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: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 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: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 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 explosives and propellants containing hexanitrohexaazaisowurtzitane （CL-20） and aluminum （Al） powders show excellent energy properties， and Al/CL-20-based energetic materials have become the focus of research. By using polyvinylidene fluoride （PVDF） as binder combined with nano-aluminum （nAl） powders and CL-20， the nAl@PVDF and nAl@PVDF@CL-20 composite energetic particles could be prepared via microfluidic technology. The morphology， internal structure， and particle size of two composite particles were observed by scanning electron microscope （SEM） and laser particle size analyzer. Chemical structure of composite particles was analyzed by Fourier transform infrared spectrometer （FTIR）. Thermogravimetry-differential scanning calorimetry （TG-DSC） was used for thermal analysis. The results show that the as-prepared composite particles exhibit high sphericity， good dispersibility， and uniform particle size distribution with the particle size of 10-20 μm. The components of composite particles are well-distributed， and there is no chemical bond between the components. Thermal analysis results display that both nAl@PVDF and nAl@PVDF@CL-20 composite particles exhibit pre-ignition reaction between PVDF and surface oxidation layer of nAl. The heat released from the pre-ignition reaction could promote the decomposition of PVDF. The decomposition reaction of CL-20 could be accelerated by combining with nAl and PVDF. Compared with nAl/PVDF/CL-20 material acquired by mechanical mixing， nAl@PVDF@CL-20 composite particles prepared by microfluidic method possess homogeneous component distribution.

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 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: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: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: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: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.

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