High-Temperature Corrosion Behaviors of Ni-Based Alloys in Carbon Dioxide

抄録

The high-temperature corrosion behaviors of Ni-based alloys including Hayness 230, Hayness 282, Inconel 740H, Inconel 617, Inconel 625 in CO₂ environment at 800 ℃ for 1000 h were studied. The corrosion performance of the alloys was measured by Mettler electronic balance, and the surface behavior of oxide were characterized by X-ray diffraction, scanning electron microscope, and energy dispersive spectrometry. The results show that the oxidation kinetics of Ni-based alloys in high-temperature carbon dioxide environment obeyed a parabolic oxidation law. The weight gain of investigated alloys followed in order: Hayness 282 > Inconel 740H > Inconel 617 > Inconel 625 > Hayness HR230. The external oxide scales of alloys of Ni-based alloys were mainly Cr₂O₃ and MnCr₂O₄. But the alloys (282, 740H, 617) containing Ti were composed of TiO₂ and Cr₂O₃. Internal oxidation was observed, which consisted of TiO₂ and Al₂O₃. The mass change of 282 and 740H were higher due to internal oxidation caused by high Al and Ti contents, and this phenomenon had also been observed in air, wet air and water vapor. There is almost no carburization of Ni-based alloys in CO₂ environment. Ni-based alloys have excellent performance in high temperature CO₂ environment, mainly due to the high Cr content of investigated alloys, which will form a protective chromia-rich scale.