CHINESE JOURNAL OF ENERGETIC MATERIALS
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  • Methodology Design for Calculating Steric Hindrance Index as a Descriptor for the Shock Sensitivity of Energetic Materials
    CJEM | 2021 No.3
  • Characterization Technology of Damage Power of All-Energetic Penetrating Warhead to Multilayer Steel Medium
    CJEM | 2021 No.2
  • Numerical Simulation of Small-angle Ultrasonic Testing for Inner Cracks in Curved PBX Structure
    CJEM | 2021No.1
  • PDF HTML Export Preparation and Properties of Al/Bi2O3-HNIW Hybrid Composites
    CJEM | 2020No.12
  • Double-nozzle Microjet Direct Writing and Properties of CL-20 Based Energetic Film
    CJEM | 2020No.11
  • Damage-ignition Simulation for Typical Pressed and Casted PBX under Crack-extruded Loading
    CJEM | 2020No.10
  • Thermodynamic on the Formation of CL-20/1,4-DNI Cocrystal
    CJEM | 2020No.9
  • Preparation and Reaction Characteristics of Spherical Al-Si Alloy Fuel
    CJEM | 2020No.8
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    • CAO Shi-jin, LI Zhong-you, XIONG Wei-qiang, WANG Peng, ZHANG Tian-fu, CHENG Di, GAO Yang

      Online:April 13, 2021  DOI: 10.11943/CJEM2020270

      Abstract:To improve the energy property and low vulnerability of cast HMX-Al based explosives, high solid -content aluminized PBX were designed by analyzing the influences of Al and HMX contents on detonation properties. A casted PBX GOL-42 of 90% solid content with HTPB/IPDI binder was manufactured by introducing desensitizers and process agents and was optimized by three-grade grain-size distribution. The GOL-42 explosive showed good processing and safety properties. The detonation property, low vulnerability, mechanical property, thermal property and accelerated storage property were measured by their corresponding standard test methods. The results showed that its measured density, detonation velocity, detonation pressure, Gurney coefficient of Φ25 mm cylinder test was 1.782 g·cm-3, 8251 m·s-1, 26.9 GPa, 2.76 mm·μs-1, respectively. And in the low vulnerability examinations, including bullet impact test, slow cook-off test and fast cook-off test, all the reaction grades were combustion. Its estimated storage life was over 20 years. GOL-42 showed perfect overall properties and was predicted as a long-life low vulnerability cast explosive.

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    • WANG Qing-chen, XIA Yang-feng, LIU Long, ZHANG Yan-qiang, CHEN Lei, YANG Wen-fang

      Online:April 13, 2021  DOI: 10.11943/CJEM2020287

      Abstract:In order to obtain high energy density liquid propellant fuels and increase the payload of the launch vehicle, 20 different methyl-substituted bicyclobutyl derivatives were designed, and the influence of the structure of bicyclobutyl derivatives on performance was studied through theoretical calculations. Results show that with the increasing number of methyl substituents, the heat of formation and specific impulse of bicyclobutyl derivatives show a decreasing trend. When the substituent is para-substituted, its molecular stability is the best, and the heat of formation and specific impulse are larger, while the ortho-position substitution has a weakening effect on the heat of formation and specific impulse of bicyclobutyl derivatives. Among the designed compounds, the specific impulse of bicyclobutyl is the highest. When the mixing ratio of bicyclobutyl and liquid oxygen is 28.5∶71.5, the specific impulse can reach 304.52 s, and the main combustion products are CO(34.64%), CO2(13.89%) and H2O (29.54%). The comprehensive performance of all designed products is better than that of rocket kerosene. This study provides theoretical support for the design and synthesis of high-energy fuels.

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    • GENG Ting-jing, QIANG Hong-fu, WANG Zhe-jun, WANG Xue-ren, YUE Chun-Guo, WANG Jia-xiang, ZHOU Cheng-zhe

      Online:April 13, 2021  DOI: 10.11943/CJEM2020324

      Abstract:To study the biaxial compressive mechanical properties of solid propellantn, it is necessary to determine the optimal propellant specimen configuration. This configuration should be compatible with the testing machine and test fixture and meetthe requirements of biaxial deformation characteristics. Based on the finite element numerical simulation calculation, the deformation stress contour of the three-component HTPB composite solid propellant specimens with eight different configurations under biaxial compression loading were obtained. Moreover, the optimal propellant specimen configuration was verified by conducting the dynamic biaxial compressive mechanical properties test on the corresponding specimen. Results show that the stress contour of all specimens under small deformation (strain within 10%) is uniform overall. However, the requirement of the plane stress does not meet during deformation of the specimens with an aspect ratio greater than 1. Furthermore, the average value of plane stress, dispersion of plane stress, the whole stress stability factor and the stress concentration factor were selected as the optimizing objective function of the propellant specimen configuration. The contrastive analysis shows that the optimal configuration is a 25 mm cube. Finally, the validity of the above determinated optimal configuration was verified by analyzing the characteristics of stress-strain curves of the propellant specimens obtained under dynamic biaxial compressive loading condition

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    • ZHANG Tian-wei, DAI Shu-lan, LI Man-li, CHEN Chun-lin

      Online:March 16, 2021  DOI: 10.11943/CJEM2020236

      Abstract:In order to investigate the mechanical response process of the porous propellant under impact loading and the effect of geometric parameter changes on the mechanical properties of the particles, ANSYS/LS-DYNA was used to establish the numerical models of seven-hole and nineteen-hole propellants to simulate the force of the particles under impact loading. Then, the models of single-hole propellant, seven-hole and nineteen-hole propellants with aspect ratios of 1∶1 and 2∶1, and lace-shaped seven-hole and nineteen-hole propellants were established to study the influence of the number of holes, aspect ratios and shape on propellant stress. The results show that the particles rebound after being compressed, the stress on the surface in contact with the drop hammer increased gradually from the center to the boundary, and the middle of the particles expanded. The increase of the number of holes will change the continuity of the stress distribution on the end surface due to the stress concentration at the hole. Compared with the single-hole propellant, the duration under stress and the maximum compressive displacement of the seven-hole propellant are increased by 3.39% and 3.76%, respectively, whereas the duration under stress and the maximum compressive displacement of the nineteen-hole propellant are increased by 10.17% and 15.05%, respectively. When the number of holes remains constant and the aspect ratio increases from 1∶1 to 2∶1, the peak stress decreases and the peak compressive displacement increases. The lace-shaped particles were more prone to cause stress concentration in the concave of lace than the cylindrical ones. The study of the stress response process of the propellant and its influencing factors provides fundamental data to study the mechanical properties of the propellant.

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    • WANG Jia-lun, ZHANG Hong-bao, LIU Chun-zhu, LI Hang, MENG Zi-hui, XUE Min

      Online:March 31, 2021  DOI: 10.11943/CJEM2020313

      Abstract:It was proved that the sensitivity, safety and density of explosive compound were extremely affected by its morphology and particle size. The influence factor of hexanitrohexaazaisowurtzitane (CL-20) particle size was studied in the recrystallization process with the ultrasonic-assisted recrystallization method, the anti-solvent method and the optimization of agitator type, respectively . The effects of continuous and intermittent ultrasonic with different ultrasonic frequencies (20-40 kHz) were also investigated in order to obtain the small particle size product. In the recrystallization process with anti-solvent method, ethyl acetate and chloroform were applied as solvent and anti-solvent respectively. The dropping acceleration of chloroform (20, 50, 100 mL·h-1), the ratio chloroform and ethyl acetate (1∶1, 1∶2, 1∶3), the recrystallization time (24, 48, 72 h) and temperature (30, 40, 50 ℃) were optimized by orthogonal experiments. In addition, three types of agitator including four straight-blade open turbine, six straight-blade turbine and double-layer dispersing discs were performed in the CL-20 product morphology study together with their stirring speed effect. It was concluded that the assistance of intermittent ultrasonic could considerably reduce CL-20 crystal size. Particle size of 14 μm CL-20 could be obtained by ultrasonic assistant method while the frequency was controlled at 40 kHz with every 30 minutes vibration after 5 minutes stop. Moreover, L9(34)orthogonal experiments were designed and particle size of 140 μm CL-20 could be achieved when the crystallization time, temperature, the chloroform dropping rate, and the dropping amount was 72 h, 30 ℃, 20 mL·h-1 and 150 mL, respectively. Furthermore, three kinds of agitators were employed in the recrystallization process which obviously effected CL-20 morphology and particle size. A controllable particle size between 40-100 μm CL-20 crystals with spherical shape, a smooth and uniform surface were prepared with the double-layer dispersion disc. Comparing with the four straight blades open turbine type and the six straight blades turbine type agitator, it is proved that the product with desired impact sensitivity and friction sensitivity could be prepared by the double-layer dispersion disc method, which characteristic drop height and the explosion probability were 23.5 cm and 44%, respectively.

