UDC 669.018.25
Yu. Yu. Rumyantseva1, *, T. Polchyk1, S. O. Lysovenko2
1Lukashevych Research Network, Krakow Institute of Technology, Krakow, Poland
2V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*yrumuanceva@gmail.com
Synthesis of magnesium-aluminum spinel at high temperatures and pressures in the systems Mg2B2O5–Al, MgO–Al2O3, MgO–Al2O3–Al (pp. 3-9)
The possibility of obtaining MgAl2O4 at high temperatures and pressures for the systems Mg2B2O5–Al, MgO–Al2O3, MgO–Al2O3–Al by the HPHT synthesis method was investigated. It was found that for the Mg2B2O5–Al system, the largest amount of MgAl2O4 was observed at a pressure of 2 GPa and a temperature of 1600 ºС. Further increase in pressure and temperature leads to an increase in the content of boron-containing phases. For the MgO–Al2O3 and MgO–Al2O3–Al systems, as well as for the Mg2B2O5–Al system, a decrease in the content of the MgAl2O4 phase was observed with an increase in the pressing pressure, which indicates that an increase in pressure for all systems suppresses the interaction of the initial components. The addition of aluminum as a liquid-phase component allowed to expand the pressure interval in which the formation of the MgAl2O4 phase was observed, which indicates the prospect of using such an approach to obtain MgAl2O4 in the future.
Keywords: magnesium-aluminum spinel, high pressure, chemical interaction, liquid-phase sintering.
UDC 620.22-621.921.34
B. T. Ratov1, V. A. Mechnyk2, *, M. O. Bondarenko2, V. M. Kolodnitsky2, **, E. S. Gevorkyan3, V. A. Chyshkala4, N. S. Akhmetova1, S. P. Staryk2, V. V. Belorusets2, P. S. Sundepova5
1NAO “Kazakh National Research Technical University named after K. I. Saptayev”, Almaty, Kazakhstan
2V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
3Ukrainian State University of Railway Transport, Kharkiv, Ukraine
4V. N. Karazin Kharkiv National University, Kharkiv, Ukraine
5Sh. Yesenov Caspian University of Technology and Engineering, Aktau, Kazakhstan
*vlad.mechnik2019@gmail.com
**vasylkolod56@gmail.com
The structure of the Fe‒Cr‒Cu‒Ni‒Sn matrix with different ZrO2 contents for sintered diamond-containing composites (pp. 10-22)
The possibility of creating materials for use as a matrix for sintered composite diamond-containing materials (CBM) is shown. The results of experimental studies of the dependence of the structure of 26Fe‒25Cr‒32Cu‒9Ni‒8Sn CBM matrix samples manufactured by spark-plasma sintering on the ZrO2 additive content (in the range from 0 to 10%) are presented. The development of metal matrix composites based on Fe‒Cr‒Cu‒Ni‒Sn matrices with ZrO2 additives is a new approach to replacing raw materials commonly used in tools for the stone-working industry. In the initial state, the sample of the composite 26Fe‒25Cr‒32Cu‒9Ni‒8Sn had an uneven distribution of elements. It is shown that the addition of ZrO2 micropowder to the composition of the composite 26Fe‒25Cr‒32Cu‒9Ni‒8Sn allows the formation of a structure whose parameters can be purposefully controlled by changing its concentration. Under such conditions, composites containing the ZrO2 additive have a more uniform distribution of elements. Stable correlations between the content of the ZrO2 additive and the microstructure parameters have been established.
Keywords: composite, iron, chromium, copper, nickel, tin, zirconium dioxide, structure, spark-plasma sintering.
UDC 666.3/.7:669.018.2
Peixun Wang1, 2, Jiuyang Li1, 2, Luyu Yang1, 2, Yi Wu1, 2, *1Key Laboratory of New Processing Technology for Nonferrous Metal & Materials, Ministry of Education, Guilin, Guangxi, P.R. China
2College of Materials Science and Engineering, Guilin University of Technology, Guilin, Guangxi, P.R. China
wuyimail@sohu.com
Effect of holding time on the properties of high-entropy nitride ceramics (Ti0.25V0.25Cr0.25Nb0.25)N0.825 with N-vacancy diffusion (pp. 23-33)
To obtain high-entropy ceramics, the starting material TiN0.3 with anionic vacancies was used as a sintering aid, equimolarly mixed with VN, CrN and NbN. It is shown that high-entropy nitride ceramics with a single rock salt phase were successfully synthesized within 5 min, the samples reached maximum values of hardness, flexural strength and fracture toughness – 21.51±1.50 GPa, 1271±24 MPa and 3.63±0.35 MPa×m1/2, respectively, when aged for 15 min.
