Abstract:Aiming at the lack of reliability quantitative design method of the Exploding Foil Initiator （EFI）， the reliability design method for the Four-point Array output interface of EFI is studied. Firstly， based on the Stress-strength interference model， the reliability quantitative design method considering double margin coefficients is proposed， and the quantitative model between output performance parameters and reliability index is constructed. Then， the output performance of the output interface on different design parameters is simulated， and the quantitative models between the output performance parameters and structural design parameters is established. Finally， combined with the above two types of quantitative models， the structural parameters that meet the requirements of the output interface reliability design index of the four-point array slapper detonator are given. The results show that the method can effectively improve the reliability design accuracy of EFI’s output interface and then achieve accurate design.

Abstract:In order to study the interaction between igniting pyrotechnics and packaging cellulose materials during the working process of traditional igniters for rocket engines and the influence of the structure of igniting pyrotechnics on flame propagation characteristics， igniting pyrotechnics/cellulose composite samples were prepared. The effects of cellulose shell on the thermal reaction performance of igniting pyrotechnics were studied by simultaneous thermal analysis （DSC-TG） and Fourier transform infrared spectroscopy （FTIR）. On this basis， the influence of charge structure， charge amount and formula composition on flame propagation process and combustion temperature distribution was studied by using simulated combustion chamber. The flame structure and flame temperature distribution of different igniters were obtained by high-speed camera and high-speed infrared thermal imager， and correlated with the collected pressure data. The results show that the cellulose shell reduces the total heat release of the condensed phase reaction of the black powder and the Mg/PTFE ignition powder. When the cellulose content is 33.33%， the total heat release of the two igniting pyrotechnics is reduced by 66.36% and 29.98%， respectively. However， the heat release of B/KNO₃ increased by 2.39 times. The analysis of gas phase decomposition products and combustion condensed phase products showed that cellulose did not change the thermal reaction path of black powder and Mg/PTFE. The simulation of ignition process shows that the pre-ignition phenomenon will occur in the ignition and combustion process of the black powder igniter with a cylindrical charge of 10 g. The igniting pyrotechnics generates a large amount of gas to carry some unburned particles to break the shell before ignition. The cellulose shell has a certain pressurization effect， which lays a pressure foundation for the establishment of the initial flame. The charge structure and charge quantity have no significant effect on the combustion temperature of the igniter， and the difference of the combustion temperature does not exceed 50 ℃. However， the working time of the igniter of the square and annular igniter cartridges is shorter， which is about 42.4% shorter than that of the small cylindrical and shaped igniter cartridges， which is beneficial to improve the ignition efficiency. In terms of formula influence， Mg/PTFE has the highest combustion temperature and the shortest working time， while the combustion temperature of large particle size black powder is higher than that of small particle size， so the former works longer.

Abstract:In order to obtain super thermite with spherical core-shell structure for 3D printing of energetic materials， Al_2#@CuO and Al_2#@Bi₂O₃ super thermites possessing highly spherical core-shell structure were prepared by spray granulation method for directly coating solid particles. The influence of construction parameters （particle size ratio and solid content） on particle size of super thermite was studied by using NanoMeasure statistical software. The spherical core-shell structure was characterized by scanning electron microscopy and X-ray diffraction. The flowability of super thermite was characterized using the angle of repose method. The ignition characteristics were observed using high-speed cameras. The results show that two types of super thermite possessing highly spherical core-shell structure were prepared using construction parameters of solid content 25%， 2# aluminum powder， and nano metal oxide （CuO， Bi₂O₃） particle size. The structure was an ideal spherical core-shell structure， with an average particle size of about 40 μm. The average thickness of the shell is 7.79 μm （Al_2#@CuO-25%）， 10.47 μm（Al_2#@Bi₂O₃-25%）. Compared with the mechanically mixed sample， the flowability of super thermite with spherical core-shell structure displays a great improvement. The angle of repose of Al/CuO system reduces from 48.8° to 22.9°， and the angle of repose of Al/Bi₂O₃ system decreases from 37.3° to 16.6°. The combustion time of Al_2#@CuO super thermite with spherical core-shell structure increases from 100 ms to about 0.9 s， indicating that microstructure variation has an impact on its combustion characteristics.

Abstract:In order to study the low hygrothermal aging mechanism of Al/Zr/KClO₄ ignition agent， samples were aged at 85， 71， 60 ℃ and 50 ℃ . Thermal analysis， X-ray photoelectron spectroscopy （XPS） and scanning electron microscopy （SEM） X-ray spectroscopy （SEM-EDS） were used to analyze the thermal decomposition performance of Al/Zr/KClO₄ ignition agent and the changes of surface elements and morphology with temperature and time. The results show that some molecules on the surface of KClO₄ crystal are degraded to KClO₃ and KCl with the increase of aging time. The surface of Zr is further oxidized to ZrO₂ under the action of heat， and Al does not change significantly. Meanwhile， the surface morphology of each component did not change. The thermal decomposition activation energy and enthalpy of Al/Zr/KClO₄ ignition agent showed a decreasing trend with the increase of aging time. Compared with the unaged ignition agent， the activation energy decreased by 29.57 kJ·mol^-1 and the enthalpy decreased by 160 J·g^-1 after aging at 85 ℃ for 160 days. The aging mechanism function of ignition agent was obtained by fitting reaction rate， enthalpy value and surface element parameters of each component. It was found that the reaction rate， oxidation of Zr and degradation of KClO₄ could reflect the effect of time and temperature on low hygrothermal aging of ignition agent. The aging mechanism function was N-order reaction， the aging process is the oxidation of Zr and the degradation of KClO₄. The oxidation rate and reaction degree of Zr is greater than the degradation of KClO₄， and the aging activation energy was 95.86-128.90 kJ·mol^-1.

