UDC 541.16
S. F. Matar1, V. L. Solozhenko2, *
1Lebanese German University (LGU), Sahel Alma, Jounieh, Lebanon
2LSPM–CNRS, Université Sorbonne Paris Nord, Villetaneuse, France
*vladimir.solozhenko@univ-paris13.fr
New ultrahard carbon allotropes from crystal chemistry and first principles: rhombohedral ene-C21 and yne-C24 (pp. 3-12)
Rhombohedral ene-C21 and yne-C24, characterized by the presence of C=C and CºC bonds, respectively, inserted into the 9R polytype of diamond C18, are proposed as new ultrahard carbon allotropes from crystal chemistry and first principles. Like 9R C18, they belong to the cfe topology characteristic of layered SiC polytypes. With ultrahard properties approaching those of diamond and lonsdaleite, ene-C21 and yne-C24 are dynamically stable with phonon features identifying high-frequency C=C and CºC vibrations similar to molecular allene and acetylene. The electronic band structures correspond to insulating C18, metallic ene-C21 and semiconducting yne-C24.
Keywords: diamond polytypes, hybridization, density functional theory, hardness, phonons, electronic structure.
UDC 666.3:539.5
Yu. Yu. Rumyantseva1, *, S. O. Lysovenko2, V. Z. Turkevich2, P. P. Klimchik1, N. M. Bilyavina3, V. M. Bushlya4, D. O. Savchenko2, S. An. Klymenko2, D. V. Turkevich2
1Łukasiewicz Research Network – Krakow Institute of Technology, Krakow, Poland
2V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
3Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
4Division of Production and Materials Engineering, Lund University, Lund, Sweden
*yrumuanceva@gmail.com
Features of the Reactive Interaction of Boron Nitride with Tantalum Nitride in the Presence of Microfibers and Liquid Aluminum (pp. 13-16)
The results of thermodynamic modeling of superhard materials based on cubic boron nitride (cBN) with a tantalum nitride (TaN) binder and aluminum additives, as well as microfibers of various physicochemical nature (oxide (Al2O3, Mg2B2O5) and non-oxide (SiC, Si3N4)) are presented. The theoretically calculated chemical interaction between the components of superhard composite materials was experimentally verified. It was found that the chemical nature of microfibers significantly affects the reaction interaction between the cBN matrix material and the TaN bonds with the participation of liquid aluminum with the formation of tantalum boride.
Keywords: thermobaric sintering, cubic boron nitride, thermodynamic modeling, microfibers.
UDC 549.211
R. Wirth1, *, V. M. Kvasnytsia2, **, A. Schreiber1
1Helmholtz Center Potsdam and German Research Center for Geosciences, Section 3.5: Interface Geochemistry, Telegrafenberg, Potsdam, Germany
2M. P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation, NAS of Ukraine, Kyiv, Ukraine
*wirth@gfz-potsdam.de
**kvasnytsya@ukr.net
Octahedral growth structures on impact diamond (pp. 17-25)
Nano- and micrometer-sized growths on the (0001) surface of impact apographite diamond are characterized. The growths are documented as octahedra, occasionally cubes, their growth and germination twins, and irregular growths. The features of the internal structure of these growths and their chemical composition are studied. Previously published conclusions about their globular structure and block growth mechanism are refuted. The mechanism of formation of these growths is presented.
Keywords: diamond, crystal morphology, paramorphosis, growth mechanism.
UDC 666.3:539.5
T. B. Serbeniuk1, , T. O. Prikhna1, *, V. B. Sverdun1, V. V. Oliynyk2, V. I. Hryhoruk2, V. V. Zagorodniy2, M. V. Karpets1, S. S. Ponomaryov3, A. A. Marchenko1, L. O. Polikarpova1
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
3V. E. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, Ukraine
*serbenuk@ukr.net
**prikhna@ukr.net
The influence of changing the concentration of the graphite component in the structure of AlN-based composite materials on their electrodynamic properties (pp. 26-36)
In the frequency range of 1–10 GHz, the electrodynamic properties of new composite materials made by the free-sintering method based on AlN with the addition of 1–5% (by mass) of diamond powder were investigated. Studies of the structure and phase composition established that during the sintering process, the process of graphitization of diamond powder occurs, and according to X-ray phase analysis, after refining the results by the Rietveld method, the content of the graphite phase was 0.8, 1.7, 3.8% (by mass) for materials to which 1, 3, 5% (by mass) of diamond powder were added, respectively, before sintering. The study of electrodynamic characteristics showed an increase in the apparent and real dielectric constants with increasing graphite content. The dielectric losses at a frequency of 10 GHz increased from 0.05 to 0.08 for composites in the case of increasing the amount of graphite phase from 0.8 to 3.8% (by mass).