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    • BI Zhi-xiong, LI Xue-jiao, WU Yong, WANG Quan, DAI Xuan-de, RONG Kai

      Online:April 09, 2021  DOI: 10.11943/CJEM2021028

      Abstract:In order to improve the utilization rate of explosive energy and reduce the mass of welding explosive, it was proposed to use self-restrained explosive to carry out explosive welding research. T2/Q345 weldability window was obtained through theoretical calculations. T2 copper and Q345 steel were respectively used as the substrate and flyer layers, and honeycomb explosive of two layers was used as welding energy to carry out T2/Q345 explosion welding research. The results show that the T2/Q345 composite plate obtained by honeycomb explosive of two layers with self-restrained capability has good bonding performance. Compared with single-layer explosives with corresponding detonation velocities of 2505 m/s and 3512 m/s, T2/Q345 explosive welding obtained by honeycomb explosive of two layers can save 54.4% and 31.4% explosive by weight, respectively. The honeycomb explosive improves the utilization rate of explosion energy converted into kinetic energy of flyer layer. In addition, with the increase of collision point distance, the interface of the T2/Q345 composite plate changes from flat to wavy.

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    • LIU Xu-wen, HU Yan, YE Ying-hua, SHEN Rui-qi

      Online:March 30, 2021  DOI: 10.11943/CJEM2020196

      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.

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    • SHU Jun-xiang, ZHANG Xu, PEI Hong-bo, ZHENG Xian-xu, LIU Cang-li

      Online:April 12, 2021  DOI: 10.11943/CJEM2020329

      Abstract:To obtain the influence of submillimeter-sized gap or cushion on the behavior of flyer driven by the detonation of a triaminotrinitrobenzene(TATB)-based explosive, the precise detonation tests with submillimeter-sized gap or cushion were designed. The velocity histories of flyer driven by the triaminotrinitrobenzene(TATB)-based explosive and influenced by the submillimeter-sized gap or cushion were recorded by a laser interferometer (photon Doppler velocimeter). The results show that the jump-up velocity of the flyer with the influence of submillimeter-sized cushion is lower than the case of flyer attached to explosive, but the final velocity is higher (around 20 m·s-1 or 1% of the final velocity). While the influence of submillimeter-sized gap is greater than that of submillimeter-sized cushion that, the final velocity is 50 m·s-1 (2%) higher than the case of flyer attached to explosive. Simultaneously conducted numerical simulations show that both the point and line initiation conditions do affect the velocity history of the flyer, and the final velocity increases with the influence of submillimeter-sized gap and with either initiation condition. The theory analysis indicates that the introduction of submillimeter-sized gap between flyer and explosive results in weaker interaction between detonation products and flyer for the isentropic expansion of detonation products, and then leads to less entropy increasement of the system, higher energy for driving the flyer, and higher final velocity of the flyer. Additionally, different gap sizes result in different influences as the dominant mechanism varies.

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    • HU Hong-Wei, WANG Jian, FENG Hai-yun, LI Dao-kui, GUO Hong-wei

      Online:April 12, 2021  DOI: 10.11943/CJEM2021026

      Abstract:To investigate the coupling effect and propagation law of shock wave for underwater array explosion with multiple charges. The shock wave parameters of group charge, two charges and four charges were measured by underwater explosion test. The influence of charge quantity and array distance on peak pressure, impulse and loading time of shock waves were analyzed and revealed. the relationship beween array explosion shock wave and distances. The results showed that the shock wave (symmetrical center line) can be superimposed in the focusing direction for two-charge explosion. The shock wave pressure intensity increased by 22.8%-55.4% in the scale distance of 2-6 m·kg-1/3, and the gain increased gradually with the increase of propagation distance. For four-charge array explosion, the peak pressure of the shock wave in the focusing direction was close to that of group charge. For the same explosion points and layout of the array explosion, the impulse and shock wave loading time can be improved by increasing the array distance. The loading time of shock wave pressure increased with the increase of charge quantity and array distance. For two-charge and four-charge explosion, the peak pressure and impulse of multiple shock waves were still consistent with explosion similarity law, but the loading time of shock wave pressure was not.

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    • DUAN Ying-liang, HAN Yong, RAN Jian-long, TAN Kai-yuan, ZAN Ji-chao, JIA Lu-chuan

      Online:April 09, 2021  DOI: 10.11943/CJEM2021009

      Abstract:In order to precisely validate the parameters of detonation reaction rate model of explosives, a HMX/TATB based explosive PBX-1 was the research subject, and the mushroom test was conducted to study the corner-turning performance of explosives with various detonation propagation diameters. Then the mushroom test was simulated by LS-DYNA program with the three-term ignition and growth model calibrated by Lagrangian gauges measurements. The accuracy in calibrated parameters of the reaction rate model was validated by observing the growth and propagation of detonation waves and by comparing the corner-turning parameters. The comparison between experiments and numerical simulations shows that, the mushroom test can reflect the discrepancy of detonation growths of detonation waves in different directions. Finally, it was proved that the parameter validation of the reaction rate model of explosives is feasible by Mushroom test..

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    • WANG Ning, SU Jing, GUAN Hong-bo, CHENG Jie, CHENG Li-guo, LI Jun

      Online:April 09, 2021  DOI: 10.11943/CJEM2021021

      Abstract:In order to analyze the mechanism of shock sensitivity of CL-20/HMX cocrystal close to that of HMX, ReaxFF molecular dynamics simulation was used to investigate the mechanical-thermal structural changes and subsequent initial chemical reactions in CL-20/HMX cocrystals with or without voids. The structural deformation and subsequent chemical reaction process are effectively analyzed by using the momentum mirror model combined with shock-front absorbing boundary condition. When shocks subjected to CL-20, HMX, and CL-20/HMX, it is found that the response speed of CL-20 is faster than that of HMX, while CL-20/HMX"s response speed is very close to HMX"s. Besides, the response speed of CL-20/HMX [100] shocks is faster than [111] shocks. This phenomenon is related to alternative arrangement of CL-20 and HMX molecular layers and the relative slip amount. When CL-20/HMX with 20 nm diameter void is shocked along the [100] direction at particle velocity of 2 km·s-1, hydrodynamic jet collapse does not occur instead of viscoplastic pore collapse. It largely promotes the rapid decomposition of CL-20 and HMX molecules in the high temperature and high pressure conditions formed by pore collapse and the viscoplastic deformation of crystal structure. A new hot spot formation from the void collapse further enhances the shock loading process.

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    • WANG Shu-you, NAN Yu-xiang, JIANG Jian-wei, HAN Wei, TAN Jie, CHEN Dong-ping

      Online:April 08, 2021  DOI: 10.11943/CJEM2020301

      Abstract:A pair of pressed combined CL-20-based and JO-8(HMX-based)explosives are selected to investigate the improvements in the explosion driving performance by using more powerful explosive. This paper presents the test results of detonation velocity, detonation pressure and Gurney coefficient from devices loaded by CL-20-based explosive and JO-8, respectively. Enhanced warhead performance has been demonstrated in static experiments of prefabricated fragment warhead and shaped charge. The results show that the fragment velocity (kinetic energy) driven by CL-20-based explosive is 5.1%-7.3% (10.5%-15.1%) higher than that driven by JO-8. The penetration of shaped charge loaded by CL-20-based explosive is 3.3%-12.6% larger than that loaded by JO-8.

