UDC 621.921.34-488:621.891
E. Uhlmann, M. Bruecher, R. Kott (Berlin)
Tribological Behavior of CVD Diamond as Cutting Tool Material
UDC 666.233
IN. M. Overturned, O. B. Loginova, O. G. Kulyk, A. I. Borymskyi, P. AND. Nagorny (Kyiv)
Capillary phenomena, phase equilibria and crystallization of diamond in the Co—Mn—C system
Peculiarities of spontaneous crystallization of diamond from a Co—Mn—C melt are investigated and their interrelationship with capillary phenomena and phase equilibria is considered.
UDC 621.9.025.7
AND. G. Knyazeva (Tomsk, Russia), I. L. Pobol (Minsk, Belarus)
Analysis of final stress in the STM-base connection
Presented are the results of experimental and theoretical studies of the method of obtaining a permanent connection of ceramics, including superhard materials with metals or hard alloys. The results of studies of the adhesive interaction of cubic boron nitride (CBN) with active solders, diffusion processes at the boundaries of CBN-solder-base, mechanical tests of the strength of such compounds, and the distribution of final stresses in the system are considered. Analytical solutions to the problem of diffusion of elements from the solder in the KNB have been constructed. The interrelationship of stresses and strains in the attached element of the KNB with the intensity of diffusion of the active element in it is considered.
UDC 541.13
I. AND. Novoselova, E. IN. Panov, E. N. Fedoryshena, L. AND. Romanko, A. G. Gontar, V. Yu. Horokhov (Kyiv)
Electrochemical behavior and corrosion of a-C:H films in neutral aqueous solutions
Data on voltammetry, optical microscopy of the surface, kinetics of the redox reaction in the Fe(CN)6 system for a-C:H films on various substrates in aqueous solutions are presented.
UDC 621.791.357:669.35
IN. M. Overturned, S. M. Samokhin, O. G. Kulyk, M. AND. Opanasenko (Kyiv)
Peculiarities of the contact interaction of dispersion-hardened copper with adhesively active metals and their kinetic characteristics of spreading and wetting
The processes of wetting and spreading of liquid solders based on copper, containing adhesively active elements titanium, zirconium, hafnium, on the surfaces of composite copper and its components — oxygen-free copper and aluminum oxide — are investigated. The contact interaction of zirconium with oxygen-free and dispersion-hardened copper was investigated using the DTA method. The results of the research made it possible to establish a relationship between the processes occurring during heating of dispersion-hardened copper in contact with zirconium, and the kinetic patterns of wetting of composite copper with copper-zirconium melts. It was established that the specific features of wetting, which distinguish the [Cu-44 ‰ (at.) Zr]-composite copper solder system from other studied systems, are largely due to a complex mechanism, as well as a wide temperature range of contact interaction in the indicated system.
UDC 661.657.5
N. P. Bezhenar, S. AND. Bozhko, N. N. Beliavyna, V. I. Markiv, P. AND. Nagorny (Kyiv)
Phase composition of polycrystals obtained during reaction sintering of cubic boron nitride with aluminum
The phase composition of polycrystals obtained by reaction sintering of BNcf powders with aluminum was investigated using X-ray diffraction analysis, depending on the pressure and temperature of sintering, and the dispersion of cubic boron nitride. It is shown that the crystallization of aluminum borides is preceded by the formation of a boron solution in the Al melt. With increasing temperature and decreasing pressure, higher aluminum borides prevail. The possibility of regulating the phase composition of polycrystals is shown.
UDC 536.631
A.A. Leshchuk, N.V. Novikov (Kiev), V.I. Levitas (Lubbock, USA)
Thermomechanical model of the phase transformation of graphite into diamond
A thermodynamic criterion for the phase transformation of graphite into diamond is proposed, taking into account the contribution of the potential energy of elastic deformation to the free energy of the system. Curves of the direct transformation of graphite into diamond have been determined, which are in good agreement with known data. It is proved that the predominant contribution of the energy of the internal tension is in the amount of excess of the transformation pressure above the equilibrium one at the given temperature.
UDC 669.018.25
L. G. Bodrova, V. P. Bodrov, V. IN. Lazaryuk (Ternopol)
High-temperature oxidation of a hard alloy based on titanium and niobium carbides with a nickel-chromium bond
The process of oxidation in air of a hard alloy based on titanium and niobium carbides with a nickel-chromium bond was studied by the thermogravimetric method in the temperature range of 1173-1393 K. At the initial stage, the kinetic process is described by a logarithmic dependence, and then by a linear or parabolic one. The values of the apparent activation energy for the logarithmic, linear, and parabolic sections of the kinetic curves are 156, 117, and 218 kJ/mol, respectively. The features of structure formation, morphology, and phase composition of the surface layers of the TiC—NbC—(Ni,Cr)—AlN hard alloy after high-temperature oxidation in air are studied. In the process of oxidation, a dense intermediate sublayer is formed in the outer layer of scale, which leads to slow the diffusion of oxygen into the inner layer of scale, which positively affects its protective properties.
UDC 621.921.34-492.2:539.89
AND. AND. Bochecka, A. N. Lutsenko (Kyiv)
Kinetics of compaction of diamond powder at different temperatures under the action of high pressure
The kinetics of compaction of polycrystals obtained from diamond powder with a particle size of 28-40 μm at a pressure of 8 GPa and temperatures of 1390, 1550, 1770, and 1910 C were studied. The selected sintering model. The effective viscosity values for the observed viscous flow are determined. Two stages during sintering are distinguished: the first is associated with processes leading to an increase in the degree of plastic deformation, the second – with relaxation and restoration processes.
UDC 681.7.062
L. V. Poperenko, V. A. Odarych, V. S. Stashchuk, V. V. Vovchenko, V. O. Lysyuk (Kyiv)
Ellipsometric studies of copper mirrors obtained by diamond microturning
The nature of the irregularities that arise in the surface layer of copper mirrors obtained by diamond microturning was investigated using the ellipsometric method. The intensity of the reflected radiation was measured and the magnitude of the main angle and ellipticity were determined. High sensitivity of these parameters to the studied methods of applying the reflective layer and deposition modes was revealed. It was established that the action of a number of technological factors can lead to a change in the structure of the substance throughout the thickness of the deposited layer (galvanic deposition mode) or in a thin surface layer (turning mode).
UDC 621.923.6
IN. M. Pacevsky, A. IN. Shevtsov (Voronezh, Russia)
Mathematical modeling of the diamond lapping process
The method of developing a program for controlling the process of diamond grinding with a free abrasive based on mathematical modeling of the quantitative and qualitative composition of diamond grains directly involved in processing is described.
UDC 621.83
Yu. AND. Makhovsky (Kryvyi Rih)
The task of “writing” the tooth profile of the pinion gear wheel into the profile of the worn wheel tooth of the involute gear
The problems of restoring the operability of the large-module gear transmission of the drive of the ore grinding mill by switching to another type of transmission – gear-roller are considered. It is suggested to use gears of a worn involute transmission as blanks for the wheels of the gear-roller transmission.