UDC 548.211
V. M. Kvasnytsia
Institute of Geochemistry, Mineralogy and Ore Formation named after M. P. Semenenko, NAS of Ukraine, Kyiv, Ukraine
vmkvas@hotmail.com
Rare diamond microcrystals (pp. 3–10)
Rare forms of diamond growth and dissolution are described using the example of its microcrystals from the Neogene titanium-zirconium placer Samotkany on the Ukrainian Shield. These include diamond crystals with complex facets, crystals of microblock growth, skeletal crystals, crystals with vertex forms, crystals with natural dissolution and perfect twins. It is argued that diamond microcrystals differ from their macrocrystals in the richness of crystallization forms.
Keywords: microdiamond, crystal morphology, simple forms, microtopography, growth and dissolution forms.
UDC 539.89
D. A. Stratiychuk1, K. V. Slipchenko3, *, V. Z. Turkevich1, N. M. Bilyavina2, V. M. Bushlya3, Ya.-E. Shtol3
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2Taras Shevchenko National University of Kyiv, Kyiv, Ukraine
3Lund University, Lund, Sweden
*kateslipchenko@gmail.com
Sintering of superhard materials based on cBN with Ti4WC5 (pp. 11–17)
The physical and mechanical properties and structure of superhard materials of the cBN–Ti4WC5–Al system were studied. The materials were sintered under a pressure of 7.7 GPa in a wide (1600–2450 °C) temperature range. It was found that the formation of a dense material with high physical and mechanical characteristics occurs at a temperature of 1800 °C. Further increase in sintering temperature has a minor effect on the properties of sintered materials. The formation of titanium diboride and a minor increase in the lattice parameters of Ti4WC5 were detected at sintering temperatures above 2000 °C. According to X-ray diffraction analysis, this may be caused by the diffusion of Al into the Ti4WC5 lattice. The cutting ability in longitudinal turning of AISI 316L stainless steel correlates with the sintering temperature, the average tool wear is within 60–82 μm.
Keywords: CNB, sintering, microhardness, high pressure.
UDC 661.657.5:548.3
V. A. Mukhanov1, O. O. Kurakevych2, V. L. Solozhenko1, *
1LSPM-CNRS, Université Paris Nord, Villetaneuse, France
2Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie (IMPMC), Sorbonne Université, Paris, France
*vladimir.solozhenko@univ-paris13.fr
The effect of doping on the lattice parameter and properties of cubic boron nitride (pp. 18–29)
The effect of doping cubic boron nitride with beryllium, silicon, sulfur and magnesium on the crystal lattice parameters, electrical conductivity and electron paramagnetic resonance spectra was studied. It was found that the degree of doping increases significantly in the case of crystallization of cubic boron nitride from BN solutions in supercritical ammonia at a pressure of 3.9–4.2 GPa and a temperature of 1100 °C in comparison with the classical synthesis from melts of the Mg–B–N system at a pressure of 4.2 GPa and a temperature of 1400 °C. Doping with silicon and beryllium leads to the appearance of semiconducting properties in cubic boron nitride.
Keywords: cubic boron nitride, doping, lattice parameter, supercritical fluids, semiconductor properties.
UDC 539.23:538.975
Yu. O. Kosminska*, G. S. Kornyushchenko, Y. V. Gannich, V. I. Perekrestov
Sumy State University, Sumy, Ukraine,
*y.kosminska@phe.sumdu.edu.ua
Obtaining and physical properties of multicomponent coatings based on W, Ta, Hf, Ti, Mo, Cr, Al and C (pp. 30–38)
A new technological approach has been developed to obtain multicomponent coatings by ion sputtering a rod composed of washers of elements such as W, Ta, Hf, Ti, Mo, Cr, Al and C, and coaxially located in a pipe with an internal diameter of 39 mm. At concentrations in the coatings of 41–55% (at.) of carbon and 34–37% (at.) of titanium, an fcc phase with lattice parameters close to those of the TiC compound is formed, and at the maximum concentration of Ta, Hf, Ti, Mo, Cr and W, a transition to an amorphous state occurs with a simultaneous increase in microhardness to 21 GPa.
Keywords: multicomponent coatings, carbon, carbides, elemental composition, phase composition.
