Corrosion of Al-Fe Coatings for Wet-Seal Area in Molten Carbonate Fuel Cells

Abstract

The corrosion behavior of Al-Fe coatings was studied in the wet-seal atmosphere of molten carbonate fuel cells (MCFC). Fe-8Al, Fe-16Al, Fe-25Al, Fe-36Al, and Fe-70Al (in at.%) specimens were tested in Li/K carbonate at 650℃ by a single cell test and an immersion test. In general, the corrosion resistance of the Al-Fe coatings was enhanced due to the formation of a protective LiAlO2 layer. However, when the Al-Fe coatings didn't have sufficient content of aluminum enough for maintaining the protective layer, the corrosion resistance of the Al-Fe coatings was severely degraded by the growth of non-protective scales like LiFeO2. The test results revealed that the aluminum contents in the coatings should be higher than 25 at.% in order to form and maintain the protective LiAlO2 layers.