Study of Physical Structural and Thermal Properties Of Calcium Borosilicate Glass Sealants

Abstract

Planar design of Solid Oxide Fuel Cell (SOFC) is better than tubular design due to its higher current density and simple manufacturing. However, the planar design of SOFC requires sealants at the edges of the cells to prevent fuel leakage and air mixing at higher temperature. The glass and glass ceramics are most suitable and compatible with other components of SOFC at working temperature of SOFC (800-1000oC). In the present study a series of SiO2-B2O3-CaO-A2O3 (A= La, Y) compositions have been synthesized by taking appropriate proportion (mol %) of each oxide constituents. Mixture of these components were heat treated for different time durations and then characterized by using various techniques viz X-Ray diffraction (XRD), Fourier Transform Infra Red spectroscopy (FTIR) and dilatometry to determine the possible reaction phases and prominent band formation. Amorphous nature of all the cast samples is confirmed by x-ray diffraction. During heat treatment main phase formed was La2SiO5. The FTIR spectra of all the samples exhibit three bands i.e, 400-600 cm-1 , 650-800 cm-1 and 800-1300 cm-1. Transmission bands of all glass samples are composed of silicate and borate chains. The dilatomtery analysis were done to find the thermal expansion coefficient (TEC) and stability respectively. In order to understand the crystallization kinetics these samples were heat treated at 900oC for various heat treatment durations. A detailed structural, thermal and properties of calcium borosilicate glasses has been presented in this report.