Abstract:In order to solve the problems of crystal transformation and low forming efficiency of the main explosive in hexanitrohexaazaisowurtzitane （CL-20） based all-liquid explosive ink micro-jet printing， suspension explosive ink compatible with 3D micro-jet printing was designed and prepared by using polyvinyl alcohol （PVA） aqueous solution as colloidal suspension and micro-nano CL-20 particles as suspension particles. 3D micro-jet technology was used for printing the explosive ink. The properties of the samples were characterized by densitometer， laser confocal microscope， scanning electron microscope， X-ray diffractometer and nano-indentation instrument， respectively. The impact sensitivity， friction sensitivity， and detonation velocity of the samples were also tested， which was used for the study of the relationship between the content of CL-20 and the properties of micro-detonation agent. The results showed that the "coffee ring" phenomenon became more obvious with the increasing content of micro-nano CL-20 particles in the explosive ink， and the thickness of the single layer deposition of the powder line became thicker， while the density decreased gradually. The main explosive CL-20 exhibited no crystal transformation in the 3D microjet printing process and was ε type. When the ratio of micro-nano CL-20 particles to binder was 9∶1， the measured density of the sample was 1.638 g·cm^-3 （86.19% TMD）， and the elastic modulus was 5.43 GPa. The impact sensitivity， friction sensitivity and detonation velocity were 4 J， 240 N and 7689 m·s^-1， respectively， showing better safety performance and micro-scale detonation transmission ability.

Abstract:In view of the urgent demand for high-temperature resistant initiators for pyrogenic products in complex application environments in deep space， primary explosive based on composite films of MXene/Cd（N₃）₂ with high-temperature resistant was prepared by surface self-assembly of electrostatic interaction. The morphology and structure of the composite film primary explosive were characterized by scanning electron microscopy， energy dispersive X-ray spectroscopy， X-ray diffraction and infrared spectroscopy. The thermal properties were studied by differential scanning calorimetry and thermogravimetry， and the detonation process was recorded by high-speed photography. The results show that cadmium azide was evenly distributed on the MXene layer， and there was no deposition and stacking in the large gap. The introduction of MXene can effectively promote the thermal decomposition rate of cadmium azide. The combination of MXene material and cadmium azide didn’t affect the crystal form and detonation performance of cadmium azide. The prepared MXene/Cd （N₃）₂ composite film primary explosive can realize ignition and detonation with less charge.

Abstract:To search green， low-toxicity lead-free primary explosive， a new tetrazole derivative ligand 1H-5-acylhydrazide tetrazole （TZCA） and its complex Ni（TZCA）₂（ClO₄）₂ （ECCs-1） were synthesized by hydrazinolysis and coordination reactions using ethyl 1H-tetrazole-5-carboxylate as the raw material. The molecular structure and thermal decomposition properties of the title complex were tested by X-ray single crystal diffraction， IR diffraction， NMR， elemental analysis， thermogravimetric and simultaneous thermal analyzers. The heat of combustion of ECCs-1 was tested by oxygen bomb calorimetry and its energy parameters were predicted based on Hess law and K-J equation. Sensitivities of ECCs-1 were tested by BAM test methods. The results show that the density of TZCA is 1.83 g·cm^-3， monoclinic crystal system， C2/c space group， the stacking mode is V-staggered stacking. The density of ECCs-1 powder is 1.90 g·cm^-3， impact sensitivity is 17 J， friction sensitivity is 72 N， thermal decomposition temperature is 336 ℃， activation energy of the thermal decomposition reaction is 183.3 kJ·mol^-1， thermal explosion critical temperature is 309.8 ℃， activation entropy is 46.745 J·K^-1·mol^-1， and the activation enthalpy is 178.563 kJ·mol^-1. The hot baking and lead plate tests both show that ECCs-1 has a good detonation performance.

Abstract:As information， intelligence and miniaturization progresses in ammunitions， Micro-Electrical-Mechanical System （MEMS） based initiator was derived to meet the need of the information of energy-transferring， miniaturization on structure and integration of energy sequence. As one kind of a system-level MEMS initiator， the present micro fire-train was integrated based on initiation detonation mechanism of the flyer impacting the next booster explosive. By focusing on the application and technical requirements of micro fire-train， the state-of-art of the fire-train was reviewed from five aspects， including the micro-heater design and firing energy control， microscale detonation energy control and devitrization， energy transmission and safety control， micro fire-train design and integration， and reliability evaluation of the fire-train. Based on the analysis of state-of-art of micro fire-train， some suggestions for future development were proposed， and the key points for the further development of micro fire-train are discussed： strengthen the basic research of initiation and detonation mechanism under micro scale； promote digital engineering and improve forward-design capability； build mass production capacity including element-level， component-level and system-level of the micro fire-train； enhance the qualification and improve technology maturity of micro fire-train. It is vital useful for the peers to pay more attention on the design， fabrication， test and evaluation of the micro fire-train.

Abstract:To study the safety of pulse excitation of hot bridge wire EED， we established a numerical model for the temperature rise of the hot bridge wire EED， and the ignition criterion of hot bridge wire EED was obtained. Based on the above， we designed the calculation procedure for the critical ignition current of the hot bridge wire EED and revealed the influence of single pulse and pulse train current excitation parameters on the critical ignition current of hot bridge wire EED. The results showed that under single pulse excitation and when the pulse width was less than 5 μs， the ignition energy of the hot bridge wire EED was fixed， which suggested that the bridge wire-reagent system was in an adiabatic state. So the ignition state was related to the energy input to the bridge wire. However， when the pulse width was greater than 15 ms， the critical ignition current of the hot bridge wire EED was fixed. So the ignition state was related to the electric power of the bridge wire. Another difference was that under narrow pulse train current excitation， the time constant of the curve for critical ignition current with repetition period was independent of the pulse width. Furthermore， when the repetition period was greater than 1.25 ms， the bridge wire-reagent system exhibited no thermal accumulation effect， and the critical ignition current was the same as the single pulse current excitation. However， when the repetition period was lower than 1.25 ms， the bridge wire-reagent system exhibited the thermal accumulation effect， which resulted in rapid decrease of the critical ignition current as the repetition period decreased.

