The corrosion behavior of five commercially available alloys (AISI 316L, AISI 310S, Inconel 601, Thermax 4762, and Kanthal A1) in molten carbonate under reducing gas atmospheres was investigated with cyclic voltammetry and quasi-stationary polarization curve measurements. The reactions that proceed on these materials at distinct potentials could be deduced by comparison of the cyclic voltammograms and polarization curves with those of pure metals and model alloys. The shape of the polarization curves of all materials strongly depends on the preceding electrochemical treatment. A polarization curve recorded immediately after immersion of a sample resulted in a high anodic current. This implies that the passivation of the materials is poor. When a specimen was conditioned at -1060 mV for 10 h before recording the polarization curve, the anodic current diminished, which indicates passivation. This occurred for all materials except AISI 316L. A ranking of the corrosion properties was determined from polarization curves of samples that had been conditioned assuming the current densities to be representative. The resistance against corrosion of the alloys increases in the order : AISI 316L < Inconel 601 < AISI 310S < Kanthal A1 = Thermax 4762. Because the current densities were recorded at molten carbonate fuel cell (MCFC) anode potentials, this order may also apply for real MCFC operation conditions. The order determined from electrochemical experiments is in agreement with the results of exposure tests which are more time-consuming. This study confirms that the presence of large amounts of chromium and significant additions of aluminium have a beneficial effect on the corrosion resistance of stainless steel and nickel-base alloys.