Alkali Effect on the Electrical Stability of a Solid Oxide Fuel Cell Sealing Glass

Abstract

An alkaline-earth silicate (Sr–Ca–Y–B–Si) sealing glass with varying content was developed and evaluated for solid oxide fuel cell (SOFC) sealing applications. Two metallic interconnect plates were sealed with the glass and tested for electrical stability in a dual environment at elevated temperatures under a dc loading of . The metallic interconnect material, a ferritic stainless steel, was tested in the as-received state and after surface aluminization. The isothermal aging results showed stable electrical resistivity at for ∼600 to 800 h for all the sealing glasses, with or without . The electrical resistivities at were several orders of magnitude higher than the typical SOFC stack components. However, the glass with high alkali content (5%) showed excessive interfacial reaction, which resulted in debonding from both the as-received and the aluminized steel. Interfacial microstructures were characterized and possible reactions were discussed.