BAMO-THF共聚醚原位结晶包覆HMX

为了降低HMX的机械感度,以BAMO-THF共聚醚和甲苯二异氰酸酯(TDI)为包覆材料,用原位结晶方法对HMX颗粒进行了表面包覆,制备了BAMO-THF/HMX复合颗粒。采用扫描电镜(SEM)、傅里叶红外分析仪、X射线衍射(XRD)、激光粒度仪、X射线光电子能谱(XPS)对包覆前后HMX颗粒进行了表征。结果表明,包覆处理后的HMX晶体质量得到明显改善,晶体形貌更规整、颗粒表面缺陷显著减少,其撞击感度和摩擦感度分别从包覆前的88%和92%降到24%和40%。     

NTO包覆HMX的钝感研究

为降低HMX的机械感度并维持其爆炸性能,采用溶液重结晶法用较钝感的3-硝基-1,2,4-三唑-5-酮(NTO)包覆HMX,并测试了其机械感度和爆速。通过SEM观察了包覆HMX的粒径、形貌及包覆钝感的工艺条件。结果表明,包覆HMX的表面形态主要受水与N-甲基吡咯烷酮(NMP)体积比、搅拌速率和冷却速率的影响。当水和NMP体积比为5、搅拌速率为300r/min、冷却速率为6K/min时,包覆HMX的表面形态最好;以水和NMP为溶剂,包覆HMX的H50值提高了14.8cm,撞击感度降低了66%,且摩擦感度从100%降低至50%。包覆HMX的爆速降低了2.8%,基本可以维持爆炸性能不变。     

TEX对HMX的包覆降感

为降低HMX的机械感度并保持其爆轰性能,采用溶液-水悬浮包覆法,利用4,10-二硝基-2,6,8,12-四氧杂-4,10-二氮杂四环[5.5.0.0~(5,9).0~(3,11)]十二烷(TEX)和氟橡胶F_(2603)对HMX进行包覆降感;考察了TEX与HMX的粒度级配、主炸药质量比以及黏结剂用量对包覆炸药感度的影响;观察了TEX/HMX包覆炸药的微观形貌,测试其晶型结构、撞击感度、摩擦感度和爆速等参数,并进行了对比分析。结果表明,TEX可在HMX的表面形成保护层;黏结剂F_(2603)质量分数3%时为最佳用量,且包覆后HMX的晶型保持不变,仍为β型;超细TEX(d_(50)=4.532μm)和HMX(d_(50)=10.234μm)粒度级配下的降感效果最好,与原料HMX相比,TEX/HMX(质量分数30%TEX)混合炸药的撞击感度和摩擦感度分别降低了48%和68%,在装药密度为1.72g/cm~3时的实测爆速可达到7 932m/s。     

微/纳米HMX粒度级配对TNT基熔铸炸药性能的影响

为了提高TNT/HMX熔铸炸药的装药质量,将HMX进行微/纳米粒度级配后应用于TNT基熔铸炸药中。分别采用场发射扫描电子显微镜(FESEM)和固体密度排水法研究了HMX微/纳米粒度级配对TNT/HMX(质量比为40∶60)熔铸炸药的微观结构与密度均一性的影响;测试了含不同HMX微/纳米粒度级配的TNT基熔铸炸药的抗压强度、抗拉强度、撞击感度、摩擦感度和爆速。结果表明,与采用单一粗颗粒HMX(d_(50)=100μm)所制备的TNT基熔铸炸药相比,当采用质量分数15%纳米级HMX(d_(50)=100nm)、15%微米级HMX(d_(50)=5μm)、70%粗颗粒HMX(d_(50)=100μm)时,制备的TNT基熔铸炸药药柱内部缺陷少,密度均一性好,抗压强度提高200%,抗拉强度提高128%,撞击感度降低45.5%,摩擦感度降低46%,爆速增加32m/s,表明综合性能得到明显提高。     

