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Abstract In this paper, an integrated component of the three-electrode planar switch and the exploding foil bridge was fabricated on the ceramic substrate by the magnetron sputtering process and wet etching process, which was beneficial to the miniaturization, low energy and integration of the explosion foil initiator system. We discussed the self-breakdown voltage of the three-electrode planar switch under different structural parameters and established the formula of self-breakdown voltage. By testing the discharge performance of the integrated component under a charging voltage of 1300 V~1500 V, we obtained a delay time of about 300 ns for the component, which is lower than the delay time when the spark gap switch is used. This result showed that the inductance of the entire circuit was lower than the inductance of the conventional circuit. We conducted a preliminary study on whether the integrated components are affected by changing of the working environment. Finally, based on this integrated component, we have used LTCC technology to produce a new highly integrated EFI system. Highlights • The integrated component we designed is suitable for exploding foil initiator system. • We discussed the SBV of the planar switch under different structural parameters and established the formula of SBV. • We have prepared a new highly integrated EFI system using LTCC technology based on the integrated components designed. [ABSTRACT FROM AUTHOR]

Addition of a safety control function to the micro-igniter (MI) and improvement of its output energy are key steps required to realize attitude control, state maintenance, and orbit adjustment of micro-aerospace vehicles using a micro-thruster. To solve the system misaction caused by traditional MI due to false triggering, a microelectromechanical system (MEMS) safety device based on Lorentz force is proposed, which can operate reliably under the driving condition of 0.5 T/0.5 A, and increase the safety control function for the MI. In addition, with the aim of addressing the problem that energy attenuation and unreliable ignition of the micro-thrusters are caused by the gap between the MI and the fuel, this paper proposes a hybrid integration process for an energy amplification element (Al/Ni energetic film) and an MI (Ni-Cr) to form a Ni-Cr@Al/Ni energetic MI (EMI). By optimizing the modulation ratio (3:2) and modulation period (75 nm) of the energetic film, the preparation of the integrated EMI is completed. Electrical explosion performance analyses of the micro-igniter are performed. Under 50 V/33 μF capacitor discharge excitation, TheAl / Ni energetic film can increase the output energy of MI by 17.54 mJ. Through the non-contact (2 mm) ignition capability test, the EMI can reliably ignite 30 mg B/KNO 3. Compared with the traditional MI, EMI has the advantages of high output energy per unit space and has a function of non-contact ignition. The EMI has strong application prospects in the aerospace vehicle launch and attitude adjustment field. [Display omitted] • A MEMS safety device based on Lorentz force is proposed. • The safety device can effectively isolate the energy output of the micro-igniter. • The Al/Ni energetic film can increase the output energy of micro--igniter by 17.54 mJ. • Through the non-contact (2 mm) ignition capability test, the energetic-micro-igniter can reliably ignite 30 mg B/KNO 3. [ABSTRACT FROM AUTHOR]

Spherical explosives had regular shape and smooth surface, which gave them low sensitivity, excellent flowability, and high bulk density, thereby yield good charging performance. Traditional spherization methods always resulted in irregular shape, low sphericity, and uneven size. In this paper, a novel droplet microfluidic technology was used to fabricate hexanitrostilbene (HNS) microspherical with nitrocellulose (NC) as adhesive. The farication process (e. g., HNS concentration, NC concentration, flow rate) was fully investigated in pursuing for the ideal farication condition. The chemical structures, crystalline structures, and thermal stability of HNS were preserved. Meanwhile, the flowability and bulk density of HNS microspheres were significantly improved (Repose angle: HNS microsphere vs raw HNS, 33.1 vs 39.2°; bulk density: HNS microsphere vs raw HNS, 0.466 vs 0.301 g cm−3), which enhanced the charging and pressing performance of HNS. Unlabelled Image • Droplet microfluidics was firstly used for the spheroidization of HNS. • HNS microspheres with arrow size distribution were successfully synthesized. • The flowability of HNS microspheres were superior to that of raw HNS. • This work provided a novel method for the spheroidization of explosives. [ABSTRACT FROM AUTHOR]

• A versatile microreaction system for handling high-solid-content fluids was set up. • The stability of fluids with Zr powder was investigated by UV–vis spectroscopy. • The surface reaction mechanism of Zr powder based on HF concentration was proposed. • The contradiction between the activity and sensitivity of Zr powder was reconciled. The regulation of energy release characteristics and safety of highly active metal fuels has attracted significant attention. In response to the limitations of using hydrofluoric acid (HF) to modify zirconium (Zr) powder in batch reactors, a microfluidic method coupling ultrasound and coaxial flow microreactors was proposed to achieve the control of the microstructure on the surface of Zr powder. The fluid flow and mixing characteristics in the microreactor were analyzed using on-line detection devices, leading to the determination of suitable fluid parameters. Through analysis of the reaction process between Zr and HF, a reaction model based on the HF concentration was established and subsequently verified through a microreaction system. The results indicate that the HF concentration greatly influences the morphology and composition of Zr powder, thereby determining the material and structural transformation of the Zr powder surface. The excellent thermal oxidation performance and electrostatic safety of HF-modified Zr powder were confirmed through thermal analysis and electrostatic discharge sensitivity tests. This study provides valuable insights for controlling the microstructure and properties of ultrafine Zr powder. [ABSTRACT FROM AUTHOR]

