Crystallization of Li₂O-2SiO₂ Glass under High Hydrostatic Pressures

Abstract

The concentration of nuclei (Nv) in a Li2O.2SiO2 (LS2) glass was measured using a newly developed differential thermal analysis technique, after densifying the glass at 1,3, or 6 GPa pressure at 400oC for 20 min. Nv increased from 38 x 1012 m-3 for an asmelted glass to 82 x 1012 m-3 for a glass subjected to a pressure of 1 GPa, and remained nearly constant with further increase of pressure of up to 6 GPa. This increase in Nv is equivalent to nucleating this LS2 glass at the temperature (455oC) of its maximum nucleation rate for 2 h. the average effective activation energy for crystallization for the densified glasses, 292 ± 10 kJ/mol, was also the same as that for an as-melted (undensified and unnucleated) glass. the present results show that applying an external pressure on this LS2 glass shifts its nucleation curve to lower temperatures causing nuclei to form even at 400oC. a decrease in viscosity at all temperatures with the application of pressure is suspected to be a reason for the enhanced nucleation observed for this LS2 glass.

Meeting Name

106th Annual Meeting of the American Ceramic Society (2004, Indianapolis, IN)

Department(s)

Materials Science and Engineering

Keywords and Phrases

Crystallization; Glass

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2004 John Wiley & Sons, All rights reserved.

Publication Date

01 Jan 2004

Link to Full Text

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