Optimization of Tensile Strength Measurements on Glass-Ceramic Sealant Used for SOFC Stacks
The goal of our recent studies is to improve the characterization methods of mechanical strength in order to obtain quantitative results and to achieve the understanding needed to design more robust SOFC stacks. For this purpose, computer simulations using finite element analyses (FEA) have been performed. By modelling different joint configurations, it was possible to homogenize the stress distribution along the sealing layer and to optimize the geometries of the components. It was shown that bending of the metallic components as well as residual thermal stresses had a strong effect on the initial sample setup with thin cylinders. An optimized design for the tensile components allows a more uniform distribution of tensile stresses within the sample. Different joining conditions were investigated and the calculations were verified by experiments. Scanning electron microscopic analyses were carried out on cross sections and broken samples, which allow to evaluate the microstructure of the composite and its interfacial reactions. The mechanical strength values obtained by the improved characterization method represent a tenfold increase compared to the values published in .
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