UDC 548.661.66+539.233
AND. AND. Shulzhenko1, *, L. Yavorska2, **, A.N.Sokolov1, V. G. Gargin1, N. N. Belyavina3
1Institute of superhard materials named after IN. N. Bakulya National Academy of Sciences of Ukraine, Kyiv, Ukraine
2The Institute of Advanced Manufacturing Technology, Krakow, Poland
3Kyiv National University named after Taras Shevchenko, Kyiv, Ukraine
*shulzhenko35@mail.ru
**lucyna.jaworska@ios.krakow.pl
Phase transformations of n-layer graphene into diamond under conditions of high pressure and temperature (p. 3–13)
The influence of high pressure (7.7 GPa) and temperature (1700°C) in the presence of carbon solvents (Ni–Mn alloy, iron) on the phase transformations of both graphene plates with a high degree of crystallinity, having less than four monolayers and a thickness not exceeding 5 nm, and multilayer graphene powders (10–20 monolayers) with a thickness of 8–12 was studied experimentally nm Factors both promoting and hindering the synthesis of diamond from graphene in the presence of carbon solvents have been established. It is shown that the mechanism of transformation of multilayer graphene into diamond at high pressure and temperature according to the two-stage scheme of diamond synthesis (i.e., after three-dimensional structural ordering of graphene in the first stage) is preferable.
Key words: graphene, graphite, diamond, synthesis, phase transformation.
UDC 621.921.34:548.736.15
T. IN. Kovalenko*, S. AND. Ivakhnenko, V. IN. Lysakovsky, S. AND. Gordeev, A.IN.Burchena
Institute of Superhard Materials named after IN. N. Bakulya National Academy of Sciences of Ukraine, Kyiv, Ukraine
*tetiana.v.kovalenko@gmail.com
Defect-impurity composition of diamond single crystals grown in the Fe–Mg–Al–C system (pages 14–19)
The peculiarities of the formation of the defect-impurity composition of diamond single crystals grown in the Fe–Mg–Al–C growth system by the temperature gradient method at a pressure of 7.2–8.2 GPa and a temperature of 1700–1900°C were investigated. It is shown that with an increase in the magnesium content in the growth system, the type of grown crystals changes in the sequence IIa → IIb.
Keywords: diamond single crystals, Fe–Mg–Al–C system, boron, defect-impurity composition.
UDC 539.533
WITH. N. Dub1, *, I. AND. Petrusha1, V. M. Bushlia2, T.Taniguchi3, V. AND. Belous4, G. N. Tolmachova4, A. IN. Andreev3
1Institute of superhard materials named after IN. N. Bakulya National Academy of Sciences of Ukraine, Kyiv, Ukraine
2University of Lund, Lund, Sweden
3National Institute of Materials Science, Tsukuba, Japan
4NSC Kharkiv Physical and Technical Institute,
Mr. Kharkiv, Ukraine
*sergey-dub@bigmir.net
Theoretical shear strength and initiation of plastic deformation during nanodeformation of cubic boron nitride (pp. 20–34)
Nanoindentation in the mode of continuous control of contact stiffness was used to study the initiation of plastic deformation during nanodeformation of cubic boron nitride (cBN), which made it possible to detect the elastoplastic transition in the contact and measure the yield strength of cBN at the nanolevel. For the (111) cBN single crystal, a sharp elastoplastic transition (pop-in) was observed as a result of homogeneous or heterogeneous nucleation of dislocations in the dislocation-free region under the contact. The analysis of the data obtained during the homogeneous generation of dislocations in the contact area made it possible to experimentally estimate the theoretical shear strength of cBN and its ideal (elastic) hardness. For a sample of fine-grained cBN with a nanotwin substructure, a smooth elastoplastic transition was observed as a result of the movement and propagation of dislocations already existing in the contact region.
Key words: cBN, mechanical properties, nanoindentation, dislocation generation, theoretical shear strength.
