| Abstract Scope |
Hydrogen-rich high temperature environments are becoming more prevalent due to the need to substitute natural gas. Many chemical processes, including solid oxide electrolyzer cells (SOECs) and their periphery, are facing hydrogen and water vapor degradation. Candidate materials, e.g. for interconnects, for these environments require high electrical conductivity, creep resistance, and microstructure and phase stability at temperatures above 825°C. As potential materials, six ferritic interconnect materials with decreasing amounts of chromium (AISI446, Crofer 22 APU, Crofer 22 H, AISI442, AISI410, P91) and three Ni-based alloys (Haynes 244, Haynes 233, Haynes 230) were evaluated for their stability in 10% H2/90% H2O and 50% H2/50% H2O between 700-900°C up to 1000 hours. The degradation mechanisms of these selected candidate materials for SOEC components were investigated and characterized. The materials show different behavior in terms of scale growth, changes in the subsurface zone and changes in the mechanical properties from hydrogen uptake. |