Abstract:In order to investigate the infrared extinction performance of nickel-plated graphene and explore the best formulation， nickel-plated graphene was prepared by the redox and chemical plating methods. The influence of various factors on the extinction performance of nickel-plated graphene was analyzed by designed orthogonal experiments with the infrared decay rate as the evaluation index， and the optimal formulation was determined. The infrared transmittance of nickel-plated graphene was measured in a smoke-screen chamber test. The average mass extinction coefficient of nickel-plated graphene was calculated by linear fitting according to the “Lambert-Beer” law. The results showed that the optimal process parameters for the preparation of nickel-plated graphene were： c（NiSO₄·6H₂O）=20 g·L^-1， c（NaH₂PO₂·H₂O）=24 g·L^-1， c（C₆H₅Na₃O₇·2H₂O）=10 g·L^-1， c（NH₄Cl）=30 g·L^-1， pH=8-9， and plating temperature of 65 ℃. The nickel-plated graphene prepared under the optimal conditions exhibited good infrared extinction in both mid- and far-infrared wavelengths. The average mass extinction coefficients of the nickel-plated graphene in the infrared bands of 3-5 μm and 8-14 μm were 2.38 m²·g^-1 and 2.19 m²·g^-1， respectively. Compared with the modified graphene， the average mass extinction coefficients of nickel-plated graphene in the mid-infrared bands were improved by 30% and 35%， respectively， which have broader application prospects.

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:In order to investigate the application effect of fluorocarbon resin （FEVE） in explosive ink， a new type of oil-in-water emulsion bonded system was designed by employing polyvinyl alcohol （PVA） aqueous solution as water phase and FEVE/ethyl acetate solution as oil phase. By adding sub-micron CL-20 particles into bonded system， CL-20-based explosive ink was prepared for direct writing. Scanning electron microscope， rheometer， X-ray diffractometer， and impact and friction sensitivity tester were used to characterize morphology and detonation performance of printed samples. The results show that PVA/FEVE oil-in-water emulsion binder system can stably exist for 174 h. The CL-20 explosive ink with 90% solid content exhibits optimal rheological properties and good printability. The obtained direct writing sample with microporous internal structure displays a smooth surface， and the crystal form of CL-20 explosive is still ε type. The impact energy and friction force of printed samples are 216 N and 4.5 J， respectively. Compared with raw ε-CL-20， impact sensitivity and friction sensitivity of printed samples are reduced by 125% and 200%， respectively. The detonation velocity， critical detonation corner turning， critical detonation thickness of 1-mm line width， and critical detonation size of square section of printed samples are 6772 m·s^-1， 160°， 0.039 mm， and 0.4 mm×0.4 mm， respectively， which show excellent micro-scale detonation capability.

Abstract:In order to explore a continuous， safe and controllable microfluidic synthesis strategy of emulsion explosive， silicon-based microporous array chips with four apertures（10 μm，20 μm，30 μm，40 μm） were designed and prepared by MEMS technology， and the microfluidic reaction device of emulsion explosive was constructed. It is found that the main factors affecting the droplet size of dispersed phase in latex matrix are micropore diameter and continuous phase velocity. The effects of pore size and oil-water two-phase flow rate on the particle size distribution and exothermic properties of emulsion droplets were studied. The results show that the particle size distribution of dispersed droplets in the matrix is the narrowest when the pore size is 30 μm and the continuous phase flow rate is 0.5 mL·min^-1 and D₅₀=8.169 μm. Microporous array chip can generate highly homogeneous droplets in batch， which provides a new choice for emulsification in the preparation of emulsion explosive.

