Controlled Substrate Destruction Using Nanothermite

Abstract

The experiments described in this paper look to further transient electronic device development by exploring the fracturing capabilities of aluminum copper (II) oxide and aluminum bismuth (III) oxide nanothermites. In particular, a quick, inexpensive test was developed that was able to characterize the substrate fracturing capability of these selectively deposited energetic materials. Using this test, aluminum bismuth (III) oxide nanothermite with near stoichiometric composition was shown to be an effective mate-rial for fracturing silicon wafers of two different thicknesses for the configuration considered. Nanothermites were deposited at various equivalence ratios, resulting in a range of damage, which enables material preparation in a given practical application to be based on the desired level of resultant fracturing. This data was subsequently compared with thrust measurements and gas shock formation in an effort to correlate thrust production to the severity of fracturing produced.

The Effects of Confinement on the Fracturing Performance of Printed Nanothermites

“…A range of fragmentation of representative silicon substrates was expected to be seen by varying the equivalence ratio. This range of destruction would then indicate the fracturing performance of a given nanothermite mixture at several equivalence ratios, as it did in previous substrate shattering experiments [13]. Equivalence ratio is defined by…”

“…Fragments of the silicon substrates were collected post-event to characterize the fracturing performance. A range of equivalence ratios of Al/Bi 2 O 3 nanothermite were tested to compare to previous unconfined nanothermite experiments performed by Fleck et al over a similar range [13]. In the current study, Al/CuO nanothermite was prepared at f = 1 only with the goal of observing any fracturing of the silicon wafers with this fuel/oxidizer formulation since, from previous work and thermochemical calculations, we anticipated the best fracturing performance for a stoichiometric equivalence ratio.…”

“…MP05776) printed with a resolution of 0.2 mm. This support structure has been shown to be effective in the past for this type of application [13]. A silicon substrate (Ultrasil Corporation, < 1 0 0 > orientation) was placed on the two support ledges in the center of the stand.…”

“…One application in which nanothermites show particular potential is in the integration with, and controlled fracturing of, electromechanical systems [13]. Previous attempts have been made to create transient electronic devices, including systems that utilize chemical degradation [14][15][16][17], applied thermal loads [18][19][20][21], and the shattering of components [22].…”

“…A recent study investigated the fracturing capabilities of aluminum bismuth (III) oxide (Al/Bi 2 O 3 ) and aluminum copper (II) oxide (Al/CuO) nanothermites [13]. Silicon wafers of various thicknesses served as representative substrates in place of actual electromechanical systems.…”