Date of Award

12-2013

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Materials Science and Engineering

Major Professor

Carl J. McHargue

Committee Members

Kurt E. Sickafus, William J. Weber, Ali Passian, Claudia Rawn

Abstract

This research has discovered the following new information:

a) The threshold fluence for amorphization of single crystal α-Al2O3 [alpha alumina] samples irradiated with 175 keV Zr+ [Zr+] ions at room temperature is 1.5×1016 [1.5E16] Zr/cm2 [Zr+/cm2] which is a much lower fluence than the previously thought.

b) A buried amorphous layer sandwiched between two highly-damaged crystalline regions was observed in samples irradiated with 175 keV Zr+ to a fluence of 1.5×1016 Zr+/cm2 and higher at room temperature.The amorphous region contains short range order similar to γ-Al2O3 [gamma alumina]; it is deficient in oxygen containing Zr-rich nano-clusters.

c) Ion-beam induced epitaxial recrystallization occurred at room temperature due to oxygen irradiation of the amorphous phase. It is the first observation at low temperature.

d) Irradiation of Zr-implanted α-Al2O3 [alpha alumina] samples with oxygen decreased the F-type centers concentrations.

e) Post irradiation thermal annealing of Zr-implanted α-Al2O3 samples induced amorphous to γ-Al2O3 transformation at the interface between amorphous and damaged regions.

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