UDC 548.0
A.A. Shulzhenko, A.N. Sokolov, V.N. Tkach, N.N. Belyavina (Kiev)
Features of Self-Organization of Ultradisperse Diamond at High Pressure and Temperature
The article presents experimental results on the behavior of ultradisperse diamond particles at high pressure and temperature. Products consisting only of ultradisperse diamond, as well as those obtained with the addition of boron and a liquid phase, were studied. For the first time, the possibility of obtaining volumetric well-faceted diamond single crystals up to 10 μm in size as a result of self-organization of ultradisperse diamond particles ≈ 5 nm in size in a liquid phase that does not dissolve carbon was established.
Keywords: ultradisperse diamond, high pressure, self-organization.
U<DK 546.27:539.533
A. A. Kurakevich, T. Chauveau, V. L. Solozhenko (Paris, France)
On the Crystal Lattice Parameters of the B-C Graphite-Like Phases
The structure of the BCx (x=1, 1.5, 3, 4, 32) graphite-like phases studied by X-ray diffractometry is described. The results obtained clearly indicate a turbostratic (one-dimensionally disordered) structure of all the phases under study. The crystal lattice parameters, coherent scattering region sizes, and microdeformation values were determined, which made it possible to correlate the structure and composition of the phases synthesized at the same temperature.
Keywords: crystal lattice, graphite-like phases, B-C system, X-ray diffractometry, coherent scattering, microdeformation.
UDC 621.762.5
O. N. Kaidash (Kyiv)
Features of Structural Transformations during Sintering of Nanodispersed Single-Phase Titanium Nitride Powder by Plasma-Chemical Synthesis
The results of studying free sintering of nanodispersed titanium nitride in various environments are presented. The regularities of morphological changes in the structure are compared with the rate of compaction and the data of X-ray phase and structural analysis. It is shown that due to the dissolution of oxygen and its isomorphic substitution for nitrogen in TiN, chemocoalescence of particles and their transformation into single-crystal aggregates occur, which become centers of collective growth. The occurrence of anomalous recrystallization in titanium nitride at Tcp = 1300 °C is established. It is shown that the collective recrystallization of TiN is predetermined by the migration of grain boundaries detached from the pores.
Keywords: nanodispersed powder, titanium nitride TiN, free sintering, structure, morphology, recrystallization.
UDC 620.22:669.018.25
A. F. Lisovsky (Kiev)
Formation of a gradient structure in sintered hard alloys (Review)
A review of published works on the formation of gradient structures in sintered hard alloys is presented. It is shown that three directions are being developed for the creation of gradient structures. The first of them consists in applying surface layers to a hard-alloy product by deposition in various combinations of carbides, nitrides, oxides of various chemical elements. The second direction involves the formation of a layer structure in a product during its mechanical processing or as a result of exposure to high-energy beams of electrons, ions, as well as laser processing. The third direction develops technologies for creating gradient structures in the volume of sintered hard-alloy products. All three directions pursue the goal of adapting the hard alloy product to its operating conditions and thus increasing its performance.
Keywords: sintered hard alloys, gradient structure.
UDC 544.47:661.183.2
V. K. Yatsimirsky, G. G. Tsapyuk, O. V. Ishchenko, V. E. Diyuk, T. V. Kartashova, L. M. Grishchenko (m. Kiev)
Investigation of the activity of the oxide Cu—Co—Fe catalyst in oxidized carbon
The thermal stability of brush activated carbon infiltrated with a Cu-Co-Fe oxide catalyst was assessed, and the nature and concentration of oxygen-bearing groups on the surface of the carbon were determined. Kinetic studies of the oxidation process of carbon dioxide indicate the significant catalytic activity of the oxide Cu—Co—Fe catalyst. It has been shown that treatment of the active carboxylic acid with nitrate acid leads to an increase in carboxyl groups, which are the centers of the addition of the catalytically active Cu—Co—Fe oxide system with further dissolution of the active center for low-temperature oxidation As a result, a large number of active oxidation centers are created in the surface ball of the brushed active vugill, which leads to a decrease in the oxidation temperature of the active vugill by up to 100 °C.
Key words: transition metal oxides, catalytic oxidation of carbon.
UDC 621.791: 669.017
V. I. Lavrinenko, B. V. Sitnik, V. O. Skryabin, V. M. Tkach (metro Kiev) S. S. Samotugin, V. O. Mazur, K. V. Kudinova, A. D. Chepurnoy, Yu. D. Serdyuk (metro Mariupol)
Injection of plasma treatment to replace the elemental surface of the working ball of a carbide tool, its speed and wear resistance
An investigation was carried out into the infusion of plasma cuttings into the element storage of the surface ball of a carbide tool. Shown is the change in the surface shortness that was added to the infusion in a plasma jet. The data on the operational properties of a carbide tool during precision are presented.
Keywords: plasma processing, hardness, elemental composition, carbide, working ball of the tool, wear resistance.
UDC 621.7
O. V. Titarenko, E. K. Sevidova, V. I. Kononenko (Kharkiv)
On the possibility of assessing the quality of the surface layer of thermoplastic polymeric materials by the method of a quiescent drop
The use of the method of a quiescent drop for studying the surface quality of thermoplastic polymeric materials polystyrene and polymethyl methacrylate after blade processing is considered. A correlation between the thermophysical state of their surface layer and the wettability of the surface is revealed. It is shown that the method is applicable for assessing the thermodynamic stability of the polymer surface layer structure at the final stages of optical products production.
Keywords: thermoplastic polymeric materials, quiescent drop method, blade processing, surface layer, structure, wettability, thermodynamic stability.
UDC 621.921.34-492.544.023.5:539.215
N. V. Novikov, G. A. Petasyuk, G. P. Bogatyreva (Kyiv)
Study of the influence of the modulus and shape of sieve cells on the fractional yield of powder and the dimensional homogeneity of its fractions separated during sieve separation
An original method for predictive assessment of the fractional weight yield of superhard material powders and their homogeneity by morphometric characteristics during sieve separation is presented. It has been established that of the two factors — the sieve modulus and the shape of their cells — the sieve modulus has the predominant effect on the weight content of the main fraction of the powder and its quality. As applied to synthetic diamond powders, analytical dependencies have been obtained for the calculated determination of the relative weight yield of the main fraction of the powder and its maximum homogeneity by the value of the sieve modulus used for sieve separation.
Keywords: powders of superhard materials, sieve separation, sieve cell shape, sieve modulus, fraction, weight amount, homogeneity, relationship of characteristics.