Type
Text
Type
Dissertation
Advisor
Trelewicz, Jason | Sampath, Sanjay | Welch, David O | Brogan, Jeff.
Date
2015-05-01
Keywords
Cr-Poisoning Protection in SOFCs, Functional Oxides, Thermal Spray Process, Thermoelectrics | Materials Science
Department
Department of Materials Science and Engineering.
Language
en_US
Source
This work is sponsored by the Stony Brook University Graduate School in compliance with the requirements for completion of degree.
Identifier
http://hdl.handle.net/11401/76279
Publisher
The Graduate School, Stony Brook University: Stony Brook, NY.
Format
application/pdf
Abstract
Functional oxides are important classes of materials that show a wide range of electrical and magnetic behaviors for electronics, sensors and energy harvesting/storage applications. In order to utilize these materials and their electrical characteristics, many fabrication methods are being used, such as chemical vapor deposition, physical vapor deposition and screen printing, to build thin or thick film multi-layer electronic devices. However, those existing methods require high temperature or numerous sintering processes following the deposition which restrict substrate and material selection due to chemical/mechanical stability requirements among the multi-layers. Also, in some conditions, they need a sizable vacuum chamber for a large scale deposition in order to commercialize the devices, and even then the cost of manufacturing is still expensive. Thermal spray is a directed melt-spray-deposition process in which powdered feedstock is injected into a high temperature thermal plasma/flame and propelled towards a prepared substrate with high velocity. The coating is built up by successive impingement and rapid solidification of the impacting droplets. The process allows significant material versatility and application flexibility with inherent scalability, with near ambient substrate temperatures. However, upon rapid quenching, the particles contain structural disorder and produce architectural defects such as pores, cracks, and interfaces within the coating. Compositional changes of the particles via decomposition or preferential species volatilization from the thermal and chemical gradient interactions experienced are also included in the deposit. These factors, together with process-induced residual stresses can affect electrical properties and functional performance, and have limited the application area only to the protective coatings such as thermal barrier, wear and corrosion resistance coatings. The goal of this dissertation is to elucidate the new opportunities for thermal spray as a fabrication method for functional oxide coatings by deliberately controlling the process parameters in order to achieve the required functionalities. The aims of this thesis are to provide a scientific understanding of thermal spray parametric effects, using the plasma/flame as an energetic reactive source that affects stoichiometry of the functional oxide materials and trapped states due to rapid solidification. These depositional parameters affect the electrical/magnetic and protective functional performances which are evaluated by examination of the process-microstructure-phase-functional properties relations for solid oxide fuel cells and thermoelectric applications. | 212 pages
Recommended Citation
Han, Su Jung, "Thermal spray as a processing tool for the functional oxides" (2015). Stony Brook Theses and Dissertations Collection, 2006-2020 (closed to submissions). 2205.
https://commons.library.stonybrook.edu/stony-brook-theses-and-dissertations-collection/2205