Electrochemical study on effect of Au, Ag, Pd and Pt on corrosion behaviour of Fe₃Al in molten NaCl–KCl

Abstract

The corrosion behaviour of Fe 3 Al intermetallic alloyed with 1 at-%Ag, Au, Pt and Pd in NaCl-KCl (1 : 1M) at 700uC, typical of waste gasification environments, has been evaluated using polarisation curves, linear polarisation resistance and electrochemical impedance spectroscopy measurements and compared with an Ni based alloy, namely Inconel 600. Results have shown that, for short testing times, the addition of noble elements increased the corrosion rate for base Fe 3 Al intermetallic alloy, but it was decreased for long testing times by forming a protective corrosion product layer. Additionally, base Fe 3 Al intermetallic alloy had higher corrosion rates than Inconel 600.