Pub Date : 2022-06-16DOI: 10.17073/1997-308x-2022-2-13-21
G. P. Benderskiy, Yu. M. Molostova, P. A. Rumyantsev, S. Serebryannikov, S. S. Serebryannikov
The paper studies the effect of particle sizes of hexagonal ferrite powders on their electrodynamic properties. SrTi0.2Co0.2Fe11.6O19 and BaSc0.2Fe11.8O19 hexaferrites were used as the objects of research. Grinding in a high-energy planetary mill for up to 60 minutes made it possible to obtain hexaferrite powder particles with the average size successively decreasing from 1.5–2 μm to 0.05–0.15 μm. A scanning electron microscope was used for the analysis. Samples were prepared in a mixture with a polymer binder (70% ferrite + 30% polymer), and their electromagnetic radiation (EMR) absorbing capacity was studied in the microwave range from 30 to 50 GHz. It was shown that there is practically no peak corresponding to ferrimagnetic resonance in the composite with ferrite, with a decrease in the average particle size of BaSc0.2Fe11.8O19 hexaferrite powders to 50–150 nm. The dependences of the real and imaginary parts of the magnetic permeability and dielectric constant are given in the frequency range from 107 to 109 Hz. There was no domain wall resonance in the frequency dependence of magnetic losses for a ferrite-based composite mechanically activated for 60 min. SrTi0.2Co0.2Fe11.6O19 ferrite was milled in a bead mill to particles with an average size of 150–300 nm, and then to drying, pressing, sintering at 1360 °С and subsequent grinding to a size of 200–500 μm to obtain similar composites in a bond with a polymer. It was found that the properties of compositions change significantly with a change in the magnetic component synthesis technology: no resonant pattern of EMR absorption was observed. The Curie temperature was measured using the Faraday method. It was shown that it is ~340 °С for the studied material. Therefore, the effect of precursor milling on changes in magnetocrystalline anisotropy was identified.
{"title":"Radar-absorbing composite materials based on ferrite powders","authors":"G. P. Benderskiy, Yu. M. Molostova, P. A. Rumyantsev, S. Serebryannikov, S. S. Serebryannikov","doi":"10.17073/1997-308x-2022-2-13-21","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-2-13-21","url":null,"abstract":"The paper studies the effect of particle sizes of hexagonal ferrite powders on their electrodynamic properties. SrTi0.2Co0.2Fe11.6O19 and BaSc0.2Fe11.8O19 hexaferrites were used as the objects of research. Grinding in a high-energy planetary mill for up to 60 minutes made it possible to obtain hexaferrite powder particles with the average size successively decreasing from 1.5–2 μm to 0.05–0.15 μm. A scanning electron microscope was used for the analysis. Samples were prepared in a mixture with a polymer binder (70% ferrite + 30% polymer), and their electromagnetic radiation (EMR) absorbing capacity was studied in the microwave range from 30 to 50 GHz. It was shown that there is practically no peak corresponding to ferrimagnetic resonance in the composite with ferrite, with a decrease in the average particle size of BaSc0.2Fe11.8O19 hexaferrite powders to 50–150 nm. The dependences of the real and imaginary parts of the magnetic permeability and dielectric constant are given in the frequency range from 107 to 109 Hz. There was no domain wall resonance in the frequency dependence of magnetic losses for a ferrite-based composite mechanically activated for 60 min. SrTi0.2Co0.2Fe11.6O19 ferrite was milled in a bead mill to particles with an average size of 150–300 nm, and then to drying, pressing, sintering at 1360 °С and subsequent grinding to a size of 200–500 μm to obtain similar composites in a bond with a polymer. It was found that the properties of compositions change significantly with a change in the magnetic component synthesis technology: no resonant pattern of EMR absorption was observed. The Curie temperature was measured using the Faraday method. It was shown that it is ~340 °С for the studied material. Therefore, the effect of precursor milling on changes in magnetocrystalline anisotropy was identified.","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"38 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84884878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-16DOI: 10.17073/1997-308x-2022-2-22-37
Y. Titova, A. Amosov, D. Maidan, G. S. Belova, A. F. Minekhanova
The study covers the method of azide self-propagating high-temperature synthesis (SHS-Az) to obtain a highly dispersed TiN–SiC ceramic composite with a theoretical ratio of nitride and carbide phases from 1 : 4 to 4 : 1 (in moles) using the combustion of the corresponding composition of powder reagent mixtures: NaN3 sodium azide, (NH4)2TiF6, (NH4)2SiF6 and Na2SiF6 halide salts, titanium, silicon and carbon in a nitrogen gas atmosphere. Thermodynamic calculations using the Thermo computer program showed that the optimum nitrogen pressure in the reactor is about 4 MPa, and the final composition of SHS-Az products can be completely different depending on the composition of reagents: it may include only target phases (TiN–SiC), contain silicon nitride and free carbon phases impurities (TiN–SiC–Si3N4–C) along with the target phases or consist only of nitride and free carbon phases (TiN–Si3N4–C). It was found that only target TiN and SiC phases are formed when using halide salt (NH4)2TiF6, at any ratio of nitride and carbide phases in the final powder composition. In cases where halide salts (NH4)2SiF6 and Na2SiF6 are used, target TiN and SiC phases