UDC 548.211
V. M. Kvasnytsia
M. P. Semenenko Institute of Geochemistry, Mineralogy and Ore Formation of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
vmkvas@hotmail.com
Morphology and Growth Mechanisms of Diamond Crystals (pp. 3-14)
The morphology of natural and synthetic diamond microcrystals demonstrates their growth mechanisms: dislocation (spiral), dislocation-free (two-dimensional), normal (fibrillar), and block (adhesive). These mechanisms are clearly manifested in the features of the morphology and microtopography of diamond polyhedra and xenocrystals. Most natural diamond crystals grow by dislocation and normal growth mechanisms, and synthetic diamond crystals by dislocation and two-dimensional growth mechanisms.
Keywords: diamond, crystal morphology, simple crystal forms, microtopography, growth mechanism.
UDC 62-987:621.362.1:548.55
A. V. Burchenya*, S. O. Ivakhnenko, V. V. Lysakovsky, T. V. Kovalenko, O. V. Savitsky, V. Yu. Klochok V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*burcheniaav@gmail.com
Using the differential method for determining quasi-hydrostatic pressures in the cells of six-punch presses (pp. 15-24)
Methodological approaches to measuring high quasi-hydrostatic pressures in the cells of six-punch presses, taking into account the influence of high temperatures up to 1400 °C, are described and a combined load characteristic p = f(Q) is constructed, where p is the pressure value in the quasi-hydrostatic cell, Q is the force of the plunger system. Pressure measurement in the compression cell is based on determining the temperature difference of polymorphic transformations in Fe(α→γ) and Co(α→β) and determining the melting temperature difference between Cu and Ag using resistometry at pressures of 4–7 GPa and temperatures of 500–700°C for Fe–Co sensors and 1150–1400°C for Cu–Ag sensors. To determine high temperatures at characteristic points of growth cells of six-punch presses, a method for manufacturing thermocouple blocks using cesium chloride as an electrically insulating medium and Pt/PtRh10 and PtRh6/PtRh30 thermocouples has been developed; basic requirements for their manufacture have been formulated, which ensure reliable electrical insulation of thermocouple wires and allow for continuous temperature control during growth cycles of up to 200 h and more. The influence of parasitic TERS on the readings of thermocouples arising from the influence of high pressures and the use of additional contact through hard alloy punches was assessed; calibration curves were constructed, which allow to increase the accuracy of measurement. The use of the proposed approaches to determining pressures and temperatures in the growth cells of six-punch cubic AVTs is especially useful when growing large diamond single crystals weighing more than 10 carats.
Keywords: high-pressure apparatus, diamond single crystals, high pressure, high temperature, thermocouple, resistive pressure sensors, combined load characteristic.
UDC 666.233
V. Yu. Dolmatov1, *, A. O. Dorokhov2, A. S. Kozlov1, V. A. Marchukov1, V. Myllymäki3, A. Vehanen3
1Federal State Unitary Enterprise “Special Design and Technological Bureau “Technologist”, St. Petersburg, Russia
2JSC “Plant “Plastmas”, Kopeysk, village Sovietov, Russia
3“CarbodeonLtd. Oy”, Vaanta, Finland
*diamondcentre@mail.ru
Possibility of predictive estimation of the yield of detonation nanodiamonds (DNA) from individual explosives (pp. 25-32)
An attempt was made to predict the yield of detonation nanodiamonds (DNA) from explosives with still underestimated capabilities: trinitrobenzene (TNB), hexanitroazobenzene (GNAB), tetranitrobenzotriadobenzotriazole (Z-TAKOT), trinitrotriaminobenzene – picric acid (TATB), trinitrophenol (PC), benzotrifuroxane (BTF). With a known detonation velocity of the explosive, based on previously obtained dependencies, it is possible to determine the specific power of the explosives, and then the DNA yield, or directly determine the DNA yield in a narrow range for each explosive, and subsequently verify the obtained values experimentally.
Keywords: detonation velocity, detonation nanodiamond, nanodiamond yield, forecast, explosives, specific power.
UDC 539.23:620
V. I. Ivashchenko1, O. O. Onoprienko1, *, P. L. Skrynsky1, A. O. Kozak1, O. K. Sinelnychenko1, O. I. Olifan1, P. M. Lytvyn2, O. L. Marchuk1
1I. M. Frantsevich Institute for Problems of Materials Science, NAS of Ukraine, Kyiv, Ukraine
2V. E. Lashkaryov Institute of Semiconductor Physics, NAS of Ukraine, Kyiv, Ukraine
*onopr@ipms.kiev.ua
Structure and mechanical properties of Ti–Al–C and Ti–Al–Si–C films: experimental study and calculation from first principles (pp. 33-45)
The influence of sputtering current and annealing temperature on the structure, composition and mechanical properties of Ti–Al–C and Ti–Al–Si–C films deposited on Si (100) substrates by magnetron sputtering of composite Ti–Al, graphite and SiC targets at different values of sputtering current was investigated. The study was carried out by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XRD), atomic force microscopy, hardness measurement. The deposited films had an amorphous structure with a fairly low (0.25–0.27 nm) root-mean-square roughness. During annealing in vacuum at a temperature of 800 °C, the crystalline phases Ti2AlC MAX, Al4C3, TiC2, TiO2 and the amorphous phase Al–C–O were formed in the Ti–Al–C films, and the crystalline phases Ti2Si1–xAlxC MAX, Al4C3, TiSi/TiSi2 and the amorphous phase Al–Si–C–O were formed in the Ti–Al–Si–C films. The identification of the structures was carried out using XRD, XRD methods and based on the results of theoretical calculations. In films with an amorphous structure, the hardness increased with increasing sputtering current of graphite or SiC targets, reaching maximum values of 19.1 and 17.8 GPa for Ti–Al–C and Ti–Al–Si–C films, respectively. The change in the hardness of the films is explained taking into account the evolution of the chemical bond in them.