UDC 532.64.669
O. P. Umanskyi, M. V. Pareiko, M. S. Storozhenko*, V. P. Krasovskyy
Frantsevich Institute for Problems of Materials Science of the National Academy of Sciences of Ukraine, Kiev, Ukraine
*storozhenkomary@ukr.net
Wetting and interfacial behavior of Fe-based self-fluxing alloy-refractory compound systems (p. 35–42)
In this study, the wettability and interfacial behavior of the TiC–FeNiCrBSiC and TiB2–FeNiCrBSiC systems were investigated. The wetting experiments were performed by the sessile drop method at 1150°C under a vacuum. The contact angles of TiC and TiB2 wetting by melted Fe-based self-fluxing alloy were 51° and 36°, respectively. Thermodynamic calculations were carried out to understand the metal-ceramic interaction mechanism in the TiC–FeNiCrBSiC and TiB2–FeNiCrBSiC systems. The structure of the interface region in the TiB2–FeNiCrBSiC system was characterized by optical microscopy and SEM-EDS analysis. The formation of Fe, Ni, Cr and Mo complex borides was revealed within the interface region of the TiB2–FeNiCrBSiC system.
Keywords: self-fluxing alloy, refractory compound, contact angle, titanium diboride, titanium carbide.
UDC 621.921
WITH.AND.Kuharenko, E. AND.Pashchenko*, V.N. Weaver (Kyiv)
Institute of Superhard Materials named after IN. N. Bakulya National Academy of Sciences of Ukraine, Kyiv, Ukraine
*lab6_1@ism.kiev.ua
Features of the interphase boundary of glass-metal coated powders of superhard materials with me tallic matrix (pp. 43–55)
The main results of the study of the features of the formation of the interphase boundary of glass coated on diamond and cBN powders with metals – binders of the grinding tool are presented and summarized. It is shown that the mutual diffusion occurring in the contact zone leads to an increase in adhesion at the interface of the phases, which ensures a strong fixation of the metal coating on the glass aggregate, and the glass aggregate itself in the metal bond.
Keywords: composites, silicate glass, glass coating, adhesion, contact zone, diffusion, metal bond.
UDC 66.091.1:669.295:543.442.3
W. Mao, K. Bao*, F. Cao, L. Ye, H. Xie, B. Li, W. Wang
College of Chemistry and Pharmacy Engineering, Nanyang Normal University, Henan, P.R. China
**baokeyan@126.com
Facile and scalable synthesis of Ti5Si3 nanoparticles via solid-state route in an autoclave (p. 56–61)
A novel method of the synthesis of titanium silicide nanoparticles via solid-state route in an autoclave at 700°C is reported. The reaction of titanium silicide could be described briefly as: 5TiO2 + 3Si + 20Li = Ti5Si3 + 10Li2O. The XRD pattern indicated that the product was hexagonal Ti5Si3. The Ti5Si3 particle size (about 20–40 nm) is confirmed by the TEM images. Furthermore, the thermal stability and oxidation resistance of the titanium silicide nanoparticles were also investigated.
Keywords: titanium alloys, nanocrystalline materials, X-ray diffraction (XRD).
UDC 544.47+544.146.5
S. V. Gaidai1,*, V. S. Hrynko1, M. G. Zhludenko1, A. G. Dyachenko1, V. M. Tkach2, O. V. Ishchenko1
1 Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
2 V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv Kyiv, Ukraine
*gaidaisv@mail.ru
Activity of Fe–Co catalysts supported on carbon fiber in the CO2 methanation reaction (pp. 62–70)
The catalytic activity of Fe–Co catalysts supported on carbon fiber in the CO2 methanation reaction was studied. It was shown that catalysts obtained by applying the active mass to pre-oxidized or reduced purified carbon fiber exhibit lower catalytic activity. Scanning electron microscopy has been shown that the increase in oxygen-containing functional groups on the surface of the support negatively affects the catalytic activity of samples in the methanation reaction, and also complicates the processes of attachment of metal nitrates to the surface of the support and the reduction of the active mass during the synthesis of catalysts. The highest catalytic activity in the CO2 methanation reaction was shown by the Fe:Co = 86:14 sample deposited on unmodified purified carbon fiber (T65 = 390 °C with SCH4 = 88%).
