Kelly Claunch

Graduation Semester and Year

2018

Language

English

Document Type

Thesis

Degree Name

Master of Science in Materials Science and Engineering

Department

Materials Science and Engineering

First Advisor

Choong-Un Kim

Abstract

This thesis investigates the nature of surface contamination originating from the jet-polishing process on Cu-6 wt% Al TEM disks. During previous TEM imaging and diffraction analysis performed by our group, surface contamination particles, roughly 15-60 nm in diameter, were observed on the surface of the jet-polished TEM disks. Further, TEM diffraction analysis revealed that the contamination particles were growing epitaxially on the Cu matrix. HR-SEM was used to characterize the surface contamination in terms of shape, size, composition, and distribution on the surface of the disks. Through extensive HR-SEM imaging, it was found that surface contamination particles are present on the surface of all Cu-6 wt.% Al alloy TEM disks studied in this research. Additionally, a variance in the shape and size of the contamination particles was observed among the different samples and sometimes on individual samples. Low-angle ion milling was chosen as a technique to remove the contamination particles from the surface of the Cu-6 wt.% Al alloy TEM disks. This technique was not successful in removing the particles, and thus the goals of this research moved towards suggesting a mechanism causing the epitaxial growth of the surface contamination in electrolytic conditions. After a review of different epitaxial growth modes, this thesis predicts that a kinetically-controlled 3D growth mode is responsible for the low temperature epitaxial growth of the contamination particles on the Cu-6 wt.% Al alloy TEM disks. Explaining the variance in the shape and size of the contamination particles among the samples was also a goal of this research, and this thesis suggests that this phenomenon could be caused by particle coarsening (Ostwald ripening). Most importantly, the main motivation of this thesis research is to provide awareness for future research and studies to the fact that surface contamination exists on jet-polished TEM samples and can cause deleterious misinterpretation of TEM data.

Keywords

Jet polishing, Surface contamination, Cu-based Al alloy, HR-SEM

Disciplines

Engineering | Materials Science and Engineering

Comments

Degree granted by The University of Texas at Arlington

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