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    • YANG Kai-di, ZHANG Jia-rong, XUE Qi, HUO Huan, BI Fu-qiang, WANG Bo-zhou

      Online:April 08, 2021  DOI: 10.11943/CJEM2021049

      Abstract:Using nitromethane, tere-butylamine and formaldehyde as raw materials, a novel melt-casting explosive 5-methylnitrate-1,5-dinitrooxazine (TNOP) was synthesized via condensation and nitration reactions with the total yield of 46.2%. FT-IR, 1H NMR, 13C NMR, elemental analysis and single-crystal measurement were conducted to obtain the structure of TNOP, disclosing an orthorhombic crystal structure with a space group of Pbca and the density of 1.722 g·cm-3. The melting point and thermal decomposition temperature were examined to 105.34 ℃ and 202.43 ℃ using DSC technique, respectively. Furthermore, the detonation velocity and the detonation pressure are predicted to be 8112 m·s-1 and 29.23 GPa based on calculated enthalpy of solid phase formation (-346.6 kJ·mol-1). In addition, an impact sensitivity of 50 J could be obtained for TNOP. By coordinating the energetic groups N—NO2, C—NO2 and —ONO2 and facile synthesis process, TNOP was revealed with high energy, low melting point and low sensitivity, implying the promising application in molt-casting explosive in weapons and equipment.

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    • LI Bing-bo, LUO Yi-ming, LEI Wei, ZHANG Meng-meng, WANG Wei

      Online:April 08, 2021  DOI: 10.11943/CJEM2021039

      Abstract:In order to get the phase diagrams of 3,4-dinitropyrazole (DNP)/3,4-bis(3-nitrofurazan-4-yl) furoxan (DNTF) binary mixture system and understand the eutectic melting process, DSC was used to investigate the liquefaction and melting process of DNP/DNTF mixed system with different proportions. The T-x phase diagram and H-x phase diagram were established, and the effects of different heating rates and additives on melting process of eutectic were studied. Finally, the kinetic parameters Ea and A of eutectic melting process were calculated by Kissinger equation and Šatava-Šestak equation. Results show that the mass percentage of DNP/ DNTF eutectic is 70.38/29.62 and the eutectic temperature is 76.38 ℃ based on T-x phase diagram, which is good consistent with that from H-x phase diagram as 70.57/29.43. With the increase of heating rate, the initial temperature and peak temperature of melting process are delayed correspondingly. After the addition of Octogen (HMX) and nitroguanidine (NQ), the melting point of the low eutectic is significantly delayed, while ammonium perchlorate (AP) has little effect on the melting point. The melting kinetic parameters Ea and LgA of DNP/DNTF eutectic are 19.13 kJ·mol-1 and 9.74 s-1 respectively, and the integral form of the most probable mechanism function is: Gα)=(1-α-1-1.

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    • HU Jing-wei, GAN Qiang, FENG Chang-gen, LI Chang-lin, ZHU Shuang-fei, CHENG Nian-shou

      Online:April 07, 2021  DOI: 10.11943/CJEM2020245

      Abstract:To study the influence of crystal defects on the initial reaction of hexanitrohexaazaisowurtzitane (CL-20), molecular dynamic simulation and ReaxFF-lg reactive force field are used to study the initial reaction path, thermal decomposition products, and reaction kinetics of CL-20 with vacancy defects at high temperatures of 1500-3500 K. The results show that the initial decomposition path of CL-20 with vacancy is the breaking of N─NO2 bond, the same as that of perfect crystal. The vacancy defects are proved to increase the frequency of ring-opening reactions and the production of NO2. Compared with perfect CL-20, it can be seen that the vacancy defects would reduce the CL-20 activation energy barrier and accelerate its thermal decomposition process. The reaction rate constants of CL-20 with 16.7% vacancies are 1.7 and 1.4 times higher than that of perfect CL-20 at 2000 K and 3000 K, respectively. The CL-20 molecules around the vacancy are easier to be decomposed, leading to the increase of the sensitivity of CL-20.

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    • WANG Jing, GAO Pin, WANG Gui-xiang, GONG Xue-dong

      Online:April 07, 2021  DOI: 10.11943/CJEM2020277

      Abstract:The study of polynitrogen pentazolate salts, which are usually achieved from the precursors of N5 covalent compounds, is the hotspot of research in the field of new energetic materials. In most cases, the stability of N5 covalent compounds will significantly affect the possibility of successful preparations of pentazolate salts. Herein, the calculations of dissociation energy (EBD) of the bonds in the straight side chain and activation energy (Ea) of the N5 ring were carried out for the selected eighteen non-aryl substituted N5 compounds (R—N5 or N5—R—N5) by using the B3LYP/6-31G** method of density functional theory, meanwhile, the influence of the side chain on their stabilities and pyrolysis mechanism were investigated. When R is the hydroxyl or amino group, the side chain and the N5 ring are more prone to break, making it difficult to obtain the N5- ring. When R is alkyl, the Ea of the N5 ring cleavage is relatively larger, making it more likely to produce the N5- ring, and the stability of the side chain’s C—N bond as well as the N5 ring will be little affected by the length of the alkyl chain. The sequential cleavage of two N5 rings occurs in the bicyclic molecular structures and the energy barrier of the second ring is higher than that of the first one, resulting in the formation of N2 and azide. The C—C bond on the side chain of the molecule will be broken before the break of C—N bond, which may significantly reduce the EBD of the C—N bond but have little effect on the Ea of the N5 ring. Therefore, for the preparations of pentazolate salts from covalent pentazoles, cutting off the C—C bond first may be more conducive to obtaining N5- ring.

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    • YAN Zheng-feng, WANG Ying-lei, LU Ting-ting, ZHAO Bao-dong, CHEN Bin, GE Zhong-xue

      Online:March 03, 2021  DOI: 10.11943/CJEM2020063

      Abstract:To study the synthetic mechanism and properties of 3,7-dinitro-[1,2,4]triazolo[5,1-c][1,2,4]triazine-4-amine (TTX),the synthetic mechanism of TTX was studied by density functional theory (DFT), and the influence of pH value on the cyclization reaction was investigated. Thermal properties and impact sensitivity were studied by differential scanning calorimetry (DSC) and BAM drophammer apparatus, respectively. TTX was synthesized by the coupling reaction of sodium cyanonitromethanide and azo salt of 5-amino-3-nitro-1,2,4-triazole (ANTA), followed by intramolecular cyclization reaction. TTX showed a decomposition temperature of 281.8 ℃ and a apparent activation energy of 356.7 kJ·mol-1. The impact sensitivity of TTX was measured to be 60 J. Moreover, the compatibilities of TTX with HMX, RDX, Al powder and NC was studied. TTX had a good compatibility with Al powder, but a fair compatibility with HMX and a poor compatibility with RDX and NC. Therefore, adding RDX or NC into TTK would apparently increase its sensitity.

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    • ZHAO Xiang-run, YAN Nan, GUO Chong-xing, DAI Wu-si, HUANG Jin-hong, FU Shao-bin

      Online:March 26, 2021  DOI: 10.11943/CJEM2020141

      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.

