expansion in Framework Structures
TL;DR: In this article, a theory of the negative effect of rigid rotation on the thermal expansion coefficient was developed and shown to give a negative contribution to thermal expansion coefficients, in addition to the usual positive contribution from anharmonicity of the interatomic forces.
References
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Journal ArticleDOI
An X-ray study of the temperature dependence of the quartz structure
Journal ArticleDOI
The structures of the β-cristobalite phases of SiO2 and AlPO4
A. F. Wright,A. J. Leadbetter +1 more
TL;DR: The crystal structures of the SiO4 and AlPO4 phases of cristobalite have been determined from X-ray data collected at high temperatures as discussed by the authors, and a model is suggested which gives a much better fit to the data than previously published structures.
Journal ArticleDOI
The Determination of Rigid-Unit Modes as Potential Soft Modes for Displacive Phase Transitions in Framework Crystal Structures
TL;DR: In this paper, a method for the determination of all possible phonon modes in framework crystal structures that leave the fundamental structural units (tetrahedra and octahedra) undistorted is described.
Journal ArticleDOI
Low-frequency floppy modes in β-cristobalite
Ian P. Swainson,Martin T. Dove +1 more
TL;DR: Inelastic neutron scattering and molecular dynamics simulations provide evidence for the existence of low-frequency floppy modes in the high-temperature phase of cristobalite, which are analogous to those found in network glasses as discussed by the authors.