Introduction of a Low Sealing Stress Vermiculite Based Compression Gasket for SOFCs

Compression seals are currently being used in a number of Solid Oxide Fuel Cell (SOFC) applications with degrees of success. One of the characteristics of a compression seal is that it needs compression, by way of applied load, for it to seal well. Commonly, the more load that is applied to compression seals, the better the seal quality and the lower the leakage rate. Compression seals based on vermiculite (Thermiculite (R) 866) have to date needed a minimum of 3-5 MPa gasket stress to achieve an acceptable seal, but improved sealing could be achieved with higher loads and gasket stresses. Gasket stress is a function of gasket area and applied load. This gasket stress requirement is significant; unfortunately it is not always achievable, especially given stack materials and constructions. Therefore a more desirable solution would be a compression gasket that sealed at a very low gaskets stress. This paper will outline the properties of TH870 compared to other vermiculite based compression seals. This data shows that TH870 seals at low gasket. Sealing data will be presented across a range of elevated temperatures.