Mandal, S and Chakrabarti, S and Ghatak, Shankar and Das, Swapan Kumar (2005) Ultra low and negative expansion glass-ceramic materials produced from pyrophyllite and blast furnace slag. Bulletin of Materials Science, 28 (5). pp. 437-443. ISSN 0250-4707

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Abstract

Ultra low and negative expansion glass-ceramic materials have been obtained from pyrophyllite and blast furnace slag.. The batch composition was modified with the addition of lithium carbonate, hydrated alumina, boric acid and nucleating agent (titania). The batch was melted at 1400 degrees C followed by casting in the form of bars and annealed at 510 degrees C for 4 h. The annealed specimens were subjected to heat treatment at predetermined temperatures selected from DTA study of the parent glass. Thermal expansion measurement and X-ray diffraction analysis revealed that the specimen. nucleated at 545 degrees C for 4 h and crystallized at 720 degrees C for 2 h which resulted in negative coefficient of thermal expansion [(-) 9 to (-) 2 x 10(-7)/degrees C] over the temperature range (30-600 degrees C) due to the formation of beta-eucryptite while other heating schedule showed the formation of spodumene and lithium aluminium silicates. The samples showed excellent flexural strength value and varied in the range 120-200 MPa depending upon the phases present.

Item Type:	Article
Uncontrolled Keywords:	Glass-ceramic; Li2O-Al2O3-SiO2; Blast furnace slag; pyrophyllite
Subjects:	Structural Clay Products
Divisions:	Advanced Clay & Traditional Ceramics
Depositing User:	Bula Ghosh
Date Deposited:	07 Mar 2012 11:23
Last Modified:	07 Mar 2012 11:23
URI:	http://cgcri.csircentral.net/id/eprint/963

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