are synthesized with an increased titanium content in reagents, i.e. only when composites of the 2TiN–SiC and 4TiN–SiC with an increased content nitride phase are obtained. Experimental studies of combustion products using scanning electron microscopy, energy dispersion analysis and X-ray phase analysis showed that they differ significantly from the theoretical compositions of products by the completely absent or significantly reduced SiC phase content in the final composition of powder composites synthesized during the combustion of bulk charge with carbon, and at the same time the absence of free carbon in the final composition of powder composites obtained. This difference is explained by the fact that when the combustion of a silicon and carbon powder mixture is initiated, silicon nitride is synthesized at the first stage with the temperature rising to high values of about over 1900 °C, at which the synthesized Si3N4 dissociates, and then at the second stage the resulting silicon reacts with carbon to form SiC that is more stable at high temperatures. But during combustion, very small light particles of carbon black (soot) may be removed (blown out) from a burning highly porous charge sample of bulk density by gases released at the first stage of combustion and not participate in the transformation of Si3N4 into SiC. In this regard, in case of low-carbon charge combustion, silicon carbide either does not form at all, or it is formed in small quantities compared to the theoretically possible amount, and Si3N4 silicon nitride remains the main component of the composite. A noticeable amount of SiC is formed only when burning high-carbon charges, but this amount is significantly less than the possible theoretical one, and the difference between them is replaced by the silicon nitride content. Therefore, it
{"title":"Azide self-propagating high-temperature synthesis of highly dispersed TiN–SiC ceramic nitride-carbide powder composites","authors":"Y. Titova, A. Amosov, D. Maidan, G. S. Belova, A. F. Minekhanova","doi":"10.17073/1997-308x-2022-2-22-37","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-2-22-37","url":null,"abstract":"The study covers the method of azide self-propagating high-temperature synthesis (SHS-Az) to obtain a highly dispersed TiN–SiC ceramic composite with a theoretical ratio of nitride and carbide phases from 1 : 4 to 4 : 1 (in moles) using the combustion of the corresponding composition of powder reagent mixtures: NaN3 sodium azide, (NH4)2TiF6, (NH4)2SiF6 and Na2SiF6 halide salts, titanium, silicon and carbon in a nitrogen gas atmosphere. Thermodynamic calculations using the Thermo computer program showed that the optimum nitrogen pressure in the reactor is about 4 MPa, and the final composition of SHS-Az products can be completely different depending on the composition of reagents: it may include only target phases (TiN–SiC), contain silicon nitride and free carbon phases impurities (TiN–SiC–Si3N4–C) along with the target phases or consist only of nitride and free carbon phases (TiN–Si3N4–C). It was found that only target TiN and SiC phases are formed when using halide salt (NH4)2TiF6, at any ratio of nitride and carbide phases in the final powder composition. In cases where halide salts (NH4)2SiF6 and Na2SiF6 are used, target TiN and SiC phases are synthesized with an increased titanium content in reagents, i.e. only when composites of the 2TiN–SiC and 4TiN–SiC with an increased content nitride phase are obtained. Experimental studies of combustion products using scanning electron microscopy, energy dispersion analysis and X-ray phase analysis showed that they differ significantly from the theoretical compositions of products by the completely absent or significantly reduced SiC phase content in the final composition of powder composites synthesized during the combustion of bulk charge with carbon, and at the same time the absence of free carbon in the final composition of powder composites obtained. This difference is explained by the fact that when the combustion of a silicon and carbon powder mixture is initiated, silicon nitride is synthesized at the first stage with the temperature rising to high values of about over 1900 °C, at which the synthesized Si3N4 dissociates, and then at the second stage the resulting silicon reacts with carbon to form SiC that is more stable at high temperatures. But during combustion, very small light particles of carbon black (soot) may be removed (blown out) from a burning highly porous charge sample of bulk density by gases released at the first stage of combustion and not participate in the transformation of Si3N4 into SiC. In this regard, in case of low-carbon charge combustion, silicon carbide either does not form at all, or it is formed in small quantities compared to the theoretically possible amount, and Si3N4 silicon nitride remains the main component of the composite. A noticeable amount of SiC is formed only when burning high-carbon charges, but this amount is significantly less than the possible theoretical one, and the difference between them is replaced by the silicon nitride content. Therefore, it","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"69 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76193873","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-16DOI: 10.17073/1997-308x-2022-2-70-78
A. Krokhalev, V. Kharlamov, D. Chernikov, S. V. Kuz’min, V. Lysak
