UDC 538.971; 539.124.143
G. P. Bogatyreva, V. M. Maevsky, M. A. Marinich, Yu. I. Nikitin, V. G. Poltoratsky, A. V. Kozlovsky (Kyiv)
EPR and physicochemical properties of composite materials based on nanodispersed diamonds
The adsorption and catalytic properties of a highly porous (50 and 75‰) composite material containing nanodiamond powder and a binding carbon phase are described. The mechanism of the electrolytic hydrogen evolution process is studied using electron paramagnetic resonance. It is shown that the active centers on which electrocatalytic hydrogen evolution occurs are amorphous carbon films and amorphous zones of nanodiamond particles.
UDC 621.921.34-492.2
S. K. Gordeev, S. G. Zhukov (St. Petersburg) N. V. Novikov, Yu. I. Nikitin, V. G. Poltoratsky (Kiev)
Production and study of grains from diamond-silicon carbide composite material
The results of studying grains from diamond-silicon carbide composite material sintered at low pressures are presented. The grains have high strength and thermal strength properties, high abrasive capacity and can be used in some types of abrasive tools.
UDC 539.26; 666.233
I. V. Selskaya, V. D. Aleksandrov, P. V. Selsky (Makiivka, Donetsk region)
Dependence of the real structure and growth rate of diamond films on the pressure of the gas mixture CH4 + H2 and the temperature of the substrate
X-ray diffraction study of diamond films obtained by the method of chemical transport reaction showed that the films are finely dispersed with large microdeformations and a high dislocation density. It was found that the dependences of the film growth rate and such parameters of their real structure as the average size of mosaic blocks, the magnitude of microdeformation and the density of dislocations in crystallites on the substrate temperature are extreme. A correlation was established between the dependence of the film growth rate on the substrate temperature and the dependence of the parameters of their real structure on the substrate temperature.
UDC 539.216:544.72:546.26-162
L. Yu. Ostrovskaya (Kyiv), A. P. Dementyev, V. G. Ralchenko, I. I. Kulakova (Moscow)
The effect of surface modification of polycrystalline diamond films by ion beams on their hydrophilic-hydrophobic properties
The wettability of polycrystalline diamond films with distilled water was studied depending on the chemical state and surface structure of the films modified by argon ion bombardment and annealing in air. An increase in their hydrophobic properties with increasing irradiation dose was found, which correlates with an increase in the proportion of surface carbon atoms in the sp²-hybridization state. Annealing in air leads to an increase in the hydrophilic properties of the films with an increase in their oxidation state. A method for estimating the sp²/sp³ ratio for diamond-like films based on measuring the wetting angles of the films with a testing liquid is proposed.
UDC 621.762.242: 669.27
V. P. Bondarenko, I. V. Andreev, I. V. Savchuk, L. M. Martynova, A. N. Vashchenko (Kiev)
Features of Tungsten Recovery from its WO3 Oxide in a Closed-Type Reactor
The possibility of using a closed-type reactor for tungsten recovery from its WO3 oxide was established for the first time. The regularities of the formation of especially coarse-grained tungsten powder in a closed-type reactor are described. The role of external and internal diffusion processes is revealed. The possibility of obtaining tungsten powder with particle sizes of up to 300 μm and more in a short (4 h) time is shown.
UDC 620.186:620.22-419
S. V. Tkach (m. Kiev)
Peculiarities of vicoristic scanning electron microscopy in the investigation of composite supersolid materials and rich spherical foam coatings
The features of hardware and software are examined during the modernization of analogue scanning electron microscopes, bringing their technical characteristics closer to the capabilities of current digital microscopes. We have investigated the structure of multi-spherical technological molten coatings, nano-sized solutions and composite supersolid materials based on boron nitride. It is shown that digital images of the surface in a format of 4096×3072 pixels are sufficient to characterize the macrostructure of the material.
UDC 621.921
V. I. Lavrinenko (m. Kiev) L. A. Prots (m. Uzhgorod)
Injection of crystallographic orientation of paratelurite and lithium tetraborate single crystals, extracted by melt spinning, onto the surface microrelief during mechanical processing
The flow of crystallographic orientation of oxygen-free single crystals of paratelurite and lithium tetraborate, extracted by melt spinning, onto the surface microrelief during their mechanical processing is examined. The infusion of the minds of cutting crystals, their orientation and the minds of their mechanical processing into the characteristics of the surface microrelief is shown.
UDC 539.21:621.923
O. V. Lazhevskaya, E. A. Pashchenko, Y. L. Silchenko (Kyiv)
Defects and weather resistance of polished natural stone surfaces
The defectiveness of the polished surface of natural stone has been studied.
The relationship between the defectiveness of the surface layer and the mechanism of structural changes initiated by the contact interaction of granite minerals with polishing composites is analyzed. A method for determining the concentration of defects in the polished surface of natural stone that determine the durability of its original visual characteristics is proposed.
UDC 621.539.4
V. S. Antonyuk, B. A. Lyashenko, E. B. Soroka, A. V. Rutkovsky (Kiev)
On reducing residual stresses in vacuum-plasma coatings of discrete structure
Residual stresses in vacuum-plasma coatings based on titanium nitride are determined. It is shown that replacing a continuous coating with a coating of discrete structure allows reducing residual stresses. The reduction in residual stresses depends on the size of the discrete section and is greater the smaller this section. The proposed approach allows limiting the values of residual stresses in the coating, while maintaining its continuity, and reducing the likelihood of contact failure.
UDC 666.233
V. A. Mukhanov, E. B. Filippova (Aleksandrov, Vladimir Region, Russia)
Synthesis of small high-strength diamond crystals
UDC 669.342.621.14
T. G. Afrikyan (Gavar, Republic of Armenia)
On the issue of the hardness of the diamond-bearing layer of extruded wheels