Oxygen ion diffusion in dense SrZrO₃ layer on YSZ

To investigate the oxygen ion diffusion behavior in an SOFC typically constructed of an LSCF cathode, a GDC interlayer and a YSZ electrolyte, where an SrZrO₃ is unfavorably formed from the Sr component in LSCF and the Zr component in YSZ, various thickness of dense SrZrO₃ layers were fabricated on the surface of YSZ pellet by applying SrCO₃ paste and heat treating at three different temperatures and subsequently the oxygen isotope exchange experiments were performed for the samples. The 18O profiles and associated elemental distribution were determined across the layers by secondary ion mass spectrometry. Results have revealed that the 18O profiles are found largely deviated from those expected from the bulk diffusion in the homogenized substance particularly in the vicinity of the surface of SrZrO ₃ and the phase boundaries between SrZrO₃ and YSZ.