UDC 661.868.1:544.344.015.3:536.421.1
V. Z. Turkevich, Yu. Yu. Rumyantseva*, Yu. I. Sadova, O. V. Kushch, I. O. Gladkyi, D. V. Turkevich
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*yrumuanceva@gmail.com
Thermodynamic calculations of the melting point diagram of the Fe–Ga–N system in the context of gallium nitride crystallization under high temperatures and pressures (pp. 3-10)
The problem of constructing the melting point diagram of the ternary Fe–Ga–N system under atmospheric and high (4 and 6 GPa) pressures is investigated in order to find the thermodynamic stability region of a promising wide-gap semiconductor material – gallium nitride (GaN). Thermodynamic calculations were performed using phenomenological thermodynamic models. The possibility of obtaining GaN crystals at high temperatures and pressures using iron as an alloy-solvent was proven in principle. Recommendations were given for optimizing the thermodynamic and kinetic parameters of obtaining GaN crystals using the temperature gradient method in order to improve their quality.
Keywords: Fe–Ga–N diagram, high pressures, thermodynamic calculations, Thermo-Calc.
UDC 620.22-621.921.34
B. T. Ratov1, V. A. Mechnyk2, *, M. O. Bondarenko2, V. M. Kolodnitsky2, **, E. S. Gevorkyan3
1NAO “Kazakh National Research Technical University named after K. I. Satpayev”, Almaty, Kazakhstan
2Institute of Superhard Materials named after V. M. Bakulya NAS of Ukraine, Kyiv, Ukraine
3Ukrainian State University of Railway Transport, Kharkiv, Ukraine
*vlad.me4nik@ukr.net
**vasylkolod56@gmail.com
Physical and mechanical properties of composite diamond-containing materials based on Fe‒Cu–Ni–Sn‒VN matrices sintered by vacuum hot pressing (pp. 11-25)
The effect of the concentration of nano-VN additive (in the range from 0 to 10% (by weight)) on the structure, retention of diamond grains by the metal matrix and mechanical (nanohardness H, modulus of elasticity E, material resistance to elastic deformation H/E and material resistance to plastic deformation H3/E2) properties of samples of composite diamond-containing materials (CDM) based on the matrix 51Fe–32Cu–9Ni–8Sn, formed by the method of cold pressing with subsequent vacuum hot pressing, was studied. It is shown that the structure of the sintered sample of the KAM based on the matrix 51Fe–32Cu–9Ni–8Sn consists of diamond grains and fcc solid solutions containing iron, copper, nickel and tin in different ratios. Under such conditions, no Fe, Cu, Ni and Sn elements were detected on the surface of the diamond grains, and gaps and discontinuities were observed at the diamond–matrix contact. Adding nano-VN in an amount of 2, 4, 6 and 8% (by weight) to the composition of the KAM allows the formation of a finer-grained structure consisting of solid solutions containing iron, copper, nickel, vanadium and tin, and diamond grains, on the surface of which the same elements are contained in small quantities. At the same time, the diamond–matrix contact is dense without visible gaps, discontinuities and other defects. It was found that the variation of the concentration of vanadium nitride is accompanied by a non-monotonic change in H for the entire investigated interval of the depth of immersion of the indenter into the surface of the sintered samples. The addition of 2% (by mass) nano-VN to the composition of the CAM provided an increase in H of the matrix from 5.2 to 5.6 GPa, E – from 197 to 202 GPa, H/E – from 0.0264 to 0.0277 and H3/E2 – from 3.62 to 4.30 MPa. The greatest increase in H (7.8 GPa), E (213 GPa), H/E (0.036) and H3/E2 (10.46 MPa) was found for the CAM sample containing the nano-VN additive in an amount of 8% (by mass). The indicated indicators are achieved due to the dispersion mechanism of strengthening and modification of the structure (reduction of the average grain size, formation of dense diamond-matrix contact, formation of inclusions of V, Fe, Ni and Cu on the surface of diamond grains, disappearance of pores in the metal matrix) and the phase composition of composites.
Keywords: composite, vanadium nitride, iron, copper, nickel, tin, composition, concentration, vacuum hot pressing, structure, properties.