Abstract:In order to investigate the pulse laser action process of the explosives doped with nano-aluminum powder， the plasma expansion and shock wave characteristics of single-pulse laser ablation of the PETN explosives doped with 1% nano-aluminum powder were studied by shadow measurement system， while the characteristic spectra of the explosives after laser ablation were investigated by laser induced breakdown spectroscopy （LIBS）. The results showed that when laser pulses irradiate the surface of PETN explosive doped with nano-aluminum powder， high temperature and high density plasma was formed， which expanded continuously and compressed the surrounding air to form shock wave. At 50 ns， the velocity of shock wave was 12500 m•s^-1. With the increase of time， the plasma continued to expand， the shock wave advanced forward and the velocity decreased. At 800 ns， a large number of ejection materials were observed in the shock wave. The maximum strength of the spectral lines of Al atom and AlO gas phase molecule were achieved at 1 μs， and disappeared at 10 μs， indicating that the interaction time between nano-aluminum powder and explosive was less than 10 μs. The spectral lines of C atom and CN were not detected at 20 mJ laser energy. When the laser energy increased to 30 mJ， the spectral lines of C atom and CN group were observed in the spectrum of PETN explosive doped with nano-aluminum powder， and the spectral intensity increased with the increase of laser energy. Moreover， the laser energy required for the decomposition of the PETN explosives doped with nano-aluminum powder should not be less than 30 mJ.

Abstract:In order to demonstrate the feasibility of amorphous alloy as a new type of micro-heater material， the amorphous alloy bridge wire micro-heater was designed and fabricated， and the influence of constituent components on the energy release effect of amorphous alloy material was studied by DSC thermal analysis. On this basis， the electrothermal temperature response， change in temperature coefficient of resistance and the electro-explosive characteristics of the amorphous alloy bridge wire micro-heater were investigated. Results show that the amorphous alloy is regarded as a metastable energetic material when it releases energy， and exhibits negative temperature coefficient of resistance during crystallization process， leading to that relative change in resistance is 6.38%， and the electrothermal energy transfer power is increased by 17.5%. Compared to the Ni-Cr bridge wire micro-heater with linear temperature coefficient of resistance， amorphous alloy bridge wire micro-heater characterizes a better energy release effect. These preliminarily demonstrate the feasibility of amorphous alloy as a promising initiator micro-heater material， and expand the approach on efficiency improvement of electrical initiator micro-heater.

Abstract:In order to explore the effect of microstructure and crystal organization of copper （Cu） foil on the performance of exploding foil initiator（EFI）， three Cu foils with different crystal morphologies were prepared through the closed-field non-equilibrium magnetron sputtering ion plating technique and Lift-Off etching method under the sputtering power of 150， 450 W and 800 W. Experimental characterizations of the electrical explosion performance and flyer velocity of exploding foil （EF）， and the ignition performance of EFI were conducted subsequently. Average grain size of the samples fabricated at 150， 450 W and 800 W are 19.6-36.7nm， 41.5-62.9 nm and 58.6-80.2 nm， surface average roughness are in turn 6.7， 16.9 nm and 46.2 nm， and the adhesion force are 42.436， 55.569 mN， and 71.135 mN， respectively. Of which， the Cu foil prepared at 800 W exhibits the largest and the most uniform grain size， the densest and smoothest grain， the fewest grain boundaries， the largest surface roughness and the strongest adhesion force. The corresponding EF has the smallest resistance and inductance， highest energy conversion efficiency and flyer velocity. The 50% firing sensitivity of the integrating EFI sputtered at 800 W are 19.1% and 22.6% higher than the samples sputtered at 450 W and 150 W， respectively.

Abstract:In order to enhance the energy-release efficiency of aluminum powder， the inert alumina layer of micron-sized aluminum was replaced by cobalt layer with higher thermal conductivity via combining the replacement and subsequent electroless plating methods. Thus the Al@Co core-shell particles were obtained. The cobalt shell thickness was respectively confirmed as 90， 150， 200 and 250 nm. Scanning electron microscopy， transmission electron microscopy， energy dispersion spectrum， vibrating-sample magnetometer， and thermal tests were conducted. The results show that the cobalt shell is dense and uniform with controllable thickness， and the natural oxidation resistance of the particles rises with the increasing shell thickness. And the particles exhibit typical ferrohysteresis loops， further confirming the presence of ferromagnetic cobalt. Al@Co core-shell particle with 200 nm-cobalt coating can fully overcome the endotherm resulting from the melting of aluminum， showing sharp exothermic with the enthalpy energy of 521.40 J·g^-1， which is a promising selection of fuel component in novel green primary explosives.

Abstract:In order to obtain a fully solution-based explosive ink that was compatible with inkjet printing technology and stably detonated at the microscale， an energetic ink was designed by exploiting 3，4-dinitrofurazanfuroxan （DNTF） as the main explosive and polydimethylsiloxane （PDMS）/nitrocellulose （NC） as the composite binder. The rheological properties and printability of energetic inks were explored by viscometer， electron densitometer， and high-speed photographic instrument. The microscopic morphology， mechanical properties， and safety performance of inkjet-deposited samples were characterized using scanning electron microscopy， nanoindenter， and BAM impact sensitivity tester. The results show that the DNTF-based energetic ink is compatible with inkjet printing technology. The composite bonding system could bind the explosive particles tightly. The maximum elastic modulus of DNTF-based composites reaches up to 6.438 GPa； Compared with the raw DNTF， the impact sensitivity and friction sensitivity of DNTF-based composites increase by 6.5 J and 24 N， respectively. In the groove with 100 mm length， 1 mm width， and 1 mm depth， the detonation velocity of sample reaches 7927 m·s^-1.