Keywords: high-entropy nitrides, nitrogen vacancies, creep strength, fracture toughness, spark plasma sintering.
UDC 621.921.34:621.791.36
Jun Zhang1, 2, 3, Kai Li1, 2, 3, Zhe Zhang4, Jiarong Chen1, 2, 3, Peicheng Mo1, 2, 3, Xiaoyi Pan1, 2, 3, Qiaofan Hu1, 2, 3, Chao Chen1, 2, 3, *
1Guangxi Key Laboratory of Superhard Material, China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd., Guilin, Guangxi, P.R. China
2National Engineering Research Center for Special Mineral Material, China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd., Guangxi, P.R. China
3Guangxi Technology Innovation Center for Special Mineral Material, China Nonferrous Metals (Guilin) Geology and Mining Co., Ltd., Guilin, Guangxi, P.R. China
4Guilin Tebon Superhard Materials Co ., Ltd., Guilin, Guangxi, P.R. China
*814294424@qq.com
Effect of Cu–Sn–Ti solder alloy on morphology, bonding surface and mechanical properties of brazed diamond grains (pp. 34-44)
The characteristics of 70Cu–20Sn–10Ti solder powder, which is used for brazing diamond grains in vacuum at 960 °C for 20 min, were investigated. The study covered the macroscopic and microscopic morphology of the Cu–Sn–Ti/diamond composite, the products and thickness of the interfacial reaction layer, the surface morphology of diamond grains, and the phase and morphology of surface attachments after the reaction. The effects of graphitization and diamond strength after the reaction were studied. The results showed that the solder alloy could effectively climb to the diamond grain and had excellent wettability. Under a microscope, a reaction layer of TiC was observed at the interface between them, the thickness of which was ~ 1.92 μm, which led to the realization of chemical-metallurgical bonding. After brazing, the uncoated surface of the diamond grains looked smooth and did not show graphitization, with the exception of minor graphitization in several corrosion pits. No significant changes in the compressive strength of diamond were observed before and after brazing.
Keywords: Cu–Sn–Ti alloy, diamond, brazing, interfacial reaction, graphitization, compressive strength.
UDC 621.315; 666.3.017; 537.226.1
V. I. Chasnyk1, *, D. V. Chasnyk2, O. M. Kaidash3, I. P. Fesenko3, S. A. Kukharenko3
1State Enterprise Research Institute “Orion”, m. Kyiv, Ukraine
2Ukrainian Research Institute of Special Equipment and Forensic Examinations of the Security Service of Ukraine, Kyiv, Ukraine
3V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*vassiliyiv@gmail.com
The Effect of the Surface Condition of a Volumetric AlN–Mo Composite Absorber on Reducing the Reflection of Microwave Radiation (pp. 45-54)
To further improve the designs and ensure stable operation of electrovacuum devices operating in the microwave range at frequencies of 1–100 GHz, the absorption characteristics of microwave radiation were improved. The extremely complex task of obtaining bulk absorbers from AlN–Mo composites with a high (10–12.3 dB) attenuation level, corresponding to a microwave absorption coefficient of 37–56 dB/cm, has been solved, and a good low (1.5–1.6) value of the voltage standing wave coefficient (VSC) has been achieved in the frequency range of 9.3–10 GHz. It has been established that chemical treatment of the absorber surface, which consists in removing molybdenum particles from it with a mixture of acids, improves the matching by reducing the microwave reflection values, and accordingly, the maximum VSC by 26–30%.
Keywords: aluminum nitride, molybdenum, microwave absorption, bulk absorber, traveling wave lamp, matching, voltage standing wave coefficient (WSWC).
UDC 620.22:621.921
V. I. Kushch*, A. S. Manokhin, S. A. Klymenko
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*vkushch56@gmail.com
Theoretical assessment of brittle strength of cBN–TiN two-phase ceramics (pp. 55-59)
A theoretical methodology for assessing the brittle strength of multiphase polycrystalline materials is presented and the results of its application to cBN–TiN two-phase ceramics are presented.
Keywords: multiphase ceramics, brittle strength, micromechanical model, Weibull statistical theory.
