Doctoral Dissertations

Raul Florez

Keywords and Phrases

Electron Irradiation; Ion Irradiation; Raman; TEM; XRD; Zirconium Carbide

Abstract

A comprehensive understanding of the microstructural evolution of Zirconium Carbide (ZrC2) ceramics under irradiation conditions is required for their successful implementation in advanced Gen-IV gas-cooled nuclear reactors. The research presented in this dissertation focusses on elucidating the ion and electron irradiation response of ZrC2 ceramics. In the first part of the research, the microstructural evolution was characterized for ZrC2 ceramics irradiated with 10 MeV Au3+ ions up to doses of 30 displacement per atom (dpa) at 800 ºC. Coarsening of the defective microstructure, as a function of dose, was revealed by transmission electron microscopy analysis. The lack of change in the irradiated microstructure, at doses above 5 dpa, indicated that a balance between irradiation damage accumulation and dynamic annealing of defects was reached. It was also found that concurrent oxidation occurred during the ion irradiation. The effects of irradiation on the morphology and microstructure of the initial oxide formed on the surface of ZrC2 were investigated. The concomitant reduction in size and surface coverage of the oxide nodules at high doses, indicated that oxide dissolution was the predominant mechanism under irradiation conditions.

In the second part of the research, Zirconium Carbide (ZrC2) was irradiated with 10 MeV Au3+ ions to a dose of 10 dpa and subsequently with 300 keV electrons in a transmission electron microscope (TEM). It was found that high-energy electron irradiation of pre-damaged ZrC2 foils induce atomic mixing via radiation enhanced diffusion (RED), producing surface oxidation of the TEM foil.

Advisor(s)

Graham, Joseph T.

Committee Member(s)

Fahrenholtz, William
Hilmas, Greg
Crespillo, Miguel L.
Castano Giraldo, Carlos Henry

Department(s)

Nuclear Engineering and Radiation Science

Degree Name

Ph. D. in Nuclear Engineering

Publisher

Missouri University of Science and Technology

Publication Date

Fall 2019

Journal article titles appearing in thesis/dissertation

  • The irradiation response of ZrC ceramics at 800 oC
  • Early stage oxidation of ZrCx under ion-irradiation at elevated temperatures
  • Sequential Ion-Electron Irradiation of Zirconium Carbide Ceramics: Microstructural Analysis
  • Fabrication and Microstructural Analysis of Hot-Pressed ZrCx with low Hf-content

Pagination

xv, 179 pages

Note about bibliography

Includes bibliographical references.

Rights

© 2019 Raul Fernando Florez Meza, All rights reserved.

Document Type

Dissertation - Open Access

File Type

text

Language

English

Thesis Number

T 11661

Electronic OCLC #

1139709434

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