Abstract:In order to explore the influence of temperature impact and cycling on ignition time of laser pyrotechnics，the laser initiators with carbon doped tetraammine bis（5-nitrotetrazolato） cobalt（Ⅲ） perchlorate （BNCP） as primary explosive and fiber-window structure were employed to study performance of BNCP， structure change of laser initiators and structural constraint between fiber and explosive under different temperature alternating experiments （47 h and 94 h）. The experiment results show that the ignition time can reach less than 0.2 ms indicating a great ignition performance before temperature alternating experiment. However， the ignition time delayed more than 0.5 ms after 47 h temperature alternating experiment and some initiators delayed more than 1 ms even misfired after 94 h temperature alternating experiment. The crystal grains of BNCP broke up and the bulk density decreased from 0.43 g·cm^-3 to 0.32 g·cm^-3 after alternating temperature experiment. However， the change of bulk density has no influence on thermal decomposition and ignition performance. The difference of expansion coefficient between ceramic fiber optic components and igniter shell leads to a gap between fiber and doped BNCP during alternating temperature experiment. The gap has a great influence on both laser spot intensity and hot spot diffusion. With structural constraints of fiber and explosive increasing， the ignition gap can decrease effectively during alternating temperature environment and the environment adaptability of laser initiators can be improved.

Abstract:Copper（Ⅰ） 5-Nitrotetrazolate （DBX-1） is a green primary explosive without toxic heavy metal， which has been always attracted much attention since its discovery. DBX-1 is considered to be the most likely to replace lead azide （LA） as a result of its suitable ignition sensitivity， excellent detonation ability and output ability， good compatibility and temperature resistance. Sodium 5-nitrotetrazolium （5-NaNT） is the starting material for the preparation of DBX-1. This work addresses the synthesis problems of 5-NaNT based upon the review on the research progress of DBX-1. This work introduces both the development process of DBX-1 from laboratory synthesis to 100-gram preparation and the synthetic path evolution of 5-NaNT. Here is mainly focused on the synthesis method， performance evaluation and verification of DBX-1.Finally， it points out that some key issues must be cracked before application， such as the synthesis of 5-NaNT with safety and efficiency， the optimal technology of preparation， the sensitivity adjustment of DBX-1.

Abstract:As the core components of electrical initiators， transducers are essential for the safety and reliability of electrical initiators. The development trends of miniaturization of the structure of electrical initiators， informatization the transducing process and integration of the firing sequence have put forward higher requirements for transducers. How to realize reliable ignition under low energy stimulation and enhance the ignition output capacity has become one of the major issues for the current research of transducers. To this end， this review summarized the latest research progress on the low-energy firing and output efficiency enhancement of electrical initiator transducers in recent years from the perspectives of the preferential selection of transducer substrate and resistive materials， the optimal design of firing structure， the efficiency enhancement of self-contained energetic integration and energetic film composite. On this basis， the focuses of future research on the efficiency enhancement of transducer are discussed： establishing a gene pool of transducer material parameters， improving the efficiency of transducer firing structure optimization design by means of machine learning algorithms， conducting basic research on novel transducer systems such as wide-bandgap semiconductor materials， and exploring the integration of novel energetic films such as energetic Metal-Organic Frameworks （MOFs） and chalcogenide on transducers.

Abstract:To investigate the effects of temperature on the electrical explosion and ignition of semiconductor bridge （SCB）， the electrical explosion characteristics and ignition performance of SCB with the ambient temperature of 25 ℃ and -40 ℃ were studied by a capacitive discharge method， and a mathematical model was established. The ignition temperature of Al/CuO nanothermite was tested at ambient temperature of 25 ℃ and -40 ℃， respectively. The ignition sensitivity of SCB was measured by the D-optimization method. When the charging voltage increases from 30 to 50V， the difference of critical initiation time reduced from 0.47 to 0.25 μs. The difference of critical initiation energy increased from 0.16to 0.65 mJ. Results shown that with the increase of charging voltage， the influence of ambient temperature on the critical initiation time decreased， and the influence on the critical initiation energy increased. Both the ignition temperatures of Al/CuO nanothermite at 25 ℃ and -40 ℃ are 740.7 ℃. The 50% ignition voltage at ambient temperature of 25 ℃ is 0.6 V lower than that at -40 ℃.

Abstract:In order to solve the problems of long time consumption， high cost and low material utilization in the deposition and forming methods of commonly used thin-film energy conversion component， silver film bridge were prepared by inkjet printing. The morphology and thickness of the silver film bridge were test by scanning electron microscopy （SEM） and atomic mechanics microscopy （AFM）， and the ignition performance was studied. The results show that the thickness of the silver film bridge is 2.1 μm， and the surface roughness is good. The performance test results show that the silver film bridge has two situations of electric heating and electric explosion under different input energy. Under 47 μF pulse discharge， the 50% ignition voltage of the silver film bridge dipped with lead stiphenate （LTNR） is 6.65 V. and the foot-to-foot can withstand 25 kV electrostatic discharge （discharge capacitance is 500 pF， 5 kΩ resistor in series）， which can pass the 1A1W5min test of insensitive electric initiating device.

