UDC 666.233
A. L. D. Skury, G. S. Bobrovnitchii, S. N. Monteiro (Rio de Janeiro, Brazil)
Influence of the graphitization process on the synthesis of diamonds in the C—Ni—Mn system
UDC 666.233-492.2
W. S. Vianna, G. S. Bobrovnitchii, S. N. Monteiro (Rio de Janeiro, Brazil)
Study of the variation of the electric current during the synthesis of diamond powders
UDC 666.233:536.775
E. N. Yakovlev (Troitsk)
Thermodynamic conditions for the formation of diamonds from hydrocarbons
The thermodynamic conditions necessary for the formation of diamonds during the destruction of hydrocarbons (methane, naphthalene) are considered and it is shown that they depend not only on p, T-parameters, but also on the ability of the hydrocarbon-containing ampoule to pass hydrogen. A model is proposed that reflects the features of hydrocarbon pyrolysis at high pressures.
UDC 549.21+666.233
I. I. Fedorov (Novosibirsk)
Experimental and thermodynamic modeling of oxidation-reduction conditions of the genesis of natural diamonds
The oxidation-reduction conditions of the stability of metal-carbon melts at high p, T-parameters were studied and it was found that diamonds crystallizing from them selectively capture oxidized components of the fluid. When hydrogen affects silicate, oxide, sulfide-carbon compositions, diamond formation occurs at p, T-parameters of catalytic synthesis. The velocities of movement of metal inclusions in diamonds under the action of a temperature gradient were measured.
UDC 621.921.34—492.2: 541.128.13
G. P. Bogatyreva, M. A. Marinich, G. A. Bazaliy, V. L. Gvyazdovskaya, E. V. Ishchenko, A. V. Yatsimirsky (Kiev), M. R. Tarasevich, G. V. Zhutaeva (Moscow)
Study of catalytic reactions occurring on a diamond surface in liquid and gaseous media
The possibility of using diamond submicron and nanodispersed powders in heterogeneous and electrochemical catalysis was studied. The temperature of the 100 ‰ transition of CO to CO2 served as a measure of catalytic activity of the studied materials, and the apparent and specific exchange currents served as a measure of electrocatalytic activity. It has been shown for the first time that synthetic submicron and nanodispersed diamond powders are catalysts for heterogeneous and electrochemical catalysis, promising for use in the energy, space and other industries.
UDC 539.89:621.762.5:621.921.34-492.2
A. A. Shulzhenko, A. A. Bochechka, G. S. Oleynik, V. G. Gargin, L. A. Romanko, N. N. Belyavina, S. N. Dub, V. V. Rogov (Kyiv)
Sintering of diamond nanopowder of static synthesis and properties of polycrystals based on it
The results of a study of the processes of consolidation and structure formation during sintering under high pressures and temperatures of diamond nanopowders of static synthesis, prepared by desorption of gases from their surface and sealing the working volume under vacuum conditions, are presented. Plastic fragmentation of the original particles was discovered. The hardness and crack resistance of the obtained diamond polycrystals were determined. Cutters were made from them and tested during microturning of parts made of polystyrene and aluminum.
UDC 620.179.14
Z. T. Nazarchuk, V. G. Ribachuk, B. S. Filyushin (m. Lviv)
Magnetic structuroscopy of supersolid materials
The principles of daily coercimeters are analyzed, which are used to solve the problems of magnetic structuroscopy. The robotic coercimeter VKS-968M, designed for monitoring viruses from sintered supersolid materials, is examined. It has been shown that the use of a three-phase electrical circuit for the magnetization of controlled viruses, as well as the use of a Montgomery coil for the creation of a demagnetizing magnetic field, allows one to significantly change the voltage and dimensions I’ll fix it.
UDC 539.216.2
L. A. Romanko (Kyiv), S. I. Khandozhko (Cluny, France)
Microstructure and electrical properties of thin films of boron nitride
Comprehensive studies of the mechanical, optical and electrophysical properties of BN films were carried out at the stage of deposition of a layer of textured hexagonal boron nitride (hBN). It is shown that hBN films with high compressive stress are characterized by a more ordered structure and have a short-range order. They are photosensitive in the visible spectral range and the temperature dependence of their electrical conductivity is determined by the activation mechanism with a constant activation energy. With an increase in the ion beam energy at low compressive stress, the topological disorder increases, the films acquire properties characteristic of polycrystalline structures.
UDC 621.724 (923)
V. M. Volkogon, V. S. Antonyuk (Kiev)
On the role of graphite-like boron nitride in the formation of residual stresses, strength and performance of materials based on wurtzite boron nitride
The features of the formation of physical and mechanical properties of polycrystalline materials (PSTM) based on wurtzite boron nitride – hexanite-A are studied. The influence of the graphite-like modification BN2 present in hexanite-A on the level of residual stresses after its sintering was assessed, and their relationship with strength and performance of PSTM. The results of the study of the BNв-based material confirm the presence of residual stresses caused by the presence of graphite-like boron nitride.
UDC 546.281
N. F. Gadzyra, G. G. Gnesin, A. A. Mikhailik (Kyiv)
Segregation phenomena in powders of a nonequilibrium solid solution with an excess of carbon atoms replacing silicon atoms in the SiC structure
The mechanism of synthesis of nonequilibrium silicon carbide powders with a reduced lattice parameter using thermally expanded graphite (TEG) is considered. The features of the structural state of the synthesized powders are studied using scanning and transmission electron microscopy, high-resolution X-ray diffraction, and nuclear magnetic resonance (NMR).
UDC 621.91.01:681.3.06
S. P. Vyslouh (Kyiv)
Determination of technological parameters of new tool materials
The article considers the issues of determining the technological parameters of new tool materials. Numerical methods, pattern recognition methods and nonlinear mathematical programming methods are used to establish optimal conditions for their use.
UDC 621.922.02-49.2:697.8.052
Yu. D. Filatov, V. I. Sidorko, V. P. Yashchuk, G. F. Gorbachov, V. V. Skryabin, V. G. Kramar (Kyiv)
Finishing and surface control of parts made of aluminosilicate materials
The article presents the results of a study of the regularities of the finishing process of aluminosilicate materials. The influence of the elastic modulus of the working layer of the tool on the nature of its wear and the shaping of the treated surfaces is studied. The results of the study of the state of surfaces processed in the nonequilibrium polishing mode are presented.
UDC 539.218:621.921.34-492.2
A. A. Bochechka, L. A. Romanko, V. S. Gavrilova (Kiev)
On the density of particles of dynamic synthesis diamond nanopowder
UDC 536.76
A. A. Kurakevich (Kyiv)
On the issue of the applicability of the Avrami relation in describing the kinetics of solid-phase transformations