Structural and thermal properties of glass composite seals and their chemical compatibility with Crofer 22APU for solid oxide fuel cells applications

In the present investigation, glass composite seals have been prepared by mixing the different glass compositions in fixed ratio and then ball milling for 5 h. The main aim of this approach is to investigate the sealing and bonding issues in solid oxide fuel cells (SOFC) without using unreactive particles in glass matrix. The structural and thermal characteristics of these composites were studied using particle size analyzer, zeta potential, dilatometry, differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA). X-ray diffraction has revealed phase formation in all composites after 1000 h heat-treatment at 850 °C. In addition to this, the chemical compatibility of the prepared glass composites with the interconnect Crofer 22APU has been studied using scanning electron microscope (SEM), electron probe microanalysis (EPMA), energy dispersive spectroscopy (EDS) and dot-mapping techniques. The interfacial study has revealed that GG6 and GG7 composites have good adhesion without delamination, cracks or pore formation. Chromate formation occurred in GG3 and GG4 composite couples, though no delamination was observed at the interface of GG4 composite with Crofer 22APU. GG5 could not form a diffusion couple due to its high viscosity and very low coefficient of thermal expansion.