Recent trends in nanothermites: Fabrication, characteristics and applications

Abstract

Energetic materials (EMs) are a group of distinctive materials that release an enormous amount of amassed chemical energy in a short time when incited by external mechanical or thermal factors. They comprise of propellants, explosives, and pyrotechnics. Unlike conventional micro-energetic materials, nano energetic materials (nEMs), due to their smaller particle size ranging from 1–100 nm, exhibit higher specific surface area (~10–50 m2 g−1), reduced ignition temperatures from 2350 K to approx.1000 K for particle size from 100 μm to 100 nm respectively, higher energy densities (up to 50 MJ kg−1), burning rates ~30.48 mm s−1 at 6.894 kPa with specific impulses up to 542 s (5320 m s−1), low impact sensitivity (<4–35 J). Such exceptional properties of nano energetic composites, i.e., thermites (a combination of metal-fuel/metal oxide particles), find applications, namely in, munitions, pyrotechnics, energetic micro-electromechanical system (MEMS) chips. This review provides valuable insight into the synthesis methods of nano energetic composite systems (e.g., Al/CuO, Al/KMnO4, Al/Fe2O3, Al/SnO2, Silicon-based systems), their characteristic properties, behavior under certain conditions and applications. Furthermore, the review converses about the advancements made in the last few decades by many researchers, along with the technological gaps that need to be addressed for futuristic applications.

Application of different Nanocatalysts in industrial effluent treatment: A review

“…Toxic organic pollutants are broken down into other materials [139] or fully mineralized components, producing water, carbon dioxide, or other inorganic ions. In general, a semiconductor such as TiO 2 is capable of absorbing light with a wavelength equal to or greater than the wavelength of the semi- conductor bandgap, resulting in the creation of electron-hole (e --h + ) pairs [140,141]. Reduction-oxidation reactions involve the interaction of nanocatalyst with adsorbate molecules.…”

Review of the Problems of Additive Manufacturing of Nanostructured High-Energy Materials

“…The last two decades have seen remarkable developments in the field of energetic materials. There has been a gradual transition from the use of nitrocarbon energetic materials, such as TNT, RDX and CL-20, to microstructural composites and nanothermites [ 52 ]. Thermite is a powder mixture composed of oxygen donor particles, such as a metal oxide and an oxygen scavenger represented by a reducing metal (fuel).…”

“…In contrast to micro-sized energetic materials, nanothermites have a higher specific surface area (~10–50 m 2 /g), a lower ignition temperature, a higher energy density (up to 50 MJ/kg), a shorter ignition time, a higher burning rate [ 54 , 55 ] and a lower impact sensitivity (<4–35 J) [ 52 ]. The combustion of nanothermites often occurs due to the dispersion of condensed products by gases (advection), which provides a flame propagation velocity of up to 2400–2600 m/s [ 56 , 57 , 58 ]; this is significantly higher than that of micron-sized thermites.…”

“…In addition to high sensitivity, there are other factors limiting the use of nanothermites [ 14 ], including stability problems, for example, oxidation [ 59 ] or coalescence [ 60 , 61 , 62 ] during storage; the difficulty of obtaining a homogeneous composite mixture [ 55 , 63 ]; gradual increase in the viscosity of compositions with a binder [ 64 ]. Furthermore, toxicological hazard remains an important issue when handling nanopowders [ 52 , 53 ].…”

Explosive Burning of a Mechanically Activated Al and CuO Thermite Mixture

“…To date, a large number of publications have appeared devoted to the study of various ways to increase the rate of energy release during termite combustion by increasing the contact surface between the fuel and the oxidizer in nanoscale mixtures. The classification of the various termite compositions and the description of the various manufacturing methods are given in a number of books and review articles [4][5][6][7][8][9][10][11]. There are many advantages to using nano-sized thermite mixtures.…”