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.