降感HMX的制备及性能测试

为了改善奥克托今(HMX)结晶形态并降低感度,以二甲基亚砜为溶剂,以水为非溶剂,以糊精为晶体控制剂,对普通HMX采用溶剂/非溶剂重结晶法处理,制备降感HMX。使用电子偏光显微镜、液相色谱仪分析测试了HMX重结晶前、后的晶体形貌和质量,表明重结晶后HMX的晶体颗粒更加规整圆滑,近似球形,并且纯度达到99.15%。撞击感度实验表明,重结晶后HMX的撞击感度比普通HMX降低32%。     

冲击波作用下HMX晶体的细观响应

用折光匹配显微技术(OMS)、表观密度浮沉法(SFM)、微聚焦CT扫描表征了HMX晶体内部缺陷尺寸、数量。结果表明,D-HMX较普通HMX含有较大尺寸内部缺陷的数量较少,普通HMX含有大量10-5mm3以上缺陷,普通HMX和D-HMX晶体均含有大量10-6mm3量级以下缺陷。利用基于细观结构的冲击波效应数值模拟方法,研究了晶体内部缺陷尺寸对其冲击波温升效应的影响。模拟结果表明,在低压条件下,等效半径为20~40μm的内部缺陷在冲击波加载下温升较高,等效半径为10~15μm的内部缺陷温升相对较低。当冲击波压力增高至5.8GPa,等效半径为10μm内部孔洞在冲击波作用下温升可达到850K以上,两者的冲击波感度接近。     

反应装甲冲击引爆试验研究

研究了HMX基钝感炸药的机械感度.根据测试结果初步确定了反应装甲的装药配方,最终装药配方由改变模拟反应装甲上、下板的材料和厚度以及穿甲弹与反应装甲法线的夹角,用反应起始装药的引爆效果确定.结果表明,钝感炸药的撞击感度、摩擦感度均随HMX粒度的减小而降低,随钝感剂含量的增加而降低;反应装甲的装药配方为HMX97%、钝感剂3%.从理论上分析了炸药粒度变化对机械感度影响的机理,以及在穿甲弹参数和速度一定的条件下,反应装甲装药结构对冲击引爆的影响.     

硝酸铵粒度对改性硝酸铵机械感度的影响

为使粉状改性铵油炸药在性能上真正代替铵锑炸药,了解硝酸铵粒度与炸药机械感度的关系,参照GJB772A-97标准对不同粒度的改性硝酸铵的机械感度进行了测定.研究表明,改性硝酸铵的粒度对其机械感度有明显影响,在一定粒度范围内,随着改性硝酸铵粒度的增大,机械感度有所增大;当粒度继续增大时,机械感度随着粒度的增大而下降.从理论上分析了改性硝酸铵粒度变化对机械感度影响的机理.     

机械粉碎法制备纳米HMX及其机械感度研究

采用机械粉碎法制备了纳米HMX,用纳米激光粒度仪和场发射扫描电子显微镜(FESEM)对其粒度分布、颗粒的大小和形貌进行了表征,测试了原料HMX和纳米HMX的摩擦感度、撞击感度和冲击波感度.结果表明,制备的HMX粒径基本小于100 nm;与原料HMX相比,纳米HMX的摩擦感度有较大幅度降低,撞击感度和冲击波感度分别降低107.0％和62.1％,安全性明显提高.     

常温下重质碳酸钙的研磨改性一体化工艺研究

在粒径为45 μm重质碳酸钙的浆料中加入硬脂酸,利用研磨改性法,在研磨粉碎的同时制备了改性碳酸钙浆料,烘干粉碎后再对碳酸钙干粉进行改性。利用激光粒度分析等手段分别对碳酸钙干粉的粒度、表面活化度、吸油值、白度做了研究。结果发现,常温下可以实现重质碳酸钙研磨改性一体化工艺。研磨后碳酸钙颗粒的粒径由45 μm降至2 μm。随着硬脂酸的添加量逐渐增加,重质碳酸钙的活化度增加,吸油值下降。当硬脂酸的添加量增至2%（质量分数）后,重质碳酸钙的活化度超过98%,吸油值降至0.267 g/g。重质碳酸钙研磨改性一体化工艺有利于降低重质碳酸钙的生产成本,增加产品的竞争力。     

Effect of Crystal Quality and Particle Size of HMX on the Creep Resistance for TATB/HMX Composites

