The in situ oxidation of Ni-5at.%Al and Ni-15at.%Al alloys in Li+K carbonate melt were investigated by measuring open-circuit potential and electrochemical impedance spectroscopy under an O2+CO2 gas mixture in the ratio 90:10 at a total pressure of 1 atm at 650 °C. In situ oxidation processes of Ni-Al alloys demonstrate three stages. The period of the oxidation process depends on the aluminum content in the alloy. The final product has probably a multilayer structure, where the inner part is compact (probably also multilayer in nature) and the outer part (solution side) is porous. Ni-5at.% Al electrode exhibited excellent stability during one-week immersion in the carbonate melt. Extension of cathode lifetime in molten carbonate fuel cells (MCFC) appears possible if the Ni cathode is modified by the addition of small concentration of aluminum.
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