PNNL

Abstract

A novel mica-based hybrid compressive seal was examined the stability at elevated temperatures under the compressive stress. The hybrid mica compressive seals were composed of the Muscovite mica and two compliant inter-layers and were reported earlier to have ultra-low leak rates at 800oC. In this paper, we examined the mid-term (~350-700 hours) stability of the mica-based compressive seals with three different inter-layers: a low melting borosilicate glass, a glass ceramics, and a metallic material. The 800oC leak test results showed excellent stability for the three different inter-layers in air at a compressive stress of 100 psi that the leak rates remained almost unchanged during the test. Microstructure characterization of the interface showed very limited interfacial reaction or glass penetration at the 8YSZ substrate interface. The results clearly demonstrate the applicability of the mica-based compressive seals for solid oxide fuel cells.