Influence of laser wavelength on the critical energy density for initiation of energetic materials

Critical densities of the energy of laser initiation of PETN containing nanoscale aluminum inclusions at radiation wavelengths of 1064 and 532 nm were measured experimentally. The critical initiation-energy density that corresponds to a 50%th probability of explosion was 1.15 J/cm² for the first harmonic of a neodymium laser and 0.7 J/cm² for the second. The dependence of the efficiency of radiation absorption by aluminum on the size of metal nanoparticles for the first and second harmonics of a neodymium laser is calculated. It is shown that the particle diameter corresponding to the absorption efficiency maximum and the amplitude of the maximum depend on the radiation wavelength. The absorption efficiency maximum for the first harmonic is observed in an inclusion 204 nm in diameter, and for the second, in an inclusion 96 nm in diameter. The amplitude of the maximum increases from 0.351 at a wavelength of 1064 nm to 0.490 at a wavelength of 532 nm. Dependences of the critical initiation energy density for energetic materials on the radius of metallic nanoparticles are calculated. Qualitative agreement between theoretical and experimental results is shown.     

微型火工品用药剂研究

微型火工品是一种基于MEMS火工技术的火工品.其装药尺寸很小,为了使火工品能正常作用,要求药剂的临界尺寸应尽可能的小.所以研究药剂的临界尺寸对药剂在徽型火工品中的应用有重要意义.本文介绍了药剂临界尺寸的影响因素,在此基础上阐述了徽型火工品用药剂的选取原则.通过对斯蒂芬酸铅和AP/NC固体复合推进剂在不同配方、不同配比下...     

Effect of absorption heterogeneities on the laser triggering of explosive decomposition

Tomsk. Translated from Fizika Goreniya i Vzryva, Vol. 24, No. 6, pp. 98–100, November–December, 1988.     

Effect of absorbing impurities on explosive initiation by laser light

Tomsk. Translated from Fizika Goreniya i Vzryva, Vol. 25, No. 1, pp. 3–9, January–February, 1989.     

Criteria of excitation of explosive decomposition of silver azide by pulsed radiation

The process of explosive decomposition of silver azide in a pulsed electron radiation field was studied by the method of high-speed time-resolution optical spectroscopy. The criteria of excitation of explosive decomposition were determined. It is shown that in the case of short pulses, the critical parameter is the integral energy of the exciting pulse, whereas with the use of long pulses it is the pulse energy flux density.Published for purposes of discussionKemorovo. Translated from Fizika Goreniya i Vzryva, Vol. 28, No. 4, pp. 87–90, July–August, 1992.     

CO-induced decomposition of small Pt particles in K-LTL zeolite

Reduced Pt/K-LTL has been studied with XAFS spectroscopy before and after CO admission at room temperature. The results of the EXAFS data-analysis show that after reduction very small platinum metal particles are present consisting of five to six atoms. CO admission at room temperature leads to complete decomposition of the platinum metal particles and the formation of a platinum carbonyl cluster most probably stabilised by the zeolite walls. Modelling shows that the platinum carbonyl cluster just fits inside the pores of the zeolite-LTL. Analysis of the white line intensities of platinum L_II and L_III X-ray absorption edges reveals that after reduction and in the presence of chemisorbed hydrogen the platinum metal particles in Pt/K-LTL have 0.12% more d-band vacancies than bulk platinum metal. This value increases to 0.34% after CO admission implying-backdonation from platinum to CO, a positive charge on Pt in the newly formed cluster or a combination of both. The results of this study have a large impact on the interpretation of existing literature FTIR CO data obtained on Pt/K-LTL. The results question the validity of CO chemisorption carried out to determine the dispersion of very small platinum particles.     

Action of a laser on a porous explosive substance,without initiation

We have studied the crater formation in specimens of porous explosive materials, the change in the light transmission of thin explosive layers, and the distortion in the shape of light pulses transmitted through such layers, at laser emission energy densities which do not produce initiation of the explosive. It has been demonstrated that these pehnomena are, a consequence of the optical breakdown of a dielectric (the explosive) and the process separating the ranges, in terms of radiant energy density, of linear and nonlinear light interaction with the explosive material.Chernogolovka. Translated from Fizika Goreniya i Vzryva, No. 2, pp. 97–101, March–April, 1991.     

