The role of aluminum particle size in electrostatic ignition sensitivity of composite energetic materials

Desensitizing nano powders to electrostatic discharge ignition

“…Weir et al later [6] extended this correlation to nano-scale particle mixtures and showed that for aluminum combined with molybdenum trioxide (MoO 3 ) ESD ignition sensitivity increased as the Al particle size decreased. They showed that 0.05 micron diameter Al þ MoO 3 measured 530 nS conductance and required 0.25 mJ of electrostatic energy to spur ignition.…”

“…They showed that 0.05 micron diameter Al þ MoO 3 measured 530 nS conductance and required 0.25 mJ of electrostatic energy to spur ignition. Likewise, 20 micron diameter Al þ MoO 3 measured 0.00053 nS conductance and could not ignite with less than 100 mJ of electrostatic energy [6]. Nanoparticles inherently exhibit heightened surface area to volume ratio, manifest significantly more surface energy, and are more reactive than their micron scale counterparts.…”

Electrostatic Discharge Sensitivity and Resistivity Measurements of Al Nanothermites and their Fuel and Oxidant Precursors

“…The data display a series of trends based on fuel and oxidant as follows: (i) a marked decrease in sensitivity of CuO or Fe 2 O 3 -based systems relative to those of MoO 3 . This trend is illustrated by the increase in the minimum ESD response energy down any and all of columns 1-6 in Table 1 [10] observed an oxidant sensitivity trend Bi > Mo >> Cu for L-Al and micrometric oxides, whilst Weir et al [17,18] observed the reverse trend for Mo and Cu with oxide passivated aluminium fuel. Although the literature data may appear contradictory, it is believed here to simply represent the complex relationship between particle properties and ESD sensitivity.…”

“…The extent to which nanothermites conduct spark-generated current may be central to the rationalisation of ESD sensitivity. The conductivity of thermite materials has been explored previously [17,18]. Low voltages were employed (typically 1 V) to avoid resistive heating and nanothermite ignition.…”

3D ordered macroporous NiO/Al nanothermite film with significantly improved higher heat output, lower ignition temperature and less gas production

“…Their intrinsic feature is to release heat, gas, and power rapidly upon the stimulus of thermal, electrical or optical actuation. Over the last decades, it has been demonstrated that thermites prepared in nanoscale are shown to be efficient in increasing heat release, reducing ignition delay and enhancing mechanical properties compared to their bulk or macro counterparts [4][5][6][7][8][9]. In addition, their properties can be tuned by controlling interface contact and optimum molar ratio of the two components [10].…”