UDC 661.883.2
Liangbiao Wang, Qinglin Cheng, Dejian Zhao, Weiqiao Liu, Tinghai Yang, Juanjuan Lu, Weiqiao Liu, Kailong Zhang*, Huaxu Gong, Hengfei Qin
Jiangsu Key Laboratory of Precious Metals Chemistry and Engineering, School of Chemistry and Environment Engineering, Jiangsu University of Technology, Changzhou, P. R. China
*lbwang@jsut.edu.cn
**klzhang@jsut.edu.cn
Solid-state synthesis and characterization of hafnium diboride nanoparticles (pp. 39–45)
Hafnium diboride (HfB2) nanoparticles were prepared by the solid-state reaction of hafnium dioxide, magnesium metal, and sodium borohydride at 700 °C in an autoclave. The structure and morphology of the obtained product were investigated by X-ray powder diffraction, transmission electron microscopy and scanning electron microscopy. The image obtained by transmission electron microscopy shows that the average size of HfB2 nanoparticles is ~ 30 nm. The oxidation behavior of HfB2 was studied by thermogravimetric analysis. It has good thermal stability and resistance to oxidation in air at temperatures below 380 °C. In addition, a possible mechanism for the formation of HfB2 is discussed.
Keywords: solid-state method, X-ray diffraction, hafnium diboride, nanoparticles, chemical synthesis.
UDC 548.5
Guangjin Gao1,2, Shangsheng Li1, 2, *, Meihua Hu1, 2, Xiaolin Zhou1, Xiangyi Luo1, Taichao Su1, 2, Mingming Guo1, 2, Junzhuo Wang1, 2, Yue You1, 2
1School of Materials Science and Engineering, Henan Polytechnic University, Jiaozuo, P. R. China
2Jiaozuo Engineering Technology Research Center of Advanced Functional Materials Preparation under High Pressure, Jiaozuo, P. R. China
*lishsh@hpu.edu.cn
Formation of parasitic crystals during the growth of flattened large synthetic single crystals of type Ib diamond (pp. 46–56)
The influence of crystal growth rate and catalyst components on the formation of a defect in the form of a parasitic crystal during the long-term growth of a flattened large crystal of type Ib diamond from the NiMnCo–C system at high pressures and temperatures was investigated. It is shown that the growth rate of diamond crystals is closely related to the generation of parasitic diamond crystals. The influence of the catalyst composition on the formation of a parasitic crystal during diamond crystal growth was analyzed by studying the micromorphology and nitrogen content in diamond. The results of scanning electron microscopy showed that the surface of crystals synthesized with a low-viscosity catalyst is rough, and with a high-viscosity one is smooth. The results of Fourier transform microinfrared spectroscopy studies revealed that the nitrogen content in crystals synthesized with a FeNi catalyst was significantly lower than in crystals synthesized with NiMnCo. The FeNi catalyst effectively avoids parasitic crystals and is more suitable for the growth of high-quality large-sized diamond single crystals
Keywords: flattened large diamond type Ib, parasitic crystal, growth rate, alloy-catalyst.
UDC 621.95
L. M. Devin*, M. E. Stahniv
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv
*ldevin@ism.kiev.ua
Axial force during drilling of carbon fiber with drills made of diamond-hard alloy plates (pp. 57–65)
The results of the study of axial force during drilling of carbon fiber with different cutting modes and different geometry of drills made of diamond-hard alloy plates are presented. The patterns of changes in the characteristics of the drilling process during stationary cutting and at the stages of cutting and exit of the drill from the workpiece are given. The influence of the width of the transverse edge on the magnitude of the axial force is studied.
Keywords: drilling of carbon fiber, diamond-hard alloy plates, axial force, transverse cutting edge, drill cutting, drill exit.
V. I. Lavrinenko1, V. Yu. Solod2, I. S. Kashinsky2, V. L. Dobroskok3
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2Dnipro State Technical University, Ministry of Education and Science of Ukraine, Kamyanske, Ukraine
3National Technical University “Kharkiv Polytechnic Institute”, Ministry of Education and Science of Ukraine, Kharkiv, Ukraine,
*lavrinenko@ism.kiev.ua
**morbo92@gmail.com
***vldob314@gmail.com
Determination of oxides intended for modification of the surface of diamond grains by their functional characteristics (pp. 66–73)
Restrictions on the choice of oxides that can be effective in modifying the surface of synthetic diamond grinding powder grains with heat-resistant oxides are determined. It is shown that the first group of the most effectively used for surface modification of diamond grinding powders includes the following oxides – B2O3, TiO2, SiO2 and Al2O3, the second group, less effective, – ZnO, BaO and CaO. To achieve an additional positive effect from the modification, it is possible to consider double modification of the surface of diamond grains with a mixture of oxides of the first group and chlorides (СаСl2, NaCl).
