Bonding of sealant/interconnect joints in solid oxide cell stacks

Residual stresses in solid oxide cell (SOC) stacks or components are potential fracture sources which needs to be investigated in order to enhance the reliability of the stacks. One of the most important joint materials in solid oxide cell stacks are glass sealants/steel interconnects at which chemical and mechanical characteristics are changed during service. Chemical reactions occur at the interface and change its chemistry. Mechanical stresses are formed with changing materials chemistry. Moreover, thermos-mechanical behavior mismatches lead to residual mechanical stress upon cooling/heating. An analytical model based on the classical beam bending theory was used in this study for calculating the residual stresses in this joint hybrid structure when the device is cooled down to room-temperature. Two potential commercial steel materials (SS430 and Crofer 22APU) were considered as the glass sealant counterpart.