Effect of copper alloying addition on the electrochemical corrosion behaviour of Fe3Al intermetallic in sulphuric acid solution

The effect of Cu alloying addition on the corrosion resistance of iron aluminide Fe3Al has been investigated. In this work, the corrosion behaviour of Fe3Al-5Cu (at%) alloys has been assessed by open circuit potential, potentiodynamic polarisation and electrochemical impedance spectroscopy (EIS) measurements carried out in a 0.5 M H2SO4 solution, without stirring and in contact with the air. For comparison, the electrochemical tests have also been performed on Fe3Al intermetallic. The obtained electrochemical results indicate that iron aluminide Fe3Al-5Cu exhibits superior corrosion resistance as compared to Fe3Al. This improvement may be ascribed to the formation of a copper-enriched surface layer which shows higher protective effectiveness than that formed on Fe3Al intermetallic.