Crystallization of Gahnite in CMAS Glass Forming System - Mechanism and Process Kinetics

Abstract:

The crystallisation mechanism of glass-ceramic materials from a CMAS group Al0.37B0.34Fe0.01Mg0.02Zn0.29Ca0.05Si0.78O3 was tested under non-isothermal conditions by the DTA method. Glass-ceramic material of two-phase composition with precipitation of crystallites from islet silicates Zn2SiO4 and a crystalline phase from a spinel group, gahnite ZnAl2O4 was obtained in the system under investigation. Activation energy of a crystallization process Ea was determined and a crystal growth morphology parameter n was computed. It was revealed that in the test material from a CMAS group one could obtain the crystalline phase in the form of ghanite as a result of a controlled process of crystallization. The occurrence of a spinel phase caused the obtained glass-ceramic material had higher fracture toughness (KIC) than material from a CMAS group, containing pyroxene crystalline phases typical for this system.

• Periodical: Advances in Science and Technology (Volume 68)
• Pages: 59-64
• DOI: https://doi.org/10.4028/www.scientific.net/AST.68.59
• Online since: October 2010
• Authors: Daniela Herman, Tomasz Okupski, Wiesław Walkowiak
• Keywords: Crystallization Process, Gahnite, Glas Ceramics

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