Keywords: magnetron sputtering, MAX-phase, structure, first-principles calculation.
UDC 536.775:546.26-162
Delong Xie1,2,3, *, Feng Lin1,2,3, Xiaoyi Pan1,2,3, Leyin Xiao1,2,3, Chao Chen1,2,3
1Guangxi Key Laboratory of Superhard Materials, Guilin, P.R. China
2Chinese National Engineering Research Center for Special Mineral Materials, Guilin, P.R. China
3China Nonferrous Metal (Guilin) Geology and Mining Co, Ltd, Guilin, P.R. China
*xiedelonghn@foxmail.com
Effect of the interface between diamond grain and pre-doped Fe–Co–Cu powders and their thermodynamic behavior (pp. 46-54)
The uncontrolled distribution of Fe, Co and Cu metal elements on the diamond surface and the Gibbs free energy that change the transformation behavior during the vacuum hot pressing sintering process were investigated. The reaction products on the diamond surface after sintering with pre-doped Fe–Co–Cu powders were investigated by X-ray diffraction, Raman scattering spectra and infrared radiation. The distribution of each element of the pre-doped Fe–Co–Cu powders on the diamond surface was analyzed by energy dispersive X-ray spectroscopy, and the change in Gibbs free energy during the transformation was calculated using thermodynamic theories. It is shown that after sintering with pre-doped Fe–Co–Cu powders, graphitization occurs on diamond surfaces and the cobalt content increases at the contact point. Under vacuum sintering with hot pressing, the calculated change in Gibbs free energy is negative, indicating that graphitization is a spontaneous process.
Keywords: pre-doped powder, interface effect, graphitization, thermodynamic behavior.
UDC 004.942:621.921.34:621.3.032.213.62
Fuming Deng*, Cen Hao, Zhenhai Guo, Shuang Wang, Xiang Bo, Qing Lei
Institute of Super-hard Cutting Tool Materials, China University of Mining and Technology, Beijing, P.R. China
*dfm@cumtb.edu.cn
Modeling study of the uniformity of the air flow field of the HFCVD deposition system considering the arrangement of the filaments (pp. 55-71)
The filament CVD method has many advantages, such as the use of simple equipment, easy operation and low cost, which allows it to be widely used in the industrial production of diamond-coated tools. The research results showed that when the filament distance Tw = 10 mm, the uniformity of the air flow field was the best, and the arrangement of the filaments with distances Tw1 = 14 mm, Tw2 = 10 mm, Tw3 = 10 mm, Tw4 = 8 mm, Tw5 = 8 mm contributed to the increase of the coating performance. The experimental results are consistent with the simulation results and it is proved that they can be used to control the real production process.
Keywords: filament spacing, uniformity, modeling, air flow field.
UDC 621.9.025.77:615.46:616.728
S. V. Sokhan*, A. L. Maistrenko, A. I. Borymsky, V. V. Vozny, V. G. Sorochenko, M. P. Gamanyuk, E. M. Zubanev
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*svsokh@gmail.com
Changes in diamond finishing indicators of ceramic balls made of boron carbide and silicon nitride (pp. 72-82)
For diamond finishing of ceramic balls made of B4C and Si3N4, the patterns of changes in the indicators of productivity and machining accuracy were experimentally studied, namely: the average diameter of balls in a batch, the variability of the diameter of balls in a batch and the arithmetic mean of the variations of the diameter of balls, as well as the rate of change of these indicators. As a result, linear or nonlinear approximation models of these indicators were obtained, on the basis of which a method for determining the allowance at different stages of finishing was developed depending on the given value of the variation of the diameter of balls.
Keywords: ceramic balls, boron carbide, silicon nitride, diamond finishing, ball diameter and its variation, variability of the diameter of balls in a batch, approximation models, allowance for finishing.
UDK 621.922.34
V. I. Lavrinenko*, A. G. Lubnin, V. M. Tkach, I. P. Fesenko, V. V. Smokvyna
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*lavrinenko@ism.kiev.ua
Feature and structural organization of a single-layer diamond-electroplated coating for a straightening tool (pp. 83-90)
The features of obtaining the structural organization of a single-layer diamond-electroplated coating for a straightening tool were investigated, which was considered as the orientation and anisotropy of diamond grains in the structure of the coating layer and also as the introduction into the coating together with large diamond grains of a finely dispersed filler, the particle size of which is two orders of magnitude smaller. Comparison of the galvanic nickel bond applied by different methods in terms of orientation and anisotropy of the surface layer confirmed a significant difference in the structure. The features of the diamond-electroplated coating with the introduction of silicon carbide and boron micropowders into it are presented. It is shown that due to technological methods it is possible to influence the structural organization in the working layer of such a single-layer diamond tool and change its properties in a targeted manner.
Keywords: diamond-plated coating, ruling tool, structure, structural organization, hardness, thermal conductivity.