Abstract:An aluminized AP/HTPB propellant formulation was experimentally studied, and the effect of formulation parameters i.e. particle size of AP, catalysts on burning rate and pressure exponent were discussed. The results show that the burning rate of propellant decreases with increasing the average AP particle diameter but with large diameters the dependence of burning rate becomes weak. Liquid ferrocene catalyst is more effective to increase the burning rate as compared to solid iron oxide. A 50% rise in burning rate with liquid ferrocene catalyst is observed while 22% rise with solid catalyst.The experimental results of burning rate and pressure exponents were compared with the calculated results of the combustion model. Model predictions and the experimental data are in good agreement.

Abstract:The constant-volume combustion energy Δ_cU (4HDNPPb,s,298.15 K) of lead salt of 4-hydroxy-3,5-dinitropyridine (4HDNPPb) was determined as (－7385.82±3.14) J·g^－1 at 298.15 K by a precise rotating bomb calorimeter. The standard molar enthalpy of combustion Δ_cH^θ_m (4HDNPPb,s,298.15 K) and standard molar enthalpy of formation Δ_fH^θ_m (4HDNPPb,s,298.15 K) of 4HDNPPb were calculated to be (－4499.63±1.92) kJ·mol^－1 and (－796.65±2.32) kJ·mol－1,respectively. Moreover,the catalysis of composite catalyst system,4HDNPPb/energetic copper salt mixture or 4HDNPPb/non-energetic copper salt mixture on the combustion of RDX-CMDB propellant was investigated. The results show that composite catalyst, 2.5%/0.5%-ω(4HDNPPb)/ω(2HDNPCu) mixture or 2.5%/0.5%-ω(4HDNPPb)/ω(-Cu,copper phthalate) mixture,has higher catalytic efficiency in catalyzing RDX-CMDB propellant combustion and enables the pressure exponent of the propellant to be less than 0.3。

Abstract:The thermal behaviors of the smokeless NEPE propellants with and without CL-20 are studied by TG-DTG and PDSC. Experimental results show that there are two decomposition stages on the TG-DTG and PDSC curves of the propellants with and without CL-20 at normal and high pressure,and CL-20 decomposition at high pressure is in the first exothermic decomposition stage with the temperature range of 180-210 ℃. The total apparent decomposition heats of the propellants increase with the increase of the pressure and the content of CL-20,obviously.

Abstract:Thermal decomposition of NEPE propellant containing hexanitrohexaazisowurtzita (HNIW) was investigated by thermogravimetry (TG) and differential scanning calorimetry (DSC). The results show that when RDX was replaced by HNIW by half in the propellant, the mass loss of nitric esters mainly took place from 80 ℃ to 145 ℃. Furthermore, when the temperature went up to 145 ℃, RDX and HNIW influenced each other for their thermal decomposition with a major exothermic peak appearing in DSC curve. When RDX was replaced by HNIW totally in the propellant, the mass loss between 145 ℃and 240 ℃ was split in two steps, i.e. decomposition nitric esters and partial decomposition of HNIW. This phenomenon fully shows that the incorporation of nitric esters greatly affects thermal decomposition of HNIW.

Abstract:The composition of burning gases and energetic properties of hydroxylamine nitrate （HAN） based underwater monopropellants were calculated by balance constant method, D₁ with formula of HAN/dioxane/water=59.15/10.85/30.00 were burned in the liquid regenerative closed bomb,and the effects of different charge densities on combustion properties were analyzed qualitatively. The energetic characteristics and surface wake of D₁ propellant were analyzed and compared to that of LP1846 and OTTO-Ⅱ propellant. The results show that the specific impulse and characteristic velocity of D₁ propellant come up to 2343.53 N·s·kg^-1 and 1466.32 m·s^-1 respectively,higher than LP1846′s 2157.99 N·s·kg^-1 , 1341.04 m·s^-1 and OTTO-Ⅱ′s 2038.52 N·s·kg^-1. Moreover,the water-soluble gas products of D₁ propellant come up to 77.7% of the total molar mass of gas products,therefore,the surface wake of D1 propellant is smaller and concealment characteristic is better than that of OTTO-Ⅱpropellant.

Abstract:A new method for respective determination of Pb,Cu and Ca in a propellant sample was proposed by flame atomic absorption spectrometry with the microwave assisted digestion to the sample digested by HNO₃. The results of determining Pb, Cu and Ca in the propellant samples, show that the RSDs(relative standard deviations) are in the range of 1.13%~3.23%(n=5) and the recovery is 99.38%~100.60%. The method is simple, rapid and highly accurate.

Abstract:Attaching covers on the shaped liner,an explosively formed projectile(EFP) with stabilizing fins can be produced. The recovery results indicate that the number of EFP fins is corresponding with the number of the covers attached to the liner. Moreover, the thickness of the covers also has the effect on the mold results of the fins. So it is acceptable that the number and the shape of the covers are based on the number and shape of the fins.

