UDC 536.4.001.57:004.942:62-987
O. O. Leshchuk, O. P. Antonyuk, T. O. Prikhna, V. E. Moshchil (Kyiv)
Modeling of temperature fields and thermal stresses in high-pressure apparatuses for processing samples of high-temperature superconductors
The thermally stressed state of the cell of high-pressure apparatuses of the “cylinder-piston” and “anvil with recesses” types for processing samples of high-temperature superconductors was calculated using computer modeling in order to determine the influence of the physical characteristics of the cell materials on the distribution of temperature and thermal stresses in it.
UDC 537.226:538.95
I. Kh. Abdukadyrova (Tashkent)
Temperature-frequency dependences of dielectric losses in irradiated aluminum oxide
The effect of ionizing radiation on the electrophysical properties of aluminum oxide is considered. The peculiarities of the temperature and frequency dependences of the tangent of the dielectric loss angle before and after the action of radiation on crystalline samples are established, and the regularities of their changes are determined. It is assumed that the revealed non-linear change in the dependence of the tangent of the dielectric loss angle on the frequency of irradiation in the region of appearance of dielectric absorption is caused by polarization processes.
UDC 535.343.546
AND. P. Fesenko, V. AND. Chasnyk, M. AT. Kuzenkova, G. WITH. Oleynik, V. IN. Panichkina, V. B. Sverdun, N. IN. Sergiyenko, M. G. Skryshevska (Kyiv)
Dielectric properties of AlN-based composites in the microwave region
The dielectric properties of ceramic-metal composites AlN—Mo and AlN—W, which have a high density and a homogeneous structure depending on the content of the refractory metal, are described. It is shown that the dielectric permittivity and dielectric losses depend on the concentration of the metal phase. Thus, the dielectric permittivity of the composites increases with a change in the metal content, and, accordingly, the dielectric losses increase. The dielectric properties of AlN—Mo and AlN—W composites depend weakly on the frequency of the electromagnetic field in the microwave region. The relationship between the structure, phase composition and dielectric properties of the obtained composites is discussed.
UDC 666.233
V. Yu. Dolmatov, V. G. Sushchev (St. Petersburg) T. Fujimura (Tokyo, Japan) M. V. Veretennikova (St. Petersburg)
The nature of cluster nanodiamonds of detonation synthesis and physical and chemical aspects of their nitric acid purification technology
The data that allow to more accurately characterize the nature of such a complex formation as detonation nanodiamonds are presented, as well as the main regularities of the limiting stage of the chemical cleaning process — washing of UDA from acids.
UDC 621.793
Yang Li, Yu Zhi-ming, Yin Lei, Li Yong-xia, Zou Dan (Changsha, P.R. China)
Effect of Two-Step Pretreatment on CVD Diamond Formation on WC—6 ‰ Co and WC—3 ‰ Co
Diamond films were deposited on WC—3 ‰ Co and WC—6 ‰ Co substrates via Hot Filament Chemical Vapor Deposition (HFCVD. Prior to the deposition, two-step surface pretreatment was carried out. The surface morphology, the texture and the adhesion of the diamond films were investigated by the use of Scanning Electron Microscope (SEM), Energy Diffraction Scanner (EDS) X-ray Diffractometer and Rockwell Hardness Tester. The results have shown that prolongation of the etching time using Murakami reagent reduces the surface cobalt more effectively. The roughness of the as-etched surface of the substrate is also increased accordingly, which results in a good adhesion between the diamond film and the substrate. Under the same pretreatment conditions, the quality of the diamond coating on WC—6 ‰ Co samples is much better than that on WC—3 ‰ Co. The adhesion between diamond films and the cemented carbides can be greatly enhanced by reducing the content of cobalt on the surface of the WC substrate.
UDC 621.923.042
M. N. Sheiko, O. IN. Khimach (Kyiv)
Grooving with diamond bars in the light of mechanical and statistical methods is presented about abrasive diamond machining. Message 1. Reduction to the processing scheme with continuous feed to depth
The process of mortise grinding of abrasive wheels with diamond bars from grinding positions in non-traditional modes is considered. The application of the device of the mechano-statistical theory of grinding, developed earlier by the authors, made it possible to establish the patterns of changes in the power characteristics of the straightening and the Ra parameter of the surface roughness of the product. For the first time, the reduction of the process to the processing scheme with continuous feed to depth was established. The calculation of the editing characteristics illustrates the possibilities of controlling the process by means of the variation of the parameters of the tool design.
UDC 621.9.025
G. G. Dobrovolsky, P. Yu. Sakseev (Kyiv)
Diamond microturning of silicon and germanium (review)
Foreign publications describing the process of diamond microturning of semiconductor materials (silicon, germanium) and their products are considered. The directions for further research of this process are determined.
UDC 621.9.025.7.048.7
N. IN. Novikov, A. AND. Shepelev, V. G. Sorochenko, V. WITH. Kovalenko, L. F. Golovko (Kyiv)
Application of laser technologies for the production of disk diamond tools
It is proposed to improve the quality of diamond tools with the help of laser processing. It is shown that laser heating can be used to increase the dispersion and homogeneity of the structure of the diamond-containing layer of the tool, to sinter pre-prepared briquettes of the diamond-containing charge, to manufacture single-row multilayer diamond tools using strong and wear-resistant bonds.
UDC 622 24.051.4
Ya. B. Nemyrovsky (Kyiv)
Restoration of calibrating reamers for diamond drilling
The distribution model of an unequally rigid pipe with rigid and plastic sections is described. Taking into account the modeling results, the design of the expander for rock drilling is proposed, allowing for its multiple restoration. The optimal distribution modes of the worn expander and the required geometry of the deforming element are determined.
UDC 621.913:621.833
A. V. Kryvosheya, O. U. Petasiuk, V. E. Melnyk (Kyiv) A. V. Korynets (Zhytomyr)
Methodology of assignment and mathematical description of initial shape-forming profiles
The developed generalizing initial shape-forming contour is described, as well as the method of its assignment using the theory of multiparametric mapping of affine space. Differential and general characteristics of the complex initial shape-forming contour are determined.