UDC 541.16
V. V. Ivanovskaya, A. L. Ivanovsky (Yekaterinburg)
Modeling of new superhard carbon materials based on fullerenes and nanotubes
A brief overview of the current state of theoretical research aimed at finding superhard materials based on carbon fullerenes and nanotubes is presented. Information is presented on the elastic properties of the main classes of condensed phases formed during the interaction of fullerenes and (and) nanotubes both due to weak (van der Waals type) bonds and as a result of their polymerization with the emergence of strong covalent sp³ bonds. Models of new hypothetical carbon nanostructured materials (the so-called autointercalated hyperdiamonds, covalent lattices of tubes, cubic crystals of tubes, etc.) are discussed. Their elastic characteristics are considered in relation to their atomic structure, features of the electronic structure and chemical bonding. The problems of synthesis of these systems are briefly considered.
Keywords: fullerenes, nanotubes, crystalline phases, hardness, atomic structure, chemical bonding, modeling.
UDC 669.018.25
A. F. Lisovsky (Kyiv) E. O. Tskitishvili (Makiivka) A. I. Kulik (m. Svitlovodsk) O. F. Kurochkin, V. G. Lyasov (m. Krivy Rig) V. V. Pashinsky, A. D. Ryabtsev, D. G. Sidorenko, A. V. Feofilaktov (m. Donetsk)
Technology for the production of large-sized carbide particles and the development of their industrial production for the metallurgical industry of Ukraine
Scientific research has been published that formed the basis of the technology for the production of large-sized carbide rolls, and the specifics of the production of carbide rolls for equipping the metallurgical industry.
Keywords: sintered hard alloys, large-sized products, technology, rolls.
UDC 621.367. (035)
G. K. Burkat, V. Yu. Dolmatov (St. Petersburg, Russia) E. Osawa (Ueda, Nagano, Japan) E. A. Orlova (St. Petersburg, Russia)
Study of the properties of chromium-diamond coatings based on detonation nanodiamonds from various manufacturers
The article presents the studied dependence of the most important operational parameters of chromium-nanodiamond coatings on the quality of the studied detonation nanodiamonds and the method of their dispersion in an aqueous suspension. It is shown that the best result in terms of microhardness of coatings in the hard chromium plating mode is achieved using nanodiamonds produced by NanoCarbon Research Institute (Japan), which actually form a dispersion of individual particles (≈ 4-5 nm) in water, and the best wear resistance of chromium-nanodiamond coatings is provided by using detonation nanodiamonds produced by FSUE SKTB Technolog (Russia).
Keywords: chromium-nanodiamond coatings, detonation nanodiamonds, properties, dispersion, microhardness, wear resistance.
UDC 544.72:548.5
N. T. Loladze, M. P. Tserodze (Tbilisi, Georgia)
On the Effect of Surface Properties of Metallic Melt on the Process of Diamond Formation in the Me-C System
The results of a study of the contact interaction of Ni-Mn melt with pyrographite depending on the content of Cu and Cr additives in it are presented. Such physicochemical parameters as the surface tension of liquid Ni-Mn-Cu and Ni-Mn-Cr melts and the wetting angle of graphite are determined. The surface energy at the metal-graphite interface and the expected interfacial energy at the diamond-metallic melt interface are calculated. The effect of these quantities under conditions of high p, T parameters on the process of diamond formation in the Ni-Mn-Cu-C and Ni-Mn-Cr-C systems is established.
UDC 621.941
L. N. Devin, A. G. Sulima (Kyiv)
Features of the cutting process on the first and last revolution of the part when entering and exiting the cutter
A method for calculating stresses in the cutter during its cutting in and exiting the part is described. It is established that during the first and last revolutions of the part, the front angle of the tool differs significantly from the values characteristic of stationary turning. Changes in the front angle affect the magnitude and sign of stresses on the front and rear surfaces of the cutter, and taking it into account allows calculating stresses and subsequently assessing the probability of tool failure.
Keywords: cutting in and exiting the tool, stress calculation, cutting edge rounding, front angle, chip shrinkage, round diamond-carbide plate.
UDC 621.921.34
V. A. Mukhanov, I. M. Filippov, V. S. Kovalenko (Aleksandrov, Vladimir Region, Russia)
Extraction of serviceable abrasive powders from spent abrasive-oil suspensions — waste from strip sawing. The methods of extraction of diamond powders from diamond-sapphire-oil suspensions and silicon and boron carbides from abrasive-quartz-oil suspensions for reuse are described.
Keywords: strip sawing, abrasive-oil mixture, diamond-sapphire-oil suspension, abrasive-quartz-oil suspension, silicon carbide, boron carbide.
UDC 621.928.4; 621.921.1:621.922.34
G. A. Petasyuk (m. Kiev)
Interpretation and applied aspects of various morphological characteristics of powders on dhard materials
The results of the study of the information and geometric essence of the latest morphological characteristics of powders of superhard materials and the degree of their sensitivity to changes in powder quality are presented. A new original method for indirect determination of the average value of the sharpening angle of the cutting edges of abrasive powder grains is presented. For the first time, an empirical mathematical model of the relationship between the sharpening angle of the cutting edges and the equivalent diameter of the grains of synthetic diamond micropowders with their abrasive ability is obtained.
Keywords: abrasive powders, synthetic diamond powders, two-dimensional morphological characteristics, two-dimensional geometric characteristics, sharpening angles of the cutting edges, abrasive ability, relationship of characteristics.
UDC 669.25/27.539
O. V. Kharchenko, M. M. Prokopiv (Kyiv) Yu. D. Serdyuk (Mariupol city)
Structure of hard alloys of the WC—Co group after sintering in a gas environment
The structure of hard alloys of the WC—Co group after sintering in vacuum and in a gas environment without pressure and under gas pressure is reported.
Keywords: hard alloy, vacuum sintering, sintering in a methane-hydrogen environment, compression sintering, structure.