Transmission electron microscopy and x-ray diffraction studies of the detonation soot of high explosives

Kashkarov, A. O.; Pruuél, É. R.; Тен, К. А.; Рубцов, И. А.; Gerasimov, E. Yu.; Zubkov, P. I.

doi:10.1088/1742-6596/774/1/012072

Cited by 16 publications

(12 citation statements)

References 10 publications

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“…Representative transmission electron microscopy images of different categories of nanocarbon particulates found in the soot samples are shown in Figure 5. Consistent with previous reports, [ 45,54–57 ] TEM observations revealed a mixture of different carbon allotropes present in the soots of most explosives. Mixtures of nanodiamond and graphite fibers were observed in soots generated by Comp B, HNS IV, TNT, and FOX‐7.…”

Section: Resultssupporting

confidence: 92%

Raman signatures of detonation soot

Villa‐Aleman

Darvin

Nielsen

et al. 2022

J Raman Spectroscopy

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Soot generated from the detonation of nine explosives was investigated with Raman microspectroscopy and high-resolution transmission electron microscopy (HRTEM). The first order bands, located at approximately 1,580 (G), 1,350 (D1), 1,620 cm À1 (D2), 1,500 (D3), and 1,200 (D4), are used to provide information on the carbon allotropes and defects. The intensity ratios and the full-width at half-maximum provide an indication of the disorder in the material. The Raman spectra of soot acquired from the detonation of nine explosives showed differences which can be used to identify the precursor explosive. Most differences in the spectra were correlated with the presence of amorphous carbon in the soot. In additional to identification of distinct bands in the spectra via deconvolution, principal component analysis was also used to differentiate the different types of soot. HRTEM performed on soot samples with different explosive precursors identified several distinct allotropes of carbon such as nanodiamonds, carbon onions, graphite fibers, and amorphous carbon.

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Section: Resultssupporting

confidence: 92%

Raman signatures of detonation soot

Villa‐Aleman

Darvin

Nielsen

et al. 2022

J Raman Spectroscopy

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“…Exact mechanisms of nanodiamond formation during these detonations are uncertain; some posit a liquid to solid transition while others claim diamond forms under a process more similar to chemical vapor deposition . Other high explosives such as HNS, TATB, and BTF produce widely varying nanostructured particulates with differing morphologies and graphitic vs. diamond content . Of interest is what extent the explosive composition vs. the pressures and temperatures attained affect resultant condensed carbon particulates.…”

Section: Introductionmentioning

confidence: 99%

Observation of Variations in Condensed Carbon Morphology Dependent on Composition B Detonation Conditions

Hammons

Nielsen

Bagge‐Hansen

et al. 2020

Propellants Explo Pyrotec

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Carbon particulates generated during detonation depend upon high explosive type, composition, and detonation conditions. Although explosive composition greatly affects particulates, the focus of this work is on how detonation geometries that induce much higher temperatures and pressures in the high explosive lead to differing particulate morphologies. In this study, two geometries were used: Detonations were initiated in Composition B cylinders at one end in conventional detonations and initiated at both ends to produce colliding detonations. Each of these detonations was observed on the sub‐μs timescale using fast radiography capturing images of the front moving through the cylinder, and colliding detonation fronts in real‐time. These imaging experiments were complemented with time‐resolved small‐angle x‐ray scattering (SAXS) experiments that were able to observe and determine the varying condensed carbon morphologies at different locations and times in each detonation. The detonations could be timed in such a way that the spatial and temporal dependence of the carbon morphology could be superimposed onto radiography images collected at the same point in time. The complementary approach is able to show that the carbon condensates are much larger when formed in the elevated temperature and pressure conditions near the location of colliding detonation fronts. Thermochemical modeling suggests that these larger particulates form either in the diamond phase or on the liquidus line of the carbon phase diagram. The increase in size observed by SAXS may correlate well with the increased residence time deeply in the diamond phase. These particulates can be described as nano‐sized phases with some surface texture or otherwise near‐surface intra‐particle heterogeneity.

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“…The liquid phase of carbon is very difficult to study experimentally and has been observed above the graphite/diamond/liquid triple point at ~12 GPa/5000 K using laser or Joule heating of bulk carbon 16,17 . In detonation literature, however, the liquid state is usually inferred from the size and morphology of nanodiamonds in late time detonation products, notably for BTF 18,19 . From these indirect observations, liquid droplet formation and solidification have been suggested to occur over several microseconds through coalescence of smaller droplets and concomitant adiabatic cooling; however, no early time experimental results have verified the existence of liquid carbon or the timescales suggested during HE detonation 2 .…”

Section: Introductionmentioning

confidence: 99%

Detonation synthesis of carbon nano-onions via liquid carbon condensation

et al. 2019

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Transit through the carbon liquid phase has significant consequences for the subsequent formation of solid nanocarbon detonation products. We report dynamic measurements of liquid carbon condensation and solidification into nano-onions over ∽200 ns by analysis of time-resolved, small-angle X-ray scattering data acquired during detonation of a hydrogen-free explosive, DNTF (3,4-bis(3-nitrofurazan-4-yl)furoxan). Further, thermochemical modeling predicts a direct liquid to solid graphite phase transition for DNTF products ~200 ns post-detonation. Solid detonation products were collected and characterized by high-resolution electron microscopy to confirm the abundance of carbon nano-onions with an average diameter of ∽10 nm, matching the dynamic measurements. We analyze other carbon-rich explosives by similar methods to systematically explore different regions of the carbon phase diagram traversed during detonation. Our results suggest a potential pathway to the efficient production of carbon nano-onions, while offering insight into the phase transformation kinetics of liquid carbon under extreme pressures and temperatures.

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Transmission electron microscopy and x-ray diffraction studies of the detonation soot of high explosives

Cited by 16 publications

References 10 publications

Raman signatures of detonation soot

Raman signatures of detonation soot

Observation of Variations in Condensed Carbon Morphology Dependent on Composition B Detonation Conditions

Detonation synthesis of carbon nano-onions via liquid carbon condensation

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