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    • GUO Wei, CAO Wei, TAN Kai-yuan, DUAN Ying-liang, SONG Qing-guan, HAN Yong

      Online:March 22, 2021  DOI: 10.11943/CJEM2021002

      Abstract:To study the influence of RDX-based metallized explosive components on detonation process,the detonation reaction zone parameters of RDX-based metallized explosives were studied by the interface particle velocity history using photonic Doppler velocimetry (PDV). Two kinds of RDX-based metallized explosives were granulated, one composition incorporates aluminum (RDX/AP/Al), and the other incorporates hydrogen storage alloy (RDX/AP/Al/B/MgH2). The metallized explosives were initiated by detonation wave, and the detonation reaction zone parameters were analyzed and compared with those of phlegmatized RDX. The results show that the addition of AP/Al component reduced the CJ detonation pressure of phlegmatized RDX from 25.8 GPa to 20.1 GPa. In addition, the detonation reaction zone time (53.6 ns) and length (0.29 mm) of metallized explosives were both higher than those of phlegmatized RDX (24.3 ns, 0.15 mm). The addition of B/MgH2 further increased the detonation reaction time (58.0 ns) and length (0.30 mm) of the explosive. The addition of high-energy metal fuel reduced the output pressure of explosives, but increased the detonation reaction zone time and length of explosives.

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    • WANG Hui-si, TAO Bo-wen, ZHANG Xiao-ping, GU Jian, LI Lei, DU Fang, HUANG Dan-Chun, CHENG Hong, LI Wei

      Online:March 31, 2021  DOI: 10.11943/CJEM2020247

      Abstract:In order to improve the combustion efficiency of Al powder, Al/modified fluororubber composite fuel(FKM-GW@Al) was prepared with the self-made silane modified fluororubber(FKM-GW) using the sol-gel method. The stability of FKM-GW@Al in solvent was studied, and the results show it is difficult to peel off the FKM-GW with functional groups, while the FKM-GW@Al has strong stability in ethyl acetate. The application of FKM-GW@Al in NEPE high-energy and low burning rate solid propellant formula was studied. Results show that after replacing Al powder by FKM-GW@Al (fluorine mass fraction 2.58%), the heat of explosion of the propellant increased from 6348.8 J·g-1 to 6831.6 J·g-1, the content of activated aluminum in residuesdecreased from 1.02% to 0.06%, and both the static and dynamic burning rates of the propellant containing FKM-GW@Al decreased. The thermal decomposition properties of FKM-GW@Al and the propellant containing FKM-GW@Al were studied by DSC-TG, and the influence mechanism of FKM-GW@Al on combustion characteristics of the propellant was analyzed.

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    • PAN Peng-yang, WANG Ke-xin, YI Zhen-xin, ZHANG Lin, ZHU Shun-guan

      Online:March 31, 2021  DOI: 10.11943/CJEM2020264

      Abstract:As the most commonly used primary explosive, 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, furoxan, fused-ring, coordination compound, copper azido, and nano-thermite. Among of these initiating agents: (1) tetrazoles have excellent detonation performance but low safety performance; (2) furoxans 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 azido 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.

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    • WANG Wei, XIAO Jun, RAN Zhen, Zheng Xiao-tao, FU Bo

      Online:March 30, 2021  DOI: 10.11943/CJEM2021023

      Abstract:In order to further improve the compactness of energetic powder materials, an ultrasonic-assisted isostatic pressing method is proposed, and an experimental prototype is designed and produced. The simulation software COMSOL is used to analyze the sound field of a single ultrasonic vibrator and the whole isostatic ultrasonic assisted molding system, and the influence of the cover thickness, 10 MPa pre-pressure and ultrasonic power voltage amplitude on the sound field distribution is studied. The simulation results show the rationality and feasibility of the ultrasonic-assisted isostatic pressing. The press molding experiments of polymer-bonded explosive(PBX) simulants are carried out whether to consider ultrasonic-assisted and 10 MPa pre-pressure conditions. The computed tomography(CT) and scanning electron microscope(SEM) are used to test and analyze the samples. The results show that the internal uniformity and compactness of the materials with ultrasonic-assisted and 10 MPa pre-pressure are better than those materials without, and their internal grains are finer and the grain distribution is more uniform.

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    • ZHOU Meng-lei, NAN Feng-qiang, HE Wei-dong, WANG Mo-ru

      Online:March 30, 2021  DOI: 10.11943/CJEM2020202

      Abstract:With extrusion deposition technology as the core, based on the features of high viscosity and no-resistant to high temperature for propellant, the extrusion deposition rapid prototyping system for propellant was designed and a complete prototype was built. Using a certain ZY propellant as raw material, different materials with concentrations of 27.3%, 33.3%, 38.5%, 42.9%, 46.7% and 50% were prepared. Through 3D printing extrusion experiments, it is found that there is a polynomial function relationship between the inner diameter of the needle and the material concentration. The filling speed range is 2~4 mm·s-1, the filling rate range is 70%~90%, and the temperature range of the bottom plate is 25~45 ℃. On this basis, the propellant 3D printer was used to print the propellant, and the compression test was carried out. The results showed that the compression strength of the propellant could reach up to 230 MPa.

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    • ZHU Ying-zhi, YANG Feng, XU Yuan-gang, ZHOU Xin-li, LU Ming

      Online:March 02, 2021  DOI: 10.11943/CJEM2020304

      Abstract:A new high-energy compound 3,4-bis((4-chloro-3,5-dinitro-1H-pyrazol-1-yl)methyl)-furoxan was synthesized by using 4-chloropyrazole as raw material, and its single crystal was obtained by solvent evaporation. The structures of this compound and its intermediates were characterized by 1H and 13C NMR, FT-IR, DSC and TG, and the crystal structure of the product was characterized by X-ray single crystal diffraction. Results show that the compound belongs to the orthorhombic space group Pbca, a=10.1817(7) ?, b=16.1917(11) ?, c=21.7300(16) ?, V=3582.4(4) ?3α=90°, β=90°, γ=90°, Z=8, Dc=1.836 g·cm-1. The Kamlet-Jacobs semi-empirical equation was used to predict the explosion velocity of 8304 m·s-1 and the explosion pressure of 30.5 GPa. The sensitivities of this compoundwere measured by the BAM standard method, and the measured impact sensitivity is 9 J and the friction sensitivity is 180 N.

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    • LI Jing, JIN Shao-hua, LAN Guan-chao, CHAO Hui, LU Zhi-yan, CHEN Shu-sen, LI Li-jie

      Online:March 22, 2021  DOI: 10.11943/CJEM2020310

      Abstract:The HNIW/FOX-7-based PBX has been aged 7, 14, 21 d and 28 d at 71 ℃ according to GJB736.8-90 initiators and pyrotechnics test method, respectively. And the morphology and thermal decomposition properties of PBX molding powder before and after aging were characterized. The PBX molding powder was tested by FTIR and XRD. The variation rules of size, mass and mechanical properties of the PBX columns have been measured before and after aging tests. Results show that the mass and size change rate are both within 1%, which meets the evaluation standard of MIL-STD-1751, indicating that PBX columns are still at an acceptable level after aging tests. The surface morphology of PBX molding powders has changed in varying degrees. There are more surface cracks and the surface morphology are more uneven with the increase of the aging time. Moreover, FTIR and XRD results indicate that the molecular structure and crystal form of HNIW/FOX-based PBX have not changed after aging tests. Besides, the analyses of thermal decomposition performance show that the thermal decomposition activation energy of PBX molding powders have decreased after aging tests with the decreases of -5.23%, -5.88%, -7.00% and -8.23%, respectively, which demonstrates that PBX still has good thermal stability after aging tests. The results of mechanical properties show that the compressive strength of HNIW/FOX-7-based PBX increases by 3.18, 3.40, 3.67 MPa and 3.79 MPa, respectively, and the modulus increases by 0.65, 0.79, 0.91 GPa and 0.96 GPa respectively after aging for 7, 14, 21 d and 28 d. Therefore, the change rate of compressive strength and elastic modulus of PBX columns are positively correlated with the aging time, indicating that the compressive strength of PBX columns increases after aging test.

