UDC 669.018.25
A. F. Lisovsky and S. I. Shestakov (Kiev)
Formation of gradient structure in high-pressure apparatus for diamond synthesis
Considerable tensile stresses which arise on the working surface of a carbide die during its operation are responsible for premature failure of high pressure apparatus (HPA). Performance method for increasing a die service life is the development of gradient structures in its bulk. Gradient structures permit to raise the tensile strength of cemented carbide in given areas the tensile strength of cemented carbide in given areas of the die as well as to optimize its elastoplastic stress-strain state.
UDC 548.33
V. F. Britun, A. V. Kurdyumov, V. B. Zelyavsky, I. A. Petrusha (Kyiv)
X-ray diffraction study of CVD-BN texture evolution during phase transformations of rhombohedral modification at high pressures and temperatures
The texture of phases formed during crystal-oriented transformations in pyrolytic BN at a pressure of 7.7 GPa and temperatures from room to 2000 C was studied using transmission X-ray photography and reflection diffractometry. A universal dependence was obtained linking the scattering angle of the axial unlimited texture and the azimuthal extent of texture maxima in the X-ray diffraction pattern. Texture characteristics and mutual orientations of phases at different stages of p, T-treatment were determined. The prospects for using highly textured pyro-BN deposits and implementing martensitic transformations in them for obtaining crystal-oriented superhard materials were shown.
UDC 546
A. V. Lysenko, V. G. Poltoratsky, V. N. Tkach (Kyiv)
High-Molecular Studies of Synthesis, Structure, and Properties of a-C:H Films
The molecular-chemical features of condensation of hydrogenated carbon films are studied. Chemical reactions that determine the mechanism of polycondensation of a-C:H films are considered. High-molecular analysis methods revealed the formation of a network macromolecular structure in a-C:H carbon. Based on the analysis of the morphology of the carbon networks, a conclusion was made about the composite structure of the synthesized a-C:H carbon. It is shown that the hydrogenation method allows synthesizing both molecular and chemical a-C:H compositions. It is established that the molecular compositions of a-C:H are formed on the basis of a quasi-graphite matrix reinforced with globular or tubular polyfullerenes and are not directly related to diamond-like forms of carbon. The features of the synthesis of chemical compositions a-C:H, which also include diamond-like carbon a-C:H, are briefly considered. The densitometric, sclerometric, elastic and electrophysical properties of a-C:H films are studied. A significant relationship between the structure and properties of a-C:H films is revealed. Some current issues of systematization of various forms of carbon a-C:H are touched upon.
UDC 548.4:549.211:666.233
T. D. Ositinskaya, S. A. Ivakhnenko, G. P. Bogatyreva (Kyiv)
On the assessment of the concentration of vacancies in diamond irradiated with electrons
The cross-section of the displacement of a carbon atom in diamond under irradiation with 3.5 MeV electrons is estimated taking into account the step function of the probability of defect formation. For type IIa diamonds irradiated with electrons at 300 K, the known experimental data for vacancy concentrations and their formation rates are analyzed. It is shown that the calculated displacement cross sections s are 10-25 times higher than the experimental data, so a new calculation of s for diamonds is necessary taking into account the real, rather than step, probability function of defect formation during irradiation.
UDC 658.012.122 : 621.921
P. I. Kravets (Kyiv)
Intelligent models and fuzzy algorithms and their application to optimize the synthesis of superhard materials. Message 2
A linguistic algorithm for correcting the control parameters of the synthesis of superhard materials in order to optimize the synthesis results and fuzzy algorithms for a clear assessment of the synthesis results are considered, methods for their adjustment and recommendations for use are proposed.
UDC 621.762:666.233.54
S. K. Avramchuk, V. M. Volkogon (Kyiv)
Structure, phase and chemical composition of atomized Ni-Mn alloy powders for diamond synthesis
The effect of cooling rate in the range of 100-100,000,000 K/s of Ni-Mn alloys on their structure, homogeneity, phase and chemical composition was studied. It was found that at a cooling rate of 103-104 K/s, a dendritic fine-grained structure is formed, and a further increase in the rate promotes homogenization of the solid solution with a uniform distribution of components and refining of the alloy. Carbides in a dispersed state are uniformly distributed throughout the structure, representing a quasi-eutectic, which ensures the congruence of melting of powder particles. The presence of the NiMn intermetallic compound in the Ni-Mn-C system alloys was confirmed by the DTA method.
UDC 621.762
L. G. Bodrova, G. M. Kramar, P. S. Kisly, V. V. Lazaryuk (Ternopil)
Features of sintering alloys based on titanium, vanadium and nio carbides bia
The sintering features of TiC, (Ti, V)C and (Ti, Nb)C alloys with different contents of vanadium and niobium carbides and metal binder were studied. The parameters and activation energy of the sintering process of alloys with 10, 18, 24 ‰ (by weight) Ni—Cr binder at different stages of sintering were calculated. A mass transfer mechanism was proposed.
UDC 620.178.15:678.046.78-419
A. A. Shepelev, V. I. Lavrinenko, V. A. Murovsky, V. T. Fedorenko, A. G. Gontar, L. N. Lavrinenko (Kiev)
Development of diamond metal-polymer tool composites based on programmed sintering technology
A technology for programmed sintering of polymer composites based on STM and abrasive materials in the controlled parameters mode “temperature-pressure-time” has been developed, the functional characteristics of the tool product have been optimized, and the competitiveness of grinding tools made of STM has been achieved by reducing the impact of resource and technological factors on the production process. The functional characteristics of multicomponent polymer composites have been optimized, and a new tool composite based on the “polymer-metal-filler” system has been proposed.
UDC 621.922.079:678
S. V. Sokhan (Kyiv)
Loading conditions of the lapping tool during diamond-abrasive finishing of spherical parts
The dynamics of finishing abrasive machining of spherical parts by free lapping is studied for the case when the profiles of the part and the tool are completely matched with each other in shape. Analytical expressions are proposed to describe the dependence of force factors on the kinematic-geometric and force parameters of the process. The results of modeling the module of the distributed reaction of the part and its normal component, the dependence of the total moment of the reaction of the part and the angle of its inclination on the cutting coefficient for the case of diamond finishing of the surface of a spherical ceramic head with a diameter of 32 mm made of aluminum oxide are presented.
UDC 621.762
T. M. Duda, V. N. Tkach, E. F. Kuzmenko (Kyiv)
Grain composition of activated and metallized ultrafine diamond powders
The fractional change in the grain composition of ultrafine diamond powders (UDP) activated with palladium and metallized with nickel, copper and titanium was studied using scanning electron microscopy and X-ray spectral microanalysis with software and digital image processing.
UDC 666.3/7:621.931
V. B. Shipilo, A. G. Dutov, N. V. Shipilo, V. A. Komar (Minsk, Belarus)
Impurity composition of single-crystal diamond powders of various fractions
The results of a study of the presence of various impurity elements Mn, Ni, Fe, Cr, Na, Al and W in diamond powders are presented depending on the size of the diamond and the content of graphite in the reaction mixture.
UDC 548.33
V. L. Solozhenko, S. N. Dub, N. V. Novikov (Kyiv)
On the question of the hardness of cubic boron carbonitride
UDC 621.762.5
A. A. Shulzhenko, A. N. Sokolov (Kyiv)
New super-hard boron-based material obtained at high pressure and temperature
UDC (549.211:549.07):548
V. S. Solovyov, G. A. Gusakov, O. V. Krekoten, S. V. Reiman, G. A. Dubrov, S. G. Bokhan, V. V. Tikhonov (Minsk, Belarus)
Large synthetic diamonds for instrumental use.