Glass-based seals and ceramic protective coatings for solid oxide cells: current status, issues and perspectives

Reference	Presenter	Authors (Institution)	Abstract
06-081	Federico Smeacetto	Smeacetto, F.(Politecnico di Torino);	The development of seals for solid oxide cells is still a significant challenge as they must meet very restrictive requirements, withstand the severe environment of the solid oxide cells and be thermo-mechanically compatible with the materials to which are in contact. Glasses and glass-ceramics are likely to be the materials of choice, because of superior gas tightness in comparison with other types of sealants and higher stability in extreme working conditions, depending on the stack operating temperature. The crystallization and the sintering behavior of different glass-based systems is reviewed and discussed; the thermo-mechanical and thermo-chemical compatibility between the glass-ceramic seals and both uncoated and Mn-Co spinel-coated stainless steel is also examined. Manganese cobalt spinel oxides are promising materials as protective coatings for solid oxide cell interconnects; these coatings have been demonstrated to be very effective in reducing the interconnect corrosion. The doping of manganese cobaltite spinel with transition metals such as Fe and Cu has been previously evaluated in improving electrical conductivity and chromium retention capability, with coatings and powders processed by different methods. Nevertheless, there is a lack of long term studies at real SOC operating conditions where oxidation kinetics, area specific resistance, are evaluated to assess the effectiveness of coating protection. The use of electrophoretic deposition (EPD) technique to simultaneously co-deposit the MnCo spinel and the dopants is reviewed and discussed with respect to structural, compositional changes, sintering behavior and oxide scale growth during 2500-5000 hours long term tests. This presentation will give with a short review of current solutions and challenges concerning glass-based seals and ceramic protective coatings, looking into future perspectives.
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