Bi-layer glass-ceramic sealant for solid oxide fuel cells

A bi-layered concept of glass-ceramic (GC) sealant is proposed to overcome the challenges being faced by solid oxide fuel cells’ (SOFCs). Two separated layers composed of glasses (Gd-0.3 and Sr-0.3) were prepared and deposited onto interconnect materials using a tape casting approach. After heat treating the bi-layered structure at 850 °C for 1–100 h, smooth and void free interfaces over the entire cross-section of joint were obtained. Micro-Raman analysis confirmed the presence of a higher amount of residual glassy phase in Gd-0.3 in comparison to Sr-0.3. The bi-layered GC showed good wetting and bonding ability to the Crofer22APU metallic plate. Slight increase of electrical conductivity with increasing annealing time was observed due to partial crystallization of the glass, but the overall conductivity levels of GC bi-layers were low enough to grant good electrical insulation. This set of relevant properties makes the investigated bi-layered sealants suitable for SOFC applications.