Electrophoretic deposition and mechanistic studies of nano-Al/CuO thermites

Abstract

Articles you may be interested inStructural and dielectric properties of laser ablated BaTiO3 films deposited over electrophoretically dispersed CoFe2O4 grains A pressure-driven flow analysis of gas trapping behavior in nanocomposite thermite films In situ microscopy of rapidly heated nano-Al and nano-Al / WO 3 thermites

Controlling Material Reactivity Using Architecture

“…[ 24 ] The chosen fi lm thicknesses are based on prior work, where thicker fi lms were found to react nearly an order of magnitude faster than thin ones due to the increased ability to trap intermediate gases and induce local pressurization. [ 19,25 ] More importantly, at these two thicknesses the reactivity was found to be insensitive to small changes in thickness, which is important to the current work in case there are slight batch-tobatch variations in the deposited fi lm thickness.The two architectures examined are referred to as "channels" and "hurdles", with the primary difference being the orientation of the RM relative to the desired direction of propagation. Three parameters are investigated: i) fi lm thickness ( L 0 ), ii) edge-to-edge spacing between adjacent fi laments ( d ), and iii) the orientation of the assembled material.…”

“…[ 18 ] Particle advection is also important, since small particles can be rapidly entrained by fl uids and have suffi cient momentum to be transported large distances. [19][20][21][22] Using RMAs, we hypothesize that both the convective and advective components of energy transport can be controlled by the architecture, so long as the architectural length scales are commensurate with the length scale over which these transport phenomena occur.To create model RMAs, we use 3D printing to fabricate substrate architectures, followed by the deposition of RM onto the surface to a desired thickness. More details of combining these processes can be found in a previous publication.…”

Morphology of Electrophoretically Deposited Films on Electrode Strips

“…28 At longer times, the simulation curve is well fit bym = −0.425 + 0.00153t (R 2 = 0.999, dashed line in Figure 4c). The linear dependence of mass on time can be justified because at long times, the electric field at the surface of the deposit is approximated by the field around a point charge located at the origin, and thus the flux of material, which is proportional to the electric field, goes like r(t) −1 , while the surface area of the deposit goes like r(t), where r(t) is the distance from the center of the electrode to the film surface.…”

“…26,27 One such experimentally relevant geometry, the planar strip electrode, 13,[28][29][30] seems to have escaped the attention of the modeling community. A key feature of this geometry, which is absent in the geometries studied previously, is the presence of electrode edges which we show locally enhance the electric field and significantly affect the morphology of the deposit.…”

“…A key feature of this geometry, which is absent in the geometries studied previously, is the presence of electrode edges which we show locally enhance the electric field and significantly affect the morphology of the deposit. In this article, we use finite element analysis to develop a model of the electrophoretic deposition of material onto a metallic strip under potentiostatic conditions in the geometry studied experimentally by Sullivan, et al 28,29 -a finite width strip electrode opposing a parallel planar electrode. We also provide an experimental study of such a deposition and show that the model qualitatively captures the key trends.…”