UDC 621.315
V. I. Chasnyk1, I. P. Fesenko2, L. M. Vovk3, O. M. Kaidash2,*
1State Enterprise Research Institute “Orion”, Kyiv, Ukraine
2V. M. Bakul Institute of Superhard Materials of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
3Ukrainian Research Institute of Special Equipment and Forensic Examinations of the Security Service of Ukraine, Kyiv Kyiv, Ukraine
*oka07@ism.kiev.ua
High microwave absorption in a free-sintered AlN–SiC composite in the frequency range of 9.5–34.2 GHz (pp. 26-39)
For high-output microwave vacuum devices, volumetric absorbers with a high microwave absorption coefficient are required. For the use of AlN–SiC composites in them, the absorption of microwave radiation was studied and it was found that high absorption in the AlN–50% (by mass) SiC composite can be achieved due to the presence of micron and submicron-sized SiC particles, which provide complex and repeated absorption of microwave radiation. The absorption coefficient L is 4.6 dB/mm in discs measuring Æ4.2×Æ1.0 mm and 6.6 dB/mm in rings measuring Æ4.2×Æ1.9×1.0 mm. It is proposed to compare composites with dielectric losses not in terms of ɛ² or tg δ, but directly in terms of the absorption coefficient of microwave radiation obtained in real operating conditions of a volumetric absorber in a microwave device. The relationship between the quality factor, attenuation, and the absorption coefficient of radiation is revealed. It is shown that in the frequency range 1–40 GHz ɛ¢ and ɛ² are frequency-dependent quantities, however, at a frequency of more than 8 GHz their ratio ɛ²/ɛ¢ = tg δ is a constant quantity and does not depend on the frequency. In the investigated composite, the experimental values are ɛ¢ = 32 and ɛ² = 7 at a frequency of 3.3 GHz, and the calculated ɛ¢ = 19.3 and ɛ² = 6.2 at a frequency of 34 GHz.
Keywords: AlN–SiC composite, bulk microwave energy absorber, composite with dielectric losses, microwave radiation absorption, Q factor, radiation attenuation, radiation absorption coefficient, real and imaginary parts of the complex dielectric permittivity.
UDC 621.762:669.018.25
G. L. Zhunkivskyi, O. M. Grigoriev, D. V. Vedel*
Institute for Problems of Materials Science named after I. M. Frantsevich, NAS of Ukraine, Kyiv, Ukraine
*vedeldv@gmail.com
Interaction of zirconium diboride with iron and stainless steel Kh18N10T (pp. 40-49)
The interaction of ZrB2 with Fe and its alloy Kh18N10T in the temperature range of 1200–1700 °C was studied. It was found that up to a temperature of 1400 °C in the ZrB2–Fe system, there is no interaction with the formation of new phases. In the ZrB2–Kh18N10T system, starting from 1200 °C, the process of diffusion of chromium and iron from stainless steel into ZrB2 is activated with the formation of a compacted layer of the ZrB2–(Fe,Cr)2B composite on its contact surface. During contact melting in the ZrB2–Fe system, the crystallized alloy is a composite of zirconium and boron-doped iron-reinforced ZrB2. In the ZrB2–X18H10T system, iron doped with zirconium, nickel, chromium, titanium, boron, and reinforced ZrB2 were found in the structure. Therefore, iron and low-alloy steels can work in contact with ZrB2 in a neutral or reducing environment up to temperatures not higher than 1200 °C, and its alloys of the heat-resistant and stainless steel class, regardless of the environment, up to 1000 °C.
Keywords: zirconium diboride, iron, interaction, eutectic, contact melting.
UDC 669.018.95:539.4.015:665.3:621.762.5
E. R. Ferhatly*, A. V. Kovalska, Y. I. Bogomol
National Technical University of Ukraine “Igor Sikorsky Kyiv Polytechnic Institute”, Kyiv, Ukraine
*elmiabdulla@gmail.com
Microstructure and micromechanical properties of directionally crystallized composites of the B4C–(TixZr1–x)B2 system (pp. 50-57)
Composites of the B4C–(TixZr1–x)B2 system were obtained by the crucible-free zone melting method, the structure of which is a boron carbide matrix in which inclusions of the (TixZr1–x)B2 solid solution are evenly distributed. X-ray phase analysis of the obtained composites was carried out, which showed the presence of the following phases in their compositions: B4C, TiB2, ZrB2, (TiZr)B4 and (Ti0.39Zr0.61)B2. The influence of ZrB2 concentration in composites of the B4C–(TіxZr1–x)B2 system on structural, geometric and mechanical characteristics was revealed.
Keywords: boron carbide, directionally solidified eutectic, solid solution, eutectic composites, composite, microhardness, fracture toughness.