The paper presents the results of studies into the microstructure, chemical and phase composition of coatings deposited on a steel substrate using the sliding explosive loading of Cr3C2 chromium carbide and titanium powder mixtures. The equilibrium phase composition of coatings was calculated by computational thermodynamic modeling using the Thermo-Calc software package. The structure and elemental composition were studied using a FEI Versa 3D scanning electron microscope with an integrated EDAX Apollo X system for energy dispersive X-ray microprobe analysis. A Bruker D8 Advance diffractometer was used for X-ray phase analysis. It was shown that when the powder layer is loaded by a sliding detonation wave, it can be shifted along the substrate surface due to the horizontal mass velocity component of compacted material particles. This shift causes the inner layer of the compacted powder and the surface layer of the substrate to melt as a result of friction. The presence of a liquid phase prevents the compacted powder layer deceleration so that the major part of it is removed from the substrate surface. The liquid phase remaining on the surface undergoes rapid quenching due to heat removal into the substrate and forms a deposited coating containing both the components of the initial powder mixture and the components of the substrate to be coated. It was established that the deposited layer structure features by extremely high dispersion (grain size does not exceed 250 nm), and its phase composition turns out to be close to a thermodynamically equilibrium one. When using powder mixtures of chromium carbide with 40% titanium, a coating is formed consisting of titanium carbide with a metal binder based on solid solutions of iron and titanium in chromium.
本文介绍了用Cr3C2碳化铬和钛粉混合物滑动爆炸加载在钢基体上沉积涂层的微观结构、化学成分和相组成的研究结果。利用heat - calc软件进行计算热力学建模，计算涂层的平衡相组成。利用FEI Versa三维扫描电子显微镜和集成EDAX Apollo X系统进行能量色散X射线微探针分析，研究了其结构和元素组成。采用Bruker D8 Advance衍射仪进行x射线相分析。结果表明，在滑动爆震波的作用下，由于压实材料颗粒的水平质量速度分量，粉末层可以沿着衬底表面发生位移。这种转变导致压实粉末的内层和基材的表层由于摩擦而熔化。液相的存在阻止了压实粉末层的减速，使其主要部分从基材表面去除。保留在表面上的液相由于热量进入基体而经历快速淬火，并形成沉积的涂层，其中包含初始粉末混合物的组分和待涂覆的基体的组分。结果表明，沉积层的结构具有极高的分散性(晶粒尺寸不超过250 nm)，其相组成接近热力学平衡。当使用碳化铬和40%钛的粉末混合物时，会形成一层由碳化钛和基于铁和钛在铬中的固溶体的金属粘合剂组成的涂层。
{"title":"Using explosion loading to obtain coatings of chromium carbide and titanium mixtures in deposition mode","authors":"A. Krokhalev, V. Kharlamov, D. Chernikov, S. V. Kuz’min, V. Lysak","doi":"10.17073/1997-308x-2022-2-70-78","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-2-70-78","url":null,"abstract":"The paper presents the results of studies into the microstructure, chemical and phase composition of coatings deposited on a steel substrate using the sliding explosive loading of Cr3C2 chromium carbide and titanium powder mixtures. The equilibrium phase composition of coatings was calculated by computational thermodynamic modeling using the Thermo-Calc software package. The structure and elemental composition were studied using a FEI Versa 3D scanning electron microscope with an integrated EDAX Apollo X system for energy dispersive X-ray microprobe analysis. A Bruker D8 Advance diffractometer was used for X-ray phase analysis. It was shown that when the powder layer is loaded by a sliding detonation wave, it can be shifted along the substrate surface due to the horizontal mass velocity component of compacted material particles. This shift causes the inner layer of the compacted powder and the surface layer of the substrate to melt as a result of friction. The presence of a liquid phase prevents the compacted powder layer deceleration so that the major part of it is removed from the substrate surface. The liquid phase remaining on the surface undergoes rapid quenching due to heat removal into the substrate and forms a deposited coating containing both the components of the initial powder mixture and the components of the substrate to be coated. It was established that the deposited layer structure features by extremely high dispersion (grain size does not exceed 250 nm), and its phase composition turns out to be close to a thermodynamically equilibrium one. When using powder mixtures of chromium carbide with 40% titanium, a coating is formed consisting of titanium carbide with a metal binder based on solid solutions of iron and titanium in chromium.","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"13 2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90078397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-06-16DOI: 10.17073/1997-308x-2022-2-52-60
V. T. Telepa, M. Alymov, А. Shcherbakov
The effect of activation energy on phase transformations (transitions) in the W–C system during the synthesis induced by an external heat source was investigated by electrothermal explosion (ETE) under pressure. The ETE technology combines self-propagating high-temperature synthesis (SHS) with additional sample heating by Joule heat – electric current passing through the synthesized mixture, and it makes it possible to determine the chemical reaction rate that is highly susceptible to external impacts such as pressure, concentration, sample shape, any film present on combustion products, etc. The chemical reaction rate, i.e. external source current, may be controlled by changing the activation energy. The study was conducted in the following conditions: temperature Т = 293÷3700 K; carbon concentration of 49.8–50.2 at.