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Abstract:In order to explore the possibility of substituting nanothermite-explosive hybrid composites for primary explosive， nano-Al， nano-Bi₂O₃， raw HNIW and nano-HNIW were used to prepare Al/Bi₂O₃-HNIW by two methods： solvent-nonsolvent method （SN） and physical mixing method （PM）. The properties of Al/Bi₂O₃-HNIW were characterized and tested by scanning electron microscope （SEM）， X-ray diffractometer （XRD）， X-ray photoelectron spectroscopy （XPS）， closed bomb test and lead plate test. Results show that Al/Bi₂O₃ is uniformly coated on the surface of HNIW by SN. The optimal mass ratio of Al/Bi₂O₃ to HNIW for Al/Bi₂O₃-HNIW （SN） is 3∶7， with a high pressurization rate of 2.914 GPa·s^-1， which is triple of Al/Bi₂O₃-HNIW （PM），and the pressurization time is shorter. The electrostatic sensitivity of Al/Bi₂O₃-HNIW （SN） is significantly lower than lead styphnate and lead azide， and even PETN. Al/Bi₂O₃-HNIW（SN） can detonate RDX using PETN as intermediate charge. Al/Bi₂O₃-HNIW （SN） is expected to be used as a substitute for primary explosive for its excellent safety and initiation performance.

Abstract:Deuterated nitroguanidine （NQ-d₄） and deuterated 1，1-diamino-2，2-dinitroethylene （FOX-7-d₄） were synthesized via H/D exchange starting from nitroguanidine （NQ） and 1，1-diamino-2，2-dinitroethylene （FOX-7）. The target products were characterized by IR， NMR （¹H and ¹³C）， HPLC， TG-DTG， DSC and neutron diffraction. DSC/TG data show that the decomposition temperatures of NQ-d₄ and FOX-7-d₄ were 2.5 ℃ and 2.6 ℃ higher than those of NQ and FOX-7， respectively. The deuteration rates of NQ-d₄ and FOX-7-d₄ are respectively 95.27% and 98.87% as measured by neutron diffraction. The purities of NQ-d₄ and FOX-7-d₄ are respectively 99.51% and 99.28% obtained by HPLC via area normalization method.

Abstract:Phonon spectra play an important role in studying the thermodynamic properties of solids and the microscopic process of initiating chemical decomposition reactions， which can help to reveal the microscopic physical mechanism of initial thermal decomposition mechanism， detonation performance and sensitivity. In this work， the density functional theory with dispersion correction was used to calculate the phonon spectra and thermodynamic properties of 2，4，6，8，10，12-hexanitrohexaazaiso-wurtzitane（CL-20）/1，4-dinitroimidazole（1，4-DNI） cocrystal and co-formers. Through analyzing the phonon density of states， the way in which the phonon mode stores and transfers energy was determined， the direction of thermal energy flow was proposed， and the trigger bond and impact sensitivity order were predicted. The results show that the initial bonds of ε-CL-20 and CL-20/1，4-DNI cocrystal are predicted to be N─NO₂ bonds on CL-20 molecules； the initial thermal decomposition of 1，4-DNI may be related to the ring-opening of imidazole. By comparing the phonon density of states of CL-20 and 1，4-DNI molecules in cocrystal and its pure components. It can be found that the thermal stability of both CL-20 and 1，4-DNI molecules were improved in cocrystal， so that the thermal stability of the cocrystal being superior to the co-formers. According to the "doorway" mode phonon number and characteristic vibration frequency Δω_d， the order of the impact sensitivity is predicted of to be ε-CL-20>CL-20/1，4-DNI>1，4-DNI， completely consistent with the experimental measurement results. The thermodynamic parameters of CL-20/1，4-DNI cocrystal and co-formers have been calculated by phonon spectra， at the same temperature， the order is CL-20/1，4-DNI>ε-CL-20>1，4-DNI. In addition， low-frequency phonons contribute the most to heat capacity（C_V）， and the chemical bond breakage caused by energy transfer may undergo a multi-phonon up-pumping process.

