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Kinetics of Nucleation and Crystal Growth in Glass Forming Melts in MicrogravityThis flight definition project has the specific objective of investigating the kinetics of nucleation and crystal growth in high temperature inorganic oxide, glass forming melts in microgravity. It is related to one of our previous NASA projects that was concerned with glass formation for high temperature containerless melts in microgravity. The previous work culminated in two experiments which were conducted aboard the space shuttle in 1983 and 1985 and which consisted of melting (at 1500 C) and cooling levitated 6 to 8 mm diameter spherical samples in a Single Axis Acoustic Levitator (SAAL) furnace. Compared to other types of materials, there have been relatively few experiments, 6 to 8, conducted on inorganic glasses in space. These experiments have been concerned with mass transport (alkali diffusion), containerless melting, critical cooling rate for glass formation, chemical homogeneity, fiber pulling, and crystallization of glass forming melts. One of the most important and consistent findings in all of these experiments has been that the glasses prepared in microgravity are more resistant to crystallization (better glass former) and more chemically homogeneous than equivalent glasses made on Earth (1 g). The chemical composition of the melt appears relatively unimportant since the same general results have been reported for oxide, fluoride and chalcogenide melts. These results for space-processed glasses have important implications, since glasses with a higher resistance to crystallization or higher chemical homogeneity than those attainable on Earth can significantly advance applications in areas such as fiber optics communications, high power laser glasses, and other photonic devices where glasses are the key functional materials.
Document ID
20010057229
Acquisition Source
Marshall Space Flight Center
Document Type
Conference Paper
Authors
Day, Delbert E.
(Missouri Univ. Rolla, MO United States)
Ray, Chandra S.
(Missouri Univ. Rolla, MO United States)
Date Acquired
August 20, 2013
Publication Date
March 1, 2001
Publication Information
Publication: Microgravity Materials Science Conference 2000
Volume: 1
Subject Category
Solid-State Physics
Distribution Limits
Public
Copyright
Work of the US Gov. Public Use Permitted.
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