Degradation of 316L steel interconnects in molten carbonate fuel cells

Keywords

molten carbonate fuel cells, interconnects, 316L stainless steel, high-temperature corrosion, surface and internal oxidation.

Cite as

Majewska K., Szczesniak A., Martsinchyk A., Shuhayeu P., Dybinski O., Podhurska V. Ya., Chepil R. V., Kuprin О. S., Reshetnyak E. M., and Milewski J. Degradation of 316L steel interconnects in molten carbonate fuel cells. Physicochemical Mechanics of Materials. 2026. 62(3), 48-56.

Abstract

The degradation mechanisms of austenitic AISI 316L stainless steel, used for manufactu­ring interconnects of molten carbonate fuel cells (MCFC), under both real operating con­ditions and laboratory modeling were investigated. The structure-phase state of inter­connect surfaces after operation in the cathode (oxygen–carbon dioxide mixture) and the anode (hydrogen–water vapor–carbon dioxide mixture) MCFC environments, as well as 316L steel specimens after contact with the electrolyte (molten 62Li₂CO₃/38K₂CO₃ salts) at 650°C in laboratory conditions, were studied. In the cathode environment, intensive oxidation, carburization, and formation of unstable oxycarbide phases are observed, whereas in the anode environment the formation of iron- and chromium-containing oxides predominates. The molten electrolyte is identified as the most aggressive degradation factor, causing selective leaching of chromium and nickel, intergranular corrosion, and deep internal oxidation. The obtained results indicate the limited durability of MCFC interconnects made of 316L steel without the application of protective coatings.

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