Bonding characteristics of glass seal/metallic interconnect for SOFC applications: Comparative study on chemical and mechanical properties of the interface

Glass and glass–ceramics have been extensively used as seal material in planar solid oxide fuel cell (SOFC) stack. The main objective of the present work was to investigate the joining properties of a silicate based glass-ceramic as seal material with two different ferritic stainless alloys as interconnect, i.e. SS430 and Crofer 22APU. For a straight-forward approach to evaluate sealing materials, sandwiched samples will allow interfacial strength measurements and macroscopic overview on the interfacial situation of a glass–ceramic material. A convenient method for determining the interfacial fracture energies is double cantilever beam (DCB) test. The method allows to measure the crack-growth resistance of these materials to be able to use fracture mechanics design methods. Stable crack growth is necessary to get reliable and unambiguous fracture toughness data. If the fracture toughness values are determined from test configurations that do not allow stable crack growth, then the measurement may be related more to crack initiation than crack growth. In such cases, the calculated value of the fracture toughness may depend on the geometry of the machined notch.