Characterization SOFC Interconnect Materials: Sandvik Sanergy HT and Crofer 22 APU

Metallic interconnect plate materials used in solid oxide fuel cells must withstand both oxidizing and reducing conditions occurring on cathode and anode side of the cell, respectively. Ferritic steels with high chromium content are considered only economically and technically viable alternative. For this application, the formed chromium oxide scale is sufficiently protective and conducting. However, chromium evaporation from the interconnect materials causes cell degradation. To minimize this effect, and still have a sufficiently conductive oxide, a chromium barrier layer is needed, e.g by coating the material with a metal precursor that is oxidised. In this work, a new promising interconnect material Sanergy HT (AB Sandvik Materials Technology , Sweden) and the widely used Crofer 22 APU (ThyssenKrupp AG, Germany) were studied. Tested materials were uncoated Sanergy HT, uncoated Crofer 22 APU, and also Co-coated Sanergy HT. These materials were tested ex-situ with chromium evaporation measurements under oxidizing conditions, mass gain measurements under both oxidizing and reducing conditions, and also contact resistance measurements. Materials were also tested under real operating conditions in single repeating units. After each test the samples were analyzed by SEM/EDX on polished and FIB cut cross sections. Complementary analyses were done with XRD. Results of these tests will be published in the poster presentation.