UDC 546.26-162:620.22-419.8
N. V. Novikov, Yu. I. Nikitin, G. P. Bogatyreva, M. G. Loshak, V. G. Poltoratsky, Ya. V. Ivaskevich (Kyiv)
On porous composites from ultra-dispersed diamonds obtained by compaction at low pressures
A highly porous composite material was created using nanodiamond powders compacted at low pressures. Technological equipment was developed and improved, optimal modes for obtaining the material were substantiated, its physical and mechanical properties and recommended area of effective application were described.
UDC 539.26:548.4:666.233
V. M. Maevsky, S. A. Ivakhnenko, O. A. Zanevsky, I. S. Belousov, T. V. Kovalenko, A. V. Kozlovsky (Kiev)
Mandelstam-Brillouin Light Scattering in Single-Crystal Synthetic Diamonds
The elastic properties of natural and large synthetic diamond single crystals of different types were studied using the Mandelstam-Brillouin light scattering method. The obtained data showed that the elastic constants of undoped and nitrogen- and boron-doped synthetic diamonds are close to those of natural diamonds. Small differences in the values of these constants are associated with different stresses in the crystal lattice due to different amounts of defects and macroinclusions in the samples. It is shown that the Mandelstam-Brillouin light scattering method can be used for non-destructive assessment of the quality and identity of the elastic properties of single-crystal diamonds obtained by different methods and with variations in the technology of their manufacture.
UDC 541.12.034:546.273
L. F. Kulikova, N. A. Bendeliani (Troitsk, Moscow Region, Russia)
Crystallization of cubic boron nitride in ammonium borate melts
In the p, T-region of stability of the cubic phase of boron nitride, the chemical reaction of boron with a mixture of hydrazine and water was experimentally studied in order to obtain ammonium borates of the general composition x(NH4)2O×B2O3, the melts of which activate the transition of the hexagonal modification of BN to the cubic one. It was found that the baric dependence of the onset temperature of this transition found for the composition at x = 5 is universal for a wide (½ < x ≤ 5) range of x values.
UDC 621.793.002.3-419
V. Yu. Dolmatov, G. K. Burkat, E. A. Orlova, M. V. Veretennikova (St. Petersburg)
Electrochemical deposition of metal alloys with detonation nanodiamonds
It was shown that the introduction of detonation nanodiamonds into electrolytes for the electrochemical deposition of Sn-Pb, Sn-Sb and Ag-Sb alloys leads to a significant improvement in the properties of the coatings, such as wear resistance, microporosity, solderability and the scattering capacity of the electrolytes.
UDC539.4:620.2
M. G. Loshak, S. B. Polotnyak, L. I. Aleksandrova (Kiev)
Numerical modeling of the stress-strain state of tungsten hard alloys after sintering
Numerical modeling was used to estimate the stress-strain state that is formed in individual elements of the microstructure of tungsten hard alloys with different cobalt content as a result of their cooling to room temperature after sintering. It was shown that the stress state in the carbide and cobalt phases is non-uniform. The sign and magnitude of stresses in individual elements of the structure of hard alloys depend on the contact conditions of carbide grains and the cobalt phase and the nature of the transfer of compressive load during alloy cooling through tungsten carbide grains and cobalt phase interlayers.
UDC 541.138.2:546.261
V. A. Lavrenko, A. P. Umansky, V. A. Shvets, V. P. Konoval, A. D. Panasyuk, S. S. Chuprov (Kiev)
Corrosion of composite materials based on titanium and chromium carbides in seawater
The potentiodynamic method was used to study the corrosion characteristics of ceramic and metal-ceramic composite materials based on individual carbides and double titanium-chromium carbide in seawater. It was shown that both types of materials have higher corrosion resistance compared to stainless steel due to the formation of oxide films on their surface. The introduction of a metal binder (especially Ni-Cr) into the composition of composite materials does not reduce, but rather slightly increases the corrosion resistance of double titanium-chromium carbide.
UDC 621.921: 666.1
S.A. Kukharenko, A.E. Shilo, E.K. Bondarev (Kyiv)
Structural transformations in a mixture of glasses of sodium borosilicate and lead zinc borosilicate systems upon heating
The results of a study of the interaction in a mixture of oxide glasses with different softening temperatures in sodium borosilicate Na2O—B2O3—TiO2—SiO2 and lead zinc borosilicate PbO—ZnO—B2O3—SiO2 systems upon heating are presented. The prospects of using a mixture of glasses for the manufacture of composite tool materials on ceramic bonds with high performance characteristics are shown.
UDC 621.919
O. A. Rosenberg (Kyiv) Yu. A. Tsekhan (Voronezh, Russia) S. E. Sheikin (Kyiv)
On some patterns of strengthening of the surface layer during deforming drawing
The zone of localy plastic deformation during the process of deforming drawing. It was established for the first time that when using solid lubricants, a texture is formed in the surface layer of the workpiece, and that local plastic flow of metal in the contact zone occurs under any deforming drawing conditions. A method for calculating the depth of the hardened layer at the design stage of the technological process is proposed.
UDC 621.9.025.7
S. A. Klimenko (Kyiv)
Ranking of tool polycrystalline superhard materials by wear resistance
The possibility of using deformation-spectral analysis for the purpose of ranking the wear resistance of polycrystalline superhard materials for tool purposes without conducting resistance tests during cutting is shown.
UDC 669.312.621.95
T. G. Afrikyan (Gavar, Republic of Armenia)
Temperature conditions of extrusion and sintering of diamond extruded wheels
The temperature field of extrusion during the formation of the body and diamond-bearing layer of diamond grinding wheels was studied, its optimal values were established (press mass – 85-90 °C, press mold – 35-45 °C). The mode of preliminary heat treatment was determined – heating at a rate of 3.5 degrees / min to 160 ° C and holding for 5 minutes.
UDC 661.657.5
V. A. Mukhanov (Aleksandrov, Vladimir Region, Russia) A. V. Guryev, V. V. Guryev, V. V. Malchukov (Tomilino, Moscow Region, Russia)
Extraction of cubic boron nitride from sinters