ABSTRACT
Advanced energetic materials (EMs) play a crucial role in the advancement of microenergetic systems as actuation parts, igniters, propulsion units, and power. The sustainable electrosynthesis of EMs has gained momentum and achieved substantial improvements in the past decade. This study presents the facile synthesis of a new type of high-performance CuN3@CuCl hybrids via a co-electrodeposition methodology utilizing porous Cu as the sacrificial template. The composition, morphology, and energetic characteristics of the CuN3@CuCl hybrids can be easily tuned by adjusting the deposition times. The resulting hybrids demonstrate remarkable energy output (1120 J·g-1) and good laser-induced initiating ability. As compared with porous CuN3, the uniform doping of inert CuCl enhances the electrostatic safety of the hybridized material without compromising its overall energetic characteristics. Notably, the special oxidizing behavior of CuCl gradually lowers the susceptibility of the hybrid material to laser and electrostatic stimulation. This has significant implications for the passivation or self-destruction of highly sensitive EMs. Overall, this study pioneers a new path for the development of MEMS-compatible EMs, facilitating further microenergetic applications.
ABSTRACT
It is highly desired but still remains challenging to design a primary explosive-based nanoparticle-encapsulated conductive skeleton for the development of powerful yet safe energetic films employed in miniaturized explosive systems. Herein, a proof-of-concept electrochemical preparation of metal-organic frameworks (MOFs) derived porous carbon embedding copper-based azide (Cu(N3 )2 or CuN3 , CA) nanoparticles on copper substrate is described. A Cu-based MOF, i.e., Cu-BTC is fabricated based on anodized Cu(OH)2 nanorods, as a template, to achieve CA/C film through pyrolysis and electrochemical azidation. Such a CA/C film, which is woven by numerous ultrafine nanofibers, favorably demonstrates excellent energy release (945-2090 J g-1 ), tunable electrostatic sensitivity (0.22-1.39 mJ), and considerable initiation ability. The performance is superior to most reported primary explosives, since the CA nanoparticles contribute to high brisance and the protection of the porous carbon network. Notably, the growth mechanism of the CA/C film is further disclosed by detailed experimental investigation and density functional theory (DFT) calculation. This work will offer new insight to design and develop a CA-based primary explosive film for applications in advanced explosive systems.
ABSTRACT
In this study, CoFe2O4 is selected for the first time to synthesize CoFe2O4/Al nanothermite films via an integration of nano-Al with CoFe2O4 nanowires (NWs), which can be prepared through a facile hydrothermal-annealing route. The resulting nanothermite film demonstrates a homogeneous structure and an intense contact between the Al and CoFe2O4 NWs at the nanoscale. In addition, both thermal analysis and laser ignition test reveal the superb energetic performances of the prepared CoFe2O4/Al NWs nanothermite film. Within different thicknesses of nano-Al for the CoFe2O4/Al NWs nanothermite films investigated here, the maximum heat output has reached as great as 2100 J·g-1 at the optimal thickness of 400 nm for deposited Al. Moreover, the fabrication strategy for CoFe2O4/Al NWs is also easy and suitable for diverse thermite systems based upon other composite metal oxides, such as MnCo2O4 and NiCo2O4. Importantly, this method has the featured advantages of simple operation and compatibility with microsystems, both of which may further facilitate potential applications for functional energetic chips.
ABSTRACT
Microigniters play an important role for the reliable initiation of micro explosive devices. However, the microigniter is still limited by the low out-put energy to realize high reliability and safety. Integration of energetic materials with microigniters is an effective method to enhance the ignition ability. In this work, a Al/Co3O4 nanothermite film with a three-dimensionally ordered macroporous structure was prepared by the deposition of nanoscale Al layers using magnetron sputtering on Co3O4 skeletons that are synthesized using an inverse template method. Both the uniform structure and nanoscale contact between the Al layers and the Co3O4 skeletons lead to an excellent exothermicity. In order to investigate the ignition properties, a micro-energetic igniter has been fabricated by the integration of the Al/Co3O4 nanothermite film with a semiconductor bridge microigniter. The thermite reactions between the nanoscale Al layer and the Co3O4 skeleton extensively promote the intensity of the spark, the length in duration and the size of the area, which greatly enhance the ignition reliability of the micro-energetic igniter. Moreover, this novel design enables the micro-energetic igniter to fire the pyrotechnic Zr/Pb3O4 in a gap of 3.7 mm by capacitor discharge stimulation and to keep the intrinsic instantaneity high and firing energy low. The realization of gap ignition will surely improve the safety level of initiating systems and have a significant impact on the design and application of explosive devices.
ABSTRACT
Mn2O3 has been selected to realize nanothermite membrane for the first time in the literature. Mn2O3/Al nanothermite has been synthesized by magnetron sputtering a layer of Al film onto three-dimensionally ordered macroporous (3DOM) Mn2O3 skeleton. The energy release is significantly enhanced owing to the unusual 3DOM structure, which ensures Al and Mn2O3 to integrate compactly in nanoscale and greatly increase effective contact area. The morphology and DSC curve of the nanothermite membrane have been investigated at various aluminizing times. At the optimized aluminizing time of 30 min, energy release reaches a maximum of 2.09 kJâg(-1), where the Al layer thickness plays a decisive role in the total energy release. This method possesses advantages of high compatibility with MEMS and can be applied to other nanothermite systems easily, which will make great contribution to little-known nanothermite research.
ABSTRACT
An activated RDX-Fe2O3 xerogel in a Si-microchannel plate (MCP) has been successfully prepared by a novel propylene epoxide-mediated sol-gel method. A decrease of nearly 40 °C in decomposition temperature has been observed compared with the original cyclotrimethylene trinitramine (RDX). The RDX-Fe2O3 xerogel can release gas and solid matter simultaneously, and the ratio of gas to solid can be tailored easily by changing the initial proportions of RDX and FeCl3·6H2O, which significantly enhances the explosive and propulsion effects and is of great benefit to the applications. The approach, which is simple, safe, and fully compatible with MEMS technology, opens a new route to the introduction of organic energetic materials to a silicon substrate.
ABSTRACT
A three-dimensionally ordered macroporous Fe(2)O(3)/Al nanothermite membrane has been prepared with a polystyrene spheres template. The nanothermite, with an enhanced interfacial contact between fuel and oxidizer, outputs 2.83 kJ g(-1) of energy. This is significantly more than has been reported before. This approach, fully compatible with MEMS technology, provides an efficient way to produce micrometer thick three-dimensionally ordered nanostructured thermite films with overall spatial uniformity. These exciting achievements will greatly facilitate potential for the future development of applications of nanothermites.
ABSTRACT
Density functional computations were performed on two tetracoordinated Ni(II) complexes as high nitrogen content energetic materials (1: dinickel bishydrazine ter[(1H-Tetrazol-3-yl)methan-3yl]-1H-tetrazole and 2: dinickel tetraazide ter[(1H-Tetrazol-3-yl)methan-3yl]-1H-tetrazolate). The geometrical structures, relative stabilities and sensitivities, and thermodynamic properties of the complexes were investigated. The energy gaps of frontier molecular orbital (HOMO and LUMO) and vibrational spectroscopies were also examined. There are minor Jahn-Teller distortions in both complexes 1 and 2, with two long Ni-N bond lengths and two short ones. The enthalpies of combustion for both complexes are over 3600 kJ/mol. The N-N bond lengths in the moieties of hydrazine and azide ligands increase in the coordination process compared to those of the isolated molecules.