UDC 621.923
V. I. Lavrinenko
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
lavrinen52@gmail.com
Modern developments in diamond processing processes and features of surface modification of diamond grains for directed change of their properties (Review) (pp. 60-83)
Modern developments in diamond processing and dressing processes, features of surface modification of diamond grains for directed change of their properties are considered. The scientific principles underlying the development of plastic grinding processes for brittle materials are presented. Attention is paid to the relationship between such indicators as specific energy, diamond tool wear and surface roughness. It is shown that the laser rough dressing method is used to quickly remove the excess abrasive layer, and the electric discharge precision dressing allows to increase the profile accuracy and restore the cutting ability of the grinding wheel. The positive effects of the use of defective porous diamond grains are proven. Diamond grains with high self-sharpening and improved retention in the binding material are obtained. The effectiveness of adding B2O3, TiO2 and Al2O3 oxides during the modification of the surface of diamond grains for protection against oxidation is proven. Attention is drawn to the positive effect of a multilayer coating containing cBN. It is shown that the addition of B4C and V2O5 improves the retention of diamond grains in diamond-containing composites.
Keywords: diamond processing, cutting surface, modification of the surface of diamond grains, plastic grinding, dressing of diamond wheels, CVD diamond, diamond tool, dressing tool.
UDK 621.921.34-492.2:621.793.6:544.023.5:539.215
G. A. Petasyuk, V. I. Lavrinenko*, V. G. Poltoratsky, O. O. Pasichny, O. U. Petasyuk
V. M. Bakul Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
*petasyuk@ukr.net
**lavrinen52@gmail.com
Study of the relationship between the technological properties of cubonite grinding powders modified with a combined coating and the performance characteristics of grinding wheels made using such powders (pp. 84-96)
A quantitative analysis of the correlation relationship between the technological properties of cubonite grinding powders modified with a combined coating and the performance characteristics of grinding wheels made using such powders was carried out. The values of the pairwise correlation coefficients between the relative loss of abrasive and the roughness of the treated surface by the parameter Ra (dependent factors), the technological parameters of the coating, the processing performance and some morphometric characteristics and technological properties of the modified grinding powders (independent factors) were obtained. It was found that the greatest influence on the relative consumption of cubonite grinding powder in the grinding wheels is caused by the processing productivity (correlation coefficient – 0.884) and such morphometric characteristics as the roughness of the grain projection (correlation coefficient – 0.28) and the external specific surface of the powder (correlation coefficient – 0.294). In the case of the roughness of the processed surface by the parameter Ra, the greatest influence on it is also the processing productivity with a correlation coefficient of 0.856 and the specific perimeter of the grain projection with a correlation coefficient of 0.12. Suggestions are presented for the use of the obtained results.
Keywords: correlation relationship, technological properties, grain, grinding powder, cubonite, combined coating, grinding wheels.
UDC 666.792.34:539.89
V. Z. Turkevich1, *, O. O. Matviychuk1, Li Decheng2, D. V. Turkevich1
1V. M. Bakuly Institute of Superhard Materials, NAS of Ukraine, Kyiv, Ukraine
2Kyivska Polytechnika Applied Technology Research Institute, Chongqing, China
*vturk@ism.kiev.ua
Thermodynamic modeling of the sintering process of diamond-hard alloy plates in the С–Co–W system under a pressure of 6 GPa (pp. 97-100)
Within the framework of phenomenological thermodynamics models, using the Thermo-Calc software package and using the interaction parameters from the literature data and the equation of state of competing phases, polythermal sections of the phase diagram of the carbon–cobalt–tungsten system at pressures of 0.1 MPa and 6 GPa and the phase composition of the diamond layer of diamond-hard alloy plates were calculated. Comparison of the calculation results with experimental studies of the phase composition of samples of diamond-hard alloy plates sintered at high pressures and temperatures showed their correspondence.
Keywords: phase diagram, high pressures, diamond composites.
UDC 621.921.34:546.26:541.124.7
Danhui Han*, Chong Peng, Guangtong Zhou, Bingtao Hu
State Key Laboratory for High Performance Tools, Zhengzhou Research Institute for Abrasives & Grinding Co., Ltd, Zhengzhou, P.R. China
*zwxlby@126.com
Rapid synthesis of nanodiamond/graphene oxide composites using the explosive characteristics of graphene oxide (pp. 101-104)
Nanodiamond particles and graphene oxide (GO) powders were used as raw materials to create nanodiamond/reduced OG (rOG) composites using the explosive reaction of OG. The results of X-ray diffractometry, Fourier transform and X-ray photoelectron spectrometry indicate that rapid heating can induce explosive reactions in the OG. Through this explosive reaction, the OG is rapidly reduced to graphene. The results of scanning electron microscopy indicate that the OG has undergone significant expansion and exfoliation, and the nanodiamond particles have been completely transferred to the layers of the OG.
Keywords: graphene oxide, nanodiamond, explosive reaction, bond.