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    • HANG Gui-yun, YU Wen-li, WANG Tao, WANG Jin-tao, SHEN Hui-ming

      Online:March 23, 2021  DOI: 10.11943/CJEM2020322

      Abstract:Cocrystal is composed of different neutral components through intermolecular non-bond interactions at molecular level and it has fixed ratio and particular structure. Cocrystallization technology is a novel method for ameliorating properties of energetic materials and it has wide development prospect and application value. It can decrease the sensitivity, improve the mechanical properties, thermal performance, and energy density of energetic materials. The research progress of preparation and application of energetic cocrystals was summarized, including the current research status, preparation method, characterization methods, and formation mechanism. The existing problems of energetic cocrystals were introduced: first, the properties of some cocrystal explosives need to be further improved; second, the preparation of cocrystal requires harsh conditions with low product yield; third, the characterization and test methods lack variety. The further development direction of cocrystal explosives were pointed out: strengthen the research of multiple components energetic cocrystals, improve the technologies to increase the yield, investigate the crystallization dynamics behavior to seek for the best cocrystallization conditions, and look for effective means to characterize the cocrystal structure.

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    • WU Hao, DUAN Zhuo-ping, BAI Meng-jing, HUANG Feng-lei

      Online:March 12, 2021  DOI: 10.11943/CJEM2020298

      Abstract:To study the thermal response of two new DNAN-based aluminized explosives RB-2X(DNAN/HMX/Al/binder) and RM-2X(DNAN/HMX/NTO/Al/binder), small-scale cook-off experiments and simulations of RB-2X at a heating rate of 1.0 K·min-1 and RB-2X at heating rates of 1.0 K·min-1 and 0.5 K·min-1 were conducted. The numerical simulation used multi-component grid cell calculation method and considered the air gap formed by cooling and contraction of fused cast explosive. The thermal response of explosives were analyzed. The comparisons of ignition time between simulation and experiment show that the ignition time deviation of RB-2X explosive is 1.13%, and the maximum deviation of RM-2X explosive is 5.63%. The influence of the air gap between the explosive and the inner wall of the bomb on ignition time was also analyzed. The results show that the delay time increases gradually with the increase of gap width, and when the air gap expands to 0.75 mm, the delay time is stable at 90 s, indicating that the air gap has a significant influence on the explosive ignition time. The thermal response of large-scale cook-off bomb with RM-2X explosive was predicted. The results show that the temperature at center point can be significantly reduced at ignition by increasing of ammunition size and heating rate. The state of DNAN changes from total melting to solid-liquid coexistence.

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    • LI Ke-jia, TANG Yong-xing, HUANG Wei

      Online:March 03, 2021  DOI: 10.11943/CJEM2020321

      Abstract:Planar heteroaromatic compounds containing amino and nitro functional groups usually have excellent detonation performances. Hereby, the -NH- bond bridging two high-nitrogen fused rings was adopted aiming at constructing a nitrogen-rich energetic compound with a planar structure. The resulting compound is expected to have a regular packing in crystal and favorable detonation performance and stabilities. Reaction of 2,6-diamino-3,5-dinitropyrazine (2) with K2CO3 gives rise to 6-(2,6-diamino-3,5-dinitropyrazine)-1,2,4-triazole[4,3-b][1,2,4,5]tetrazine (3) in a high yield of 81.3%. Compound 3 was characterized by NMR, IR, single crystal X-ray diffraction. The thermal decomposition process of 3 was studied by differential scanning calorimetry (DSC), and its decomposition temperature (onset) is as high as 254.6 ℃. The detonation performances of 3D=7568 m·s-1P=23.5 GPa) were calculated by Gaussian 09 and Explo5 software.

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    • ZHU Guo-hao, YE Bao-yun, AN Chong-wei, KONG Sheng, WANG Jing-yu

      Online:March 02, 2021  DOI: 10.11943/CJEM2020314

      Abstract:In order to improve the efficiency of charging and molding of the explosive network, as well as the energy performance, high-energy azide binder 3,3-diazide methyl oxetane-tetrahydrofuran copolymer (PBT), ultraviolet (UV) curing acrylate and hexanitrohexaazaisowurtzitane (CL-20) were selected as bonding system and main explosive respectively, an ultraviolet assisted curing CL-20-based energetic ink was designed, and using a 3D printing device to write. Rheometer, scanning electron microscope (SEM), X-ray diffractometer (XRD), Shore durometer were employed to characterize and test the rheological properties, microstructure, crystal form and hardness of the molded composite. Results show that the ink system is stable when the content of CL-20 is 82%. The curing efficiency of ink is fast with UV assisted, and the surface of molded sample is smooth. The hardness is 70 HA, the impact sensitivity test shows that the special height of the composite is 20 cm higher than the raw material; the test of detonation performance shows that the detonation wave can transfer 90° corner, and the critical detonation size reaches 0.387 mm when the line width of charge is 1.2 mm.

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    • ZHANG Pan, YANG Feng, LU Ming

      Online:February 08, 2021  DOI: 10.11943/CJEM2020289

      Abstract:Using 4,5-dicyano-2-aminoimidazole as the raw material, 4,5-Bis-(chloro-dinitro-methyl)-2-diazoimidazole is produced through three-step reaction of oximation, chlorination, diazotization and nitration. X-ray single crystal diffraction analysis, Fourier transform infrared spectroscopy (FT-IR), nuclear magnetic resonance spectroscopy (1H NMR, 13C NMR) were used to characterize its structure; Study its thermal performance by differential scanning calorimeter and thermogravimetric analyzer; Use Gaussian09 and EXPLO5 v6.01 to optimize its structure and estimate its performance. The results show that the crystal of 4,5-Bis-(chloro-dinitro-methyl)-2-diazoimidazole belongs to the triclinic system and belongs to the P1 space group. The unit cell parameters are a =6.6196 (10) ?, b=8.1685(13) ?, c =13.0272(19) ?, V=666.96(18) ?, α=100.166(4)°,β=102.560(4)°,γ=97.153(5)°,Z=2, F(000)=368; Dc=1.848 g·cm-3. Its thermal decomposition temperature is 122.14℃.The theoretical detonation velocity is 8574 m·s-1, and the theoretical detonation pressure is 32.8GPa. Test the sensitivity according to the BAM standard method, the impact sensitivity is 4J, and the friction sensitivity is 100N.

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    • ZHANG Meng-meng, LUO Yi-ming, LI Bing-bo, FANG Xue-qian, YANG Hui

      Online:January 20, 2021  DOI: 10.11943/CJEM2020076

      Abstract:To research the influence of the additives such as RDX, Al, AP and polymer PBNMO on the moulding and mechanical characteristics of DNAN, the crystallization process of different intermixtures and the initial solidification temperature were observed mainly by photic microscope. The solidification rate was calculated by measuring the solidification time and the distance change. The effects of additives on the molding process were studied by testing the relative density of the Φ20 mm samples. The effects of additives on the mechanical properties were studied by testing the tensile strength and the compressive strength. Results show that those additives could improve the crystallization process, increase the relative density and decrease the solidification rate of DNAN. The mechanical properties such as the tensile strength,compressive strength and the anisotropy of the DNAN were improved by adding polymer PBNMO. The tensile strength was over 6MPa. The results showed that DNAN based explosives with fine crystals, less defects and better mechanical properties could be got by the synergistic effects of RDX, Al, AP and PBNMO.

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    • WEN Wen, WANG Shu-juan, DAI Xiao-gan, CHAI Chuan-guo, XIANG Yong, HUANG Qian, WEN Yu-shi, LI Ming

      Online:January 26, 2021  DOI: 10.11943/CJEM2020163

      Abstract:Ammunitions might experience safety threats of high-temperature heating, high-speed fragment impact, and their combined effects in battlefield. In order to investigate the reaction phenomenon of insensitive explosive PBX-C04 under high-speed impact and the effects of high-temperature and booster charge on this reaction phenomenon, the insensitive explosive safety experiments under high-speed fragment impact were carried out, and the influences of high-temperature and insensitive booster charges(HNS) were considered. Based on the air overpressure, witness plate wreckage and chemical-physical analysis of remained explosives on the scene, the explosive reaction levels of PBX-C04 was assessed comprehensively, and the influences of high temperature and booster charge were studied. The results show that PBX-C04 at room temperature exhibits excellent safety characteristic under high-speed fragment impact, it merely reacted to burning when impacted by a fragment with velocity up to 1970 m·s-1. When the booster charges of HNS was included, the reaction levels of PBX-C04 correspondingly deteriorated into deflagration. However, when heated to 200 ℃ before impact test, the high-speed impact safety of PBX-C04 equipped with booster charge deteriorated remarkably into detonation.

