Mechanism of Consolidation of Nanoparticles in Diamond-Boron Oxide System at High Pressure and Temperature

Bykov, A.; Oleynik, G. S.; Ragulya, A. V.; Timofeeva, I. I.; Klochkov, L. A.; Kovalev, A. V.

doi:10.4028/www.scientific.net/msf.518.189

Cited by 2 publications

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References 3 publications

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“…In parallel, CSRs expand to 46-51 nm. It is assumed that this CSR expansion under high pressure and at room temperature results from the coherent aggregation of nanoparticles by the mechanism of cooperative diffusion coalescence [14]. This process may be regarded as a basis for subsequent structural transformations.…”

Section: Resultsmentioning

confidence: 99%

Making and structural features of Ti-N-B and Ti-N-C nanocomposites

Быков

Timofeeva

Klochkov

et al. 2008

Powder Metall Met Ceram

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0.5 ) and obtaining high-density ceramics with enhanced mechanical properties. An x-ray structural analysis is used to examine how the 5 crystalline structure evolves during temperature-pressure treatment, which produces new ceramic materials. Based on the properties of the polycrystalline materials obtained, the temperature-time mode for the consolidation of initial nanopowders is determined to ensure favorable parameters of sintered nanograined ceramics.Refractory compounds with unique properties [1, 2] are widely used in producing composite materials. Therefore, the properties of refractory compounds need to be further improved by making complex polyatomic compounds with controlled composition and obtaining their superfine or nanostructured forms.Nanostructured materials exhibit excellent mechanical properties. Therefore, it is important to examine the formation of nanograined polycrystals in the sintering of refractory nanopowders to produce nanostructured ceramics.One of the efficient methods to produce nanocrystalline materials is to sinter nanopowders under high quasihydrostatical pressures. Grigorii Samsonov regarded high pressures as an important parameter that can substantially improve properties [3].High pressures lead to nonequilibrium thermodynamic conditions within the material sintered. The nonequilibrium of the system is enhanced by rapid heating under pressure (50-100 °C/sec). Nanodisperse systems are, in turn, thermodynamically nonequilibrium as there is excess free surface energy. Such a compressed porous system evolves in accordance with Le Chatelier's principle and tends to become less nonequilibrium because of the mobility of atoms. The mobility of atoms may intensify when different phases interact under pressure-temperature impacts leading to the efficient densification of the system. High pressures, which initiate the intensive deformation of the system, substantially contribute to the consolidation. This paper examines how ceramic nanograined polycrystals based on Ti-N-B and Ti-N-C refractory titanium compounds are produced. MATERIALS AND METHODSNanocrystalline mixtures of titanium nitride (80 wt.%) and titanium diboride (20 wt.%) powders and titanium carbonitride powder were used as the initial materials. They were produced by plasma chemical synthesis and supplied by Plasma

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Section: Resultsmentioning

confidence: 99%

Making and structural features of Ti-N-B and Ti-N-C nanocomposites

Быков

Timofeeva

Klochkov

et al. 2008

Powder Metall Met Ceram

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“…The difficulty of sintering diamond nanoparticles is connected with the low diffusive mobility of carbon atoms in the diamond lattice, which is due to covalent type of the chemical bond [8]. Therefore, it is assumed that, for densification and sintering of these nanodiamonds, additives will be efficient if they are homogeneously distributed in the system of nanoparticles and act as scavengers for impurities located on the particles surface.…”

Section: Introductionmentioning

confidence: 99%

Nanoparticles Consolidation Mechanism at High Pressure and High Temperature in Diamond-B-Si-Cu System

Skury¹,

Monteiro

Azevedo

et al. 2012

MSF

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The synthesis of advanced materials with superior performance and properties is of growing scientific and technological interest. In particular, significant achievements have been attained in the synthesis of nanocomposites associated with superhard materials. This work investigates nanostructured composites obtained by high pressure and high temperature sintering of synthetic diamond combined with boron, silicon and copper. Diamond powder was mixed with B, Si and Cu, also in the form of powder. The mixture was then submitted to high energy wet milling until a nanopowder was formed. Sintering of this resulting nanopowder was carried out at 5.6 GPa of pressure and 1300°C. X-ray diffraction and scanning electron microscopy analysis revealed the formation of new phases in a well consolidated nanostructure with relatively high density.

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Mechanism of Consolidation of Nanoparticles in Diamond-Boron Oxide System at High Pressure and Temperature

Abstract: The high pressure sintering process of nanocrystalline diamond powder was studied. The influence of the liquid phase on the base of boron oxide was analyzed. The mechanism of cooperative-diffusive coalescence, which acts during sintering of ultradisperse diamond powders, is proposed.

Cited by 2 publications

References 3 publications

Making and structural features of Ti-N-B and Ti-N-C nanocomposites

Making and structural features of Ti-N-B and Ti-N-C nanocomposites

Nanoparticles Consolidation Mechanism at High Pressure and High Temperature in Diamond-B-Si-Cu System

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