Strategies to Improve the Effectiveness of the Thin Film Coated Interconnects

Abstract

Ferritic stainless steels are used as interconnect materials in solid oxide cells (SOFC/SOEC). To enhance their performance and extend the lifespan of SOC’s, FSS interconnects are typically coated with protective coatings. MCO coatings deposited through physical vapor deposition have been extensively studied for this purpose. However, most studies have been conducted on in isothermal conditions which do not reflect the conditions experienced in stacks. Stacks are typically conditioned at high temperatures, usually 100-250°C above the operating temperatures, to ensure gas tightness. Thus, it is important to understand the influence of pre-oxidation on behaviour of the interconnect. The influence of pre-oxidation on Ce/Co-coated Crofer 22 APU and AISI 441 is studied at 850°C in air. The samples are characterised using scanning electron microscopy. The oxidation behaviour of Ce/Co-coated Crofer 22 APU improved significantly upon pre-oxidation whereas only minimal effect was observed for Ce/Co-coated AISI 441.