Mechanism of the oxidation and degradation of the aluminide coating on the nickel-base single-crystal superalloy DD32M

The aluminide coating on the single-crystal Ni-base superalloy DD32M was prepared by the low-pressure gas phase deposition, and isothermal oxidation tests were performed in the temperature range of 900-1000 °C to check the ability of the aluminide coatings to form alumina scales with the expected protective properties. Two-stage oxidation experiments were performed to describe the high-temperature oxide scales formed and the aluminide coating changed then to put forward the mechanism of oxidation and degradation of the aluminide coating on the single-crystal Ni-base superalloy DD32M, with morphological observations and chemical analysis of the oxide-scale surface by scanning electron microscope (SEM) coupled with energy-dispersive X-ray analyzer (EDX) and analysis of crystal structure by X-ray diffraction(XRD).