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: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 synthesis performance of 3，3′-diamino-4，4′-azoxyfurazan （DAAF） by conventional methods， broaden the synthetic pathway of DAAF. A microfluidic reaction system was designed to synthesize DAAF using 3，4-diaminofurazan （DAF） as the main raw material by microfluidic technology. Orthogonal experiment was designed to optimize the synthesis conditions. DAAF with a purity of 99.33% and a yield of 89.96% was synthesized at 25 ℃， a flow rate of 4 mL·min^-1 and a length of 5 m in the outlet crystallizer. The structure of the synthesized product was characterized by infrared， nuclear magnetic and elemental analysis， and was characterized by scanning electron microscope （SEM）， X-ray diffraction （XRD）， thermal analyzer （DSC/TG） and mechanical sensitivity. The results show that DAAF was clustered flower ball with an average particle size of 5.36 µm； Microfluidic synthesis has no effect on the crystal structure of DAAF. At the heating rate of 10 ℃·min^-1， the thermal decomposition peak temperature is 262.36 ℃， and the mass loss rate during thermal decomposition is 82.79%. The mechanical sensitivity test shows that the impact sensitivity is 90 J， and the friction sensitivity is 0%. Compared with the DAAF synthesized by the conventional method， the average particle size decreased by 7.36 µm， the particle size distribution is uniform and the particle size distribution range is narrowed， the crystal structure does not change， the thermal decomposition peak temperature was advanced by 9.57 ℃， the mass loss rate was reduced by 6.99%， the impact sensitivity is increased by 5 J， and the safety performance is improved.

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: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 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:Three energetic coordination compounds with strong reducibility were prepared with cyanoborohydride （CBH） as anion， 1-vinyl imidazole （VIM） as ligand and transition metals Co， Mn and Ni as central ions. The crystal structures were determined by single crystal X-ray diffraction and their molecular formulas are Co（VIM）₄（CBH）₂， Mn（VIM）₄（CBH）₂ and Ni（VIM）₄（CBH）₂， respectively. The thermal decomposition performance， oxygen bomb calorimetry and mechanical sensitivities of the complexes were tested. The results show that the complexes have high burning calorific capacity （26.5-29.1 kJ·g^-1）， low friction sensitivity （>360 N） and impact sensitivity （>40 J）. Hypergolic testing with white fuming nitric acid shows that the complexes can combust spontaneously， and the ignition delay time is short （4-13 ms）， which confirm the high reduction activity of the complexes. To explore the application of active coordination compounds in initiating explosive devices， three new composite igniting powders were obtained by mixing three complexes with sodium bromate in the mass ratio of 1∶7， respectively. The composite powders were ignited and tested with electric heating wire. After being ignited by electric heating wire， the three composite agents can burn continuously and produce large flame. Results show that the composite agents have potential applications as new ignition agents.

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:The pyrotechnic formulation， that emitting purple light by using the synergetic effect of multi flame colorants， was designed and optimized theoretically. Based on the principle of additive color mixing， one purple-light-emitting pyrotechnic formulation containing flame colorants that generating red and blue colors was proposed. The types and contents of different colored light emitters were determined by REAL program. The color coordinates， wavelengths， color purities and chromaticity diagrams of different formulations were calculated by MATLAB program， and then the optimized pyrotechnic composition with purple light was determined. The theoretical results showed that the optimal formulation of purple-light-emitting pyrotechnics was Sr（NO₃）₂/2CuCO₃·Cu（OH）₂/Al/C₆H_9.6O_1.6 with the ratio of 48/32/12/8. The oxygen balance of the formulation was -0.11 g·g^-1 and the colored light emitters were Sr， SrO， SrOH， CuO， CuOH， and CuH， respectively. The purple chromaticity coordinate point was （0.2449，0.1497）. The virtual dominant wavelength of purple light was 446 nm， and the color purity was 0.40. The experimental measurements of the above formulation showed that the chromaticity coordinate point was （0.2425，0.1588）， the virtual dominant wavelength of purple light was 439 nm， and the color purity was 0.44. The purple light was actually produced by the mixing of red light （766 nm） and blue light （418 nm）， with good purple effect. The simulation results are in good agreement with the experimental results. This design method can provide a theoretical basis for the formulation optimization of other colored-light-emitting pyrotechnic compositions with multi flame colorants and the study of related problems.

