Influence of the Alloying Elements Mn and Co on the Electrical Resistance and Corrosion Behavior of Bipolar Plate Materials in MCFC

摘要

The electrical resistivity of the oxide scale and the corrosion behavior of alternative bipolar plates in the molten carbonate fuel cell (MCFC) were investigated. We tested different commercial stainless steels containing Co (Haynes 556) and Mn (Nitronic 30, Nitronic 50, and Nitronic 60) under MCFC conditions. Oxide-scale resistivity measurements were coupled with observations of microstructural/compositional change over time. All tested material formed multilayered oxide scales, whose phase compositions are the key factor for electrical interfacial resistivity. The high cobalt content of Haynes 556 (18 wt%) did not improve its electrical resistivity or corrosion resistance. Thus Co-containing stainless steels such as Haynes 556 do not seem to be the preferred choice for the bipolar plate materials. On the other hand, the addition of manganese led to the formation of Mn-doped oxide scales, which lowered the resistivity of the oxide scale. Also, the corrosion resistance of the Mn-containing stainless steels was better than that of 316L, the present bipolar plate material.