Defense Date

11-28-2006

Graduation Date

Fall 2006

Availability

Immediate Access

Submission Type

dissertation

Degree Name

PhD

Department

Chemistry and Biochemistry

Committee Chair

Jeffry D. Madura

Committee Member

Greg McCullom

Committee Member

Jeffrey D. Evanseck

Committee Member

Kurt Olson

Committee Member

Mitchell E. Johnson

Keywords

Computational Analysis, DACAPO, DFT, First Principles Investigation, Interfacial Adhesion Energy, theoretical chemistry, thermal barrier coatings

Abstract

This Ph.D. dissertation is centered on approximating the interfacial adhesion energies of a thermal barrier coating (TBC) within a density functional theory (DFT) framework. The strategy is to develop and validate a computational protocol to study systems which enhance the interfacial adhesion of the thermally grown oxide (TGO) to the Ni (100) substrate. The open source DFT code known as DACAPO, supported through the Technical University of Denmark, was used in this study. The investigation begins with reproducing the model system (SiO2/Ni Complex) energetic values in the DACAPO DFT platform. These results are compared to earlier work which was carried out using the VASP (Vienna AB Initio Simulation Package) platform. The variables investigated in this study included: TGO thickness (since this species grows over time in the field), TGO phase (alpha and beta), lattice mis-match, and thermal expansion stressors. The results from this study highlight a potentially new TGO base material which does not exhibit the shift in electron density (as seen in currently used Al2O3) and provides a more stable TGO network within the thermal barrier coating (TBC). Finally, the protocol mapped out in this investigation can be applied quickly to screen alternative materials in the design of a new TBC system.

Format

PDF

Language

English

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