Abstract:Using the Arbitrary Lagrangian-Eulerian (ALE) algorithm, the numerical simulation of the blasting warheads exploding in the air is realized. During the modeling process, the explosive was plotted with ALE elements, the shell with Lagrange elements and the air with Euler elements, the ALE meshes of the initial void were created in which the explosive products could flow, the meshes of explosive and the initial void were joined with common nodes, and the fluid-structure interaction was defined between the meshes of the explosive, shell and air. The diffusion of explosive products and the pressure distribution were obtained. The overpressure values at different distance to the explosion center were presented. The results show that the relative errors between the simulation results of overpressure and the experimental results at different distance to explosion center is less than 10%.

Abstract:ε-HNIW was heated at 70 ℃,80 ℃,90 ℃ or boiling points in five solvents ( water,toluene,n-butyl ether,cyclohexane and heptane) for 240 min, respectively. The FTIR spectra of specimens sampling at different times indicate that polymorph transformation of ε-HNIW is related to dipole moment of solvents. When ε-HNIW was heated at the above temperatures for 240 min in solvents with dipole moments (water, toluene and n-butyl ether), the polymorph transformation took place,while in those with zero dipole moment (cyclohexane and heptane) under the same conditions, no polymorph transformation occured.

Abstract:The polarographic and voltammetric behaviors of ［Cd(CHZ)₃］(NO₃)₂ were studied. The results show that optimized conditions are as follows: purging time 300 s,equilibration time 10 s, 30% HCl 2.4 mL, start potential －０．８ V, end potential －0.45 V, voltage step time 0.8 s, scaning rate 7.4 mV·s^－１, peak potential of Cd²⁺ －0.58 V,deviation ±0.05V. And lots of data show that ten times of K⁺、Ni⁺、Zn²⁺ and Fe³⁺ have no effect on the determining results. Furthermore, the voltaic property of deoxidize peak and oxidation peak was studied by using cyclic voltammetry. Experiments indicate that the electrode reaction is not reversible, but adsorptivity on the surface of the electrode exists.

Abstract:3,4-Diaminofuraza (DAF) is an important precursor to synthesize furazan energetic materials. Three convenient methods for the preparation of DAF were described. The results indicated that DAF can be obtained not only at about 1 atm pressure but also at high pressure from the diaminoglyoxime (DAG) starting from the amination of glyoxal by one or two-step. The yield (43%) of DAF prepared from glyoxal with other raw materials by only one step is larger than those (11% and 39%) of the other two methods, but the reaction conditions must be controlled exactly and the reaction time is slightly longer.

Abstract:3,6-Dihydrazine-1,2,4,5-tetrazine and its energetic salts were synthesized from the easily available starting materials like triaminoguanidine and 2,4-penatanedione. The synthesis route in literature was magnified properly. Moreover, the synthesized compounds were characterized by spectra analysis(IR, NMR, EA and MS) and the explosive properties (impact and friction sensitivity) and thermal properties (TGA/DTG) were studied.

Abstract:The radiation mechanism,formulation composition,properties test and the disturbance on night vision equipment with strong flash blindness ammunition are studied. The results show that the trinary formulation containing KClO₄,Al and epoxy resin(mass ratio is 50∶50∶3) has higher radiation and lower sensitivities. The ammunition security is greatly improved when 1% micro-powder graphite is added into the trinary formulation. When 80 g charge amount of trinary formulation(the mass ratio of KClO₄,Al and epoxy resin is 50∶50∶3) is loaded into the simulation bomb, the luminesced intensity at visible region is more than 5.0×10⁷ cd and the radiation intensity at near-infrared band exceeds 2.1×10⁵ W·sr^-1. Moreover,40 g charge amount of the trinary formulation has obvious disturbance on night vision equipment at 37 m.

Abstract:In order to study combustion characteristics of RDX nitramine propellant furtherly,the burning rate pressure exponents for three RDX nitramine propellants were investigated by closed bomb test and data-treatment in the different range of pressure,and were compared with that of the single base propellant. Results show that the burning rate pressure exponent for single base propellant with loading density 0.2 g·cm^-3, is 0.869 at 50-100 MPa,and 0.926 at 150-217 MPa,and it increases as pressure increasing. But the results are reverse for the RDX nitramine propellants,especialIy for RGD and JMZ nitramine propellants whose buring rate pressure exponent is over 1 under 150 MPa,and below 1 at higher pressure. In addition,the values of burning rate pressure exponent of multi-perforation granular propellants are smaller obviously than that of single′perforation cylinder propellants.

Abstract:The changes of color change time (t_c) of standard methyl-violet test paper and stabilizer content in propellants in the standard methyl-violet test at 134.5 ℃ for three single-base (SB) propellants and at 120 ℃ for three double-base propellants and one triple-base propellant aged at 85 ℃ with ageing time (t_a) of the propellants are determined by heat test and chemical analysis method. The data of the t_c vs t_a relationship obtained are analyzed by variance test. The results show that the t_c vs t_a relationship is obvious for SB propellants and is not obvious for DB- and TB-propellants, which indicate that the methyl-violet test is not suitable for rating the stability of DB and TB-propellants.