Abstract:In order to achieve the high safety of ignition device and micro package volume， a MEMS ignition device has been designed with a double-layer barrier electro-thermal safety and arming device in this work. The device is of three core components including an igniter， a safety and arming device， and an ignition powder， all of which are assembled linearly within an overall size of Φ10 mm×3.3 mm. The S&A device has a double-layer structure with bistable function. The frontend initiator， which is fabricated on a ceramic circuit board， is a NiCr bridge foil to be covered with an Al/CuO energetic film. The two pads from the circuit board lead the bridge foil electrode to the backend device， there by reducing the package volume of the sequence. BPN is selected as the ignition powder in the device. According to the safety and arming function test， the ignition device can prevent the igniter from lighting the ignition powder in safety condition， when the size of the Al/CuO is set to Φ800 μm×30 μm. Otherwise， the BPN ignition powder can be ignited in arming condition.

Abstract:The planar thin film transducer chip was designed with longitudinally integrated PN junction structure diode， and integrated through microelectronics technology for excellent security performance and high integration characteristics. Each of three different-sized chips with 1.0 mm×1.0 mm，1.5 mm×1.5 mm and 2.0 mm×4.0 mm， were designed under four breakdown voltages of 8， 18， 28， 34 V， and two kinds of resistance ，3 Ω and 4 Ω. The ignition tests were carried out on the integrated chip to study the impact of the integrated structure on the burst performance of the transducer. Results from the static electricity of these chips show that the larger the size of the integrated thin film chip is， the stronger the antistatic ability， the greater the resistance in the bridge area of the chip， and the more vulnerable to electrostatic interference are. The electrostatic protection performance of designed chip can reach 500 pF/500 Ω/25 kV. The smaller the breakdown voltage is， the greater the bypass current capacity， the greater the impact on the burst performance of the transducer， and the greater the breakdown voltage， but the smaller the electrostatic protection effect are on the energy converter. For initiating explosive devices to be ignited under 33 μF/16 V， the integrated chip with an 18V breakdown voltage should be selected. Therefore， when the integrated thin film chip is applied， it is necessary to select an appropriate breakdown voltage according to the working voltage of the transducer for both a protection against static interference and a necessary avoidance in failure of its normal function.

Abstract:Inkjet printing technology is an advanced micro-manufacturing technology based on ink droplets， which integrates jetting technology， discrete stacking numerical control manufacturing， and computer-aided design. It is one of the important loading approaches for micro-structured energetic devices such as MEMS pyrotechnics. In the ink-jet printing process， the precise control of droplets is the key to improving the printability and accuracy of the targeted materials. Based on the systematic investigation of the inkjet printing forming mechanism， the physical characteristics of ink and the influence of printing process parameters on the formation of ink droplets were discussed， and the reason and control methods for the "coffee ring" effect were also summarized. The controlling strategies of droplet formation and deposition in the ink-jet printing process were described. At the same time， the application of ink-jet printing technology in booster， nano-thermite， etc. was reviewed， and the development direction of inkjet printing technology in energetic materials was prospected. The drop-on-demand and control with picoliter of ink-jet printing technology provides a prerequisite for the precise charging of micro-nano-structured energetic agents and has good application prospects in MEMS pyrotechnics and special-shaped energetic devices.

Abstract:In order to develop a micro-scale booster for Micro Electro-Mechanical Systems （MEMS） pyrotechnics with excellent mechanical properties. A fully soluble explosive ink was designed with hexanitrohexaazaisowurtzitane （CL-20） as the main explosive， hydroxyl terminated polyether （HTPE）/ nitrocellulose （NC） as the bonding system， ethyl acetate as the co-solvent， and a certain amount of toluene diisocyanate （TDI）. Inkjet printing technology was used to achieve high-precision charge molding， and the cross-linking reaction of isocyanate and hydroxyl group was used to enhance the mechanical properties of micro charge. The density， micro morphology， thermal stability， crystal form and mechanical properties of the samples were characterized by electron densitometer， scanning electron microscope， differential scanning calorimeter， X-ray diffraction and nanoindenter. The results show that the density of the printed sample is 1.70 g·cm^-3， which is 88.54% of the theoretical maximum density. The crystal form of CL-20 in the printed sample is determined by ε type change to β type. The apparent activation energy of thermal decomposition is 173.00 kJ·mol^-1， which is 13.17 kJ·mol^-1 higher than that of the raw material CL-20. The nanoindentation test results show that the elastic modulus of the printed sample is 10.47 GPa and the hardness is 0.22 GPa， showing good mechanical properties. Inkjet printing charge has good detonation transmission ability， and the critical detonation size and detonation velocity are 1 mm×0.18 mm and 8054 m·s^-1， respectively.

Abstract:To promote the stable production and wide application of silver acetylide-silver nitrate （Ag₂C₂·AgNO₃）， the structural morphology and thermal decomposition characteristics were systematically studied by X-ray powder diffractometry， Fourier tranform infrared spectrometer， scanning electron microscopy， differential scanning calorimeter and thermogravimetric-mass-infrar- ed spectrometry techniques. The results indicate that the prepared Ag₂C₂·AgNO₃ sample is in the form of nanospheres with particle sizes ranging from 400 to 500 nm. There is only one exothermal decomposition process of Ag₂C₂·AgNO₃ with a peak temperature of 234.9 ℃， a weight loss of 8.72%， and a heat release of 1449 J·g^-1，at a heating rate of 10 ℃·min^-1. The apparent activation energy and pre-exponential constant of decomposition process are obtained as 108.9 kJ·mol^-1 and10^8.94 s^-1， respectively. Moreover， the gaseous decomposition products of Ag₂C₂·AgNO₃ were NO， NO₂ and CO₂.

