Oxidation Kinetics Of Microcrystalline Ni-11.5cr-4.5co-0.5a1 Superalloy Sheet Fabricated By Electron Beam Physical Vapor Deposition At 800 Degrees C

Isothermal oxidation of microcrystalline Ni-11.5Cr-4.5Co-0.5A1 superalloy sheet fabricated by Electron Beam Physical Vapor Deposition (EBPVD) at 800 degrees C in air was investigated. The oxidation kinetics of microcrystalline Ni-11.5Cr4.5Co-0.5A1 superalloy sheet followed a parabolic power law at initial oxidation stage, and cubic power law for long oxidation terms. The fine oxide grains could be formed on microcrystalline superalloy surface. Taking the short circuit diffusion through grain boundaries into account, an oxidation kinetic with cubic power law was derived. The excellent results in agreement with the experimental data were obtained. (c) 2007 Elsevier B.V. All rights reserved.