화학공학소재연구정보센터
Journal of the Electrochemical Society, Vol.165, No.3, F181-F188, 2018
Durability of LSCF-Coated Fe-Cr-Al Alloy for SOFC Applications
The long-term durability of La0.6Sr0.4Co0.2Fe0.8O3 (LSCF)-coated Fe-Cr-Al alloy was investigated as a novel current collector material for SOFCs. The LSCF coating and subsequent heat-treatment at 700-900 degrees C changed the microstructure of the surface oxide layer to a columnar structure of nanosize gamma-Al2O3 arranged in the same direction, in which a small amount of Sr3Al2O6 contributes to the electronic conduction. The LSCF coating decreased the alloy oxidation rate by 23% at 700 degrees C compared to the case without coating, following the parabolic growth law. Raising the temperature from 700 degrees C to 900 degrees C increased the oxidation rate of the LSCF-coated alloy by 51 times. The oxidation mechanism at 900 degrees C was considered to be similar to that at 700 degrees C, because of the similarity in microstructure, crystal structure, elemental composition and electrical conductivity. It was estimated that the Cr2O3 layer begins to grow on the inner side after roughly 6,000 h at 700 degrees C, when the thickness of the surface oxide layer exceeds 1 mu m. The same.-Al2O3 columnar microstructure still covered the surface after 12,000 h. However, further improvement in durability and electrical conductivity is needed to meet the requirements for practical application. (C) 2018 The Electrochemical Society.