Effect of Sintering Temperature on the Mechanical Properties of Film Gd0.2Ce0.8O1.9 Electrolyte for SOFCs Using Nanoindentation
The mechanical properties of thin film gadolinia doped ceria (Gd0.2Ce0.8O1.9, GDC) electrolyte, for solid oxide fuel cells (SOFCs), with different levels of sintering density were investigated by the nanoindentation technique. Electrolyte thin film supported on Ni-GDC cermet was made by co-sintering at several temperatures between 1350 and 1450 ºC. The microstructures of the electrolyte films and the cells performances were studied by scanning electron microscope (SEM) and current-voltage tests, respectively. In order to determine the mechanical properties, a Berkovich indenter was used at different applied loads (30, 50 and 100 mN). Plastic deformation took place, so Oliver and Pharr equations must be applied to evaluate the hardness and Young’s modulus of the electrolyte film. The residual nanoindentations were observed by optical microscope (M.O.) and field emission scanning electron microscope (FE-SEM). The present study reveals that the nanoindentation is a non-destructive and ideal technique to determinate the quality and the mechanical properties of the thin film of a SOFC. The results also show that the hardness decreases with the increasing of the applied load, which is attributed to the indentation size effect.
Solid Oxide Fuel Cells (SOFCs), Gadolinia doped ceria (GDC), Electrolyte film, Nanoindentation, Hardness, Young’s modulus
The present work was financed by the Spanish MCTE under Project MAT2008-06785-C02-01, XaRMAE (Xarxa de Referència en Materials Avançats per a l’Energia, Generalitat de Catalunya) and the aid of the Commissioner for the University and Investigation of the University Department of Innovation and Company of the Catalan Autonomous Government of Catalonia and the European Social Fund. The authors would like to thank Serveis Cientificotécnics for SEM data and Emilio Jiménez (Centre d’Integritat Estructural i Fiabilitat dels Materials, UPC) for experimental data.
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