Keywords: CO2 methanation, deposited Fe–Co catalysts, carbon fiber.
UDC 621.923
Yu. D. Filatov*, V. I. Sidorko, S. V. Kovalev, A. G. Vetrov
Institute of Superhard Materials named after V. N. Bakulya, NASU, g. Kyiv, Ukraine
*filatov@ism.kiev.ua
Shaping of flat surfaces of optoelectronic elements during diamond polishing (pp. 71–77)
On the basis of the physical-statistical model of the formation of sludge particles of the processed material during diamond polishing, an analysis of the removal performance and the accuracy of the geometric shape of the flat surfaces of optoelectronic elements made of quartz, aluminum nitride, and gallium nitride was carried out. The most rational values of the kinematic parameters of the machine setting, at which the required forming accuracy is achieved, are determined. The results of the experimental verification of the calculation data of the polishing productivity and the deviation of the shape of the treated surfaces are given.
Key words: diamond polishing, productivity, shape deviation.
UDC 621.922.34
M. N. Sheiko*, V. N. jump
Institute of Superhard Materials named after IN. N. Bakulya National Academy of Sciences of Ukraine, Kyiv, Ukraine
*max-kiev@i.ua
Diamond-galvanic coating with diamond micropowder protection in the straightening tool. Message 1. Coating mode (pages 78–87)
A method of protection of the diamond-galvanic coating in the straightening tool made by the electroplating method is proposed, consisting in the use of diamond micropowder contained in the surface layer of the nickel bond of the coating and protecting the bond surface from hydroabrasive wear. A method of calculating the mode of nickel deposition – the basis of applying a diamond-galvanic coating – is presented, taking into account the change in the area of the free surface of the deposition due to the cross-sectional area of the diamond grains of the working fraction and micropowder, which allows you to calculate the speed, time of deposition, the final thickness of the coating and its protective sublayer.
Key words: diamond-galvanic coating, straightening tool, electroplating method, protection, diamond micropowder, coating application mode.
UDC 546.26.057:662.237.3
IN. Yu. Dolmatov1, *, A. Vehanen2, V. Myllymӓki2
1 FSUE “Special Design and Technology Bureau “Technology”, St. Petersburg, Russia
2Carbodeon Ltd. Oy, g. Vantaa, Finland
*diamondcentre@mail.ru
The influence of the composition of the water armoring of the charge from the trot alloy with hexane on the yield and quality of detonation nanodiamond and diamond charge during detonation synthesis (pp. 88–92)
Detonation synthesis factors that determine the yield of detonation nanodiamonds, diamond charge and their quality are given. The influence of such an important factor as the composition of the armor (shell) of the explosive charge is described. Three different options for detonating an explosive charge – gas, water, ice, and their advantages and disadvantages are considered. The influence of the composition of mixtures of aqueous solutions of various substances (organic and inorganic) on the result of detonation synthesis is shown.
Key words: detonation synthesis, armor, diamond charge, detonation nanodiamonds, mixture of TNT and hexane, urotropin, non-combustible impurities, explosive chamber.
UDC 661.657.5:536.421.1:539.89
V. L. Solozhenko*, V. A. Mukhanov
LSPM–CNRS, Université Paris Nord, 93430 Villetaneuse, France
*vladimir.solozhenko@univ-paris13.fr
On melting of boron subnitride B13N2 under pressure (pages 93–95)
Melting of rhombohedral boron subnitride B13N2 has been studied in situ at pressures up to 8 GPa using synchrotron X-ray diffraction and electrical resistivity measurements. It has been found that above 2.6 GPa B13N2 melts incongruently, and the melting curve exhibits a positive slope of 31(3) K/GPa that points to a lower density of the melt as compared to the solid phase.
Keywords: boron subnitride, melting, high pressure, high temperature.