Specific features of the structure of detonation nanodiamonds from results of electron microscopy investigations

Байтингер, Е. М.; Belenkov, E. A.; Brzhezinskaya, M. M.; Greshnyakov, V. A.

doi:10.1134/s1063783412080057

Cited by 28 publications

(7 citation statements)

References 19 publications

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“…These data evidence an insignificant increase in interatomic distances and, consequently, the crystal-lattice parameters of nanodispersed diamond particles when compared with the bulk diamond crystal and experimentally confirm the calculations presented in [24]. An insignificant exceeding of the lattice parameter of DND nanocrystals when compared with the bulk diamond crystal was also noted in [23,25]. We can assume that, in addition to other factors, the effect of increasing interatomic distances in lattices of nanodispersed diamond crystals probably introduces the partial contribution to the observed decrease in the pycnometric density of NND and DND powders when compared with the density of bulk diamond crystals (Table 1).…”

Section: Resultssupporting

confidence: 86%

“…A tremendous number of works (for example, [13,[25][26][27][28][29][30]) is devoted to the problem of studying the fine structure of nanodispersed diamonds, but detonation-synthesis nanodiamonds are considered in most of them. Some authors consider the structural features of diamond nanoclusters of the static [21] and laser synthesis [6,23], as well as diamond nanoparticles revealed in meteorites [31].…”

Section: Resultsmentioning

confidence: 99%

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Comparison of Morphological and Structural Characteristics of Nanopowder Particles Fabricated by Grinding Natural Diamond and Detonation Synthesis

Sharin

Sivtseva

Yakovleva

et al. 2020

Russ. J. Non-ferrous Metals

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Specific features of the morphological and structural characteristics of nanopowder particles fabricated by grinding bulk natural diamond and by detonation synthesis are investigated. It is shown by highresolution transmission electron microscopy, scanning electron microscopy, and low-angle X-ray scattering that, in contrast with the detonation synthesis nanopowder, which consists of similar in size and isometrically primary particles, natural diamond particles fabricated by grinding have a broader spread in regards to size and a preferentially platelet form. It is established by the X-ray structural phase analysis and Raman spectroscopy used in addition to above-listed methods that the structure of particles of nanodiamond formed from natural diamond is similar to the structure of detonation-synthesis nanodiamond. Each particle of natural nanopowder, similarly to detonation-synthesis nanodiamond, consists of a diamond core having a crystal lattice of the cubic crystal system and a shell containing mainly nondiamond forms of carbon with sp 2 hybridization with a complex structure. The data on the evaluation of the average particle size of nanopowders of natural diamond and detonation synthesis by three methods, including BET, show results that satisfactorily agree with each other. Herewith, an average particle size of natural powder nanoparticles is close to 24 nm, while that of detonation-synthesis nanodiamonds of the UDA-S-GO brand produced by FRPC Altai is close to 5.6 nm. An insignificant increase in interatomic distances in diamond nanocrystals is revealed when compared with the bulk diamond crystal. The investigation and analysis of numerous images of natural diamond nanocrystals and detonation synthesis nanocrystals formed by high-resolution transmission electron microscopy show that the dislocations and point defects are most often defects in nanodiamonds.

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Section: Resultssupporting

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Comparison of Morphological and Structural Characteristics of Nanopowder Particles Fabricated by Grinding Natural Diamond and Detonation Synthesis

Sharin

Sivtseva

Yakovleva

et al. 2020

Russ. J. Non-ferrous Metals

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show abstract

“…While the impact of scattering in a diamond monocrystal is minimum at the boundaries, the sintered detonation diamond with a size of a nanocrystal of about 4.5 nm [15] demonstrates the maximum impact of the boundaries upon scattering. The quasi-ballistic character of the motion of phonons in diamond nanocrystals [4] and the anomalously high specific surface of the boundaries that reaches 300 m 2 / g [16], give grounds to conclude that the scattering material plays a dominant role in the formation of thermal resistance at the boundaries.…”

Section: Resultsmentioning

confidence: 99%

Heat-conducting properties of thermobarically-sintered detonation nanodiamond

Плотников

Bogdanov

et al. 2022

Lett. Mater.

