NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
Crystallization of a Li2O2SiO2 Glass under High Hydrostatic PressuresThe crystallization behavior of a Li2O.2SiO2 (LS2) glass subjected to a uniform hydrostatic pressure of 4.5 or 6 GPa was investigated between 550 and 800 C using XRD, IR, Raman, TEM, NMR, and DTA. The density of the glass subjected to 6 GPa was between 2.52 plus or minus 0.01 and 2.57 plus or minus 0.01 grams per cubic centimeters, depending upon the processing temperatures, and was higher than that of the stoichiometric LS2 crystals, 2.46 plus or minus 0.01 grams per cubic centimeter. Thus, crystallization in 6 GPa glass occurred in a condition of negative volume dilatation, deltaV = V(sub glass) - V(sub crystal), while that for the 4.5 GPa glass occurred in the condition deltaV greater than 0. For deltaV greater than 0, which also includes the control glass at ambient (one atmosphere) pressure, the glasses always crystallize Li2Si2O5 (orthorhombic, Ccc2) crystals, but for deltaV less than 0 (6 GPa), the glasses crystallize Li2SiO3 crystals with a slightly deformed structure. The crystal growth rate vs. temperature curve moved to higher temperature with increasing pressure, and was independent of the sign of deltaV. These results for the effect of hydrostatic pressure on the crystallization of LS2 glass were discussed from thermodynamic considerations.
Document ID
20040070922
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Fuss, T.
(Missouri Univ. Rolla, MO, United States)
Day, D. E.
(Missouri Univ. Rolla, MO, United States)
Lesher, C. E.
(California Univ. Davis, CA, United States)
Ray, C. S.
(NASA Marshall Space Flight Center Huntsville, AL, United States)
Date Acquired
August 21, 2013
Publication Date
January 1, 2004
Subject Category
Lunar And Planetary Science And Exploration
Meeting Information
Meeting: 106th Annual Meeting of the American Ceramic Society
Location: Indianapolis, IN
Country: United States
Start Date: April 18, 2004
End Date: April 21, 2004
Sponsors: American Ceramic Society
Funding Number(s)
CONTRACT_GRANT: NAG8-1465
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.

Available Downloads

There are no available downloads for this record.
No Preview Available