Two kinds of reduced sensitivity high explosive 1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocane (RS‐HMX) with different particle sizes were selected to enhance the energy output and the mechanical properties of insensitive high explosive 1,3,5‐triamino‐2,4,6‐trinitrobenzene (TATB). Mechanical sensitivities, dynamic mechanical analysis, and non‐linear time dependent creep behaviors of TATB/HMX composites were investigated and discussed in relation to the structural characteristics. Compared with TATB/conventional HMX (C‐HMX) sample, both the impact and friction sensitivities of TATB/RS‐HMX were reduced. It revealed that TATB/fine grains RS‐HMX composites had the highest storage modulus and minimum steady‐state creep strain rate due to the increased coherence strength and the inhibited slide of the single layer of TATB crystal. The creep resistance also showed clear dependence on the particle size of RS‐HMX. The overall results indicated that RS‐HMX had good potential in high energetic, safe, and load‐bearing material applications.     

钢模压制下高品质HMX晶体的损伤规律

为了揭示粒度分布与压制期内含能晶体损伤程度的关系,研究了3种不同粒径的高品质HMX炸药在压制后微结构和粒度分布的变化。结果表明,随着HMX晶体粒径的增大,晶体表面逐渐形成裂纹,其尖端和棱角发生破碎。当晶体尺寸达到222.5μm时会出现明显的穿晶断裂。采用两种粒度的HMX级配,可减少对晶体中的损伤。压缩刚度法所得HMX的黏结强度和光电子能谱所得PBX造型粉的包复度表明,随着颗粒粒径的增大,炸药的包覆效果和力学强度降低,导致压制PBX中更多晶体的破碎。     

Investigation of HMX‐Based Nanocomposites

Advanced munition systems require explosives which are more insensitive, powerful, and reactive. For this reason, nano‐crystalline explosives present an attractive alternative to conventional energetics. In this study, formulations consisting of 95 % octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine (HMX) and 5 % polyvinyl alcohol (PVOH) were prepared with mean crystal sizes ranging from 300 nm to 2 μm. The process to create these materials used a combination of mechanical particle size reduction and spray drying, which has the advantages of direct control of crystal size and morphology as well as the elimination of ripening of crystals (which occurs during slurry coating of nanomaterials). The basic physical characteristics of these formulations were determined using a variety of techniques, including scanning electron microscopy and X‐ray diffraction. Compressive stress‐strain tests on pressed pellets revealed that the mechanical properties of the compositions improved with decreasing crystal size, consistent with Hall‐Petch mechanics. The 300 nm HMX/PVOH composition demonstrated a 99 % and 129 % greater strength and stiffness, respectively, than the composition with 2 μm HMX. The formulations were subjected to the Small Scale Gap Test, revealing a significant reduction in shock sensitivity with decreasing crystal size. The formulation containing 300 nm HMX registered a shock initiation pressure 1.6 GPa above that of the formulation with 2 μm HMX, a 44 % improvement in sensitivity. These results serve to highlight the relevance of structure‐property relationships in explosive compositions, and particularly elucidate the substantial benefits of reducing the high explosive crystal size to nano‐scale dimensions.     

高品质压装HMX基PBX炸药的冲击波感度

为改善HMX基PBX的安全性能,通过隔板试验研究了高品质HMX的粒度对压装PBX炸药冲击波起爆性能的影响.结果表明·对于相对密度较高(98.5％TMD)的压装HMX基PBX,与普通品质(平均粒径30μm)相比,使用高品质HMX(20 μm)后PBX的冲击波感度下降了7％,当高品质HMX的粒度增至150μm后,其冲击波起...     

