Evaluation of a Novel Perovskite-based Conversion Coating For Corrosion Protection of 13Cr Ferritic Stainless Steels Under Relevant SOFC Oxidizing Conditions

摘要

Low Cr stainless steels could represent a cost-effective alternative to high Cr alloys for use as metallic interconnects at the lower end range of Intermediate Temperature Solid Oxide Fuel Cells (IT-SOFCs). Main drawback is represented by their insufficient long-term corrosion resistance, requiring suitable corrosion protection methods to avoid both electrical contact and chrome evaporation related issues. In this work, the stability of a perovskite conversion coating applied onto a commercial 13Cr ferritic stainless steel has been evaluated during prolonged exposure at 700°C in static air atmosphere. The passivation layer was produced with a molten carbonate bath treatment that resulted in the formation of a thin-film passive layer prevalently consisting of a LaFeO_3 perovskite oxide. Surface morphology and structure of the perovskite-based passive layer remained almost unchanged during 400 hour oxidation exposure thus showing promising corrosion protection ability in IT-SOFC oxidizing environments.