Abstract:The conventional lead azide （Pb（N₃）₂， LA） preparation process has problems such as the risk of self-explosion. Aiming at the above problems， the spin-T microfluidic chip with the characteristics of short diffusion distance， large specific surface area， and continuous reaction was used as a microreactor. And then， the LA primary explosive synthesized by microfluidics was spherically modified by using the flow-focusing droplet chip. The effects of the flow rate， crystal form control agent， and other factors on the product were investigated by SEM， XRD， and DSC. The sensitivity and explosion performance of microfluidic LA， microsphere LA， and powder LA were compared. The results show that by controlling the microfluidic reaction parameters， the particle size of the LA can be effectively controlled， and they were all α-type. After the spheroidization， the impact sensitivity H₅₀ （25.5 cm to 12.1 cm） was significantly improved， but the electrostatic spark E₅₀ （1.98 kV to 2.97 kV） and flame sensitivity L₅₀ （26.3 cm to 16.1 cm） were reduced. At the same time， the detonation pressure was increased （by 63.6%）. It shows that the microfluidic technology was an effective method that can safely prepare and modify the LA primary explosive， which provided an idea for the controllable preparation and regulation of sensitive primers.

Abstract:The in-situ construction and performance of a MEMS（micro-electro-mechanical system） planar micro detonator were introduced. The micro detonator was composed of MEMS Ni/Cr heater and direct-writing primary charge， constructed on the same plane of a silicon nitride wafer. The primary explosive cavity was etched on one side of the Ni/Cr heater， and the bridge of the heater is constructed inside the cavity. The porous copper precursor ink was written into the cavity and was converted into copper azide primary explosive by in-situ azidation reaction and the MEMS detonator was obtained. The average resistance of the micro detonator is about 4 Ω， with the initiation delay time of 8.44 μs， the 50% initiation voltage of 14.29 V， and the initiation energy of 0.33 mJ. The average charge of the detonator is 5.18 mg with a mass RSD（relative standard deviation） of 2.6%. The detonator can detonate the hxanitrohexaazaisowurtzitane （CL-20） secondary explosive reliably and completely.

Abstract:The applications and development status of in-line exploding foil ignition and related technologies were reviewed， including the compositions of in-line exploding foil ignition system， the combustion mechanism and new preparation processes of an approved pyrotechnic-boron potassium nitrate （BPN）， as well as the relevant standards of in-line exploding foil ignition at home and abroad. The in-line ignition system has the requirements of multi-function and multi-task. Therefore， the electronic safe and arm device as the control module of the ignition system device presents the development trend of programming addressing and multi-point coordination. The components of the in-line exploding foil ignition system become miniaturized and low energy consumption. The particle size of the components of BPN processed by the new preparation process was micronized and the core shell structure was generated. Hence， the combustion performance， moisture absorption and stability of BPN were optimized. The relevant standards of in-line exploding foil ignition at home and abroad were summarized and compared. The problems to be solved in the study of the in-line explosive foil ignition were analyzed， which includes the mechanism of direct ignition of BPN by slapper， the influence of BPN component particle size on impact ignition sensitivity， the influence factors and the laws of thru-bulkhead ignition of BPN， performance comparison of various thru-bulkhead ignition structures， and new preparation processes of BPN with its performance optimization.

Abstract:As a new initiation technology， laser initiation can effectively solve the safety problems existing in traditional initiation methods， such as stray current interference. As the energy output carrier in laser initiation sequence， the laser-sensitive primary explosive is an important part of the laser initiation system. At present， complex laser-sensitive primary explosive has becomes a research hotspot. The synthesis of energetic complexes with chain nitrogenous compounds， triazole， tetrazole， and tetrazine as ligands and the development status of laser initiation properties were summarized. The advantages and existing problems of various agents were analyzed， some laser initiation mechanisms were summarized， and the development of new laser-sensitive primary explosives in the future was prospected. It is pointed out that the development of new nitrogen-rich ligands is still an important direction for the future research of laser sensitive energetic complex primary explosives.

Abstract:An energetic slurry formulation was designed by light-cured liquid resin， magnesium powder （Mg）， ammonium perchlorate， and burning rate regulator. The energetic grain was printed by Digital Light Processing（DLP） photocurable 3D printing technology. The combustion process， delay performance， uniformity， and compatibility of energetic grain were evaluated， and the influence factors of delay time were analyzed. The results show that the optimal mass fraction of energetic slurry formulation is 7.53% burning rate regulator， 62.37% ammonium perchlorate， 3.22% Mg， and 26.88% light-cured resin. Performance test of slurry displays that viscosity， curing time， curing hardness， and shrinkage are 325 mPa·s， 3.2 s， 2H， and 4.98%， respectively. A cylindrical energetic grain was successfully printed with the size of Φ6 mm×11.5 mm and the average density of 1.507 g·cm^-3. The printed energetic grain exhibits evenly distributed components， good compatibility， stable combustion process， bright yellow flame， and combustion residue rate of 4.98% without black smoke generation. The average delay time and burning rate are （12.43±0.0158） s and （0.805±0.0012） mm·s^-1， respectively. The obtained delay time meets the standard of long second delay composition， and the delay accuracy conforms the requirements of second delay composition. The influence on delay time gradually decreases from ammonium perchlorate， light-cured liquid resin， burning rate regulator to Mg. The delay time of energetic grain can be controlled to achieve diverse delay targets by adjusting component content of energetic slurry.