Dependence of the Mechanical Sensitivity on the Fractal Characteristics of Octahydro‐1,3,5,7‐tetranitro‐1,3,5,7‐tetrazocine Particles

Three fabrication methods were used to synthesize HMX powders with different particle sizes and microscopic morphologies. All as‐prepared samples were characterized by laser granularity measurements and scanning electron microscopy (SEM). The mechanical sensitivity and thermal stability of the different HMX powders were characterized using mechanical sensitivity tests and differential scanning calorimetry (DSC). Size distribution data and SEM images were used to find the size fractal dimension (D) and surface fractal dimension (D_s) of HMX samples, which were calculated by the least‐squares method and fractal image processing software (FIPS), respectively. The parameters D and D_s quantize two important properties of HMX particles, namely the complexity of the particle size distribution and the irregularity of the particle surface, which affect the thermal conductivity of the particle group if it is exposed to stimuli such as impact, friction or heating. The fractal dimensions reveal the dependence of the mechanical sensitivity of HMX on the powder size, size distribution and microscopic morphology. The results indicate that the proportion of fine particles in HMX powder increases as the D value increases, which causes decreased impact sensitivity. This occurs because hot spot formation leading to an explosion is more difficult because of the improved thermal conductivity of the particle group. Similarly, the surface roughness of HMX particles increases with an increase in D_s, causing an increase in friction sensitivity because of the excessive accumulation of frictional heat. In addition, thermal analysis results indicate that the maximum thermal decomposition rate of HMX decreases with increasing D and D_s.     

Effect of Drying Conditions on the Particle Size,Dispersion State,and Mechanical Sensitivities of Nano HMX

Nano HMX was prepared using a bi‐directional rotation mill and dried in different liquids, at various temperatures, and under different conditions. It was revealed that the samples were caked seriously and the particles tend to aggregate with obviously increased size when dried through ordinary drying in different liquids at 70 °C, which also occurred after vacuum drying. The degree of caking and aggregation was enhanced with increasing temperature. The particles were prevented to grow and the samples were fluffy when supercritical drying, particularly freeze drying, was used. The mechanical sensitivities of the samples marked with I‐HMX, O‐HMX, and F‐HMX, which had average sizes of 120.36 μm, 1.18 μm, and 0.16 μm, respectively, were carried out. Compared with I‐HMX, the friction, impact, and shock sensitivities of O‐HMX were slightly lower, and a significant sensitivity decrease for F‐HMX happened with specific values of 28 %, 42.8 %, and 56.4 %, respectively, which demonstrated significant safety improvement.     

不同粒度HMX的重结晶制备和机械感度研究

采用微团化动态结晶方法和溶剂/非溶剂滴加重结晶方法制备出中位径d50分别为0.472、6.266、36.75μm的HMX颗粒,并采用粒度分析仪和扫描电子显微镜（SEM）对3种试样的粒度进行了表征。测定了3种试样的撞击感度（特性落高H50）和摩擦感度（爆炸百分数）值。测试结果表明,撞击感度随粒度减小逐渐降低,并且在粒度降至亚微米级时降到最低;摩擦感度随粒度减小先升高再降低,而且粒度在10μm～50μm时最为钝感。     

粒度对硝铵类炸药静电火花感度的影响

采用喷射细化法和滴加法分别制备了3种粒度的RDX、HMX、PETN粉末。采用激光粒度分析仪和扫描电子显微镜（SEM）对样品进行了表征,并对其进行了静电火花感度实验。结果表明,随着粒度的减小,RDX、HMX、PETN 3种样品的静电火花感度均逐渐升高。从理论上分析了硝铵类炸药粒度对其静电火花感度的影响。     

Influence of Particle Size and Mixing Technology on Combustion of HMX/Al Compositions

In this work, two widely used components of high‐energy condensed systems – HMX and aluminium – were studied. Morphology, thermal behaviour, chemical purity and combustion parameters of HMX as a monopropellant and Al/HMX as a binary system were investigated using particles of different sizes. It was shown that in spite of the differences in composition and particle size, combustion velocities are almost identical for micrometer‐sized HMX (m‐HMX) and ultrafine HMX (u‐HMX) monopropellants under pressure from 2 to 10 MPa. Replacement of the micrometer‐sized aluminium with ultrafine one in the system with m‐HMX leads to a burning rate increase by a factor of 2.5 and the combustion completeness raise by a factor of 4. Two mixing techniques to prepare binary Al/HMX compositions were applied: conventional and ‘wet’ technique with ultrasonic processing in liquid. Applying wet mixing results in a burning rate increase of 18% compared to the conventional mixing for systems with ultrafine metal. The influence of the component's particle size and the composition microstructure on the burning rate of energetic systems is discussed and analysed.