%; quasi-static compression at P = 96 MPa; external source voltage and current density V = 10 V, I = 20 МА/m2, respectively; samples 8 mm in diameter weighing 6 g. The Т–τ thermogram of the W–C system was used to determine the following parameters: four stages of the synthesis process, temperatures of special points of phase transformations, temperature boundaries of phases and process activation energy. Thermograms of intermediate states are presented as isothermal plateaus of phase transformations. The analysis of experimental results and the physical representation of the process make it possible to assert that temperature plateau parameters are the effective value of activation energy for synthesis mode maintenance. Each of the 4 W–C mixture synthesis stages is described. Pre-explosion stage I – sample heating in the temperature range of Т = 293÷563К, endothermic reaction, effective activation energy for synthesis mode maintenance Q = 2.96 kJ, and taking into account 1-mole mass Еа = 111.6 kJ/mol. Low-temperature (563–1190 К) stage II – ignition, Q = 5.46 kJ, Еа = 109.2 kJ/mol. High-temperature stage (III) in the range of Т = 1190÷2695К, order–disorder transformation, Q = 14.25 kJ, Еа = 424 kJ/mol. Finally, Stage IV occurs in the range of Т = 2695÷3695К, Q = 14.31 kJ, Еа = 143.2 kJ/mol. It was shown that the limiting stage with the highest activation energy is the melting process.
{"title":"Activation energy of phase transformations at high-temperature synthesis of tungsten carbide by electrothermal explosion under pressure","authors":"V. T. Telepa, M. Alymov, А. Shcherbakov","doi":"10.17073/1997-308x-2022-2-52-60","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-2-52-60","url":null,"abstract":"The effect of activation energy on phase transformations (transitions) in the W–C system during the synthesis induced by an external heat source was investigated by electrothermal explosion (ETE) under pressure. The ETE technology combines self-propagating high-temperature synthesis (SHS) with additional sample heating by Joule heat – electric current passing through the synthesized mixture, and it makes it possible to determine the chemical reaction rate that is highly susceptible to external impacts such as pressure, concentration, sample shape, any film present on combustion products, etc. The chemical reaction rate, i.e. external source current, may be controlled by changing the activation energy. The study was conducted in the following conditions: temperature Т = 293÷3700 K; carbon concentration of 49.8–50.2 at.%; quasi-static compression at P = 96 MPa; external source voltage and current density V = 10 V, I = 20 МА/m2, respectively; samples 8 mm in diameter weighing 6 g. The Т–τ thermogram of the W–C system was used to determine the following parameters: four stages of the synthesis process, temperatures of special points of phase transformations, temperature boundaries of phases and process activation energy. Thermograms of intermediate states are presented as isothermal plateaus of phase transformations. The analysis of experimental results and the physical representation of the process make it possible to assert that temperature plateau parameters are the effective value of activation energy for synthesis mode maintenance. Each of the 4 W–C mixture synthesis stages is described. Pre-explosion stage I – sample heating in the temperature range of Т = 293÷563К, endothermic reaction, effective activation energy for synthesis mode maintenance Q = 2.96 kJ, and taking into account 1-mole mass Еа = 111.6 kJ/mol. Low-temperature (563–1190 К) stage II – ignition, Q = 5.46 kJ, Еа = 109.2 kJ/mol. High-temperature stage (III) in the range of Т = 1190÷2695К, order–disorder transformation, Q = 14.25 kJ, Еа = 424 kJ/mol. Finally, Stage IV occurs in the range of Т = 2695÷3695К, Q = 14.31 kJ, Еа = 143.2 kJ/mol. It was shown that the limiting stage with the highest activation energy is the melting process.","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85424668","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-24DOI: 10.17073/1997-308x-2022-1-76-87
A. Ilyushchanka, A. Liashok, L. Dyachkova, V. Biryukov
Machines and mechanisms contain units responsible for their movement and stopping, and such units use friction materials. These units include oil-cooled brakes, hydromechanical transmissions, and clutches. They use mainly copper-based friction materials providing the high coefficient of friction and wear resistance. These materials feature by effective heat dissipation since a large amount of heat is released in these areas for a short period of time. The paper presents the results of studies into the effect of iron addition into a frictional powder material based on BrO6 and BrO12 bronze on its structure, mechanical and tribotechnical properties. It was shown that the introduction of iron contributes to an increase in the coefficient of friction from 0.034 to 0.055 for the BrO6-based friction material and from 0.042 to 0.073 for the BrO12-based friction material. It was determined that the ultimate compression strength of the BrO12-based friction material is 340 MPa without iron addition, 310 MPa at 10 vol.% of iron, and 180 MPa at 50 vol.% of iron. This is due to the fact that the iron content of more than 30 vol.% results in the change of the frame structure of the material to the matrix one having a sintering temperature higher than the temperature used in the paper for friction material sintering. It was found that for the BrO6-based friction material there are both rounded and elongated inclusions in the copper phase up to 2.5 μm in size with the iron content of 30–50 %. In the BrO12-based material there are more iron inclusions in the copper phase and their size are much larger, the length of inclusions reaches 20 μm, and the iron content in them is 49–73 %.
