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Crystallization and properties of Sr-Ba aluminosilicate glass-ceramic matricesPowders of roller quenched (Sr,Ba)O-Al2O3-2SiO2 glasses of various compositions were uniaxially pressed into bars and hot isostatically pressed at 1350 C for 4 hours or cold isostatically pressed and sintered at different temperatures between 800 to 1500 C for 10 or 20 hours. Densities, flexural strengths, and linear thermal expansion were measured for three compositions. The glass transition and crystallization temperatures were determined by Differential Scanning Calorimetry (DSC). The liquidus and crystallization temperature from the melt were measured using high temperature Differential Thermal Analysis (DTA). Crystalline phases formed on heat treatment of the glasses were identified by powder X ray diffraction. In Sr containing glasses, the monoclinic celsian phase always crystallized at temperatures above 1000 C. At lower temperatures, the hexagonal analog formed. The temperature for orthorhombic to hexagonal structural transformation increased monotonically with SrO content, from 327 C for BaO-Al2O3-2SiO2 to 758 C for SrO-Al2O3-2SiO2. These glass powders can be sintered to almost full densities and monoclinic celsian phase at a relatively low temperature of 1100 C.
Document ID
19910072294
Document Type
Reprint (Version printed in journal)
Authors
Bansal, Narottam P. (NASA Lewis Research Center Cleveland, OH, United States)
Hyatt, Mark J. (NASA Lewis Research Center Cleveland, OH, United States)
Drummond, Charles H., III (Ohio State University Columbus, United States)
Date Acquired
August 14, 2013
Publication Date
August 1, 1991
Publication Information
Publication: Ceramic Engineering and Science Proceedings
Volume: 12
ISSN: 0196-6219
Subject Category
NONMETALLIC MATERIALS
Distribution Limits
Public
Copyright
Other