Effect of LSCF Microstructure on GDC Interlayer Stability and Cation Diffusion in Porous and Dense LSCF/GDC/YSZ Triplets

摘要

We evaluated the effect of LSCF microstructure on the stability of GDC interlayer by performing cation diffusion experiments on LSCF/GDC/YSZ triplets. For this purpose, we prepared porous and dense LSCF layers on pre-annealed dense GDC/YSZ diffusion couples and performed subsequent heat treatments. Here we observe that the pre-annealing of GDC/YSZ couples, results in microstructural changes in GDC interlayer and preferential diffusion of Zr from YSZ electrolyte. Our results show that after annealing at high temperature of porous LSCF/GDC/YSZ triplets, enhanced Sr–diffusion from the grains of LSCF layers to the GDC resulted in the severe formation of SrZrO_3 at the LSCF/GDC interface, while Sr and Zr diffusion along the grains of GDC dominate in the formation of SrZrO_3 at the YSZ electrolyte than the diffusion through the cracks. On the other hand, for dense LSCF/GDC/YSZ, the cracks or crack–walls in the GDC interlayer are fast diffusion paths for cation diffusion. Our results show that the microstructure of LSCF plays an important role in understanding the formation of SrZrO_3 as well as the stability of GDC as a reaction barrier.