Abstract
Detailed nanoscale characterizations revealed the formation of a considerably higher fraction of SiO2 particles in the external Cr2O3 layer on a NiCr alloy. In addition, atom probe tomography revealed substantially lower segregation of Mn at the Cr2O3 grain boundaries in wet air compared to dry air exposures, where the intriguing formation of Mn-rich clusters was observed in the Cr2O3 grains for the very first time. These findings provided additional evidence regarding the impact of distinct transport processes through the Cr2O3 layer on the resulting oxidation rates and subsurface alloy compositional changes.
Original language | English |
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Article number | 111348 |
Journal | Corrosion Science |
Volume | 221 |
DOIs | |
State | Published - Aug 15 2023 |
Funding
G. Garner and J. Wade are thanked for the oxidation exposures. T. Lowe and D. Newberry are acknowledged for the metallographic preparations. A. Haynes and J. Poplawsky are thanked for their valuable comments on the manuscript. FIB based APT and TEM sample preparation and TEM, APT analysis was conducted using facilities at the Environmental Molecular Sciences Laboratory (EMSL), a DOE national user facility funded by the Biological and Environmental Research Program located at Pacific Northwest National Laboratory, USA . PNNL is operated by Battelle for DOE under contract DE-AC05-76RL01830. J. Haynes and J. Poplawsky are thanked for their valuable comments on the manuscript. This research was sponsored by the U.S. Department of Energy Office of Vehicle Technologies, Powertrain Material Core Program .
Keywords
- Atom probe tomography
- Chromia
- Grain boundaries
- Ni-based alloys
- Transmission electron microscopy