UDC 666.233
IN. Yu. Dolmatov1, *, N. M. Lapchuk2, T. M. Lapchuk2, B. T. T. Nguyen2, V. Myllymäki3, A. Vehanen3, Yakovlev R. Yu.4
1 FSUE “SKTB Technolog”, St. Petersburg, Russia
2Belarus State University, Minsk, Republic of Belarus
3Carbodeon Ltd Oy, Vantaa, Finland
4 Ryazan State Medical University named after Academician I. P. Pavlova, Ryazan, Russia
*diamondcentre@mail.ru
Investigation of defects and impurities in doped detonation nanodiamonds by EPR, RD and KRS methods (pp. 3–16)
Spectroscopic methods (electron paramagnetic resonance, X-ray diffraction, and Raman light scattering) of samples of detonation nanodiamonds modified at the time of synthesis by introducing dopant elements in various ways were studied. For the first time, the presence of P1 centers in detonation nanodiamond crystals was indirectly shown. The nature and distribution of spins observed by the electron paramagnetic resonance method, the composition of phases and the size of the coherent scattering region, the X-ray density of the studied samples of detonation nanodiamonds are considered.
Key words: electronic paramagnetic resonance, X-ray diffraction, Raman light scattering, detonation nanodiamond, doping, elements of the Periodic System.
UDC 544.3:621.762
AND. F. Lysovsky (Kyiv)
Institute of Superhard Materials named after IN. N. Bakulya National Academy of Sciences of Ukraine, Kyiv, Ukraine
lisovsky@ism.kiev.ua
Thermodynamics of the formation of a new phase in a composite material (pp. 17–22)
A composite material consisting of particles of a certain phase and a bond is considered. Particles of the second phase are introduced into the material, the components of which chemically interact with the components of the particles of the first phase, forming a new phase. Thermodynamic functions describing the processes of dissolution of the first and second phases in the bundle, chemical interaction of their components and formation of a new phase are obtained. The conditions under which the above processes take place are described.
Keywords: composite material, thermodynamics, phase.
UDC 538.9
R. IN. Konakova1, O. B. Okhrimenko1, *, A. F. Kolomys1, V. IN. Strelchuk1, A. M. Svetlichnyy2, O. AND. Ageev2, E. Yu. Volkov3, A. WITH.Kolomiytsev2, I. L. Zhityaev2,
AT. B. Spiridonov4
1Institute of Semiconductor Physics named after IN. THERE ARE. Lashkareva National Academy of Sciences of Ukraine, Kyiv, Ukraine
2Southern Federal University, Institute of Nanotechnology, Electronics and Instrumentation, Taganrog, Russia
3Non-commercial partnership “Southern Laser Innovation and Technology Center”, Taganrog, Russia
4Southern Federal University, Scientific and Design Bureau of Modeling and Control Systems, Taganrog, Russia
*olga@isp.kiev.ua
Self-emission properties of pointed cathodes based on graphene films on SiC (pp. 23–29)
The electrical properties of low-threshold self-emission cathodes formed by growing graphene nanocluster films on the tip surface of heavily doped n+SiC by sublimation epitaxy are considered. The quality of the graphene coating was assessed on the basis of morphological studies and Raman spectroscopy. On the basis of the volt-ampere characteristic, the output work (~0.76 eV) from the tip cathode with graphene coating was calculated. Such a low value of the work output is explained within the framework of the assumption of the nanocluster nature of the graphene film and the fact that the source of self-emission is graphene nanoclusters.
Key words: sharp cathode, graphene, silicon carbide, work output.
