Short-Term High Temperature Oxidation Behavior of Pt-Modified Ni3Al-Based Alloys

The Ni-xPt-25Al (x=0, 10, 20, 30, at%) alloys were fabricated by cold crucible levitation melting under argon atmosphere on a water-cooled Cu crucible. The effects of Pt content on crystal structures, oxidation kinetics, morphologies of oxides, and oxidation resistance of the Ni-xPt-25Al alloys were studied using X-ray diffraction, simultaneous thermal analyzer, scanning electron microscopy, and X-ray photoelectron spectroscopy (XPS). The results show that Pt-modified Ni3Al-based alloys still keep gamma' phases with increasing Pt content. In heating up and isothermal periods, the oxidation kinetics of the Ni-xPt-25Al (x=0, 10, 20, 30, at%) alloys yield to the linear and parabolic kinetic laws, respectively. Pt plays a beneficial role in promoting the formation of oxides, meanwhile, the increased addition of Pt also improves the integrality and compactness of the oxide films.