Laser ignitibility of insensitive secondary explosive 1,1-diamino-2,2-dinitroethene (FOX-7)

Abstract

An experimental investigation into laser ignitibility of insensitive secondary explosives, 1,1-diamino-2,2-dinitroethene (FOX-7) has been carried out, using a diode laser of continuous wave at the laser wavelength of 974 nm. The direct optical ignition of an insensitive explosive will add more safety features to insensitive munitions (IM) or explosive devices. In this study, effects of laser parameters on the ignitibility were analysed in terms of laser ignition threshold, the times to initiate the ignition and full combustion, and burning sustainability. The results have shown that carbon black (CB) as an optical sensitizer is compatible with FOX-7, and significantly enhances laser ignitibility of the explosive when a small amount of CB is uniformly doped in FOX-7. The delay times for ignition and subsequent development of sustainable burning of the material are mainly determined by ignition laser power, although the other laser parameters have effects. The minimum laser power required to ignite the optically sensitized FOX-7 was found below 10 W and a fast ignition was initiated in as short as 70 μs by a laser power of 40 W. Also the effect of the mixture uniformity of FOX-7/CB on laser ignition performance was evaluated in this study.

Laser Ignition of an Optically Sensitised Secondary Explosive by a Diode Laser

“…Laser ignition of explosive devices has been actively investigated in recent decades [1][2][3][4][5][6][7][8][9][10] with the aim of replacing electrical ignitors with laser based systems. Both ignition and initiation have been achieved by using high power lasers, e.g.…”

“…However, optical sensitisation of explosives by doping them with a small amount of light absorbing material provides an effective method to enhance the laser ignition sensitivity. Many research results [10][11][12][13][14][15][16][17] have reported significant reductions in the laser power required for ignition by using an optical sensitizing material, mostly carbon black. They showed that the addition of carbon black, at a typical doping concentration of ~3 wt.%, to explosive samples resulted in a significant increase in absorption and thus many fold enhancement of ignition sensitivity.…”

The Many Faces of FOX‐7: A Precursor to High‐Performance Energetic Materials

“…[ 15] In a continuing effort to seek less sensitive, more powerful, eco-friendly HEDMs, our interest focused primarily on the modification of the molecular structure of FOX-7 to obtain new HEDMs that contain a high percentage of oxygen and nitrogen and lower amounts of carbon and hydrogen. We noted that the molecular structure of FOX-7 contains the functional group =C(NH 2 ) 2 , similar to nitroguanidine.…”

The Many Faces of FOX‐7: A Precursor to High‐Performance Energetic Materials

“…Furthermore, the sensitivity to impact and friction of FOX-7 and, thus to involuntary detonation, is markedly lower. [15] In ac ontinuing effort to seek less sensitive,m ore powerful, eco-friendly HEDMs,o ur interest focused primarily on the modification of the molecular structure of FOX-7 to obtain new HEDMs that contain ahigh percentage of oxygen and nitrogen and lower amounts of carbon and hydrogen. Forf uture applications, FOX-7 is considered an important preferred component of propellants and has attracted interest from researchers for its high potential in diverse applications.Many studies have been performed on the synthesis, [9] molecular structure, [10] reactions, [11] theoretical calculations, [12] thermal behavior, [13] explosive performance, [14] and applications of FOX-7.…”