Off-campus Michigan Tech users: To download campus access theses or dissertations, please use the following button to log in with your Michigan Tech ID and password: log in to proxy server
Non-Michigan Tech users: Please talk to your librarian about requesting this thesis or dissertation through interlibrary loan.
Date of Award
2024
Document Type
Campus Access Dissertation
Degree Name
Doctor of Philosophy in Physics (PhD)
Administrative Home Department
Department of Physics
Advisor 1
Ravindra Pandey
Committee Member 1
Brandon Wood
Committee Member 2
John Jaszczak
Committee Member 3
Will Cantrell
Abstract
While the damages of corrosion are vast, a predictive understanding does not yet exist. Pitting corrosion is perhaps of particular interest, as a proportionally small loss of mass may affect macroscopic properties and potentially lead to system failure. This work uses Density Functional Theory (DFT) methods to begin building a predictive understanding of pit initiation. An introduction of DFT and pitting corrosion is provided in Chapters 1 and 2, respectively; followed by a sample of foundational calculations in computational electrochemistry in Chapter 3. Chapters 4 and 5 build and analyze a novel model for investigation of local surface environments preferable for halide attack, and Chapter 6 studies halide penetration.
The facet-specific surface energies for the (-102), (1-11), (10-4), (100), (101), (110), and (113) facets of alpha-Al2O3 were calculated to be 0.101, 0.130, 0.130, 0.179, 0.125, 0.218, and 0.162 (eV/Ang^2), respectively. These surface energies were then used to construct a Wulff particle of 30, 70, 100, and 220 atoms, encapsulating an array of local surface environments and geometries which may be present during alpha-Al2O3 film passivation and dissolution.
A ‘Wulff construction approach’ for the 70, 100, and 220 atom cluster models was used to provide a structural and electronic description of the preferred Cl adsorption environment; data obtained from the 30-atom cluster did not well-represent the alpha-Al2O3 system, likely due to finite system size. Broad conclusions from this work serve to broaden and reinforce existing understandings around preferred environments for Cl-adsorption. This is characterized by lower coordination number as well as hybridization of Cl-p and O-p orbitals. Perhaps surprisingly, the geometry of the adsorption site was not found to be important.
The methodologies developed in this Wulff construction approach serve to significantly decrease the number of simulations necessary to sample across a diversity of local adsorption environments. Four cluster models exposed 51 unique Cl-attack positions, representing 378 unique local environments for potential corrosion initiation.
Recommended Citation
Eggart, Lisa M., "The Influence of Chlorine In Corrosion Initiation on Alumina", Campus Access Dissertation, Michigan Technological University, 2024.
plot_coords.py (6 kB)
plot_csm.py (5 kB)
plot_ebind.py (4 kB)
plot_pdos.py (8 kB)
plot_rdfs.py (4 kB)
raster_cl.py (5 kB)