Todhunter, Raymond (1984) Crystalline phase development in cordierite glass-ceramics. PhD thesis, University of Warwick.

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Abstract

Cordierite glass-ceramics are characterised by their excellent
physical properties viz. high mechanical strength and hardness, good
thermal shock resistance and chemical durability, and therefore are
widely used in materials technology. The microstructure and phase
development of these materials during the initial stages of crystallisation
has been investigated using X-ray diffraction, Differential
Thermal Analysis and Transmission Electron Microscopy. Annealing
temperatures were chosen both above and below the glass transition
temperature, Tg, which was determined as 720°C by Differential Scanning
Calorimetry. Infra-red, u. v-visible and electron paramagnetic
resonance spectroscopy were employed as additional techniques to
investigate structural changes in the glass during phase transformations.
It has been shown that annealing above Tg promotes glass-in-glass
phase separation on a scale of ~ 100 Å by spinodal decomposition
which may well be enhanced by an incipient ordering during the annealing
process. The presence of phase separation is seen to have a profound
influence on the subsequent nucleation of a magnesium dititanate phase
and the growth of the metastable ß-quartz solid solutions, magnesianpetalite
and μ-cordierite which are capable of co-existing over the
temperature range 800-100°C. The effects of annealing and phase
separation are manifested as variations in both phase composition and
growth morphology for a given crystallisation temperature and holding
time.

Item Type:	Thesis (PhD)
Subjects:	Q Science > QC Physics
Library of Congress Subject Headings (LCSH):	Glass-ceramics, Cordierite, Crystallization, Phase transformations (Statistical physics)
Official Date:	January 1984
Dates:	Date Event January 1984 Submitted
Institution:	University of Warwick
Theses Department:	Department of Physics
Thesis Type:	PhD
Publication Status:	Unpublished
Supervisor(s)/Advisor:	McMillan, P. W. (Peter Warwick)
Sponsors:	Science and Engineering Research Council (Great Britain) (SERC) ; General Electric Company (Great Britain) (GEC)
Extent:	82 leaves
Language:	eng

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