UDC 621.623
Yu. D. Filatov1, V. I. Sidorko1, A. Yu. Boyaryntsev2, S. V. Kovalyov1, V. A. Kovalyov1
1V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2Institute of Scintillation Materials, NAS of Ukraine, Kharkiv, Ukraine
*filatov@ism.kiev.ua
Transfer energy during the interaction of an optical surface with a polishing dispersed system (pp. 58-69)
As a result of studying the mechanism of interaction of an optical surface with a polishing dispersed system during polishing, it was found that the energy transfer between them occurs according to the Förster mechanism. It is shown that during resonant energy transfer from particles of the dispersed phase of the polishing system to the treated surface and from the treated material to particles of the polishing powder, with a decrease in the spectral separation between them, the energy of the sludge particles and wear particles decreases, and the efficiency of energy transfer increases. The spectral separation was characterized by an energy detuning, which was 2.8–4.0 meV for sludge particles and 2.8–12.2 meV for wear particles. The spatial separation between the treated surface and the polishing powder particles was estimated as the arithmetic mean deviation of the polished surface profile, which was equal to 5.6–8.0 nm. It was established that the decrease in the spatial and spectral separation between the treated material and the polishing powder particles causes an increase in the size of the sludge particles and wear particles, which leads to a deterioration in the roughness of optical surfaces. It is shown that the results of the theoretical calculation of the polishing performance of optical materials coincide with the experimental results with a deviation of 2–7%.
Keywords: polishing, resonant energy transfer, polishing performance, surface roughness.
UDC 621.95
L. M. Devin*, M. E. Stakhniv, S. V. Rychev
Institute of Superhard Materials of V. M. Bakul Institute of Materials of the National Academy of Sciences of Ukraine, Kyiv, Ukraine
*ldevin350@gmail.com
Study of the acoustic emission signal at the stage of cutting and exit of the drill from diamond-hard alloy plates (ATP) during drilling of carbon fiber (pp. 70-83)
The results of the study of the acoustic emission signal during drilling of carbon fiber with different cutting modes and geometry of the drill from diamond-hard alloy plates are presented. The patterns of changes in the acoustic emission signal during the drilling process at the stages of cutting and exit of the drill from the workpiece, as well as the influence of cutting modes on the quality of the resulting hole, are established. The relationship between the level of the acoustic emission signal at the stage of exit of the transverse edge from the workpiece and the defectivity of the drilled holes is established. The influence of the width of the transverse edge on the value of the acoustic emission signal is studied.
Keywords: drilling of carbon-plastics, diamond-hard alloy plates, acoustic emission signal, transverse cutting edge, drill penetration, drill output, elastic deformation, plastic deformation.
UDC 621.921.34
T. O. Prikhna, G. D. Ilnytska, V. I. Lavrinenko*, I. M. Zaitseva, M. M. Sheiko, V. V. Smokvina, V. V. Tymoshenko
V. M. Bakul Institute of Superhard Materials, NASU, Kyiv, Ukraine Kyiv, Ukraine
*gil-ism@ukr.net
**lavrinenko@ism.kiev.ua
Improvement of the physical and mechanical characteristics of synthetic diamond powders synthesized using ferroalloys to increase the wear resistance of diamond grinding tools (pp. 84-98)
The physical and mechanical and operational characteristics of synthetic diamond powders obtained in the Fe–Co–C growth system were studied. It was shown that diamond grinding powders of different grades synthesized in this system, due to the high values of the specific magnetic susceptibility of intracrystalline inclusions of alloy-solvents, have strong magnetic properties. It was found that the strength characteristics of diamond grinding powders synthesized in the Fe–Co–C system, of different grades, both as initial and after high-temperature treatments, decrease by approximately 2.9 times with an increase in intracrystalline impurities and alloy-solvent inclusions in them, the strength index of diamond grinding powders decreases by no less than 3 times, and the coefficient of their thermal stability by 1.5 times. During the separation of diamond grinding powders with a grain size of 630/500, grade AC125 by the defectivity of the surface of diamond grains, separation fractions were obtained that differ in surface defectivity and strength indicators, while with an increase in the defectivity of the surface of diamond grains from 0.07 to 0.57%, the strength index under static compression of diamond grains decreases by 1.8 times, and their thermal stability also decreases and the content of impurities in the grinding powder increases. The ruling tool, equipped with elite diamond grinding powders of grain size 315/250 of the AC200 brand, obtained after separation of the initial grinding powder of the AC125 brand, has high wear resistance. The specific consumption of diamond grains during the ruling was 11.8 mg/kg, which is 5.25 times lower than the specific consumption in the case of using the initial diamond grinding powders of the AC125 brand.
Keywords: physical and mechanical characteristics of synthetic diamond powders, intracrystalline inclusions of alloy-solvents, growth system using ferroalloys, separation of diamond powders by surface defect values, wear resistance of the ruling tool.