Date Available
12-21-2019
Year of Publication
2018
Document Type
Doctoral Dissertation
Degree Name
Doctor of Philosophy (PhD)
College
Engineering
Department/School/Program
Chemical and Materials Engineering
Advisor
Dr. T. John Balk
Abstract
Nanostructured materials have received a surge of interest in recent years since it has become apparent that reducing the size of a material often leads to heightened mechanical behavior. From a fundamental standpoint, this stems from the confinement of dislocations. Applications in microelectromechanical devices, lithium ion batteries, gas sensing and catalysis are realized by combining the improvements in mechanical behavior from material size reduction with the heightened chemical activity offered by materials with a high surface-area-to-volume ratio. In this study, films of nanoporous Si-Mg were produced through magnetron sputtering, followed by dealloying using an environmentally benign process with distilled water. The film composition and structure was characterized both at the surface and throughout the film thickness, while the mechanical behavior was explored with nanoindentation.
Dispenser cathodes operate via thermionic emission and are an important area of interest in vacuum electron devices. While scientists have known for many years what elemental constituents are used to manufacture dispenser cathodes of excellent emission behavior, a fundamental understanding has yet to be realized. In this study, components of a scandate cathode that exhibited excellent emission behavior were characterized and used to inform the study of model thin films. Isolating relevant components of the scandate cathode for careful study could help inform future breakthroughs in understanding the working mechanism(s) of the scandate cathode. The structure, composition and electronic behavior of model W-Al alloy films were characterized experimentally and compared to computation. Moreover, a unique vacuum chamber was designed to activate modern thermionic dispenser cathodes, observe residual gas species present, and measure the work function through various state-of-the-art techniques.
Digital Object Identifier (DOI)
https://doi.org/10.13023/etd.2018.513
Recommended Citation
Maxwell, Tyler Lucius Corey, "THE PHYSICAL BEHAVIOR AND CHARACTERIZATION OF NANOPOROUS SILICON AND DISPENSER CATHODE SURFACES" (2018). Theses and Dissertations--Chemical and Materials Engineering. 94.
https://uknowledge.uky.edu/cme_etds/94
