Specific Features of Synthesis of Detonation Nanodiamonds

Abstract

It is demonstrated that the Chapman-Jouguet parameters for high explosives used in nanodiamond synthesis are located in the region of liquid nanocarbon; therefore, the chemical reaction zone of the detonation wave involves formation of carbon nanodroplets, which are later crystallized into nanodiamonds on the segment of the isentrope of expansion of detonation products, passing through the region of stability of nanodiamonds in the pressure range of 16.5-10 GPa and the temperature range of 3400-2900 K. Soot in the resultant mixture is the product of amorphization of nanodroplets rather than graphitization of ultrafine diamonds. The influence of detonation conditions of high-explosive charges in an explosive chamber on nanodiamond synthesis is analyzed.

Kinetics of electrical conductivity of TATB detonation products as an indicator of growth of carbon nanoparticles

“…The second assumption seems to be well grounded by the theory [13] and is supported by the results of gas-dynamic experiments performed with a high time resolution [17,18,20]. Hence, the experimental data support the exponential dependence of DP conductivity on temperature with an activation energy of the order of 1 eV, which is typical of the thermal mechanism.…”

“…Slow kinetics involves residual energy release in detonation products in the course of growth of carbon clusters: they are assumed to emerge in the reaction zone and then grow comparatively slowly outside the latter. The advanced concepts on the physics of formation of carbon nanoparticles are discussed in [13], where various possible mechanisms of growth of carbon nanoparticles outside the chemical reaction zone are considered in detail.…”

Molecular dynamics modelling of nanocarbon cluster properties under conditions close to HE detonation

“…This phenomenon has often been observed in experiment [1][2][3][4][5][6][7][8][9][10][11] and is a subject of theoretical research including phenomenological studies with EOS (e.g., the BKW) and macrokinetics models [12] and more detailed studies into the physics of carbon condensation in detonation products, its phase states, and kinetics of carbon particle growth/vaporization (see, for example, [13]). …”

On the mechanism of carbon nanostructures formation at reaction of organic compounds at high pressure and temperature

“…Aggregation of carbon atoms is determined by diffusion and proceeds in picoseconds. 33,40 At thermodynamic parameters characteristic for the detonation, the state of carbon corresponds to the condensed phase, 7,10 in contrast to other substances (N, N 2 , H 2 O, H, O, CO, CO 2 , etc.). Probability of aggregation at a collision of two carbon atoms is close to 100%, whereas reactions of gaseous substances under the detonation conditions require of order of 1000 collisions for one elementary reaction.…”

“…The viewpoint of the existence of single particles is shared by many authors (see for example [5][6][7][8][9][10] ). In the work, 5 a dynamic model of carbon condensation at the detonation of trinitrotoluene (TNT) was proposed based on the results of the electric conductivity investigation.…”