{"title":"Effect of iron addition on the structure and properties of copper-based friction powder material used under friction conditions with lubrication","authors":"A. Ilyushchanka, A. Liashok, L. Dyachkova, V. Biryukov","doi":"10.17073/1997-308x-2022-1-76-87","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-1-76-87","url":null,"abstract":"Machines and mechanisms contain units responsible for their movement and stopping, and such units use friction materials. These units include oil-cooled brakes, hydromechanical transmissions, and clutches. They use mainly copper-based friction materials providing the high coefficient of friction and wear resistance. These materials feature by effective heat dissipation since a large amount of heat is released in these areas for a short period of time. The paper presents the results of studies into the effect of iron addition into a frictional powder material based on BrO6 and BrO12 bronze on its structure, mechanical and tribotechnical properties. It was shown that the introduction of iron contributes to an increase in the coefficient of friction from 0.034 to 0.055 for the BrO6-based friction material and from 0.042 to 0.073 for the BrO12-based friction material. It was determined that the ultimate compression strength of the BrO12-based friction material is 340 MPa without iron addition, 310 MPa at 10 vol.% of iron, and 180 MPa at 50 vol.% of iron. This is due to the fact that the iron content of more than 30 vol.% results in the change of the frame structure of the material to the matrix one having a sintering temperature higher than the temperature used in the paper for friction material sintering. It was found that for the BrO6-based friction material there are both rounded and elongated inclusions in the copper phase up to 2.5 μm in size with the iron content of 30–50 %. In the BrO12-based material there are more iron inclusions in the copper phase and their size are much larger, the length of inclusions reaches 20 μm, and the iron content in them is 49–73 %.","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"232 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77474570","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-24DOI: 10.17073/1997-308x-2022-1-36-42
G. Smorchkov, A. Rachkovskij, G. Baranov, D. N. Kondrokhin, S. S. Kurganov
A new high-temperature antifriction composite material 90 % MoSi2 + 10 % MoS2 was developed with a static friction coefficient of less than 0.3. The material is functional at temperatures up 1500 °C under neutron irradiation in an inert gas environment. Modes of initial MoSi2 and MoS2 powder mixture preparation and hot pressing of the resulting charge in a vacuum induction unit in graphite molds were worked out at a temperature of 1600–1650 °C, specific hot pressing pressure of 25 MPa, and holding for 1 h at these values of temperature and pressure. Tribotechnical properties of the material depending on the compression force in the friction pair and on the counterbody material hardness were investigated. It was shown that the higher the compression force and the harder the counterbody material in the friction pair, the lower the coefficient of friction. The effect of temperature on the physical, mechanical and heat-transfer properties of the material was established. As the temperature increases from 20 to 1000 °C, the material compressive strength decreases from 1388 to 739 MPa. An increase in the temperature from 25 to 400 °C leads to an increase in the specific heat capacity from 427 to 596 J/(kg·K) and the coefficient of heat conductivity from 2.35 to 3.41 W/(m·K). Plain bearings made of this material successfully passed durability and reactor tests.