Abstract:In the present work it is found that the pyrotechnic composition VS-2 can be initiated with flash lamps IFC-500 and EVIS. VS-2 pyrotechnic composition contains 90% of mercury（Ⅱ） 5-hydrazinotetrazolate perchlorate and 10% of optically transparent copolymer of 2-methyl-5-vinyltetrazole and methacrylic acid （PVMT）. We have found that the flash lamps make it possible to initiate combustion of VS-2 composition with its transition to detonation both in cylindrical charges placed in brass caps of 5 mm diameter and 2 mm high， and film charges with 10 mm×80 mm in size and surface weights of 60 mg·cm^-2 and 90 mg·cm^-2， showing ignition delay times 10 μs and 3 μs， respectively. We also measured detonation velocities for VS-2 composition film charges， which were 4375-4505 m·s^-1 （of the charge being surface mass 60 mg·cm^-2） and 4221-4281 m·s^-1 （of the charge being surface mass 90 mg·cm^-2） and their blasting action on the aluminum plate. The depths of the normal shock wave imprints at the charge-barrier interface were 0.6-0.7 mm （for surface mass of the film charges 60 mg·cm^-2） and 1.2-1.3 mm （for surface mass of the film charges 90 mg·cm^-2）.

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:The lack of plenty of gas products during the combustion reaction of thermite is an important constraint on the development of high energy. To make up for the lack of gas production and improve the reactivity of nano-thermite， Al@KIO₄ and Al@NaIO₄ nano-thermites with core-shell structure were prepared by spray drying method. Scanning electron microscope， X-ray diffractometer， thermal analyzer， constant volume combustion chamber， hygroscopicity test and initiation power test were used to characterize the morphologies and structures， and also thermal properties， combustion performances， moisture-resistance performances and detonation performances. Results show that Al@KIO₄ and Al@NaIO₄ nano-thermites are seperatelly in high purities and with regular morphologies； the heat release are 1262.12 J∙g^-1 and 1414.7 J∙g^-1， respectively； the starting temperatures of the decomposition reactions are lower than the raw materials and accompanied with a large number of oxidizing gas products. The mass balances were reached on the 6th and 10th day， and the mass gains were about 0.64% and 0.65% in high humidity for the Al@KIO₄ and Al@NaIO₄ nano-thermites. Initiation power test showed that 96 mg samples charged into No.8 industrial detonator as primary explosive could completely detonate RDX， the perforation diameter of 5 mm thick lead plate showed that the initiation capacity of Al@KIO₄ and Al@NaIO₄ nano-thermites were comparable to LA. According to the perforation diameters， the order of initiating power is LA＞Al@NaIO₄＞Al@KIO₄＞LTNR.

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:To explore organic amine oxyanions with simple synthesis procedure and high energy， ethylenediamine diiodic acid and ethylenediamine hexamiodic acid were synthesized with iodic acid and ethylenediamine. The structures were characterized by single crystal X-ray diffraction， powder X-ray diffraction （PXRD） and Fourier transform infrared spectroscopy （FT-IR）. Differential scanning calorimetry（DSC）and thermogravimetric analyzer（TG）were used to study the thermal decomposition process. The power test of lead plate as main charge in 8^# industrial detonator and the burning test were carried out. The results show that two ethylenediamineIodate salts are successfully prepared. The ethylenediamine diiodic acid belongs to orthorhombic system， Pbca space group， cell parameters： a=7.4427 Å， b=6.7418 Å， c=18.2884 Å， Z=8， F（000）=760， D_c=2.982 g·cm^-3， and the peak temperature of thermal decomposition is 185.18 ℃. The ethylenediamine hexamiodate is a cocrystallization of ethylenediamine diiodate and iodate acid. It belongs to monoclinic system， P2₁/c space group， cell parameters： a=7.2350 Å， b=18.498 Å， c=7.5494Å， β=107.947°，Z=4， F（000）=996， D_c=3.840 g·cm^-3， and the peak temperature of thermal decomposition is 179.48 ℃ and 356.87 ℃. The 5 mm lead plate can not be made through when the ethylenediamine hexamiodic acid is used as main charge， while the opposite result occurs when mixed with 10% aluminum powder. The ethylenediamine diiodate can be used as a simple purple smoke agent.

