Biswas, Kaushik and Sontakke, Atul D and Majumder, M and Annapurna, K (2010) Nonisothermal crystallization kinetics and microstructure evolution of calcium lanthanum metaborate glass. JOURNAL OF THERMAL ANALYSIS AND CALORIMETRY, 101 (1). pp. 143-151. ISSN 1388-6150

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Abstract

This paper reports results on the crystallization kinetics of 35.5CaO-7.25La(2)O(3)-57.25B(2)O(3) glass under nonisothermal conditions based on the studies carried out from the differential thermal analysis upon using various well-established models. The crystalline phases formed during the optimized ceramization process have been confirmed from the X-ray diffraction. The activation energies of the first (formation of CaLaB(7)O(13)) and second (formation of LaBO(3)) crystallization events have been estimated using the conventional methods of Kissinger, Augis-Bennett, Ozawa, and Matusita, and the results are found to be in good agreement with each other. The Avrami exponents that are determined by these models for the crystallization of CaLaB(7)O(13) and LaBO(3) are found to be in the range of (1.81-2.35) and (4.03-4.65), respectively. This indicates that the formation of CaLaB(7)O(13) is dominated by a surface crystallization, whereas LaBO(3) is formed by three-dimensional bulk crystallization with an increased rate of nucleation. This observation is further validated by microstructural investigation, which shows the formation of CaLaB(7)O(13) phase as a surface layer and a bulk crystallization of LaBO(3) in optimally ceramized samples.

Item Type:	Article
Additional Information:	17th Russian International Conference on Chemical Thermodynamics in Russia, Russian Acad Sci, Kazan, RUSSIA, 2009
Uncontrolled Keywords:	Crystallization kinetics; Differential thermal analysis
Subjects:	Glass
Divisions:	UNSPECIFIED
Depositing User:	Bidhan Chaudhuri
Date Deposited:	01 Feb 2012 11:42
Last Modified:	20 Jun 2012 09:44
URI:	http://cgcri.csircentral.net/id/eprint/592

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