{"title":"MoSi2–MoS2 composite antifriction material","authors":"G. Smorchkov, A. Rachkovskij, G. Baranov, D. N. Kondrokhin, S. S. Kurganov","doi":"10.17073/1997-308x-2022-1-36-42","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-1-36-42","url":null,"abstract":"A new high-temperature antifriction composite material 90 % MoSi2 + 10 % MoS2 was developed with a static friction coefficient of less than 0.3. The material is functional at temperatures up 1500 °C under neutron irradiation in an inert gas environment. Modes of initial MoSi2 and MoS2 powder mixture preparation and hot pressing of the resulting charge in a vacuum induction unit in graphite molds were worked out at a temperature of 1600–1650 °C, specific hot pressing pressure of 25 MPa, and holding for 1 h at these values of temperature and pressure. Tribotechnical properties of the material depending on the compression force in the friction pair and on the counterbody material hardness were investigated. It was shown that the higher the compression force and the harder the counterbody material in the friction pair, the lower the coefficient of friction. The effect of temperature on the physical, mechanical and heat-transfer properties of the material was established. As the temperature increases from 20 to 1000 °C, the material compressive strength decreases from 1388 to 739 MPa. An increase in the temperature from 25 to 400 °C leads to an increase in the specific heat capacity from 427 to 596 J/(kg·K) and the coefficient of heat conductivity from 2.35 to 3.41 W/(m·K). Plain bearings made of this material successfully passed durability and reactor tests.","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"51 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90055858","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-24DOI: 10.17073/1997-308x-2022-1-66-75
M. Bychkova, O. S. Manakova, A. Akhmetov, A. Kaysinov, E. N. Avdeenko, P. Loginov, S. Vorotilo
This paper focuses on the development of composite materials based on the Fe–Ni–Cu alloy with hollow corundum microspheres (HCM). The composites were produced by means of powder metallurgy: by mixing initial metallic powders in various types of mixers followed by hot pressing. Compact samples of Fe–Ni–Cu + HCM composites featured high relative density and microstructure homogeneity. The introduction of HCM leads to a decrease in strength to 30 % (from 1125 MPa to 800 MPa at a HCM concentration of 15 vol.%). However, resulting composite materials retained high plasticity. It was established by the micromechanical modeling method that such composites have stress concentration regions not at the interface between HCM and the matrix, but on the inner surface of microspheres. On the contrary, the adjacent matrix volume around HCM features stress relaxation and «unloaded» regions formed. HCM introduction into the matrix based on the Fe–Ni–Cu alloy increases wear resulting from friction on M300 concrete by 50–170 % with a grain size of 70–100 μm and by 160–325 % with a grain size of 100–140 μm. During friction, HCMs act as a reservoir for debris (concrete particles), so the matrix surface remains free of wear products and directly contacts the material processed. The heavy wear of composites with HCM makes them promising for use as a binder in diamond tools designed for the dry cutting of concrete and reinforced concrete.
{"title":"Mechanical properties and wear resistance of Fe–Ni–Cu-based metal matrix composites reinforced with hollow corundum microspheres","authors":"M. Bychkova, O. S. Manakova, A. Akhmetov, A. Kaysinov, E. N. Avdeenko, P. Loginov, S. Vorotilo","doi":"10.17073/1997-308x-2022-1-66-75","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-1-66-75","url":null,"abstract":"This paper focuses on the development of composite materials based on the Fe–Ni–Cu alloy with hollow corundum microspheres (HCM). The composites were produced by means of powder metallurgy: by mixing initial metallic powders in various types of mixers followed by hot pressing. Compact samples of Fe–Ni–Cu + HCM composites featured high relative density and microstructure homogeneity. The introduction of HCM leads to a decrease in strength to 30 % (from 1125 MPa to 800 MPa at a HCM concentration of 15 vol.%). However, resulting composite materials retained high plasticity. It was established by the micromechanical modeling method that such composites have stress concentration regions not at the interface between HCM and the matrix, but on the inner surface of microspheres. On the contrary, the adjacent matrix volume around HCM features stress relaxation and «unloaded» regions formed. HCM introduction into the matrix based on the Fe–Ni–Cu alloy increases wear resulting from friction on M300 concrete by 50–170 % with a grain size of 70–100 μm and by 160–325 % with a grain size of 100–140 μm. During friction, HCMs act as a reservoir for debris (concrete particles), so the matrix surface remains free of wear products and directly contacts the material processed. The heavy wear of composites with HCM makes them promising for use as a binder in diamond tools designed for the dry cutting of concrete and reinforced concrete.","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"44 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76489045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-24DOI: 10.17073/1997-308x-2022-1-49-56
V. Gorina, E. G. Cheblakova
The article provides a general overview of the production methods and applications of carbon materials with a large specific surface area. The following materials were taken as objects for the study: SK-AG-3 granular activated carbon produced by OJSC «Sorbents of Kuzbass», Kemerovo, activated cellulose fiber produced by the Krasnoyarsk Chemical Fiber Plant after carbonation, graphitization, and gas-phase activation at 900 °C in carbon dioxide current, Busofit-T carbon fabric produced by OJSC «SvetlogorskKhimvolokno», thermally expanded fluorinated graphite produced by OJSC «Siberian Chemical Combine». The porous structure of these materials was investigated by low-temperature volumetric nitrogen adsorption at the ASAP 2020 unit. Nitrogen adsorption-desorption isotherms were recorded in a relative pressure range of p/p0 = 0.05÷1.0 at 77 K. The specific surface area was estimated by the BET method based on the adsorption isotherm at p/p0 = 0.05÷0.30. The specific surface area was 485, 1241, 1156 and 290.5 m2/g for activated carbon, activated carbon fibers, Busofit-T fabric and thermally expanded graphite, respectively. The volume of mesopores and their size distribution were calculated by the Barrett-Joyner-Нalenda (BJH) method in a pressure range of p/p0 = 0.35÷0.95. The volume of micropores and their size distribution were calculated by the Horvath-Kawazoe method using the nitrogen adsorption-desorption isotherm in a relative pressure range of p/p0 = 0.00÷0.01. These methods were also used to determine the average diameter of mesopores and micropores. A comparative analysis of the results obtained was carried out. A relationship between the internal structure of the investigated materials and the porous structure properties was traced. It was shown that activated carbon, fibers, and carbon fabrics are microporous materials, and thermally expanded graphite has a mesoporous structure.
