Simultaneous electrophoretic deposition of copper oxide/aluminum nanothermite films

Abstract

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] This research details simultaneous electrophoretic deposition (EPD) of copper-oxide/aluminum nanothermite films. Deposition parameters such as precursor dispersion concentration, equivalence mixing ratio, precursor particulate morphology, magnitude and duration of applied field, and number of depositions are modulated. Prepared films are characterized with regards to mass, thickness, % theoretical maximum density (%TMD), substrate adhesion, homogeneity, and equivalence ratio. The effects of these parameters on combustion velocity and flame height are investigated. Higher applied fields, longer deposition durations, and increased colloid concentration yielded films with enhanced thickness and mass validating theoretically predicted EPD behaviors. Thicker, heavier films resulted in enhanced combustion characteristics, but reactions of films below a critical mass/thickness were quenched. Optimal combustion velocities were observed for CuO/Al nanorod films prepared from solutions with precursor equivalence ratios of 2.0 (fuel-rich) due to the enhanced thermal transport from increased Al content and a higher degree of interfacial contact between fuel and oxidizer particles. Modulating the colloidal particulate morphologies is shown to greatly impact the deposition rate thereby altering the combustion performance of the deposited films. CuO/Al nanorod films exhibited average burn rates, between 7 and 8 m/s, lower than the average velocity of CuO/Al nanoparticle films, in excess of 10 m/s. Delamination of the CuO/Al nanoparticle films was also observed resulting in a peak combustion velocity of 127 m/s observed. This also exemplifies the effect of PEG as a self-assembly mechanism as cracking and delamination of the CuO/Al nanorod films was not present.