Pressure induced nucleation in Li₂O·2SiO₂ glass

Author

Tihana Fuss

Abstract

"The concentration of nuclei (Nv) in a Li₂O·2SiO₂ (LS₂) glass was measured using a newly developed DTA technique, after densifying the glass at 1, 3, or 6 GPa pressure at 400° C for 20 min. Ny increased from 38 x 10¹² m^-3 for an as-melted glass to 82 x 10¹² m^-3 for a glass subjected to a pressure of 1 GPa, and then remained nearly constant with increasing pressure up to 6 GPa. This increase in Ny is equivalent to nucleating this LS₂ glass for 2 h at the temperature (455° C) where its nucleation rate is a maximum The average effective activation energy for crystallization for the densified glasses, 292 ±10 kJ/mol, was also the same as that of the (undensified) glass nucleated at 455° C for 2 h, but was significantly smaller than that (358 ±10 kJ/mol) 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 at temperatures as low as 400° C. 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.

Advisor(s)

Day, D. E.

Committee Member(s)

Brow, Richard K.
Switzer, Jay A., 1950-
Ray, C. S.

Department(s)

Materials Science and Engineering

Degree Name

M.S. in Ceramic Engineering

Publisher

University of Missouri--Rolla

Publication Date

Fall 2002

Pagination

x, 46 pages

Note about bibliography

Includes bibliographical references (pages 41-45.

Rights

© 2002 Tihana Fuss, All rights reserved.

Document Type

Thesis - Restricted Access

File Type

text

Language

English

Subject Headings

Nucleation

Thesis Number

T 8096

Print OCLC #

51219056

Recommended Citation

Fuss, Tihana, "Pressure induced nucleation in Li₂O·2SiO₂ glass" (2002). Masters Theses. 2169.
https://scholarsmine.mst.edu/masters_theses/2169