{"title":"Porous structure features of carbon materials with extended-surface","authors":"V. Gorina, E. G. Cheblakova","doi":"10.17073/1997-308x-2022-1-49-56","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-1-49-56","url":null,"abstract":"The article provides a general overview of the production methods and applications of carbon materials with a large specific surface area. The following materials were taken as objects for the study: SK-AG-3 granular activated carbon produced by OJSC «Sorbents of Kuzbass», Kemerovo, activated cellulose fiber produced by the Krasnoyarsk Chemical Fiber Plant after carbonation, graphitization, and gas-phase activation at 900 °C in carbon dioxide current, Busofit-T carbon fabric produced by OJSC «SvetlogorskKhimvolokno», thermally expanded fluorinated graphite produced by OJSC «Siberian Chemical Combine». The porous structure of these materials was investigated by low-temperature volumetric nitrogen adsorption at the ASAP 2020 unit. Nitrogen adsorption-desorption isotherms were recorded in a relative pressure range of p/p0 = 0.05÷1.0 at 77 K. The specific surface area was estimated by the BET method based on the adsorption isotherm at p/p0 = 0.05÷0.30. The specific surface area was 485, 1241, 1156 and 290.5 m2/g for activated carbon, activated carbon fibers, Busofit-T fabric and thermally expanded graphite, respectively. The volume of mesopores and their size distribution were calculated by the Barrett-Joyner-Нalenda (BJH) method in a pressure range of p/p0 = 0.35÷0.95. The volume of micropores and their size distribution were calculated by the Horvath-Kawazoe method using the nitrogen adsorption-desorption isotherm in a relative pressure range of p/p0 = 0.00÷0.01. These methods were also used to determine the average diameter of mesopores and micropores. A comparative analysis of the results obtained was carried out. A relationship between the internal structure of the investigated materials and the porous structure properties was traced. It was shown that activated carbon, fibers, and carbon fabrics are microporous materials, and thermally expanded graphite has a mesoporous structure.","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80953999","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-24DOI: 10.17073/1997-308x-2022-1-17-25
A. Shavnev, S. V. Nerush, E. Kurbatkina, D. Kosolapov, P. Medvedev
The research focuses on aluminum composite granules obtained by the mechanical alloying of VAS1 aluminum alloy and silicon carbide initial powders. It was found that the morphology and average size of composite granules change as the time of mechanical alloying increases. There are the processes of aluminum matrix plastic deformation and the introduction of silicon carbide particles into the matrix, «cold welding» of agglomerates to each other and the growth of an average granule size up to 550 μm that occur for 40 hours of processing. After longer mechanical alloying (60 h), the structure of composite granules becomes uniform, and the average particle size reaches ~150 μm remaining virtually unchanged as the process time increases. X-ray analysis showed that there is a change not only in the morphology of composite granules, but also in their internal structure: coherent scattering regions decrease, the lattice constant of the aluminum matrix alloy changes, microdeformations and stacking faults increase. Transmission electron microscopy studies were conducted in order to study the material microstructure more deeply. Their results proved that the material has a uniform ultra-fine grain structure. The solid solution of aluminum has a maximum grain size of 160 nm. Dislocation density in the composite is rather high. The structure features nanosized plate-like Si particles and silicon carbide existing in the material as distributed splintery coarse particles. No diffusion zone between SiC particles and the base material was found.
