Thermal Aging Effect on the Joint Strength Between an SOFC Glass-Ceramic Sealant and LSM-Coated Metallic Interconnect

Lanthanum strontium manganite (LSM) has been practically coated on the metallic interconnect to prevent Cr poisoning in SOFC. The aim of this study is to investigate the joint strength between a glass-ceramic sealant and an LSM-coated interconnect steel at room temperature (RT) and 800 degrees C. Effect of long-term thermal aging is also characterized. Results indicate that LSM-coated specimens have a lower joint strength than the uncoated ones. It is attributable to the existence of pores around the interface between glass-ceramic sealant and LSM coating. However, the shear strength of LSM-coated joint specimen is enhanced by 52% at RT and by 200% at 800 degrees C after 1000-h thermal aging at 800 degrees C. The given thermal aging treatment also improves the tensile strength of LSM-coated joint specimen by 50% at 800 degrees C. It is attributed to a self-healing effect of the glass-ceramic sealant during thermal aging to reduce the pore size.