Studies on thermal and structural properties of glasses as sealants for solid oxide fuel cells

Solid oxide fuel cell (SOFC) is a very efficient and clean source of energy. The planar design of SOFC requires sealant at the edges of the cell to prevent fuel leakage (H₂, CH₄) and air mixing at its working temperature. The glass and glass ceramics are most suitable and compatible sealing materials for planar design of SOFC. In the present study a series of SiO₂ - B₂ O₃ - MgO / SrO - A₂ O₃ (A = Y, La, Al) glasses of different compositions were prepared by taking appropriate proportion (mol%) of each oxide constituents followed by mixing and melting in alumina crucible at 1550 ^{{ring operator}} C. The molten glasses were quenched in air. These samples were characterized by X-ray diffraction, Dilatometer and Fourier transform infrared spectroscopy (FTIR) techniques. FTIR study showed that absorption bands of all glass samples are composed of either silicate or borate chains. The dilatometeric analysis was also done to find the thermal expansion coefficient (TEC), softening temperature and stability of the glass samples, respectively. In order to understand the crystallization kinetics these samples were heat treated at 800 ^{{ring operator}} C for various heat treatment durations. The details of this study are presented in this paper.