UDC 666.3:539.5
T. B. Serbeniuk1, *, T. O. Prikhna1, V. B. Sverdun1, V. I. Chasnyk2, V. V. Kovylyaev3, J. Dellith4, V. E. Mosch’il1, A. P. Shapovalov1, A. A. Marchenko1, L. O. Polikarpova1
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2State Enterprise “Orion Research Institute”
3I. M. Frantsevich Institute for Problems of Materials Science, NAS of Ukraine, Kyiv, Ukraine
4Institute of Photonic Technologies, Jena, Germany
*serbenuk@ukr.net
The Effect of the Size of SiC Inclusions in the Aln–SiC Structure on the Electrophysical Properties of the Composite (pp. 30–41)
Composite materials AlN–SiC–Y3Al5O12 with a high level of microwave absorption (27–65 dB/cm) obtained by the method of free sintering of mixtures of 46% (by mass) AlN(2H), 4% (by mass) Y2O3 and 50% (by mass) SiC(6H) using SiC of different dispersions (1, 5 and 50 μm) were studied. It was shown that the specific electrical The resistance of the developed materials significantly depends on their structure: the size of SiC inclusions, the distance between them and the state of the interphase boundaries. It was found that an increase in the size of SiC inclusions in the material structure from 3 to 7 μm leads to a decrease in the specific electrical resistance from 104 to 90 Ω∙m, and when they decrease from 3 to 0.5 μm, a continuous SiC framework is formed, which also causes a drop in resistance to 210 Ω∙m. Thus, composite materials containing 50% (by mass) of SiC with a SiC inclusion size of 3 μm are the most effective for the manufacture of microwave radiation absorbers. The layers of yttrium aluminum garnet located along the boundaries of SiC grains prevent the formation of photons. the formation of solid solutions of AlN(2H)–SiC(6H) and, thus, allow to maintain a high level of dielectric characteristics of the composite material based on aluminum nitride and to ensure a high level of absorption of microwave radiation.
Keywords: AlN–SiC composite, yttrium aluminum garnet, absorption of microwave radiation, structure, Auger spectroscopy, scanning electron microscopy, electrical resistivity.
661.875.657:542.9
W. Mao, K. Bao*, G. Liu, H. Xie, C. Chen, L. Ye, B. Li, X. Zhao
College of Chemistry and Pharmacy Engineering, Nanyang Normal University, Henan, P. R. China
*maowutao@126.com
**baokeyan@126.com
Synthesis of orthorhombic chromium boride by solid state reaction (p. 42–46)
Chromium boride is characterized by interesting properties, like high melting point, hardness, and corrosion and abrasion resistances. In this paper a novel synthesis of chromium boride microparticles via a solid-state route at 600 °C is reported. The X-ray diffraction pattern taken from the reaction product indicated that the product was orthorhombic chromium boride. The CrB particle size (about 1~2 mm) is confirmed by FESEM and TEM images. Solid state reactions that were carried out in sealed autoclave systems provide an alternative, convenient, and environmentally friendly pathway for the fabrication of CrB.
Keywords: solid state reactions, chromium boride, synthesis.
621.793.002.3-419:533.273
K. S. Kim, H. K. Kim, J. H. La, K. B. Kim, S. Y. Lee*
Center for Surface Technology and Applications, Department of Materials Engineering, Korea Aerospace University, GoYang-si, Gyeonggi-do, South Korea
*sylee@kau.ac.kr
Influence of N2 partial pressure on the microstructure, hardness, and thermal stability of CrZrSiN nanocomposite coatings (pp. 47–56)
The effects of N2 partial pressure in the unbalanced magnetron sputtering process on the microstructure, hardness, and thermal stability of the CrZrSiN nanocomposite coating were investigated. A typical nanocomposite structure, composed of a crystalline phase and an amorphous phase was obtained and the distribution of these phases changed with increasing N2 partial pressure. The N1s spectra revealed the presence of two-peak characteristic of nitrogen in the CrZrN and SiNx phases, and the ratio of the peak’s SiNx to CrZrN intensity increased with increasing N2 partial pressure, indicating an increase in the amorphous phase in the nanocomposite microstructure. As N2 partial pressure increased, the CrZrSiN coating hardness decreased from 38 to 30 GPa due to the increasing amount of the SiNx amorphous phase. After the thermal stability test, the hardness values of the CrZrSiN coatings were maintained at approximately 30 GPa up to 800 °C, but the hardness decreased rapidly to 18 GPa after annealing at 900 °C. This drastic change of hardness over 900 °C was due to the formation of a Cr2O3 phase in the CrZrSiN coating.
