Influence of temperature on the oxidation behaviors of the nickel-based superalloy powders

Influence of temperature on the oxidation behaviors of the nickel-based superalloy powders was investigated by chemical analysis, scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The results indicate that the oxygen content by mass fraction of the nickel-based superalloy powders is 0.012% at room temperature (RT). The oxidation layer partly covers the powder surface in the formation of metallic element (Ni, Cr, Ti) and oxidation state (Ni(OH)₂, Cr₂O₃, TiO₂). With the increase of temperature from RT to 150 ℃, the oxygen content seems stable. As the temperature rises to 250 ℃, the oxygen content by mass fraction is 0.034%, showing the obviously increase. The powder surface is completely covered by the oxidation layer at 250 ℃, which is mainly composed of Ni(OH)₂, Cr₂O₃, and TiO₂. The elevated temperature significantly affects the oxidation behaviors of the nickel-based superalloy powders, the reasonable control of temperature can obtain the powders with low oxygen content. In this study, the maximum post-process temperature of the nickel-based superalloy powders exposed to the air is 150 ℃.