Doctor of Philosophy (PhD), Wright State University, 2019, Engineering PhD

Drop on demand (DOD) inkjet printing has been widely investigated for its low cost, noncontact, high throughput, and reproducible process advantages. This dissertation research sought to capitalize on these advantages for use in micro solid oxide fuel cells (micro SOFCs). Understanding the important variables underpinning the inkjet process, including ink formulation, jet kinematics, and process settings was essential. These variables were evaluated for their impact on drop deposition quality, resolution, microstructure, and electrochemical functionality, with the end goal of making submicron to micron scale ceramic features. Initially, the fluid kinematics of single pass printing was investigated using a dilute, solid-solvent, colloidal, ink suspension of of La0.6Sr0.4Fe0.8Co0.2O3 (LSFC) and α-terpineol. Favorable process conditions were identified that attained uniform, well-shaped, circular dots ~ 0.1 μm thick and ~ 80 μm in diameter. Multiple, sequential ink passes were employed to increase feature dimensions on the x/y/z axes. This required additional process constraints to control deposition quality and resolution of micro features including micro-dots (0-D), micro-lines (1-D) and micro-planes (2-D). Using optimal conditions, 0-D dots and 1-D lines with x/y dimensions < 100 μm and z axis dimensions < 1 μm with dense, open or networked microstructures were demonstrated; in addition 2-D planes having smooth surface and continuous intra-planar ceramic coverage with dimensions as small as ~ 100 μm by ~ 100 μm were achieved. Sintering the inkjetted submicron prototypes produced consolidated submicron films that were uniform, smooth and void of defects such as cracks or delamination. Thermal treatments resulted in grain growth from an average crystallite size of ~158 nm to ~ 356 nm. Heat treatments < 800°C were essential to avoid deleterious effects on electrochemical activity. Electrochemical characterizations of prototypes produced tolerable peak power (open full item for complete abstract)

Committee: Hong Huang Ph.D. (Advisor); Sharmila Mukhopadhyay Ph.D. (Committee Member); Jason Deibel Ph.D. (Committee Member); Lei Kerr Ph.D. (Committee Member); Thomas Reitz Ph.D. (Committee Member) Subjects: Engineering; Materials Science