Publications
Analytical Methods to Detect Trace Quantities of 1-ethyl-3-methylimidazolium tetrafluoroborate
Reliable surface detection of deposited propellant is critical to studying overspray, a primary lifetime limiting mechanism of electrospray thrusters. This work explores four methods for the detection of 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI-BF4), a room-temperature ionic liquid commonly used as propellant in electrospray thrusters: fluorescent spectroscopy, energy-dispersive X-ray spectroscopy, nonvolatile residue spectroscopy, and Fourier transform infrared spectroscopy. Successful detection of EMI-BF4 deposited onto a gold plated quartz crystal substrate by an electrospray source is demonstrated using energy-dispersive X-ray spectroscopy. Nonvolatile residue spectroscopy is shown to be capable of detecting highly diluted EMI-BF4. Fourier transform infrared spectroscopy was performed on a large drop of EMI-BF4 and differentiation between similar molecules was established. Initial surface contamination studies using UV-Vis fluorescent spectroscopy to detect the presence of EMI-BF4 on quartz crystal substrates are also conducted.
Low energy EMI-BF4 deposition on a gold coated quartz crystal with EDX spectra showing Florine peak
Gold coated crystals used as depositon targets a) High-energy deposition b) Low-energy deposition c) Blank crystal
Additive Manufacturing and Characterization of Porous
Ceramic Electrospray Emitters
This work presents a new approach for fabricating porous ceramic emitters using microscale 3D printing for electrospray thrusters and other applications. A method for tuning the ceramic’s permeability through sintering is also presented. Direct current measurements in response to an applied voltage was used to characterize the emission of individual emitters with EMI-BF4. Radiography experiments were performed at a synchrotron facility to image capillary flow inside porous emitters during initial wetting.
SEM Image of Ceramic Emitter Tip