  The reliability of perovskite material LSCF to be used as cathode parts in
solid oxide fuel cells also relies on its mechanical properties. Adequate
surface conditions are desired when the as-sintered porous thin films are
subjected to nanoindentation for mechanical property determination. In this
study, extensive cracks and considerable surface roughness were found in the
LSCF films after sintering at high temperatures. This would significantly
scatter the nanoindentation data and result in unreliable measurements. Various
attempts including the comparison of film deposition methods, drying and
sintering processes, and reformulating the ink were made to improve the surface
quality. Results revealed little dependence of cracking and surface roughness
on deposition methods, drying or sintering processes. It was found that the
critical factor for obtaining crack-free and smooth LSCF films was the ability
of the ink to be self-levelling in the earlier wet state. Reproducible
nanoindentation measurements were obtained for the films with improved surface
quality.