Keywords: composite material, AlN, graphite, microwave electronics, dielectric losses, electrodynamic properties.
UDC 666.3:661.657.2
Mantang Duan, Ye. V. Solodkyi, Yu. I. Bogomol*
National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
*ubohomol@iff.kpi.ua
State and prospects of research on the production of high-entropy boride ceramics (Review) (pp. 37-48)
The current state of development and optimization of powder synthesis methods and technologies for the production of high-entropy diborides are summarized and analyzed, the process of manufacturing dense materials is investigated, and the directions of their development are analyzed and predicted.
Keywords: high-entropy diboride ceramics, powder synthesis, extreme operating conditions.
UDC 669.018.25
I. O. Hnatenko1, *, I. V. Andreyev1, S. O. Lysovenko1, O. S. Roik2, O. S. Osipov1, T. O. Kosenchuk1
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
*gnatenko_i@ukr.net
The Influence of Barothermal Treatment Temperature of Sintered Hard Alloys on the Evolution of Their Structure and Properties (pp. 49-57)
The influence of barothermal treatment temperature at a pressure of 8 GPa and a temperature of 1450–1700 °C on the change in the structure and properties of hard alloys with different cobalt contents was studied. It was found that the use of barothermal treatment leads to a 30% increase in the grain size of the carbide phase and a decrease in the overall porosity. At the same time, the hardness and stress intensity coefficient of WC–6Co alloys treated under solid-phase sintering conditions increase. Barothermal treatment of WC–15Co alloys at the temperature of the liquid phase leads to the formation of intermetallic phases of the Co3W3C type.
Keywords: hard alloy, barothermal treatment, high-pressure apparatus, structure, hardness, X-ray phase analysis.
UDC 621.923.7
Yu. D. Filatov1, *, V. I. Sidorko2, S. V. Kovalev1, A. Yu. Boyaryntsev3, V. A. Kovalev4, O. Ya. Yurchyshyn4
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2State Enterprise “Engineering and Production Center ALKON” NTAK (ALKON) NAS of Ukraine, Kyiv, Ukraine
3Institute of Scintillation Materials, NAS of Ukraine, Kharkiv, Ukraine
4National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
*filatov2045@gmail.com
Scattering of nanoparticles of wear of polishing powder on nanoparticles of sludge during polishing of polymeric optical materials (pp. 58-68)
As a result of the study of the regularities of interaction of nanoparticles of wear of polishing powder with nanoparticles of sludge during polishing of polymeric materials using disperse systems of micro- and nanopowders based on ab initio calculations in accordance with the quantum theory of scattering, it was established that nanoparticles of wear of polishing powder are elastically scattered on nanoparticles of sludge exclusively at angles of 0° and 180° with a differential scattering cross section that exceeds its value for other angles by 104–105 times. It is shown that the total cross section of the wear nanoparticles scattering on the sludge nanoparticles decreases exponentially with an increase in their average size and increases with an increase in concentration. When polishing polymeric materials using the DS1 dispersion system with an increase in the Q factor of the resonator, the total cross section of the wear nanoparticles scattering on the sludge nanoparticles decreases exponentially. When using the DS2 dispersion system, the total cross section of the wear nanoparticles scattering on the sludge nanoparticles does not depend on the Q factor of the resonator. It is shown that the formation of a deposit of wear particles of the polishing powder on the surface of the part is most likely at maximum values of the total cross section of the scattering. The presence of a coating in the form of a film with a thickness of 1.5 and 0.3 microns, which forms a complete or partial coating of the surface of the part during the polishing of polystyrene and polyallyl diglycol carbonate using the DS2 disperse system, has been experimentally established.
Keywords: polishing, polymeric materials, scattering of nanoparticles, Q-factor of the resonator.