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    • LIU Le-hai, BI Feng-rong, YU Yang-yang, ZHANG Jun-hong, MENG Xiang-de, ZHANG Xue-ling

      Online:January 19, 2021  DOI: 10.11943/CJEM2020217

      Abstract:To study the correlation between the packed density of nonmetallic spherical spacers (NSS) and its suppression of propane explosion, a newly designed constant-volume combustion cylinder combined with high-speed schlieren photography was employed. The explosion experiments of propane-oxygen pre-mixtures with different equivalence ratios(1,1.5 and 2) were conducted in cylinders with different packed densities of NSS (21.9 kg·m-3,38.7 kg·m-3 and 45.1 kg·m-3). The effect of packed densities of NSS on maximum explosion pressures, total heat loss, flame tip velocities, flame propagation characteristics and turbulence in cylinders with different equivalence ratios of propane-oxygen were analyzed in detail. The results show that NSS has suppression effect on the maximum explosion pressure, and has promotion effect on the flame propagation process. When the packed density of NSS is 45.1 kg·m-3, the maximum explosion descending rate and heat loss in cylinders reach maxima, while the peak flame tip velocity , the maximum tip velocity difference between two points and the turbulence enhancement factor in cylinders are relatively small, which indicates the best explosion suppression performance of NSS.

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    • ZHENT Teng, LIANG Xiao-lu, ZHENG Jia-chen, ZHAO Xiang-jun, JIA Yu, HU Hong- wei

      Online:January 27, 2021  DOI: 10.11943/CJEM2020147

      Abstract:In order to study the energy release characteristics of Al/Mg/CuO reactive shells, the images of broken process of reactive shells were observed by an ultra-highspeed rotating-mirror camera, and the shock wave overpressures of varying-sized test bombs were measured by shock wave test system. The reaction time of reactive shell under explosion loads and the effects of particle sizes of reactive materials on shock wave overpressures were analyzed, then the variation of shock wave overpressures with scaled distances was obtained. The results show that reactive shells could take part in explosive reaction and release energy in a few microseconds after detonation reaction. The shock wave overpressures are enhanced and the fireball duration increases more than one time within a scaled distance of 2.52-3.15 m?kg-1/3.The overpressure of reactive shell with particle size of 7 μm is 13.3%-14.4% higher than that of reactive shell with particle size of 20 μm,which indicates that reactive materials with smaller particle size can take part in explosive reaction more easily. Compared to bare charges and aluminum shells, the overpressures and impulses of reactive shells rise significantly, increasing 6%-32% and 13%-38% respectively within scaled distances of 2.1-8.4 m?kg-1/3.

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    • ZHANG Jing-yu, MA Zhong-liang, BAI Chang-sheng, ZHANG Shi-lin, YAO Shun-long, CHEN Chun-lin

      Online:January 27, 2021  DOI: 10.11943/CJEM2020208

      Abstract:The accommodation of liquid propellant in current-used weapons and equipment makes it important for expanding its application field in various existing weapon systems in the form of general solid propellant. In the current paper, a nitrocellulose-based energetic hollow spherical shell that can be used to encapsulate the liquid propellant is designed. The preparation method is based on the spherical propellant prepared by the internal solution method and on the principle of double emulsification, using W/O type Pickering emulsifier active calcium phosphate and O/W type emulsifier sodium carboxymethyl cellulose to make the emulsion containing nitrocellulose emulsify into a monodisperse W/O/W type emulsion, then evaporate the solvent to obtain the shell. The feasibility of activated calcium phosphate on the W/O type emulsifier has been examined through triple contact angle technique using a contact angle meter. Besides, the basic morphology and particle size, as well as packing density have been characterized using a ultra-depth-of-field electron microscopy system and mass-volume method, respectively. Results show that the three-phase contact angle of activated calcium phosphate is 121.80°. The shell has a large cavity structure with a particle size of 0.7-1.1 mm and a bulk density of 0.1-0.2 g·mL-1. The microstructure demonstrated a majority of white fiber structure. In addition, embedded white particles in the fiber could also been observed. The optimized ratio of sodium carboxymethyl cellulose to active calcium phosphate, and active calcium phosphate to nitrocellulose should be 1∶1~1.25∶1 and 0.16∶1~0.24∶1, respectively.

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    • BA Shu-hong

      Online:January 27, 2021  DOI: 10.11943/CJEM2020279

      Abstract:Metal oxide is a type of ionic compound in which metal cations and oxygen anions are arranged into different crystal structures through ionic bonding. The d-shells of some metal oxides are not completely filled wtih various unique properties, such as wide band gap, high dielectric constant, active electron transfer ability and excellent conductivity, etc. So they are widely used in the catalytic field. The current research status of thermal decomposition of ammonium perchlorate catalyzed by four different types of metal oxide semiconductor materials, such as single metal oxide, composite metal oxide, doped metal oxide, and supported metal oxidewere introduced, the catalytic mechanism and factors affecting the catalytic effect are discussed. For the P-type metal oxide semiconductor materials, the narrower the band gap , the lower the Fermi energy level, the higher the escape energy, and the greater the catalytic effect. For the N-type metal oxide semiconductor materials, the wider the band gap, the higher the Fermi energy level, the lower the escape energy, and the better the catalytic effect. In order to make full use of the advantages and overcome the defects of metal oxides, impurity elements are often introduced into metal oxides to form ionic lattice defects and create new local impurity energy levels to change the electronic transition, so as to improve the catalytic performance of metal oxides. Whether composite metal oxide or supported metal oxide, there is a positive synergistic catalytic effect on AP. The development of porous nanotube P-type metal oxides, doped metal oxides, and supported metal oxide materials with small band gap is still a major concern. Exploring the core-shell composite materials based on ammonium perchlorate, P-N junction metal oxide semiconductor catalytic materials, and revealing the migration law of carriers between the two kinds of semiconductors P-N interface are expected to be a new way to improve the catalytic efficiency.

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    • FEI Teng, LAI Qi, ZHANG Wen-jin, SUN Cheng-hui, PANG Si-ping

      Online:January 22, 2021  DOI: 10.11943/CJEM2020302

      Abstract:As a typical representative of third generation energetic materials, 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane (CL-20) is currently the most powerful energetic compound that has already been commercially available. It is expected to make up for the deficiency of damage ability of second generation energetic materials, which has great application prospect in novel weapon equipment. As two of the important research directions, the optimum synthesis of CL-20 and the preparation of CL-20-based high energy and low sensitivity energetic compounds in the development of energetic materials. The development status of the intermediates in the preparation of CL-20 was analyzed and summarized. The solutions and prospects of the intermediates were also proposed. In addition, the research progress, structural characteristics and main properties of CL-20 crystal products were also discussed. Through sorting out the synthesis and crystals of CL-20, it is concluded that low-cost, high yield, high purity and environmental friendliness are the future development direction of the synthesis process of CL-20. Moreover, performance modification of CL-20 is also conducive to expanding the application direction of CL-20.

