**4. Conclusions**

Results showed that YSZ films can be obtained directly on porous LSM substrate by spray pyrolysis technique. A dense and homogeneous film can be obtained by multi-layers deposition with intermediate heat treatment.

The heat treatment at 700 °C allowed the stabilization of the zirconia cubic phase, which is the phase of interest for application as electrolyte in solid oxide fuel cells, as indicated by xray diffraction analysis and confirmed by the Fourier transform infrared spectroscopy analysis.

The type of solvent used influences in the morphology of the films obtained. Solvents that have very low boiling point lead to the uncontrolled evaporation of the solvent, forming a quite brittle film. The increase in the solvent boiling temperature helps to a proper evaporation, resulting in films with more satisfactory morphological characteristics. In all cases of one-layer deposition, heat treatment caused an increase of surface discontinuities, demonstrating its influence on the films morphology.