• The LTCC technology and MEMS was used to prepare a modular integrated EFI system. • The modular integrated EFI system has higher integration and smaller volume. • The research has realized the low voltage input and control of EFI system. • Characterization indicated that the system has higher energy utilization. In this study, the flyback high-voltage conversion unit, capacitor discharge unit, and EFI chip of the exploding foil initiator (EFI) system were highly integrated using low temperature cofired ceramic technology and MEMS, forming a modular integrated system with boost, discharge, and firing functions. The modular integrated EFI system used the design idea of system in a package, selected chip-level or planar components, eliminating the need for connecting wires and reducing the volume of the EFI system to 5.67 cm3. Compared with the traditional EFI system, while analysis from the characterization showed that the integrated structure reduced the loop inductance of the system to 27 nH, which was 55 % lesser, it accelerated the flyer to 3800 m/s, which was 15.2 % faster. These accomplishments indicated that the energy utilization rate of the integrated system was higher. The input voltage of the system was reduced from traditionally high voltage of 1250 V to lower voltage of 24 V due to the integrated-system boost function. Simultaneously, the 5 V MOS controlled thyristor (MCT) chip was selected to replace 1800 V∼2500 V spark gap switch as the working voltage, thus making 5 V the switching voltage of the system. These changes made high safety operation of the system. Moreover, the system had used modular design and manufacturing to improve its reliability and obtained the characteristics of mass production. [ABSTRACT FROM AUTHOR]

[Display omitted] • An energetic Al/Ni reactive multilayer foil is prepared by magnetron sputtering and wet etch method. • Intermetallic reaction of Al/Ni is beneficial for improving energy efficiency and plasma density. • Energy efficiency of the Al/Ni exploding foil is measured to be 30.9% higher than that of Cu exploding foil. • A direct ignition method is proposed by utilizing the abundant plasma generated at Al/Ni exploding foil, instead of driving a slapper. In order to lower the firing voltage, an energetic Al/Ni exploding foil (Al/Ni-EF) with enhanced energy efficiency and plasma density was prepared in this study, to realize the direct ignition of pyrotechnics. An Al/Ni reactive multilayer foil (Al/Ni-RMF) was firstly synthesized by magnetron sputtering and wet etch method, and its structure and exothermic behavior were investigated. Scanning Electron Microscopy, Atomic Force Microscope and X-ray Diffraction characterizations confirmed the periodic layer structure of Al/Ni-RMF with a total thickness of 4 μm. The highest heat release in Al/Ni-RMF could be achieved theoretically when the ratio of Al and Ni was 1.5, and thus the thickness of single Al and Ni layer was determined to be 300 nm and 200 nm, respectively. The obtained Al/Ni-RMF was subsequently fabricated to be an exploding foil, and its electric explosion performance was further studied. Energy efficiency of the Al/Ni-EF was measured to be 85.9% during the electric explosion process, which was 30.9% higher than that of Cu exploding foil (Cu-EF). The plasma generated at Al/Ni-EF had larger volume, longer duration time and higher temperature than Cu-EF due to the intermetallic reaction between Al and Ni, which was beneficial for the direct ignition of Boron/Potassium Nitrate composition (B/KNO 3 , BPN). Afterwards, a special Al/Ni-EF ignitor without slapper was constructed, and the fierce ignition of BPN at the minimum discharge voltage of 800 V was observed. Above results confirmed the feasibility of direct ignition, such a unique strategy was beneficial for the development of low-energy, low-cost and miniaturized ignitor. [ABSTRACT FROM AUTHOR]

Highlights • A new method of porous copper azide precursor construction is proposed. • The designed ink has sufficient surface area to ensure the azide reaction. • The binder doesn't hinder formation of pores but maintains a 3D porous structure. • The 3D porous structure maintains certain strength and adhesion after drying. • Performance of copper azide can be adjusted by tuning the ink parameters. Abstract The aim of the present work is to design a copper azide precursor direct writing ink for primary explosive-on-a-chip. The mixture of water/vinyl alcohol and isopropanol/ethyl cellulose was used as binder. Cetyltrimethylammonium bromide (CTAB) used as foaming agent and dodecanol as foam stabilizer were added into the binder to produce plenty of bubbles. 40 wt% of nano-copper powder was added into the binder and the three-dimensional porous precursor ink was obtained. After 24 h of in-situ gas–solid azide reaction, the copper precursor ink was completely transformed into copper azide. An explosive device was designed to verify the detonation performance of the copper azide by direct writing, and the result showed that it can reliably initiate the CL-20 into complete detonation. [ABSTRACT FROM AUTHOR]

In this study, we reported that two-dimensional titanium carbide (Ti 3 C 2) MXene has intrinsic catalytic activity for thermal decomposition of high-energy ammonium perchlorate-based molecule perovskite (H 2 dabco)[NH 4 (ClO 4) 3 ] (DAP-4). The micro morphology and structure of Ti 3 C 2 MXene were characterized. Thermal catalysis decomposition of DAP-4 using Ti 3 C 2 as a novel catalyst was investigated by Differential scanning calorimetry (DSC). The results showed that with 10 wt% Ti 3 C 2 added, the decomposition temperature of DAP-4 was reduced to 341.2 °C at the heating rate of 10 °C·min−1, which decreased by 43.8 °C from raw DAP-4 (385 °C). The activation energy of DAP-4 thermal decomposition effectively reduced from 181 kJ mol−1 to 155 kJ mol−1. A possible mechanism of Ti 3 C 2 MXene for the catalysis thermal decomposition of DAP-4 was proposed. This work provides a proof-of-principle concept for the thermal catalysis decomposition of ammonium perchlorate-based molecule perovskite energetic materials using the titanium carbide MXene as a catalyst. • Ti 3 C 2 MXene has intrinsic catalytic activity for thermal decomposition of DAP-4. • The decomposition temperature and activation energy of DAP-4 has reduced to 341.2 °C and 155 kJ mol−1. • A possible mechanism of Ti 3 C 2 MXene for the catalysis thermal decomposition of DAP-4 was proposed. [ABSTRACT FROM AUTHOR]