Effects of crystallographic orientation on the early stages of oxidation in nickel and chromium

Abstract

Surface orientation plays an important role in the oxidation behavior of single crystals where studies have found the relative oxidation rates for surfaces with different orientations. However, most materials are polycrystalline and contain myriad orientations that contribute to the overall oxidation process. Here we determine the effects of orientation on the early stages of oxidation behavior as a function of surface orientation for polycrystalline nickel (face-centered cubic) and chromium (body-centered cubic). After high temperature oxidation, the oxide topography is characterized using optical profilometry and the underlying microstructure is characterized with electron backscatter diffraction (EBSD). By correlating results from EBSD and optical profilometry, the oxide height is determined for each crystallographic orientation. In both Ni and Cr, a strong relationship is observed between the oxidation rate and direction of the surface normal; for Ni, (111) surfaces oxidize slowest, while (100) surfaces in Cr have the lowest oxidation rates. Although orientation-dependent oxidation rates are observed at short times, the effect is diminished at longer oxidation times.

Charge and Ion Transport in NiO and Aspects of Ni Oxidation from First Principles

“…Thus, E values change significantly with interfacial configuration, with the field strength across the Ni(111)/NiO interface substantially lower than that for the other two interfaces. Although in the absence of knowing the complete electrostatic potential drop across the oxide itself we cannot predict oxide growth rates for the various interfaces, the calculations do suggest that the electrostatic driving force for electron transfer into the NiO from the Ni metal is weakest at the Ni(111)/NiO interface, a picture generally consistent with experimental observations showing Ni metal surfaces are highly protective along the ⟨111⟩ direction and less protective along the ⟨100⟩ direction …”

Influence of grain orientation on the incipient oxidation behavior of Haynes 230 at 900 °C

“…Similar results as in present work were also reported by other researchers [41]. After investigation of the initial oxidation of polycrystalline Ni and Cr, it was reported that oxidation rate in Ni changes with crystal orientation in following order (111) b (110) b (100) while for polycrystalline Cr changes with crystal orientation as (111) N (110) N (100) [41]. Orme et al also investigated the anisotropic corrosion behavior of Inconel 600 [36] and alloy 22 [42] in HCl solution.…”

“…Here, although the oxidation velocity may still relate with the atomic density of different planes like near (111) grains always obtain higher resistance than other grains, it may also relate with the oxide surface morphology formed on grains. Similar results as in present work were also reported by other researchers [41]. After investigation of the initial oxidation of polycrystalline Ni and Cr, it was reported that oxidation rate in Ni changes with crystal orientation in following order (111) b (110) b (100) while for polycrystalline Cr changes with crystal orientation as (111) N (110) N (100) [41].…”

In Situ Investigation of the Oxidation of Cobalt‐Base Superalloys in the Environmental Scanning Electron Microscope

“…It was also reported that grain boundaries influence the formation of a protective alumina layer. In addition to the existence of grain boundaries, grain orientation is known to affect the oxide formation of pure metals and alloys …”