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    • ZHANG Jun, WU Jia-xiang, REN Xin-xin, YAO Miao, WU Shuang-zhang, HUANG Jun-yi, LI Yu-chun

      Online:January 22, 2021  DOI: 10.11943/CJEM2020197

      Abstract:In order to study the influences of ZrH2 onto mechanical properties and damage performances of Al/PTFE, both cylinder and liner specimens of Al/ZrH2/PTFE, Al/PTFE and pure PTFE were prepared by cold-pressing sintering process. The mechanical properties, impact sensitivity and damage efficiency of the three materials were contrastively studied by the tests of quasi-static compression, drop-weight impact and high-speed target impact. The experimental results showed that all three kinds of PTFE-based materials exhibited elastic-plastic mechanical behaviors and strain hardening effects. Adding a mass fraction of 10% of ZrH2 into Al/PTFE reactive material improved its yield strength and failure stress to 22.2 MPa and 93.3 MPa, respectively, increased its ignition excitation energy by 1.93 J, and participated in the reaction through activation and decomposition to ensure that its energy release level was not weakened. The two kinds of energetic liners can produce collision energy release reaction and perforation/pore enlargement sympathetic effects during its impacting process, and formed the perforation pattern of petal valgus. Compared with inert damage element, the reactive material greatly improved its hole-enlargement ability by the impact-reaction double damage effect. The introduction of ZrH2 into Al/PTFE reactive material can further enhance the damage efficiency of the material.

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    • ZHAO Xiang-run, YAN Nan, GUO Chong-xing, DAI Wu-si, YAN Li-wei, JIN Shi-xin

      Online:December 11, 2020  DOI: 10.11943/CJEM2020129

      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.

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    • LI Chang-lin, GAN Qiang, FENG Chang-gen, HU Jing-wei, ZHU Shuang-fei, CHENG Nian-shou

      Online:December 15, 2020  DOI: 10.11943/CJEM2020157

      Abstract:In order to analyze high temperature phase transformation of hexanitrohexaazaisowurtzitane (CL-20), phase transformation temperatures and coefficients of thermal expansion of ε-、β- and γ-CL-20 were studied via ReaxFF-lg reactive force field molecular dynamics, with modified valence potential intercept. To validate the applicability of selected force field,the density, cell constant, lattice energy, and sublimation enthalpy of three types of CL-20 at room temperature were calculated. The third order Birch-Murnaghan equation of state was used to fit the p-V curve of ε-CL-20, with pressure ranging from 0 to 280 GPa. And the variation of bulk modulus (B0) and its partial derivative to pressure (B0) with the increase of pressure is analyzed. High temperature phase transformation analysis shows that ε-and γ-CL-20 change phases at 398-423 K, of which the ε→γ phase transition occurs at atmospheric pressure, while the γ→ε phase transition needs 0.5 GPa or higher pressure; β-CL-20 transforms to ε crystal form at 448 K. The thermal expansion coefficient analysis shows that there is no obvious anisotropy in the high temperature thermal expansion process of ε-CL-20, while β- and γ-CL-20 show anisotropy in c direction and b direction, respectively. Results show that the modified ReaxFF-lg reactive force field is suitable for the study of phase transition of ε- β- and γ-CL-20 at high temperature and high pressure, while the accuracy of thermal expansion of β- and γ-CL-20 needs to be further improved.

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    • LIU Sai, SHI Wei, WANG Yi, ZHANG Qinghua

      Online:December 16, 2020  DOI: 10.11943/CJEM2020228

      Abstract:Due to conjugated planar molecular structure and additional N-oxide bonds, nitrogen-rich fused-ring N-oxides usually exhibit the advantages of high density, good detonation performances and good sensitivity and they have gradually become a research hotspot of energy materials. This article reviewed molecular structure, synthesis method and physical and chemical properties of twenty nitrogen-rich fused-ring N-oxides that were synthesized in the last decade. At the same time, this article compared some main physical and chemical properties between nitrogen-rich fused-ring N-oxides and their precursors. This review will provide some references for the synthesis and property investigation of new nitrogen-rich fused-ring N-oxides.

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    Vol, 29, No.3, 2021    

      >Energetic Express
    • 王军

      2021,29(3):181-181, DOI:

      Abstract:

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    • >Calculation and Simulation
    • CUI Tao, LIU Zhi-han, XIE Wei, XUE Xiang-gui

      2021,29(3):182-191, DOI: 10.11943/CJEM2020174

      Abstract:Molecular dynamics simulation is an important method to predict the shock sensitivity of energetic materials, yet it is computationally expensive and needs to use force fields that may be unavailable. Here, an algorithm was designed and implemented in a computer program in Python for calculating the Steric Hindrance Index (SHI), which is a descriptor for evaluating shock sensitivity. The algorithm 1) compresses the crystal unit cell of an energetic material keeping the molecular unit rigid to simulate deformation under shock; 2) establishes a new rectangular coordinate system for the specific slip system and rotates the cell to deal with general shock directions and slip systems; 3) assigns molecular units to layers based on the coordinate of their centroid; 4) calculates the overlapped area of each two adjacent layers after projection along the slip direction; and 5) obtains SHI by normalization of overlapped areas. For PETN, BTF, RDX, and TNT at a compression ratio of 0.1, the calculated average SHI are 0.8707, 0.7940, 0.4228, and 0.0924, respectively, which is consistent with the decreasing order of impact sensitivity mentioned in references. SHI classifies the slip systems in line with those based on molecular dynamics simulations, yet with better computing efficiency and methodological applicability.

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    • WU Jun-ying, LIU Jia-xi, YANG Li-jun, LI Yao-jiang, WU Jiao-jiao, CHEN Lang

      2021,29(3):192-201, DOI: 10.11943/CJEM2020183

      Abstract:In order to study the safety of processing explosives with femtosecond laser, a calculation model of femtsecond laser sequence machining on explosives was established, which took into account the autothermal reaction of the explosives. The processes of femtosecond laser sequence machining on three different explosives (TNT, TATB and HMX) were calculated. The safety of these processes was analyzed. Results show that the frequencies of the femtosecond laser sequence, the heat release of the autothermal reaction and the thermal diffusion coefficient of explosives will affect processing safety. Among these three explosives, the heat release of the autothermal reaction of HMX is the largest, and its thermal diffusion coefficient is the smallest, so its heat accumulation effect is the most significant. Therefore, HMX is ignited when processing with all the three femtosecond sequences with different frequencies (1×103 Hz, 1×105 Hz and 2×105 Hz). On the contrary, the heat accumulation effect of TATB is the weakest, so no ignition occurs when processing with the three femtosecond sequence with different frequencies. The heat accumulation effect of TNT is between those of HMX and TATB, so ignition only occurs when using the femtosecond laser sequence with higher frequencies. In the actual machining process, especially for the explosives with greater heat release of the autothermal reaction and smaller thermal diffusion coefficient, femtosecond laser sequence with low frequency should be selected to ensure safety.

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    • CAO Xing, CAO Hong-song, ZHANG Gen-sheng, WU Zong-ya, ZHAO Han-dong, LIU Heng-zhu, WANG Qi, LUO Pu-guang

      2021,29(3):202-210, DOI: 10.11943/CJEM2020224

      Abstract:Hollow charges usually adopt compression molding process. Using the method of continuum mechanics, a finite element simulation of the compression process model was established. First, the relative density, displacement and equivalent stress change laws of the pressing process of the JO-9159 explosive were simulated and analyzed. Then, the influences of pressing rate, initial relative density and friction coefficient on the pressing quality of JO-9159 explosive are simulated and analyzed. Results show that the JO-9159 explosive powder flows mainly in the axial direction during the pressing process, and the explosive powder flows slowly near the female mold area; when the pressing rate is 0.5 mm·s-1 and the friction coefficient is 0.25, the relative density of the charge after molding is more uniform and the amount of rebound is smaller.

