Effective Ag-CuO sealant for planar solid oxide fuel cells

Effective sealant for planar solid oxide fuel cell is one technical hurdle for its application. In this article, Ag-CuO braze, which conducted directly at 950 °C in air, has been investigated as a sealant candidate between the SS430 interconnect and the Ni/YSZ anode for the planar solid oxide fuel cells. The results for leakage rates indicate that the lowest leakage is as low as 0.001 sccm cm^-1. SEM images demonstrates that both the pure Ag and 6 mol% CuO in the braze integrates the anode inherently. However pure Ag wets poorly on the SS430 interconnect surface but 6 mol% CuO braze forms a reaction zone, upon which Ag wets well, so the hermeticity has been improved significantly. Even after experiencing 20 thermal cycles, the leakage rate is still as low as 0.002 sccm cm^-1. No significant effects of thermal cycles on the interfacial microstructure of the sealant were observed. These shows that Ag-CuO braze is a promising candidate for SOFC sealant.