Abstract: The crystallization concert and microstructural evolution of SiO2MgO-Al2O3-K2O-B2O3-F glasses with excess nucleating agent CeO2, TiO2 and ZrO2 content (5 mol%) were studied. Opaque mica glass-ceramics were prepared from such glasses by controlled heat-treatment at 1050oC; and the evolved phases are identified as fluorophlogopite mica, KMg3(AlSi3O10)F2 by XRD study. The flurophlogopite mica crystallization is improved in presence of TiO2 and ZrO2 nucleating agents. As observed from FESEM study, the glass-ceramic morphology with hexagonal card like mica-flake crystals restructured to be interlocked in presence of ZrO2 content. Nanocrystalline microstructure is obtained in presence of CeO2 content. As obtained from dilatometry, highest thermal expansion coefficient (greater than 12 x10-6/K, at 50-800) is observed in ZrO2 containing (5 mol%) glass-ceramic, and it is compatible with other SOFC components. So, ZrO2 containing SiO2-MgO-Al2O3-K2O-B2O3-F glass can be useful for SOFC sealing application.
Author: Mrinmoy Garai
Keywords: Glass, Crystallization, Glass-Ceramics, Microstructure, Fluorophlogopite