Abstract:A rapid and accurate high performance liquid chromatographic method was developed for the simultaneous determination of TATB and HMX in explosive formulations. Dimethyl sulfoxide （DMSO） was used as the solvent and ultrasonic assisted to dissolve the sample. The influences of sample weight， dissolve time， mobile phase type， chromatographic column type and detection wavelength on results were investigated. The results show that HMX and TATB were confirmed to separate within 6.5 min by using C18 chromatographic column with mobile phase of acetonitrile and water at 45/55（V/V）. And the HMX and TATB could be extracted completely at the condition of ultrasonic for 1.0 h and standing at room temperature for more than 4.0 h after they were dissolved in 250 mL DMSO. The relative standard deviation of reproducibility （n=8） was 0.55% and 0.99%， respectively. Linear relationships between values of peak area and mass concentration of TATB and HMX were good in the ranges of 0.032-0.056 mg·mL^-1（R²=1.0000） and 0.011-0.016 mg·mL^-1（R²=0.9999）.

Abstract:The single crystal of hydrazinium 3，5-dinitroamino-1，2，4-triazole （HDNAT） was cultivated by slow evaporation from solvent of methanol/water， and its crystal structure was determined by X-ray singal-crystal diffractometer. The crystal structure analysis indicates that HDNAT belongs to monoclinic system with space group P2（1）， and the crystal parameters are a = 0.35976（12） nm，b = 0.9348（3） nm，c = 1.1833（4） nm，V = 0.393.9（2） nm³，Z = 2，D_c = 1.91 g·cm^-3，μ = 0.170 mm^-1，F（000）=230. The thermal behavior of HDNAT was studied by TG-DTG. The decomposition peak of HDNAT is 193.17℃ （DSC）， and it decomposes at solid state. The composite modified double-base （CMDB） propellant formulation based on HDNAT was designed and prepared， and its energy characteristics such as explosion， specific volume， density， characteristic velocity， and specific impulse and combustion performances were tested. For HDNAT-based CMDB propellant formulation， the tested explosion is 6042 kJ·kg^-1， specific volume is 638 L·kg^-1， density is 1.767 g·cm^-3， characteristic velocity is 1592.3 m·s^-1. The study of combustion performances of Φ50 mm engine show that it has stable performances at pressure of 15 MPa， the specific impulse is 250.91 s. Compared with RDX-CMDB propellant， the burning rate of HDNAT-based CMDB propellant increases by 18.8%， and the pressure exponent in partial pressure range is above 0.4.

Abstract:Triaminoguanidinium nitrate （TAGN） was obtained via amination of guanidinium nitrate， and its structure and properties were characterized by elemental analysis， fourier transform infrared spectroscopy （FT-IR）， differential scanning calorimetry （DSC） and scanning electron microscope （SEM）. Short block-like TAGN crystal particles were prepared by ultrasound assissted cooling crystallization in water. The influencing factors of crystal modifier， ultrasonic and cooling process for controlling crystal morphology and particle size， were analyzed by SEM and particle size analysis， and results revealed that ultrasound assissted process can lead to uniform crystalline morphology with narrow particle size distribution. The crystal morphology modifier and temperature control program have a significant effect on the particle size， particle size distribution and crystalline morphology of TAGN. Under the action of ultrasonic （750 W， 20 KHz）， two kinds of high-quality TAGN crystals with uniform crystalline morphology， smooth surface without sharp edge angle， high density and narrow particle size distribution were prepared by using suitable cooling process and PVP K30 （0.03%） as the crystal morphology modifier. Compared with present manufactured raw materials，the comprehensive performance of TAGN have been improved， the characteristic explosion percentage of two kinds of TAGN decreases from 20% to 8% and 4% apart， the characteristic drop height increases 5.9 cm and 3.4 cm apart， the density increases from 1.571 g·cm^-3 to 1.586 g·cm^-3 and 1.589 g·cm^-3 apart， the onset melt point increases from 224.8 ℃ to 227.7 ℃ and 228.2 ℃， respectively. Charging with the prepared product will significantly improve the charging process performance and solid content， so as to improve weapon performance.

