Oxidation behavior of the single crystal Ni-based superalloy at 900 °C in air and water vapor

The oxidation behavior of a single crystal Ni-based superalloy TMS-82+ was studied in cyclic air and water vapor (air plus 15% H2O) at 900 °C for 200 h. Oxidation kinetics was evaluated by mass gain measurements and the oxide scale was analysed by XRD, SEM and EDS, including the quantitative elemental concentration profiles by EPMA. Water vapor accelerated the growth rate of the oxides of NiO, Cr2O3 and spinel of NiCr2O4 due to the incursion of H, resulting in a higher mass gain and a thicker oxide scale with larger oxide grains of (Ni,Co)O.