Oxidation Characteristics of Nickel-Based Superalloy Powders Exposed at Ambient Condition

The existence of adsorbed oxygen and oxides on the surface initial powders has serious effects microstructure mechanical properties powder metallurgy alloys. However, is inevitably oxidized immediately after preparation. In this work, oxidation characteristics for argon atomized a Ni-based superalloy containing Cr, Co, W, Mo, Nb, Ti Al exposure at ambient condition various time were investigated in detail. It found that gases can be absorbed surface, but most them removed by low temperature (<151.5 °C) outgassing procedure. thermodynamic calculation shows reaction occurs firstly with alloying elements rather than Ni matrix, whether room or elevated temperature. kinetic measurement indicates content approaches saturation value 24 h remains almost stable 720 h. increases decrease particle size exposure. X-ray photoelectron spectroscopy characterized that, except formed oxides, also exists as-atomized fine <30 μm >18.7 exposure, which may caused internal stress energy powder. All form directly surface. For element Ti, metastable TiO forms preparation it transforms into TiO2 Ti2O3 during results provide deep understanding oxide under treatment possible desorption approach.