Abstract:

Abstract:The mixing uniformity and processing safety of widely used zirconium/lead tetroxide （Zr/Pb₃O₄） composites are indispensable. In the current paper， a Zr/Pb₃O₄ microcapsule bonded with the adhesive alginate was prepared by crosslinking the liquid phase with sodium alginate（SA） and Ca²⁺ in aqueous phase to form calcium alginate （CA） gel. The morphology， particle size， sphericity， fluidity and apparent density of CA/Zr/Pb₃O₄ microcapsules and the traditional-made NC/Zr/Pb₃O₄ controlled sample were evaluated. The average particle size， variance， sphericity and repose angle of CA/Zr/Pb₃O₄ microcapsules is measured to 517.10 μm， 44.21 μm， 0.90， and 27.44°， respectively. The flame sensitivity， burning rate， flame length and sensitivity of CA/Zr/Pb₃O₄ microcapsules were tested to 65.38 mm， which was lower than that of Zr/Pb₃O₄ powder （81.83 mm）. Besides， the combustion rate deviation of CA/Zr/Pb₃O₄ microcapsules and Zr/Pb₃O₄ powder is 6.86 and 12.04， respectively， implying an excellent combustion consistency. Furthermore， much more flame length of 17.1 mm and burning particles than Zr/Pb₃O₄ were obtained in of CA/Zr/Pb₃O₄ microcapsules. In addition， a reduced the electrostatic sensitivity of CA/Zr/Pb₃O₄ microcapsules （156.25 mJ） and Zr/Pb₃O₄ powder （0.71 mJ） were realized. More importantly， the water-phase preparation carried out in the current paper may pave a high-safety and universal way for a variety of pyrotechnic agents.

Abstract:As a new generation of rapid prototyping technology， direct writing technology has the advantages of fast molding speed， good molding consistency， and high preparation accuracy. It has certain advantages in the preparation of MEMS energetic devices. In this paper， the common direct writing technologies of MEMS energetic devices were described. On this basis， according to the research status of direct writing technology in micro-nano energetic devices， the direct writing technologies used in micro-scale charges of MEMS energetic devices， ignition circuit and transducer element， and packaging materials were summarized. The future research directions were proposed： preparing energetic ink with high solid content and stable performance， increasing the charge density of energetic ink， preparing silver ink circuit with low sintering temperature， and at the same time developing direct writing technology for MEMS energetic device transducers and packaging materials， exploring the influencing factors and laws of direct writing accuracy， breaking through the application bottleneck of direct writing technology， and promoting the progress of engineering application of this technology.

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:In order to prevent the spacecraft from being damaged due to the high pyroshock of the separation nut， an orifice is used to suppress the pyroshock response of the separation nut during separation. Throttle holes with three diameters of Φ2 mm， Φ4 mm and Φ6 mm are set on the powder gas channel of the separation nut. The pressure， acceleration and preload of the separation nuts of different orifices in the separation process are tested simultaneously， so as to analyze the separation process of the separation nuts. According to the sequence of movement， the pyroshock load is decoupled into three types of pyroshock sources： powder combustion， preload release and piston impact. The time-acceleration （a-t） curve is transformed into a shock response spectrum （SRS）， and the contribution of each shock source is calculated. The relationship between the orifice diameter and the shock response is obtained. The results show that in the frequency domain of 500 to 10000 Hz， the contribution of gunpowder action is 8.3% to 11.0%； the contribution of preload release is 44.0% to 51.5%； and the contribution of piston impact is 40.2% to 45.0%. The maximum pyroshock response during the separation process is： 1416 g （Φ6 mm）， 1251 g （Φ4 mm） and 852 g （Φ2 mm）. It can be seen that the use of the orifice can effectively suppress the impact response of the separation nut.

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.