A new strategy based on a microfluidic platform is proposed for the rapid and high-quality control of explosives' crystal morphology.

In the letter, a highly integrated conjoined device, single shot switch and exploding foil initiator (S3-EFI) chip, was fabricated with microelectromechanical system (MEMS) scale fabrication methods. Photon Doppler Velocimetry (PDV) was utilized to characterize the behavior of the flyer at firing voltages ranging from 1.00 kV to 2.40 kV, and the fabricated device exhibits a terminal flyer velocity of 2967 m/s at 1.50 kV which is considered as an inflection point. Electrical characterizations were then performed on the conjoined chip to obtain some fundamental parameters such as current and voltage, a peak current of 1.73 kA was observed at 1.50 kV. Moreover, ultrafine hexanitrostilbene (HNS) pellets were detonated over firing voltage range 1.80 kV to 1.40 kV. These results demonstrate the feasibility of the S3-EFI chip and pave the way to non-lead high-voltage discharge circuit. To the best of our knowledge, this is the first time to integrate exploding foil initiator with high-voltage switch.

A planar trigger switch constituting of three electrodes was designed and fabricated using low temperature co-fired ceramic, and characterized under an atmospheric pressure. The results showed that when the operating voltage ranges between 77.2% and 86.8% of its self-breakdown voltage, the inductance of the switch was lower than that of commercial spark gap switch by approximately 60 nH, the current rising time was shortened by nearly 1/2, and the peak current increased by about 30%. The peak current and rising edge were 4000 A and 146 ns at 0.22 μF/2.0 kV, respectively, which was in agreement with simulation values well. Subsequently, the switch was devised to be in-situ integrated with an exploding foil initiator together. The electrical characterizations were performed on the chip, obtaining the switch’s rapid turn-on time of 29 ns and a large current density of 1.08×108 A˙cm-2 at 0.22 μF/2.25 kV. Furthermore, photon Doppler velocimetry was exploited to capture the detailed trajectory of a 50 μm-thick flyer with an extracted terminal velocity of 2200 m/s. Finally, boron-potassium nitrate pellets and hexanitrostilbene pellets were used to successfully verify the practicability of the chip in the ignition and detonation of explosives.

A planar ignitor-based on low temperature co-fired ceramic (LTCC) and pyrotechnical micro electro mechanical system (PyroMEMS) technologies was designed and prepared in this paper. The planar ignitor is mainly composed of output charge layer, silicon safe and arm (Si-S&A) layer, and LTCC circuit base. Si/Pb₃O₄, C₆H₂(NO₂)₃OK/KClO₄, and B/KNO₃ were selected as ignition charge, gas charge, and transfer charge, respectively. The ignition circuit and main structure of the planar igniter were made by the LTCC process. Si-S&A was etched from monocrystalline silicon, which does not need environmental force to disarm. Preparation process of main components of planar ignitor that is suitable for mass production was introduced in detail. Simulation of PyroMEMS S&A actuation based on pendulum method was performed to save time for proof test. Finally, experimental verification on PyroMEMS S&A actuation and combustion propagation of B/KNO₃ transfer charge were completed successfully. Results show that the idea of a planar ignitor inserted with PyroMEMS S&A device is feasible. [2018-0075]

The pulse power switch plays an important role in a wide variety of pulse power applications, such as plasma science and high-pressure-impact studies. This paper develops a shock-induced pulse power switch based on electro-explosion of exploding bridge wire (EBW). The electrical field distribution and electrothermal coupling of EBW are simulated using COMSOL Multiphysics software to assess the rationality of structural parameters. Employing microelectromechanical system (MEMS) technology, the switches are mass-produced with only three steps, improving experimental efficiency and lowering the cost. Electrical tests are conducted at a series of operation voltages varying from 600 V to 1800 V, and the results indicated that peak current increases linearly with operation voltage, while delay time and rise time all show a slowly declined trend. A potential conduction mechanism is discussed for better understanding, and switch resistance is described mathematically. Finally, microchip exploding foil initiators (McEFIs) are used as a test vehicle to verify the capability of the switch, and ultrafine hexanitrostilbene (HNS-IV) pellets are successfully detonated at 0.15 μF/1300 V after the switch is closed.