{"title":"Structural and morphological study of the Al–Si–Mg–SiC composite material produced by mechanical alloying","authors":"A. Shavnev, S. V. Nerush, E. Kurbatkina, D. Kosolapov, P. Medvedev","doi":"10.17073/1997-308x-2022-1-17-25","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-1-17-25","url":null,"abstract":"The research focuses on aluminum composite granules obtained by the mechanical alloying of VAS1 aluminum alloy and silicon carbide initial powders. It was found that the morphology and average size of composite granules change as the time of mechanical alloying increases. There are the processes of aluminum matrix plastic deformation and the introduction of silicon carbide particles into the matrix, «cold welding» of agglomerates to each other and the growth of an average granule size up to 550 μm that occur for 40 hours of processing. After longer mechanical alloying (60 h), the structure of composite granules becomes uniform, and the average particle size reaches ~150 μm remaining virtually unchanged as the process time increases. X-ray analysis showed that there is a change not only in the morphology of composite granules, but also in their internal structure: coherent scattering regions decrease, the lattice constant of the aluminum matrix alloy changes, microdeformations and stacking faults increase. Transmission electron microscopy studies were conducted in order to study the material microstructure more deeply. Their results proved that the material has a uniform ultra-fine grain structure. The solid solution of aluminum has a maximum grain size of 160 nm. Dislocation density in the composite is rather high. The structure features nanosized plate-like Si particles and silicon carbide existing in the material as distributed splintery coarse particles. No diffusion zone between SiC particles and the base material was found.","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84438229","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-03-24DOI: 10.17073/1997-308x-2022-1-26-35
Yu. A. Avdeeva, A. Ermakov, I. Luzhkova, L. Askarova
The article considers the possibility of binding free carbon existing in the VC0.40O0.53–Cfree nanocrystalline composition to the carbide phase. This composition is obtained by plasma-chemical synthesis in a low-temperature nitrogen plasma. As a carbide former, titanium was used in the form of its nickelide TiNi, which has a melting point of 1310 °С. Experiments were carried out under vacuum sintering conditions involving the liquid phase at 1500 °C for 40 min. The data obtained in X-ray diffraction, scanning electron microscopy and energy-dispersive analysis were used to determine the phase composition and microstructural features of sintered samples. Liquid-phase interaction between the VC0.40O0.53–Cfree nanocrystalline composition and titanium nickelide, the content of which varied from 10 to 99 wt.%, was studied based on the results of experiments. It was shown that the content of Cfree and VC vanadium carbide increases with the simultaneously increasing TiC content as the TiNi mass content increases in the range of 10–90 wt.%. With a further increase in the titanium nickelide content to 99 wt.%, Ti3Ni4 and Ni3Ti nickelides are present after sintering. The content of free carbon increases to 88 wt.%, and the amount of TiC decreases to 5 wt.%. The data obtained in the course of the study were used to propose various schemes of processes occurring during the (VC0.40O0.53–Cfree)–TiNi liquid phase sintering. In particular, sintering involving the liquid phase proceeds in three stages including TiNi melting, refractory base dissolution, its reprecipitation in the form of TiCx and VCx carbides, and cooling of the resulting composition. It should be noted that the mechanism of liquid-phase interaction during vacuum sintering involving the liquid phase was developed on the basis of the laws presented in the paper by M. Gumenik.
{"title":"Mechanism of liquid-phase interaction between nanocrystalline composition (VC0.40О0.53–C)–C and titanium nickelide","authors":"Yu. A. Avdeeva, A. Ermakov, I. Luzhkova, L. Askarova","doi":"10.17073/1997-308x-2022-1-26-35","DOIUrl":"https://doi.org/10.17073/1997-308x-2022-1-26-35","url":null,"abstract":"The article considers the possibility of binding free carbon existing in the VC0.40O0.53–Cfree nanocrystalline composition to the carbide phase. This composition is obtained by plasma-chemical synthesis in a low-temperature nitrogen plasma. As a carbide former, titanium was used in the form of its nickelide TiNi, which has a melting point of 1310 °С. Experiments were carried out under vacuum sintering conditions involving the liquid phase at 1500 °C for 40 min. The data obtained in X-ray diffraction, scanning electron microscopy and energy-dispersive analysis were used to determine the phase composition and microstructural features of sintered samples. Liquid-phase interaction between the VC0.40O0.53–Cfree nanocrystalline composition and titanium nickelide, the content of which varied from 10 to 99 wt.%, was studied based on the results of experiments. It was shown that the content of Cfree and VC vanadium carbide increases with the simultaneously increasing TiC content as the TiNi mass content increases in the range of 10–90 wt.%. With a further increase in the titanium nickelide content to 99 wt.%, Ti3Ni4 and Ni3Ti nickelides are present after sintering. The content of free carbon increases to 88 wt.%, and the amount of TiC decreases to 5 wt.%. The data obtained in the course of the study were used to propose various schemes of processes occurring during the (VC0.40O0.53–Cfree)–TiNi liquid phase sintering. In particular, sintering involving the liquid phase proceeds in three stages including TiNi melting, refractory base dissolution, its reprecipitation in the form of TiCx and VCx carbides, and cooling of the resulting composition. It should be noted that the mechanism of liquid-phase interaction during vacuum sintering involving the liquid phase was developed on the basis of the laws presented in the paper by M. Gumenik.","PeriodicalId":14693,"journal":{"name":"Izvestiya vuzov. Poroshkovaya metallurgiya i funktsional’nye pokrytiya","volume":"115 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87952496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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