Role of Mn Alloying Element on the Oxide Growth Behavior of 800H Nickel-Based Alloy at 900°C

Abstract

The addition effect of Mn alloying element on the oxide growth behavior of 800H nickel-based alloy has been study in this paper. The alloy was experienced a cyclic oxidation at 900 °C. The cyclic oxidation test was carried out at oxidizing temperature for one hour followed by cooling at about 200 °C for 20 minutes for each cycle. The test samples were exposed to the cyclic condition up to 150 cycles. The oxidized samples of selected cycles were characterized in term of oxidation kinetic, phase analysis using x-ray diffraction (XRD) spectrometer and oxide scale morphology in plan and cross-sectional view by using scanning electron microscope (SEM) equipped with energy dispersive x-ray (EDX) spectrometer. As a results, the oxidation kinetic exhibited a weight gain pattern as the exposure cycle increase. Several protective oxide phases which are Cr2O3 and MnCr2O4 oxides were formed. In addition, continuous oxides scale was formed on the sample surface with evidence of Cr-Mn and Cr-rich oxide as detected by EDX analysis.