UDC 544.3:661.657
IN. L. Solozhenko, A. AND. Kurakevych (Paris, France) V. WITH. Turkevich, D. IN. Turkevich (Kyiv)
To the question of phase relations in the B—BN system at high pressures and temperatures
Phase relations and chemical interaction in the В—ВН system were studied in situ by the synchrotron radiation diffraction method at pressures up to 5.3 GPa and temperatures up to 2700K. The obtained results are used for the thermodynamic analysis of this system and the construction of the state diagram at 5 GPa. The values of the thermodynamic functions of the phases competing in the В—ВН system at high pressures and temperatures are calculated within the framework of phenomenological models, the unknown parameters of which are determined from experimental data. It is shown that there is only one thermodynamically stable subnitride of boron in the system — rhombohedral B13N2, which melts incongruently and forms a eutectic equilibrium with boron.
Key words: phase relations, chemical interaction, thermodynamic analysis, state diagram.
UDC 666.233
IN. IN. Lysakovsky, S. AND. Ivakhnenko (Kyiv)
Growth kinetics of diamond single crystals in Fe—Co solvents doped with titanium and zirconium
The growth kinetics of structurally perfect diamond single crystals in Fe—Co—C solvents with additions of Ti (1.81—5.35 ‰ (at.)) and Zr (0.64—6.30 ‰ (at.)) were studied in the temperature range of 1380—1680 °C at a pressure of р = 5.5—6.1 GPa. The concentration limits for the formation of diamond single crystals of various types — Ib, IIa — were established. as well as the intermediate type Ib+IIb. The defect-impurity composition, habit, and features of the inclusions of the solvent in the grown samples of carbon are determined on the p, T-diagram of the regions of the change of the habit, the degree of structural perfection, and the inclusions, depending on the pressure and temperature.
Keywords: kinetics, single crystals, diamond, alloying, titanium, zirconium.
UDC 666.762.93:536.2:546.281.26
AND. L. Maistrenko, V. G. Kulych, V. N. Tkach (Kyiv)
Formation of a high-density structure of self-bonded silicon carbide
An alternative to traditional technologies method of manufacturing high-density ceramic products based on self-bonded silicon carbide, the blanks of which are formed by slip casting of thermoplastic masses under pressure, has been developed. The composition of the polyfraction charge was substantiated and new compositions of temporary binders with rheological properties ensuring high density of the products were developed.
Keywords:
ceramics, self-bonded silicon carbide, binary mixture of powders, fractions, partial ratio, density.
UDC 544.3:621.762
AND. F. Lysovsky (Kyiv)
Thermodynamics of particle consolidation in a nanodisperse system with macrophase inclusions
A thermodynamic study of the process of particle consolidation in a system consisting of nanoparticles, included macroparticles, and a mobile phase was carried out. A thermodynamic potential describing this process was obtained. Conditions under which the consolidation process takes place completely and, from the point of view of thermodynamics, does not take place, as well as conditions under which consolidation of only some phases takes place, are defined.
Key words: thermodynamics, nanoparticle, consolidation, inclusion.
UDC 539.266
AT. WITH. Roik, S. AT. Lysovenko, V. M. Overturned, T. IN. Gomelyako (Kiev)
X-ray study of melts of the Ni—Mn system
The results of X-ray study of melts of the Ni—Mn system in a wide concentration interval at temperatures near the liquidus line are presented. It was established that the concentration dependence of the averaged parameters of the local structure of atoms and molar volume is characterized by small positive deviations from additivity.
Keywords: Ni—Mn melt, X-ray diffraction study, local order, pair distribution function.
UDC 621.744.762
V. V. Ivzhenko, N. V. Novikov, G. F. Sarnavskaya, V. A. Popov, M. G. Loshak, L. I. Aleksandrova (Kyiv)
Investigation of the elastic aftereffect during injection molding of thermoplastic masses based on SiC, AlN, WC powders and its influence on the mechanical properties of the material of the product blanks
The change in the dimensions of the workpieces made of thermoplastic materials based on SiC, AlN, WC and paraffin powders, obtained by the injection molding method, was investigated. The influence of pressure, temperature of the process, particle sizes of powders on the elastic effect in the thermoplastic material of the workpiece, as well as the influence of injection molding parameters (pressure and temperature) on the bending strength of this material were studied.
Key words: silicon carbide, aluminum nitride, tungsten carbide, paraffin, thermoplastic mass, injection molding, bending strength, elastic effect.
UDC 621.9
WITH. AND. Klymenko, A. WITH. Manokhin (Kyiv)
Hard “shaving” turning
Presented are the results of a complex study of a highly effective method of finishing – hard “shaving” turning. The peculiarities of the oblique cutting process with a tool equipped with PSTM based on KNB are shown, the regularities formed are considered surface roughness and hardening of the surface layer during processing.
Key words: hard “shaving” turning, diagonal cutting, PSTM based on KNB.
UDC 621.941
N. THERE ARE. Stakhnyv, A. G. Sulima (Kyiv)
Patterns of changes in the cutting force when cutting in and exiting the tool from the workpiece when turning silumins with round ATP cutters
The regularities of changes in the components of the cutting force and their equivalent, as well as the area of the cut layer at the stage of cutting in and exiting the tool from the workpiece during turning of sililumins with round ATP are established.
Key words: cutting, turning, siluminy, cutting force, round diamond carbide plate (ATP).
UDC 621.921.34-2:622.24.05
N. IN. Novikov, G. P. Bogatyreva, G. D. Ilnytskaya, R. K. Bohdanov, G. F. Nevstruev, A. P. Zakora, A. M. Isonkin, V. N. Tkach, I. N. Zaitseva (Kyiv)
Increased wear resistance of drilling tools equipped with synthetic diamonds
Presented are the results of a study of the influence of the physical-chemical and physical-mechanical properties of synthetic diamond grinding powders on the operational characteristics of the drilling tool. It is shown that the wear resistance of the drilling tool increases when it is equipped with diamond grinding powders with high uniformity in strength. It has been established that the use of diamond grinding powders with a more developed surface contributes to better retention of diamond grains in the bond and reduces the wear of the drilling tool.
Key words: wear resistance, drilling tool, synthetic diamonds, grinding powders.