Oxidation resistance of nickel-based superalloy Inconel 600 in air at different temperatures

Abstract

Inconel 600 alloy is widely utilized for high temperature environment application due to the corresponding good oxidation and corrosion resistance properties. In order to estimate the high temperature oxidation resistance of Inconel 600 alloy at various temperatures, the oxidation weight gain of all specimens was measured and fitted for the curve at the temperatures of 700, 800 and 900 °C for exposure time of 100 h. The surface morphology and the component of the oxide film were analyzed by scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results indicate that the high temperature oxidation resistance of Inconel 600 alloy is excellent blew 800 °C due to the oxidation kinetic curves at different temperatures corresponding to the parabola dynamic rules. This means that the oxidation film protects the substrate well. The dense oxide layer formation containing Cr2O3 and NiCr2O4 at 700 and 800 °C and MnCr2O4 at 900 °C, respectively, is the main reason for the good oxidation resistance. In contrast, the oxide layer peels off easily under applied force as the temperature increases beyond 800 °C, on account of the complicated compositions of the oxide film and the binding force between the oxide layer and the substrate weakening. Corresponding oxidation mechanism is expected to be understood and the oxidation resistance of Inconel 600 alloy is improved through binding force enhancement.