Keywords: coating, nanocomposite, microstructure, amorphous phase.
UDC 621.723:620.669.018:45:621.9.0
O. K. Porada1, A. O. Kozak1, V. I. Ivashchenko1, *, S. M. Dub2, G. M. Tolmacheva3
1Institute of Problems of Materials Science named after I. M. Frantsevich NAS of Ukraine, Kyiv, Ukraine
2V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
3Kharkiv Institute of Physics and Technology, Kharkiv, Ukraine
*ivash@ipms.kiev.ua
Hard plasma-chemical a-SiCN coatings (pp. 57–66)
Amorphous SiCN coatings were deposited on silicon substrates by plasma-chemical deposition (PECVD) using hexamethyldisilazane as the main precursor. The effect of the deposition temperature on the structure, chemical composition and mechanical properties of the coatings was studied. It was found that at temperatures up to 400 °C, hydrogenated amorphous SiCN (a-SiCN:H) coatings were deposited, the hardness of which does not exceed 23 GPa. With further increase in temperature, the distribution of strong Si–C, Si–N and C–N bonds in the coatings practically does not change, and the number of weak hydrogen bonds С–Н, Si–H and N–H decreases. As a result of such redistribution of chemical bonds at temperatures of 650–700 °C, a-SiCN coatings with a hardness of more than 32 GPa are deposited. Vacuum annealing at 1200 °C does not significantly affect the structure, hardness and elastic modulus of a-SiCN coatings.
Keywords: a-SiCN, hard coatings, plasma chemical deposition, PECVD, hexamethyldisilazane, nanoindentation, hardness.
UDC 548.736.15:535.4
I. M. Fodchuk1, M. D. Borcha1, *, V. Yu. Khomenko1, S. V. Balovsyak1, V. M. Tkach2, O. O. Statsenko2
1Chernivtsi National University named after Yuriy Fedkovych, Chernivtsi, Ukraine
2V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*m_borcha@ukr.net
The deformation state of synthetic diamond crystals according to the backscattered electron diffraction method (pp. 67–73)
A method for determining the components of the strain tensor from the analysis of the backscattered electron intensity distributions in Kikuchi patterns is proposed. The deformation state of local areas of a synthetic diamond crystal is investigated. diamond obtained by the temperature gradient method in the Fe–Al–C system by growing on a single crystal of diamond synthesized in the Ni–Mn–C system. Characteristic tensor surfaces and deformation ellipsoids were constructed, and the features of their distribution over the crystal were analyzed. The diagonal components of the tensor were determined from changes in the intensity distributions of individual bands, the other components were determined from the displacement of the axes of the zones relative to their positions on the Kikuchi reference pattern.
Keywords: diamond, diamond films, strain gauge, Kikuchi method.
UDC 621.921.34-492.544.023.5:539.215
G. A. Petasyuk
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
petasyuk@ukr.net
System-analog method for identifying the geometric shape of the projection of abrasive powder grains (pp. 74–89)
A new improved method for identifying and quantitatively assessing the geometric shape of the projection of abrasive powder grains is presented, which is based on a system-analog approach. 2D geometric figures (circle, ellipse, triangle, canonized forms of a quadrilateral, regular pentagons, hexagons and octagons) are taken as analogues, which allow for non-additive analytical representation of the area through generating parameters, the number of which is not more than three. Differential and integral characteristics of shape similarity are introduced, and an analytical apparatus for determining the indicators of these characteristics is proposed. The results of testing the method on synthetic diamond and cubic boron nitride grinding powders are presented.
Keywords: diamond powders, grain projection shape, identification, projection analogs, quantitative evaluation, approbation.