Abstract:The refined 3，3′-diamino-4，4′-azoxyfurazan （DAAF） was prepared by surfactant assisted spraying crystallization to improve its safety and initiation performance. Dimethyl sulfoxide （DMSO） and ionized water were separately used as the solvent and antisolvent. The effects of the type and concentration of surfactants as well as the volume ratio of solvent to antisolvent on the morphology， particle size and dispersion of refined DAAF were discussed. The morphology and crystal structure of the prepared refined DAAF were characterized by field emission scanning electron microscope （FE-SEM） and X-ray diffraction （XRD）. The results show that the spherical-like DAAF with uniform particle size distribution （180-220 nm） and good dispersion can be obtained when PEG-400 with a concentration of 0.8 g·L^-1 is used as surfactant and the volume ratio of solvent to antisolvent is 1∶20. Compared with the raw material， the thermal decomposition activation energy of the refined DAAF is increased by 23.1 kJ·mol^-1， the impulse initiation current is significantly decreased to 2.1 kA， and the vacuum venting， electrostatic spark sensitivity and thermal sensitivity are all reduced， demonstrating that the refined DAAF exhibits improved thermal stability， safety and initiation performance.

Abstract:In order to design the B/KNO₃ （BPN） ignition powder formula with good combustion performance and compatibility with the direct ink writing technology， seven BPN-based ignition powder ink were designed and prepared by direct ink writing technology with different binders including polyvinylidene fluoride （PVDF）， poly （vinylidene fluoride-trifluorochloroethylene） F₂₃₁₁， poly （vinylidene fluoride-hexafluoropropylene） F₂₆₀₂， poly （vinylidene fluoride-hexafluoropropylene-tetrafluoroethylene） F₂₄₆₁， ethylcellulose （EC）， nitrocellulose （NC） and PVDF/NC. The effects of different binder on the formability， ignition/combustion and thermal decomposition performance were investigated. The results show that the change of binder composition could result in the differentiation of the consistency index of BPN ink. The order of consistency index of different ink is EC/B/KNO₃>PVDF/B/KNO₃>PVDF/NC/B/KNO₃>NC/B/KNO₃>F₂₃₁₁/B/KNO₃>F₂₆₀₂/B/KNO₃>F₂₄₆₁/B/KNO₃. The formability of the ink depend on its consistency index. The rectangularity variation tendency of the samples prepared by direct ink writing technology is consistent with the consistency index. The BPN-based ignition powder containing fluorine rubber presented a higher burning rate and a shorter ignition delay. Meanwhile， the burning rate is faster when the H content is higher in the fluorine rubber. The order of linear burning rate of the BPN-based ignition powder containing different rubber is： PVDF/B/KNO₃>F₂₆₀₂/B/KNO₃>PVDF/NC/B/KNO₃>NC/B/KNO₃>F₂₄₆₁/B/KNO₃>F₂₃₁₁/B/KNO₃>EC/B/KNO₃. However， cellulose binder did not present any significant contribution to reduce the ignition delay. Adding fluorine rubber can reduce the initial reaction temperature of BPN-based ignition powder by about 145 ℃. NC can reduce the initial reaction temperature of the main reaction of the powder by 45 ℃. The addition of EC can only reduce the initial reaction temperature of the main reaction by about 5 ℃.

Abstract:Energy Coordination Compound （ECC） has become one of the research hotspots in recent years because of its diverse Coordination modes between different metal elements and ligands， and it is expected to obtain energetic materials with highly adjustable properties. In this paper， the ways and types of assembling ECC with different ligands are reviewed， and the applications of ECC and its functional materials as initiators， propellant catalysts， flammable agents and oxidants of thermite， pyrotechnics colorants are reviewed. Studies have shown that the energetic complexes formed after the coordination of different metal ions and nitrogen-rich ligands show great potential in the field of new energetic materials， and can meet the requirements of energy， sensitivity and other properties through the change of the type and number of ligands. The law of ECC synthesis is summarized and how to improve the energy characteristics and expand the application in the future is prospected.

Abstract:Metastable intermolecular composites （MICs） have the advantages of ultra-high reaction rate， high bulk energy density and micron critical reaction propagation size. They show broad application prospects in military fields such as micro energetic devices and rocket propellants. Nano Al/CuO energetic composite films are one of the research hotspots in the field of metastable intermolecular composites. They are prepared by vapor deposition， compatible with the micromachining process of energetic micro electro mechanical systems （MEMS）， and have great application prospects in integrated energetic devices. The preparation， thermal properties， combustion properties， reaction kinetics， the effect of transition layer on the properties of Nano Al/CuO energetic composite films， energetic devices （igniters） and their application technology are reviewed， and the development direction of Nano Al/CuO energetic composite films is prospected.

Abstract:Initiating explosive devices are the first component of the weapon system， their safety and reliability directly affect the safety and reliability of the weapon system. In order to meet the development requirements of miniaturization and integration of ammunition， the fuze is needed to integrate with initiator to form a micro-initiation system with high safety， high reliability， and multi-functional integration. MEMS （Micro-Electro-Mechanical System） safety and arming device （S&A device） is one of the key technologies. The development of MEMS S&A device used in micro-fuze and micro-initiation system in recent years was summarized， and the device material， device size， driven mechanisms， driven conditions， output efficiency， application platforms， and other aspects were compared and analyzed. Combined with the structure and size of the initiating device， the working principle of micro-initiation system with built-in MEMS S&A device was proposed. This MEMS initiator with built-in S&A device meets the development requirements of the next generation initiator， and it is also one of the main development directions of initiator in the future.

