N. V. Novikov

Detonation diamonds in Ukraine

Some information on the history of dynamic synthesis of diamond in Ukraine is considered. Basic characteristics of ASM5 0.1/0 and ASM1 0.1/0 nanodiamond powders produced by static synthesis are described. The characteristics and surface properties of nanodiamond powders produced by detonation synthesis in Ukraine are presented. It is shown that the chemical activity of the particle surface can be controlled. Applications of nanopowders produced by detonation synthesis in various technologies are considered.

Comparative studies of mechanical properties of stishovite and sapphire single crystals by nanoindentation

Comparative nanoindentation tests of stishovite and sapphire single crystals have been performed. It has been found that nanohardness of the (0001) plane of sapphire at a depth of 200 nm is 29.1 ± 0.1 GPa, while the nanohardness of the (110) plane of stishovite is 38.1 ± 0.6 GPa, the tests conditions being the same. The specifics of elastoplastic transition in sapphire and stishovite single crystals and alumina-based polycrystalline ceramic when plastic deformation is localized in a submicron region have been studied. Anomalous elastoplastic transition in stishovite has been revealed. A possibility that anomalous mechanical behavior of stishovite at the nanoscale may be due to a strong softening of the lattice as a precursor of the formation of a post-stishovite phase of silica with the CaCl2 structure in an indent has been discussed.

The influence of strength characteristics of diamond grits on drilling tool performance

The paper presents the results of investigation of the effect of strength characteristics (strength, strength uniformity, thermal stability) of diamond grits on wear of impregnated drill bits and expenditure of energy for rock destruction by such tools. The influence of strength characteristics of diamond grits on the drilling tool performance has been verified experimentally. The field tests have demonstrated that the better the strength characteristics of the grits the larger the average meterage drilled per bit and the rate of penetration.

On the achievements of Bakul Institute for superhard materials, national academy of sciences of Ukraine, in the field of synthesis and sintering of superhard materials over the past 50 years of the Institute’s activities

The paper presents the progress made by Bakul Institute in the field of synthesis and sintering of superhard materials under extremely high p, T conditions over the past 50 years of the Institute’s activities.

Improving wear resistance of drilling tools fitted with synthetic diamond

The paper summarizes the findings of investigation of the influence of physicochemical and physical-mechanical properties of synthetic diamond grits on the drilling tool performance. Wear resistance of drilling tools is demonstrated to increase when they are fitted with synthetic diamond grits that are highly uniform in strength. The use of diamond grits with a better developed surface is found to provide a stronger grit retention in the bond and reduced drilling tool wear.

Magnetic methods of purification control of nanodiamond powders

Magnetic methods of quantitative determination of impurities in nanodiamond powders (NDPs) are discussed. For two types of NDPs, it is shown that the magnetic susceptibility depends on their treatment.

Methods for investigation of graphene properties

The paper presents the results of investigation of a graphene coating produced on different substrates, such as diamond, cubic boron nitride, and silicon oxide. Characterization of the presence of graphene structures is performed by Raman spectroscopy and X-ray diffraction study. The surface topography is studied by optical, electron, and tunneling microscopes. Functionalities of all the experimental techniques applied are discussed. The results obtained by a new instrument—a tunneling microscope fitted with a tip of boron-doped semiconductor diamond—are analyzed.

Cutting of polycrystalline superhard materials by jet methods

The authors study the intensity of cutting workpieces of hardmetals, polycrystalline cBN-based material and polycrystalline diamond-on-hardmetal compacts in the following operations: waterjet cutting, laser cutting, liquid-cooled laser cutting, and laser–jet cutting. Special features of cutting two-layered composites that comprise a polycrystalline diamond layer on a hardmetal substrate are analyzed. The paper demonstrates the efficiency of the hybrid machining process that combines the laser–jet and waterjet technologies and provides an effective cutting of workpieces to a required profile.

The accuracy of diffraction patterns taken in a diamond-anvil cell using an X-ray diffractometer according to the Dobrovol’skii-Shvedov method

The accuracy of the diffraction patterns taken on a DRON-3 diffractometer by the Dobrovol’skii-Shvedov method in a diamond-anvil cell has been analyzed. The generally accepted reference materials (polycrystalline silicon and NaCl) have been used as samples. The long-term stability has been checked on a steel sample.

The formation of diamond-hardmetal granules for the use in rock cutting tools

The paper describes a process of formation of diamond-hardmetal granules based on synthetic diamond grains and sintering the granules subject to the condition of minimized strength degradation of diamond. Requirements have been defined for the composition and structure of hardmetals that are used in the granules in order to ensure a reliable diamond retention. A trial application of a composite material based on diamond-hardmetal granules onto steel inserts for rock cutting tools by the intensive electric sintering method has been accomplished.