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    • >Propulsion and Projection
    • WU Peng, LI Gao-chun, HAN Yong-heng, WANG Zhe-jun, QIAN Ren-jun

      2021,29(3):211-219, DOI: 10.11943/CJEM2020096

      Abstract:In order to study the damage and failure process of adhesive interface of solid rocket motor, rectangular adhesive specimen of solid rocket motor was made based on QJ2038.1A-2004 regulation standard and tensile tests was carried out. The damage and failure mode of the adhesive interface specimen was obtained. The parameter inverse identification method which is based on step inverse and Hooke-Jevees optimization algorithm was adopted. The relevant parameters of the bilinear cohesive model of mix mode at the propellant/liner/insulator interface were obtained and were applied into the numerical simulation of the damage and failure process of adhesive specimen in tensile tests. Results show that the main failure form of adhesive interface specimen is the debonding at the interface of the propellant/liner/insulator layer; the proposed parameter inverse identification method can obtain the interface parameters of solid rocket motors well. The initial modulus, maximum bonding strength and fracture energy of the propellant/liner/insulator layer of solid rocket motors are 0.86 MPa, 0.63 MPa and 3.13 kJ·m-2 at tension speed of 2 mm·min-1, respectively. The damage of the propellant/liner/insulation layer interface makes the increase rate of stress decrease with the tensile strain. The initiation interface crack at the tip of the artificial debonding layer and the expansion along the center of the specimen, and finally penetration of the bonded specimen is the main damage and failure mode of the adhesive specimen.

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    • ZHANG Yong, DING Ya-jun, XIAO Zhong-liang

      2021,29(3):220-227, DOI: 10.11943/CJEM2020242

      Abstract:In order to study the migration phenomenon of deterrent in double-base oblate spherical propellant during storage, micro-Roman technique was used to characterize the concentration distribution of dibutyl phthalate(DBP) and poly (neopentyl glycol adipate)(NA) in double-base oblate spherical propellant after accelerated aging; and the combustion performance of double-base oblate spherical propellant was tested by the closed bomb test. Results show that the concentration of DBP and NA changed exponentially from the surface to the inside in one-dimensional direction, which conformed to Fick"s second diffusion law. During the accelerated aging process, the migration of DBP in double-base oblate spherical propellant was bidirectional, the concentration gradient of deterrent decreased gradually, the diffusion depth increased, the peak position of concentration shifted inward, and the combustion performance of double-base oblate spherical propellant also gradually decreased. High temperature would aggravate the migration of deterrent. The progressive combustion characteristic values of double-base oblate spherical propellant samples aged at 65 ℃,75 ℃ and 85 ℃ for 10 days were 1.3351, 1.2917 and 1.1888, respectively. With the increase of temperature, the progressive combustion characteristic values of double-base oblate spherical propellant decreased. Under the same aging conditions, the anti-migration characteristics of NA was higher than that of DBP.

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    • JIANG Shuai, LIU Qiong, NAN Feng-qiang, YIN Ji-hong, DU Ping

      2021,29(3):228-233, DOI: 10.11943/CJEM2020252

      Abstract:In order to understand the constant volume combustion performance of single charge and the mixed charge(MC+B) of 37-hole nitroguanidine propellant, a lace-shaped 37-hole triguanidine-15 propellant is used as the main charge (MC), and the lace-shaped 19-hole triguanidine-15 coated propellant is used as the auxiliary charge(B). The packing density is 0.20 g·cm-3, under 50 ℃, 20 ℃, -40 ℃, the effect of arc thickness on the combustion performance of single main charge and the effect of the mixing mass ratios on the combustion performance of the mixed charge (MC+B) were studied through constant volume closed-bomb test. The results show that the lower the temperature, the more obvious the erosion and combustion phenomenon of the 37-hole single main charge. At the same temperature, the greater the arc thickness of the main charge, the less obvious the erosion and combustion phenomenon, the stronger the progressive combustion, and the better the combustion performance. The higher the temperature, the greater the value of ΔLLm/L0 of the mixed charge of the same mixing ratio, the better the progressive combustion; At the same temperature, the progressive combustion of the mixed charge is stronger than that of the single main charge, and as the ratio of the coated propellant increases, the erosion combustion peak gradually decreases, indicating that the addition of the coated propellant significantly improves the progressive combustion and reduces the erosion combustion peak of the mixed charge, and at 50 ℃, 20 ℃, -40 ℃, the mixing ratio of the mixed charge to obtain better progressive combustion is 7∶3.

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    • >Safety Performance and Assess
    • GONG Zheng, TU Xiao-zhen, ZENG Gui-yu, BAI Liang-fei, CAO Ke

      2021,29(3):234-240, DOI: 10.11943/CJEM2020152

      Abstract:To gain insights into the stability of nano TATB in different storage environments, aging conditions at 90 ℃, 10%RH, 50%RH, 90%RH and 200 Pa low atmospheric pressure were considered. The microstructure evolution of nano TATB was characterized by small angel neutron scattering (SANS), scanning electron microscope (SEM), X-ray diffraction (XRD), Raman spectroscopy (Raman) and infrared spectroscopy (IR). Results show that the specific surface area of nano TATB decreases obviously after the thermal aging at 45 ℃, 60 ℃ and 71 ℃, and the higher the aging temperature, the more obvious the specific surface area decreases, accompanied by the growth of some crystal particles. The long-term stability of nano TATB crystal particles is significantly affected by the extreme humidity and heat environment (90 ℃, 90% RH). After short-term storage (5 days), the nano TATB particles grow up with the size of about 1-3 μm. The nano TATB particles also grow and form a micro flake structure after aging in a low pressure (200 Pa) environment at 90 ℃. Based on the experiment results, the growth and aging mechanism of nano TATB were discussed. The high surface energy of nano TATB facilitates TATB molecules overcoming the energy barrier, which results in the TATB molecules diffusion and rearrangement on the crystal surface and correspondingly leads to the grow-up of particles.

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    • CUI Yuan-bo, KONG De-ren, ZHANG Xue-hui, WANG Liang-quan

      2021,29(3):241-250, DOI: 10.11943/CJEM2020181

      Abstract:In order to improve the anti-electromagnetic interference capability of the electronic equipment on blast field, the characteristics of electromagnetic radiation generated by high explosive were studied. An electromagnetic radiation measurement device based on ultra-wideband omnidirectional antenna and shortwave omnidirectional antenna was designed while 8 test points were set up for electromagnetic radiation measurement of 60 kg TNT explosion. The experimental results showthat the electromagnetic radiation signals generated by TNT explosion last up to 600 ms after the explosion, the most intense period of electromagnetic radiation signal produced by TNT explosion is from 80 ms to 110 ms after the explosion. The frequency of the electromagnetic radiation signals generated by the explosion is mainly concentrated below 100 MHz, where the energy distribution in the low frequency band which below 50 MHz is the most obvious. The distance of the center of explosion hasa significant effect on the spectrum distribution of electromagnetic signals, and the frequency distribution of electromagnetic radiation in different directions was inconsistent. The electromagnetic radiation intensity generated by TNT explosion mainly ranges from 64.33 V·m-1 to 348.25 V·m-1, and the electromagnetic radiation intensity decreased largely with the increase of detonation distance. The electromagnetic radiation intensity measured by test points in different directions also hasa certain gap, and the difference ranges from 11.1% to 17.7%.

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    • >Reviews
    • WANG Jing-kai, CHEN Jie, SUI He-liang, YU Qian, YANG Xiu-lan, SUO Zhi-rong, SUN Jie, YIN Ying

      2021,29(3):251-266, DOI: 10.11943/CJEM2020146

      Abstract:The oxidation reaction of micro and nano aluminum powder is an important way of energy release and aging inactivation. Molecular dynamics and reaction kinetics provide necessary means for elucidating the microscopic mechanism of oxidation reaction of aluminum powder and quantitatively describing the oxidation process. According to the type of reaction system, the oxidation of aluminum powder can be divided into aluminum-oxygen (Al-O2), aluminum-water (Al-H2O) and aluminum-other oxides (Al-other oxides) reaction systems. The recent progress of molecular dynamics and reaction kinetics in the above reaction systems is reviewed. The mechanism of oxidation kinetics of aluminum powder and its key influencing factors, including the oxide layer, particle size, atomic diffusion rate, temperature and oxygen concentration, were discussed, which proved the flexibility and effectiveness of molecular dynamics and reaction kinetics. On this basis, the important problems in different oxidation reaction systems were analyzed and prospected. It is pointed out that the oxidation kinetics of aluminum powder under multiple factors, the kinetics of Al-water vapor reaction, and the intrinsic mechanism of Al-other oxides reaction are the key problems to be solved in the future.

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