Abstract:In order to improve the reactivity of submicron aluminum powder， Al-Cu composite metal powder was prepared by means of electric explosion composite wires. The preparation parameters were determined by monitoring the waveform with oscilloscope in the electric explosion process. The structure and morphology of the composite was characterized by X-ray powder diffraction（XRD）， scanning electron microscope（SEM）， transmission electron microscope mapping（TEM-MAPPING） and X-ray fluorescence spectroscopy（XPS）. The Al-Cu composites powder was consisted of CuAl₂ and Al. The morphology of the material was sphere with an average size 150 nm. The forming mechanism of the morphology of the as-prepared composite particles was analyzed. Both DSC and aluminum-vapor methods were employed to evaluate the reactivity of the material. The first oxidation peak temperature of Al-Cu composite metal powder was 550 ℃， as shown in its DSC curve. This parameter was decreased by 50 ℃ comparing with Al prepared with the same parameters. This results indicated that as-prepared composite particles had better reactivity. The first oxidation process of Al-Cu composite metal powder lasted from 500 ℃ to 600 ℃ within 5 mins， while the counterpart lasted from 500 ℃ to 650 ℃ within 7.5 min. Comparing with Al， the heat release rate of Al-Cu composite metal powder was increased by 33% during the first oxidation process. The reaction completeness of the as-prepared composite particles was 0.88 tested by aluminum-water reaction method， but it was only 0.73 for the counterpart. During the first 10 mins of aluminum-vapor reaction， the reaction completeness of Al-Cu composite powder was 0.36 which was as much as ten times that of the counterpart. The result suggested that the reactivity of the composite was improved a lot.

Abstract:In order to prevent the spacecraft from being damaged by the high pyroshock during the action of the pyrotechnic separation nuts， a metal rubber vibration isolator（MRVI） was used to suppress the pyroshock response caused by the impact of the piston in the separation nut. Three kinds of MRVIs with different stiffness were installed at the end of the piston movement in the separating nut， and the shock response spectrum（SRS） in the frequency domain of 500 Hz to 10000 Hz was analyzed. The results show that the pyroshock suppression effect of the MRVI mainly occurs in the frequency band above 3000 Hz， and the pyroshock suppression effect in the frequency band above 5000 Hz is the most significant. The maximum acceleration response after installing a small-stiffness MRVI is reduced from 1330 g to 852 g， and the maximum reduction in analysis frequency domain is 675 g@5993 Hz. The maximum acceleration response after installing a medium-stiffness MRVI is reduced from 1530 g to 1251 g， and the maximum reduction in analysis frequency domain is 539 g@9514 Hz. The maximum acceleration response after installing a large-stiffness MRVI is reduced from 1697 g to 1416 g， and the maximum reduction in analysis frequency domain is 538 g@8476 Hz. The use of MRVI achieves a better pyroshock suppression effect， and provides a viable method for the pyroshock reduction design of the pyrotechnical actuation devices.

Abstract:It was designed that an airtight planar triggered spark-gap switch （PTS） with parallel three-electrode structure based on printed circuit board （PCB） technology， aiming to improve the working probability of exploding foil initiator systems （EFIs）， as well as to reduce the size and cost of the system. The PTS was batched-prepared with PCB technology according to the structural parameters of three electrodes， and the outline of a single parallel PCB-PTS （P³） was 13.5 mm（l）×7.5 mm（w）×2.5 mm （h）. The 3D and sectional appearances of the P³ were reconstructed via a micro computed tomography， which indicated that PCB technology could meet the machining precision. We simulated the electrostatic field distribution among the switch gap to explain the conduction process， and the theoretical self-breakdown voltage （U_SB） was figured out based on the simulation results. Most importantly， the test results of electrical performance of the switch show that （1） the about 2000 V U_SB derived from real-world measurements was slightly lower than the calculated value； （2） P³ switched reliably at 50%-95% U_SB， and there was a constant risetime of about 121.8 ns and a peak current more than 1500 A， which fit the characteristic requirements of EFIs. Finally， P³ was applied to exploding foil initiator （EFI） to verify its practicability， and it was found that HNS-IV pellets were reliably detonated under the ignition condition of 0.22 μF/1400 V.

Abstract:As the most commonly used primary explosives， lead azide and lead styphnate are widely used in military and civilian applications. However， they are harmful to the environment and human body. Therefore， the research of new green primary explosives is an important trend. This paper reviews the synthesis and performances of six new types of initiating agents， including tetrazole， furazan， fused-ring， coordination compound， copper azide， and nano-thermite. Among of these initiating agents： （1） tetrazoles have excellent detonation performance but low safety performance； （2） furazans have higher density and good oxygen balance； （3） fused ring compounds have high thermal stability， low sensitivity and good safety； （4） the sensitivity and energy can be tailored by changing the metal ions， ligands and anions； （5） copper azide has strong detonation ability while its electrostatic sensitivity is extremely high； （6） nano-thermite has the merits of high energy density， ease of synthesis， and environment friendly， but it is difficult to achieve rapid combustion to detonation. Except for copper azide and nano-thermite， the other four types of primary explosives have complex synthesis processes and low yields. Therefore， the decreasing of sensitivity and process feasibility should be emphasized with the consideration of detonation ability for the further research of primary explosives.

Abstract:The development trend of miniaturization of modern energetic devices puts forward higher requirements for the energy density of pyrotechnic agents. In addition， as the concept of sustainable development is widely recognized and accepted， the toxicity of lead-containing explosives has increasingly aroused people"s concerns. For a long time， copper azide has been subject to extremely high sensitivity and therefore has not been widely used in weaponry and civilian blasting equipment. However， due to its green and high energy density characteristics， copper azide has attracted researchers" interest in recent years. The research progress of energetic materials based on copper azide in and abroad is summarized， mainly including the following perspectives： theoretical research on crystal structure level， synthesis methods of different ways， design and preparation of composite materials， practical application of microcharges and its performance test. As a kind of energetic material which has attracted attention in recent years， copper azide， has apparent advantages and disadvantages. The critical point to realize its potential application prospects lies in： theoretically grasping its crystal structure and reaction mechanism more deeply； making up for its overly sensitive defects while giving play to its advantages of high energy density from the perspective of structural design； to understand its performance parameters more systematically through experiments and simulations； developing advanced synthesis methods and charging technologies to meet the requirements of Micro-Electro-Mechanical System （MEMS） pyrotechnic devices for precise and reliable charging of energetic materials.