Keywords: oxides, physical properties, modification with oxides, chlorides, diamond grinding powders.
UDC 621.9.025.77:621.793
A. S. Manokhin1, S. A. Klymenko1, *, V. M. Beresnev2, V. O. Stolbovoy3, S. An. Klymenko1, Yu. O. Melniychuk1, A. G. Naidenko1, Yu. E. Ryzhov1, Li Depu4, Wang Hongshun4
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2V. N. Karazin Kharkiv National University
3Institute of Solid State Physics, Materials Science and Technology, National Scientific Center “Kharkiv Institute of Physics and Technology”
4Harbin University of Commerce, Harbin, P. R. China
*atmu@meta.ua
Wear intensity of cutting tools equipped with PcBN with nanolayer protective coatings (pp. 74–84)
The influence of protective PVD coatings of different chemical composition on the wear intensity of cutting tools equipped with polycrystalline superhard materials (PSHM) based on cubic boron nitride (CBN) is considered. Coatings with a nanolayer structure were applied to cutting inserts made of superhard composites of the BH group by the vacuum-arc method on the Bulat-6 installation. Preliminary tests, which carried out under conditions typical for finishing hardened steel, demonstrated high efficiency of coatings containing nitrides Ti, Zr, Cr. It was established that the most effective are coatings (TiAlSiY)N/CrN. Research on the kinetics of tool wear shows that under test conditions, the coating significantly reduces the intensity of tool wear on the rear surface – the wear chamfer hz of tools equipped with modified cutting inserts is on average 2.3 times less. At the same time, no significant differences in the roughness of surfaces machined with tools with uncoated and coated composites were found under test conditions. The results of the studies also indicate that coatings do not reduce the intensity of tool wear equipped with PNTM of the BH group when machining materials that contain a significant amount of carbide phase in their structure.
Keywords: cutting tool with PNTM based on CNB, protective PVD coatings, nanolayer structure, cutting processing, wear intensity.
UDC 621.9.025.77:615.46:616.728
S. V. Sokhan*, V. V. Vozny, A. S. Redkin, V. G. Sorochenko, E. M. Zubanev, M. P. Gamanyuk
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*svsokh@gmail.com
Diamond wheel wear during grinding of silicon carbide ceramic balls (pp. 85–98)
The results of an experimental study of the influence of the processing mode on the wear of the diamond wheel surface and the accuracy of a batch of balls for group diamond grinding of silicon carbide ceramic balls are presented. The grinding scheme and the wheel feed frequency have a statistically significant effect on the preservation of the original flat shape of the wheel, and the discrete wheel feed for cutting has no direct effect on the unevenness of the wheel wear. The condition for the maximum possible reduction of the ball diameter variation in the batch while maintaining the initial flat shape of the wheel as much as possible is the choice of a grinding scheme with a ball feed trajectory tangential from the inside to the outer edge of the wheel, as well as a reduction to a minimum from the studied range of the discrete wheel feed for cutting and a simultaneous increase to a maximum of the wheel feed frequency. However, the dispersion of the variation (inconsistency) of the ball diameter in the batch under such conditions does not reach the minimum possible value.
Keywords: ceramic balls made of silicon carbide, group diamond grinding, wheel feed for cutting, wheel feed frequency, ball diameter variation in the batch, dispersion of the ball diameter variation in the batch.
UDC 678.6/.7:544.23/.25.057
D. O. Savchenko1, *, E. O. Pashchenko1, O. M. Kaydash1, S. A. Kukharenko1, O. V. Buryachek2, **, Yu. Yu. Rum`yantseva1, S. V. Skorokhod1, Ya. M. Romanenko1
1V. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2Zaporizhzhya Machine-Building Design Bureau “Progress” named after Academician O. G. Ivchenko, Kyiv, Ukraine Zaporizhzhia, Ukraine
*lab6_1@ukr.net
**oleg1789@ukr.net
Mechanism of synthesis and formation of structure of hybrid oligomers based on complex compounds of oligophenylenes with metals (pp. 99–102)
The reaction mechanism of formation of a hybrid oligomer based on complex compounds of metal and oligophenylene is considered. The structure formed as a result of such a reaction is determined. The effect of the addition of dimethyl sulfoxide on increasing the yield of the main reaction product is established and the mechanism of this effect is proposed, which is based on a change in the conformational features of oligophenylenes during the synthesis process. The obtained oligomers are promising as binders for composites made of superhard materials.
Keywords: hybrid oligomer, oligophenylene, metallocene, complex metal compound, dimethyl sulfoxide.