Thermiculite® 870 is a high temperature sealing material designed for low stress sealing in solid oxide fuel cells. It is based on the mineral vermiculite and contains no organic components.
ThermiculiteŽ 870 is specifically designed for use in solid oxide fuel cells (SOFC) and solid oxide electrolysers (SOE) and has a high degree of compression combined with good sealing under low applied surface stresses.
ThermiculiteŽ 870 contains only two minerals, vermiculite and steatite. There are no organic materials or other elements (such as phosphorous or sulphur) that would contaminate SOFC or SOE cell chemistry.
ThermiculiteŽ 870 is available in sheet form:
Standard sheet size: 450mm x 350mm
Standard thicknesses:
0.5mm, 0.7mm and 1.0mm*
*Please note that these nominal thicknesses are provided as a guide. As the material is very soft the measured thicknesses may differ slightly due to compression during measurement. Special thicknesses between 0.3mm and 1.0mm are available on request. Flexitallic can provide a gasket cutting service, ideally a .dxf file of the gasket shape would be provided by the customer.
Flexitallic will review the dimensions and design and advise if cutting is feasible and provide a quote. Sample material available on request.
Click here for downloadable datasheet for more technical information >>
Thermiculite 870 test data ThermiculiteŽ 870 Gasket Test Data

Figure 1 shows load vs defection for TH870 compared to TH866. At a stress of 1 MPa TH870 compresses 0.22mm whereas TH866 gasket only compresses 0.02mm under the same load. For some SOFC designs a softer, more compressible sealing material is required. TH870 is significantly more compressible under low loads, e.g. 1MPa. TH870 is around ten times more compressible than TH866.

Figure 2 shows an 80 hour leakage test at ambient temperature. ThermiculiteŽ 870 also seals at least as effectively as TH866, but at much lower applied loads. This is the case at ambient and elevated temperatures.

For more information on Flexitallic SOFC, please contact us
The Flexitallic Group