Study Of The Compressive Seals For Solid Oxide Fuel Cells

Planar solid oxide fuel cells(SOFC) have significant advantages including simple manufacturing process, easy assembling and higher power densities. Thus more and more research work is focused on it . In Planer SOPC, the area needed to seal is very large and the requirements for the seal materials are extremely stringent, Sealing are identified as one of the main technical bottlenecks restricting the commercialization of Planar SOFC. Seeking after and empoldering the seal materials having with steady quality is significant for the development of SOFC.The aulimina-based sealing materials were prepared by tap casting, and then were pressed when using so that to seal the planar SOFC. All the works and conclusions are summarizing below:Firstly the aulimina and aluminium powders were choosed as the raw materials, so were the appropriate solvent, dispersant, plasticizers, binders.The technical parameters of tap casting for aulimina-based slurry were studied systematically.The result shows slurry has the greatest stability when using the fish oil as the dispersant and at weight fraction of 1.5%, then the slurry is suitable for tap casting. Defining R as the weight ratio of plasticizers and binders , the slurry's viscosity decreases sharply as R increases, and when R=1, the slurry has the best rheological properties. Based on the experiment data, it is found that increasing content of dimethylbenzene results in the decrease of volatility on the tap, which was propitious to eliminate the veins on the tap surface. Mixing the slurry in vacuum and adding the antifoam could eliminate the hollows on the surface of green tape. It is conclude tat through adjusting the content of plasticizers and binders and choosing suitable desiccation process , the aulimina-based seals with uniform thickness and smooth surface was successfully preparaed.The leak ration of aulimina-based seals were tested at room temperature and 800℃ with self-designed leak detecting equipment, then the cross-section of seals were observed by SEM. the effection of aluminium on the seals'configuration was studied. the results shows that the leak rate of all seals decreased as the press inceased. the SEM image of the cross-section of aulimina based seals showed that the pore size became smaller as increasing the content of aluminium. thus the addition of aluminium can effectively decrease the leak ration of the seals: when the content of aluminium was twenty percent and the applied pressure was 210KPa, the aulimina- based sealing materials had lower leak rate, which was only 0.05 mL·cm-1·min-1 at 800℃. It is conclude that the aulimina-based seals prepared by tap casting can well satisfy the requirements for the sealing materials of planar SOFC.