Abstract:A kind of closed bomb was designed and was used to measure the burning temperature of six DJ-6B primers at 15 mm to the primer. The experimental results indicate that the highest combustion temperatures of six primers are 405.87-563.28 ℃. With the heat released from the combustion of DJ-6B primer compositions using as the inner thermal resource, the burning temperature of primer compositions in the closed bomb was simulated by finite element method. The calculation results range from 423.45 ℃ to 552.95 ℃. The calculation results are consistent with experiment results.

Abstract:The application and suitable range of Arrhenius equation are discussed. The applicability of Arrhenius means in heterogeneous non-constant temperature system, thermal analysis and storage research of explosives are shown. The results show that the assumption that activation energy E and pre-exponential factor A change with temperature is approximate. If A and E don′t change seriously during the experimental temperature range, Arrhenius equation can be used. But it should be corrected if it′s used for extrapolation purpose. Moreover,corrected Arrhenius equation has different activation energy E and pre-exponential factor A at different temperature range. It was extrapolated by Bruceton manometer test results that the storage life of GI-920 explosive was 126.95 d,353.62 d,623.46 d and 1143.77 d respectively based on the decomposition extent of 1% at 90 ℃,80 ℃,70 ℃ and 60 ℃.

Abstract:Experiments of ultrasonic testing stress of PBX-9003 explosive were carried out under a big load. The sonic elastic modulus of PBX-9003 explosive was obtained. The results show that the ultrasonic velocity propagating through explosive has a distinctive change when it receives a big load. The stress tested by ultrasonic method is close to the stress loaded by mechanical method. The feasibility of ultrasonic nondestructive testing the large stress of PBX-9003 explosive is verified.

Abstract:The desensitized explosive PETN film was prepared by physical vapour deposition (PVD) technology,and SEM was used to analyze the microstructure and grain size of PETN film. The relationship between grain size of film and the critical dimension of detonation wave propagation was discussed. The results show that the grain size affects the properties of explosive film, and the decrease of grain size in explosive film helps to decrease critical dimension of detonation wave propagation and microminiaturize explosion element.

Abstract:The nanometer RDX particle was prepared by using high speed impinging method. The results show that the nanometer RDX particle with narrow size distribution can be prepared by high speed impinging method. The particle sizes (d₅₀) can be comminuted to about 46.7 nm, and the range distribution of particle size is within 0.6 nm.

Abstract:Making reference to the method for determining the environmental factors for mechanical and electrical products by intensifying test, the concept for environmental coefficient of detonators in reliability evaluation is put forward. The correctness and feasibility of this method is tested and verified by up-and-down test. The results show that the environmental coefficient of detonators is relevant to stimulus and low temperature reduces the response reliability of detonators obviously.

Abstract:The droplet size and distribution of dispersion phase for emulsion explosives matrix were tested by laser particle analyzer. The effect of the crystallizing temperature of water-phase,the stirring speed,and the contents of emulsifying agent on the droplet size and distribution of emulsion explosives were studied. The results show that the effect of crystallizing temperature of water-phase on droplet size and distribution of dispersion phase is evident under certain conditions. There is a critical stirring speed of emulsion (1230 r·min^-1） below which the effect of stirring speed on the droplet size and distribution of dispersion phase is evident but is not obvious when the stirring speed of emulsion is over the critical value. The value is 1230 r·min^-1 under the experimental conditions. The additions of superabundant emulsifier agent to emulsions have no obvious effects on droplet size and distribution of dispersion phase.

Abstract:Based on the correlations between charge and space of boreholes of blasting in rock, the initiation mechanism of fracture zones was studied according to theories of explosion and rock mechanics. The scopes of crush zone and crack zone, in a condition of decoupling charging, were calculated. The correlation between explosion gas pressure and scope of crack was put forward, and the contradiction between charge and space of boreholes was solved theoretically. The blasting experiments in field were carried out and the experimental effects are satisfactory: shattered blocks are small and smooth face is well shaped. For a tunneling cycle, explosive cost is decreased by 17.8% and the single footage is increased by 0.2 m; the rates of half-hole marks of perimeter holes and the non-smooth grades of the cut contours are more than 92% and are less than 100 mm respectively. The results will provide parameters for blasting design and engineering practices with the theoretical gists.

Abstract:The method and assessment standard of munition in slow cook-off test is introduced and the factors affecting slow cook-off response of munition are analyzed. The characteristics of slow cook-off of HTPB/AP propellants at abroad are summarized. Results show the porous materials produced by thermal decomposition of ammonium perchlorate is the important factor causing HTPB/AP propellants to demonstrate violent reactions in slow cook-off test. Furthermore, the techniques to improve the slow cook-off response of AP based propellants are pointed out.

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