Assessment of the thermal expansion mismatch in lanthanum strontium cobalt ferrite-yttria stabilized zirconia two-layers systems using photoacoustic methodology

摘要

In this letter we investigate the thermo-elastic mismatch in lanthanum strontium cobalt ferrite (La_(0.6)Sr_(0.4)Co_(0.2)Fe_(0.8)O_(3-δ)) (LSCF) films deposited onto yttria stabilized zirconia (YSZ) substrates, applicable to solid oxide fuel cells. We investigated composite LSCF+YSZ and pure LSCF films deposited onto commercial YSZ substrate. Photoacoustics was used to obtain the effective thermal diffusivity and thermal expansion coefficient of the two-layers samples,. Based on a thermal-electrical analogy model, it was possible to get the thermo-elastic properties of the films and to confirm the desired reduction on the thermo-elastic mismatch between film and substrate when comparing composite LSCF+YSZ and pure LSCF films.