Mono and multi-layer electrolytes of ceria and zirconia prepared by tape casting / Eletrólitos mono e multicamadas de céria e zircônia preparados por colagem de fita




In this work it was investigated bi-layer electrolytes prepared by the tape casting technique. These electrolytes were composed of one layer of 10 mol% gadolinia doped ceria (CDG) and another one of 8 mol% yttria-stabilized zirconia (ZEI -8). CDG tapes were prepared with powder from Fuel Cell Materials (FCM) and powder obtained by oxide mixing. ZEI-8 tapes were prepared with powder from Tosoh Corporation. In the first step, CDG and ZEI-8 tapes were prepared and dense plates were obtained after sintering. Sintered plates were characterized by impedance spectroscopy and scanning electron microscopy (SEM). At 350C, the highest electrical conductivity of CDG samples prepared with powder obtained by oxide mixing and sintered at 1600 C was 3.37 x10-4 and with FCM powder sintered at 1500 C was 4.33 x10-4 At the same temperature, ZEI-8 samples sintered at 1600 C showed 9.6 x10-5, which agrees with literature results. CDG/ZEI-8 bilayers plates were prepared either by lamination or by double tape casting, followed by sintering at 1600 C/2 h. Sintered bi-layers prepared by double tape casting were characterized by impedance spectroscopy. Electrical conductivity at 350 C was 8.82 x10-5, three times lower than CDG mono layer (3.37 x10-4 due to high resistivity of CGD/ZEI-8 interface. The bi-layers SEM analysis showed that layers thickness of CDG and ZEI-8, were 140 μm and 24 μm respectively. The adherence between CDG and ZEI-8 layers was attributed to secondary phase in the interface which was responsible for high resistivity of the CGD/ZEI-8 interface.


céria dopada oxido de zircônio colagem de fita eletrólitos engenharia de materiais e metalurgica células a combustível

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