Publication
Title
Influence of amorphous phase separation on the crystallization behavior of glass-ceramics in the $BaO-TiO_{2}-SiO_{2}$ system
Author
Abstract
 The possible role of a prior amorphous phase separation on the subsequent crystallization has been the topic of vigorous debates over the last decades and has not yet been clarified, especially regarding the role of the interfaces created by the phase separation. This study proposes to focus on the interplay between a prior amorphous phase separation and the crystallization of fresnoite in the BaO-TiO2-SiO2 system. The crystallization behavior of a non-stoichiometric composition inside the miscibility gap (called APS) is compared with the stoichiometric composition (called FRES) and a non-stoichiometric composition outside the miscibility gap (called NoAPS). The crystallization mechanisms are compared using differential thermal analysis (DTA) by calculating the Avrami parameters and the activation energies as a function of the particle size. The DTA study shows that the two non-stoichiometric compositions exhibit a pronounced surface crystallization behavior whereas FRES undergoes bulk nucleation. This is supported by a multi-scale microstructure characterization. Furthermore, this study demonstrates that the amorphous phase separation and the associated interfaces do not play any significant role in the nucleation step. Moreover, transmission electron microscope (TEM) and local orientation measurements show that the growth of the dendrites is not hindered by the SiO2-rich droplets. The final stage of crystallization of APS is tentatively explained by two composition effects that must be further investigated: the viscosity effect and the formation of a eutectic. (C) 2013 Elsevier B.V. All rights reserved.
Language
English
Source (journal)
Journal of non-crystalline solids. - Amsterdam
Publication
Amsterdam : 2014
ISSN
0022-3093
Volume/pages
384(2014), p. 61-72
ISI
000329422400010
Full text (Publisher's DOI)
Full text (publisher's version - intranet only)
UAntwerpen
 Faculty/Department Research group Publication type Subject Affiliation Publications with a UAntwerp address