Thermal chemistry and decomposition behaviors of energetic materials with trimerizing furoxan skeleton

Trimerizing furoxans are ideal molecular skeletons for the construction of high energetic substances due to their compact structures and high enthalpy of formations. To explore and compare the thermal behaviors of energetic materials with tandem trimerizing furoxan molecular skeleton, we reported the first systematic research on the thermochemical behaviors and decomposition mechanism of 3,4-bis(3-fluorodinitromethylfuroxan-4-yl)furoxan (BFTF), 3,4-bis(3-cyanofurazan)furazan oxide (BCTFO) and benzotrifuroxan (BTF). According to the research results of the DSC-TG experiments, both the substituted furoxan based energetic compounds (BCTFO and BFTF) exhibited low melting points and complicated thermal decomposition behaviors around 240 °C, while the melting point of unsubstituted furoxan (BTF) was much higher. Their detailed decomposition mechanisms were proposed based on the experimental results through tandem techniques including in-situ FTIR spectroscopy method and DSC-TG-FTIR-MS quadruple technology, which indicated that the cleavage of substituent would trigger the decompositions of BFTF and the decomposition of trimerizing furoxan skeletons almost synchronous occurrence with substituents in BCTFO. The self-oxidation-reduction of the linear and annular trimerizing furoxans lead to similar decomposition fragmented small molecule products.     

Initiation of the explosive decomposition of pentaerythritol tetranitrate with ultradispersed particle additives by laser pulses

The explosive decomposition threshold of pentaerythritol tetranitrate was studied depending on the concentrations of ultradispersed Al particles and Ni-C and Al-C mechanocomposites in the samples. It was found that the critical pulse energy density W _0.5, which corresponds to a 50% probability of explosion, reached a minimum value at additive concentrations of 0.1?C0.3 wt %: W _0.5 = 1.4, 5, or 4 J/cm² for Al, Ni-C, or Al-C, respectively.     

Effect of interfacial heat transfer on the critical conditions of shock-wave initiation of chemical reaction in porous energetic materials

This paper presents the results of numerical analysis of a viscoplastic model for hotspot formation based on the solid-state mechanism of hotspot ignition of an energetic porous material under shock-wave loading. The highly viscous pore collapse regime is considered, which is of great interest for theoretical studies of the shock-wave initiation of heterogeneous energetic materials. Interfacial heat transfer was described under the assumption that the gas is ideal and hence homobaric (uniform in pressure). Parametric analysis was conducted, and characteristic features of the effect of heat transfer and interfacial heat transfer on the critical conditions of shock-wave initiation of chemical reaction in the energetic porous material were determined.     

钝感剂在含能材料中的应用

介绍了蜡钝感剂、石墨钝感剂、硬脂酸钝感剂、键合剂型钝感剂、含能钝感剂、聚合物钝感剂及化学钝感剂等的发展情况,分析了它们的钝感机理,并对钝感剂的发展前景进行了展望。     

纳米复合含能材料的制备研究

综述了纳米复合含能材料几种制备方法:溶胶-凝胶法、溶剂-非溶剂法、高能研磨法、超临界流体法、沉淀法、微乳液法.其中对这些方法的原理和优缺点进行了述评,并对这些方法在纳米复合含能材料制备过程中的具体应用进行了介绍,指出今后研究工作中应该注意的一些问题和研究重点.     

Numerical simulation of the mechanical initiation of liquid explosive systems

The minimum initiation energy is studied numerically as a function of the thickness of a layer of viscous explosive liquid placed in a narrow gap between the plane-parallel surfaces of a striker and an anvil. The statement of the problem simulates the conditions for actual tests of explosives for impact sensitivity. For a given impact force, a layer of liquid with a “soft” type of mechanical behavior is found to exist, which most rapidly acquires energy from a striker and is heated through viscous dissipation of the mechanical energy. It also forms a layer of critical thickness that is characterized by an absolute minimum in the initiation energy. The existence of a layer with a “hard” type of mechanical behavior in the test samples explains the intrinsically nonmonotonic dependence. Translated fromFizika Goreniya i Vzryva, Vol. 35, No. 3, pp. 103–110, May–June 1999.     

新型多氮含能材料概述

主要从合成、物化性能方面简述了几类多氮含能材料:氨基/硝基杂环氮–氧化物、含能叠氮化合物、高氮化合物、钝感多氮高能炸药。结合国内外发展现状,指出了多氮含能材料技术未来发展的主要方向。