Isothermal Oxidation Behavior of Superalloy Foil Ni-19.3Cr-20Fe-0.8Al Prepared by Electron Beam Physical Vapor Deposition

The superalloy foil Ni-19.3Cr-20Fe-0.8Al prepared by electron beam physical vapor deposition was oxidized at 800 ℃and 900 ℃ for 100 h in air, respectively. And the phase composition and the oxidation behaviors were investigated using scanning electron microscopy with energy dispersive spectrometer, X-ray diffraction. The results show that the oxidation kinetics curve of the alloy foil followed a cubic power law at 800 ℃ for 100 hours in air, and the average oxidation rate was 1.7×10-10 g·m-2·h-1. The oxide scale after 800 ℃ oxidation for 100 hours consisted of double layers, a compact Cr2O3 oxide of outer layer and a quasi-continuous Al2O3 oxide of inner layer. The oxidation kinetics curve of the alloy foil followed a parabolic law at 900 ℃ for 100 hours in air, and the average oxidation rate was 5.2×10-10 g·m-2·h-1. The oxide scale after 900 ℃ oxidation for 100 hours consisted of a dense Cr2O3 oxide layer with some internal oxide Al2O3.