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The research was conducted to study the thermal conductivity of detonation nanodiamonds-based composites. Composite nanodiamond materials were obtained in the course of thermobaric sintering at the press-free high-pressure apparatus (BARS) under 5 GPa and at temperatures within the range of 1100 -1500°С. It was ascertained that unlike diamond monocrystals with their thermal conductivity reaching up to 2100 W / (mK), the thermal conductivity of a nanodiamond composite is considerably lower and does not go beyond 18 W / (mK). Specifically, the temperature dependence of the thermal conductivity coefficient of a nanodiamond composite is anomalous as compared to a similar dependence in diamond monocrystals. The thermal conductivity coefficient in diamond monocrystals grows in compliance with the rising temperature, whereas it shows practically no changes in a nanodiamond composite in the temperature range of 50 -300°С. Such a temperature dependence of the thermal-conductivity coefficient is apparently related to the features of the phonon spectrum of diamond monocrystals. This feature is stipulated by the dependence of the phonon spectrum of nanocrystals on their size, represented by a set of phonon modes in the range of the wave vector 0 < q <1 / L, i.e., the size of a diamond nanocrystal of 4.5 nm is alleged to limit the excitation of harmonics during nanodiamond composite heating, as opposed to macroscopic crystals that demonstrate the excitation of higher-frequency phonon modes during temperature growing.

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“…Thus, the existence of the SAED reflex 102 cannot be a rigorous proof of the hexagonal diamond existence. Indeed, observation of the layer packing order in diamonds by high‐resolution transmission electron microscopes show that the 100% hexagonality characteristic of the 2 H polytype is not seen in nanodiamonds, which evidences the absence of pure 2 H polytype.…”

Section: Possibility Analysis Of Experimental Diffraction Identificatmentioning

confidence: 99%

“…At best, the carbon component of this mineral is a mixture of 2 H and 3C polytypes or diamond‐like material with randomly packed layers . Various methods for synthesizing artificial diamonds almost always produce only cubic diamond . To reliably confirm that hardness of 2 H diamond polytype is higher than that of 3 C diamond polytype, it is necessary to synthesize 2 H polytype.…”

Section: Introductionmentioning

confidence: 99%

Theoretical Investigation of Phase Transitions of Graphite and Cubic 3C Diamond Into Hexagonal 2H Diamond Under High Pressures

Greshnyakov

Belenkov

Brzhezinskaya

2019

Physica Status Solidi (b)

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Possible techniques for experimentally obtaining hexagonal diamond are studied in the scope of the density functional theory method. It has been found that hexagonal diamond may be created as a result of structural transition at 61-68 GPa uniaxial compression from orthorhombic AB graphite and at 57-66 GPa from hexagonal AA graphite. Also the formation of hexagonal diamond is shown to take place in case of very strong (300-380 GPa) compression of cubic diamond. X-ray and electron-microscopic data on nanodiamonds from meteorite craters are analyzed for the presence of hexagonal diamond. The analysis shows that impact-origin carbon materials do not contain pure cubic and hexagonal diamonds, and the layers of nascent crystals of diamond polytypes are randomly packed.

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Specific features of the structure of detonation nanodiamonds from results of electron microscopy investigations

Cited by 28 publications

References 19 publications

Comparison of Morphological and Structural Characteristics of Nanopowder Particles Fabricated by Grinding Natural Diamond and Detonation Synthesis

Comparison of Morphological and Structural Characteristics of Nanopowder Particles Fabricated by Grinding Natural Diamond and Detonation Synthesis

Heat-conducting properties of thermobarically-sintered detonation nanodiamond

Theoretical Investigation of Phase Transitions of Graphite and Cubic 3C Diamond Into Hexagonal 2H Diamond Under High Pressures

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