Corrosion Behavior of Pre-oxidized GH4169 Alloy with Solid NaCl Deposited in a Wet Oxygen Flow at 600 °C

Abstract

The corrosion behavior of the pre-oxidized GH4169 alloy was studied after 20 h of exposure under a solid NaCl deposit film in a wet O₂ environment at 600 °C by mass-gain measurements, X-ray diffraction, scanning electron microscopy, transmission electron microscopy methods. The results indicate that the pre-oxidized GH4169 alloy undergoes serious corrosion in the corrosive condition. The preformed Cr₂O₃ layer is gradually destroyed by deposit NaCl, and the inner Nb₂O₅ layer beneath the complete outer Cr₂O₃ layer also reacts with NaCl to form NaNbO₃. The electrochemical test results testified the existence of electrochemical reactions during this corrosion process. The corrosion behavior of pre-oxidized GH4169 under a solid NaCl deposit film in a wet O₂ environment at 600 °C has been discussed in detail.