UDC 621.921
V. I. Lavrinenko
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
lavrinen52@gmail.com
The phenomenon of lagging in the values of the operational indicators of grinding wheels caused by the shape change of the cutting surface of the wheel in the radial direction during diamond abrasive processing (pp. 69-76)
In the process of face grinding under conditions of multi-pass and deep processing, the cutting surface of the wheel acquires shape changes in the radial direction. In the case of reaching a critical grinding performance, when the cutting surface of the wheel has no reserves for increase, a further increase in productivity leads to a sharp increase in wheel wear. Since the area of the cutting surface of the wheel is still stable, a phenomenon of lagging in the values of the operational indicators of grinding wheels may occur in the event of a decrease in grinding performance at such a constant area. Such a lag was observed for wheel wear indicators, specific energy consumption and effective power and grinding, but not for roughness indicators. It is shown that the cutting surface of the wheel can be worked on to the critical productivity value, when the area of the cutting surface reaches a maximum, and then work with lower than critical processing productivity indicators, guaranteed to achieve a decrease in wheel wear and processing energy intensity.
Keywords: deformation of the cutting surface of the grinding wheel, critical grinding productivity, wheel wear, specific processing energy intensity, diamond-abrasive processing, roughness indicators.
UDC 622.24.05
E. A. Korovyaka1, A. O. Ignatov1, A. V. Pavlychenko1, Karel Valouch2, V. O. Rastsvetaev1, *, O. V. Matyash3, M. R. Mekshun1, S. O. Shipunov1
1National Technical University “Dnipro Polytechnic”, Dnipro, Ukraine
2IHS Markit, Energy Engineering Solutions, Brno, Czech Republic
3National University “Poltava Polytechnic named after Yuriy Kondratyuk”, Poltava, Ukraine
*rastsvietaiev.v.o@nmu.one
Study of the features of the operation of drilling rock-breaking and technological tools (pp. 77-91)
A comparative presentation of the main results of the study of the mechanism of operation of drill bits with a modernized weapon system and technological tools at the wellhead is presented. An engineering methodology for calculating the minimum required value of the axial load, which ensures the implementation of a highly effective volumetric nature of destruction, is formulated. The existence of a stable relationship between the possible depth of immersion of a single rock-breaking element of the weapon and the realized rotation frequency is proven in the case of maintaining a certain value of the axial load. The rational parameters of the drilling mode for bits with a diameter of 112 and 132 mm are determined. A method of forming a scheme of the location of the armament on the bit cone is proposed, which allows to obtain an increase in mechanical speed by 50–100% in each specific case. According to the obtained values of the cruising speed of drilling with the proposed bits, some exclusion of the processes of repeated destruction of rock particles separated from the face under the cone is revealed, which allows to significantly increase the service life of the tool. The presence of improved conditions for the destruction of rocks under the action of the hydrostatic pressure of the washing fluid column in the case of using bits with modernized armament is established. The possibility of reducing the power consumption for the rotation of the drill string by an average of 2–3 times through the use of special lubricating additives for the chemical treatment of drilling fluids is shown. Simultaneously with the regulation of the lubricating ability of drilling fluids, a positive effect of active additives on the viscosity and static shear stress indices was revealed, which allows us to recommend them for use during the penetration of rocks prone to intensive absorption and sludge formation.
Keywords: well construction, rock-breaking and technological drilling tool, drill string, exploration and production drilling, superhard materials.
UDC 666.798.621.762.4
M. M. Prokopiv1, *, O. V. Kharchenko1, I. V. Tsap2, I. D. Hnylytsia2
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2Ivano-Frankivsk National Technical University of Oil and Gas, Ivano-Frankivsk, Ukraine
*keramtex@ukr.net
Cr2O3–22Cr cermet for tool applications, obtained by electrosintering at pressures up to 800 MPa (pp. 92-96)
It is shown that the structure of the Cr2O3–22% (by mass)Cr cermet, obtained from a mixture of chromium oxide and chromium by electrosintering at a temperature of 1520 °C and a pressure of 40–300 MPa, has a chromium oxide matrix, in which there are globular Cr inclusions with sizes of 0.5–20 μm, similar to the particle size of the original mixture. At pressures from 300 to 800 MPa, elongated inclusions appear in the structure, the content of which increases with increasing pressure during electrosintering due to the reduction of globular grains. The maximum values of Vickers hardness and crack resistance, determined by the Palqvist method, of the obtained cermet are 20.2 GPa and 7.6 MPa×m1/2, respectively, and the resistance under conditions of blade intermittent dry machining of 9Kh12F steel (HRC 58‒60) is at the level of resistance of ceramics based on Al2O3–TiC from the company “Sandvik Coromant” (Sweden).
Keywords: cermet, Cr2O3, Cr, structure, pressure, properties.