Abstract:The minimum ignition temperature is an important basis to determine whether the fuel air explosive has the phenomenon of fire channeling. The mixture of flammable liquid and air forms gas-liquid two-phase cloud. At present， the research on the minimum ignition temperature and the specific influence of cloud concentration， particle size and velocity on the minimum ignition temperature are still in a blank stage. In this paper， the research method of dust minimum ignition temperature is used for reference. With Godbert- Greenwald （G-G） heating furnace as the main test instrument， the minimum ignition temperature test system of gas-liquid two-phase cloud is established. On this basis， the cloud instantaneous concentration particle size test device is established. With ethanol as the experimental reagent， the particle size distribution of ethanol gas-liquid two-phase cloud was measured under the experimental conditions of 7000 g·m^-³ cloud concentration at the center of the heating furnace and 0.06-0.10 MPa fuel dispersion pressure. The effects of particle size distribution and cloud velocity on the minimum ignition temperature were analyzed and discussed. Under the concentration of 7000 g·m^-³， with the increase of pressure from 0.06 MPa to 0.10 MPa， the particle size decreased from 146.58 μm to 70.97 μm， the lowest ignition temperature of ethanol first decreased from 468 ℃ to 464 ℃， then increased to 476 ℃， and finally kept at 475 ℃. When the pressure is less than 0.07 MPa， the main factor affecting the MIT is the particle size， which decreases with the drop diameter. When the pressure is greater than 0.07 MPa， the main factor affecting the MIT is the flowing velocity. Since the velocity is constant， the minimum ignition temperature also stays stable.

Abstract:In order to investigate the gas jet flow field and thrust characteristics of solid rocket engine working underwater， an experimental study on the underwater work of rocket engine was carried out on the lifting platform connected to the hull. The expansion process of nozzle gas jet in open water was observed by high speed camera system， and the evolution process of underwater gas jet was obtained. The combustion chamber pressure and thrust of underwater rocket engine were measured. The thrust characteristics of the rocket engine under the water depth of 10 m， 30 m and 50 m were compared and analyzed. The experimental results show that when the engine is ignited underwater， the shape of gas jet is changed because of the interaction between water environment and gas， and gas liquid turbulent mixing is intense. With the increase of water depth， the combustor pressure is basically unchanged， the working thrust of the engine decreases. The relationship between thrust and water depth is nonlinear. Under the same water depth condition， the smaller the engine throat diameter， the smaller the thrust reduction， and the smaller the combustion chamber pressure， the smaller the thrust reduction.

Abstract:Electrically controlled solid propellants (ECSPs) have the characteristics of on-line combustion, power-off extinction and real-time adjustable burning rate, which has good application prospects in the field of propulsion from the micro-scale to macro-scale solid rocket motors. In this paper, the preparation methods of ECSPs worldwide in recent years are summarized, which are mainly swelling method, melt mixing method, room temperature method, freeze-thaw method and 3D printing method. The thermal stability, electric resistance characteristics, ignition and combustion performance, aging features, arc ablation and plume characteristics of ECSPs are reviewed. The hydroxylamine nitrate-based ECSPs with low toxicity, high specific impulse and high controllability and perchlorate-based ECSPs with high flameout pressure threshold are the current research focuses. The future research directions of ECSPs is to strengthen and improve the properties research of ECSPs, develop and normalize the ignition and combustion performance test devices and method, improve the burning rates of ECSPs, study the ignition and combustion mechanism of ECSPs deeply, and establish the ignition and combustion models.

Abstract:Hydroxylammonium nitrate （HAN）-based propellant has the advantages of high energy， insensitive and non-toxic combustion products. It offers advantages in the continuous start-up and thrust adjustment of propulsion system. The formula composition， decomposition characteristics， ignition and combustion performance of HAN-based liquid propellant， HAN-based gel propellant and HAN-based solid propellant were reviewed. The key points for future research were proposed： preparing high-performance catalyst bed for HAN-based liquid propellants， developing electric ignition as a reliable ignition mode； improving the ignition performance of HAN-based gel propellant， accelerating the engineering applications； exploring the combustion and flameout controllable mechanism of HAN-based solid propellant， and breaking through the bottleneck of large-scale application of the propulsion system.

Abstract:The disruptive innovating technology has developed rapidly and become a significant power of promoting science & technology development and military change. In order to realize its impact on the energetic materials studies， the concept and role of disruptive technology is introduced， and several rapid growing disruptive technologies are discussed， including ultra-high energy technology， nanometer technology， additional manufacturing technology and materials genome technology. Results show that the focus on the future disruptive technologies lies on the preparation and application of metallic hydrogen， design and 3D printing of energetic ink， establishment of energetic materials genome database and fusion of its three elements， which is new opportunities and challenges for energetic materials innovation development.

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