Understanding the Corrosion Mechanisms of Ferritic Stainless Steels in Reversible Solid Oxide Fuel Cells Operated under High Temperature and Steam Conditions

For this Phase-I STTR project, we propose to conduct specially designed corrosion experiments with vigorous analyses of reactive gases, surface and bulk properties and thermodynamics to facilitate the understanding of poorly-understood corrosion mechanisms of ferritic stainless steels (FSS) under high T and high steam conditions encountered in reversible solid oxide fuel cells (R-SOFCs). Based on the results, we will select adequate reactive element (RE) materials as a protective coating over R-SOFC’s metallic components (e.g., interconnects and substrates) using our innovative, low-cost, geometry-independent “hot dipping” coating process in Phase-II project. We highly anticipate that the new RE coatings selected based on the Phase I results can protect the FSS-based metallic components in R-SOFCs from being aggressively oxidized under harsh steam electrolysis conditions by preferentially forming a dense, continuous and thin protective scale. During Phase I, Save Mother Earth, LLC, along with University of South Carolina, will carry out (1) specially designed corrosion experiments, (2) comprehensive surface/bulk chemical and microstructural analysis, (3) Cr-transport kinetic studies and (4) thermodynamic assessments. The outcomes of this Phase-I research will lay a solid foundation for Phase II work aiming to implement RE coatings technology into R-SOFC stacks. We anticipate that the new RE coatings will reduce the corrosion rate of metallic components by 200% and enable >500 hours operation with acceptable degradation rate under simulated steam electrolysis conditions (>90% steam) specified in topic C59-09 Corrosion Tolerant and Cost-Effective Alloys for Reversible Solid Oxide Fuel Cell Systems.