Enhancement of corrosion resistance of Fe-Cr-Mo alloy to molten Al by thermal oxidation in air

Effect of oxidation on Fe-29Cr-6Mo alloy/molten Al interface reaction was investigated. Oxidation treatment was effective in enhancing the corrosion resistance to molten Al because of the dominant coverage of Cr2O3 film on sample surface. However, in the case of the sample oxidised for 4 h, because of the existence of Fe2O3 in the film, the oxide film was less effective than samples oxidised for longer duration. The lower corrosion resistance of oxidised Fe-29Cr-6Mo alloys in comparison to oxidised Co-29Cr-6Mo alloys could be related to the existence of σ phase in the former, which increased local defects within the film.