Pub Date : 2022-01-01DOI: 10.30791/1028-978x-2022-2-17-28
O. Bazyleva, V. Valitov, E. Arginbaeva, N. S. Dmitriev, A. N. Raevskikh, E. Galieva
The article presents a study of welded joints of cast intermetallic single-crystal rhenium containing VKNA-25 alloy with crystallographic orientation [001] and deformable high-temperature disk nickel alloy EP975, depending on the parameters of pressure welding under superplasticity conditions and standart heat treatment for high-temperature disk nickel alloy with regulated single-phase cooling. The study was carries out for the interdendritic region. The results of X-ray micro-spectral analysis of a solid-phase joint in the welding zone and at distances of up to 140 μm are presented in comparison with the initial chemical composition of the alloys. Found that before and after heat treatment in the welding zone and near-weld zone particles of topologically cloth-packed phases are not observed. Balance of alloying is better maintained in deformable high-temperature disk nickel alloy EP975 and this is natural, since pressure under superplasticity conditions takes place due to the disk alloy and at cast intermetallic single-crystal alloy only diffusion processes take place. Thus, high-quality one-piece connection of a disk and a blade for blisk-type structures is feasible under superplasticity only of one deformable fine-grained disk alloy and it is relevant for blisk type constructions. Blade intermetallic alloy VKNA-25 keeps thermally stable single-crystal structure.
{"title":"Stability of permanent connection of deformable high-temperature nickel based and cast intermetallic alloys obtained by pressure welding under superplasticity conditions","authors":"O. Bazyleva, V. Valitov, E. Arginbaeva, N. S. Dmitriev, A. N. Raevskikh, E. Galieva","doi":"10.30791/1028-978x-2022-2-17-28","DOIUrl":"https://doi.org/10.30791/1028-978x-2022-2-17-28","url":null,"abstract":"The article presents a study of welded joints of cast intermetallic single-crystal rhenium containing VKNA-25 alloy with crystallographic orientation [001] and deformable high-temperature disk nickel alloy EP975, depending on the parameters of pressure welding under superplasticity conditions and standart heat treatment for high-temperature disk nickel alloy with regulated single-phase cooling. The study was carries out for the interdendritic region. The results of X-ray micro-spectral analysis of a solid-phase joint in the welding zone and at distances of up to 140 μm are presented in comparison with the initial chemical composition of the alloys. Found that before and after heat treatment in the welding zone and near-weld zone particles of topologically cloth-packed phases are not observed. Balance of alloying is better maintained in deformable high-temperature disk nickel alloy EP975 and this is natural, since pressure under superplasticity conditions takes place due to the disk alloy and at cast intermetallic single-crystal alloy only diffusion processes take place. Thus, high-quality one-piece connection of a disk and a blade for blisk-type structures is feasible under superplasticity only of one deformable fine-grained disk alloy and it is relevant for blisk type constructions. Blade intermetallic alloy VKNA-25 keeps thermally stable single-crystal structure.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72759747","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 : 2022-01-01DOI: 10.30791/1028-978x-2022-3-36-45
A. Tyutyunik, V. Gurchenko, A. Mazinov
Comprehensive study of the electrochemical, electrical properties and temperature dependences of the Zn (II) hybrid organic complex based on Schiff (C48H42N6O2Zn) is carried out. In order to determine the prospects for using this compound as a semiconductor material, thin films were obtained using the centrifugation method. The method of preparation, synthesis, microscopy of the surface, as well as the method of measuring the temperature dependences of the electrical properties of the obtained thin films are described. The temperature measurement range ranged from 270 to 330 K. The energy levels of the lowest unoccupied molecular orbital and the highest occupied molecular orbital were determined using cyclic voltammetry. The activation energy calculated from linear approximations of the current-voltage characteristics in Arrhenius coordinates was 0.65 eV. Analysis of the current-voltage characteristics of the ITO – PBAL – Al structure showed that they correspond to the typical characteristics of Schottky diodes with a charge mobility of ~ 1,18·10–11 cm2·V–1·s–1.To study the mechanisms of charge transfer, the C – V characteristics of the samples were investigated at a frequency of 1 kHz. The concentration of charge carriers was calculated using the Mott – Schottky relationship.
{"title":"Study of electrochemical, electrical properties and temperature dependences of azomethine-Zn (II) ligand complexes based on pyrazolone","authors":"A. Tyutyunik, V. Gurchenko, A. Mazinov","doi":"10.30791/1028-978x-2022-3-36-45","DOIUrl":"https://doi.org/10.30791/1028-978x-2022-3-36-45","url":null,"abstract":"Comprehensive study of the electrochemical, electrical properties and temperature dependences of the Zn (II) hybrid organic complex based on Schiff (C48H42N6O2Zn) is carried out. In order to determine the prospects for using this compound as a semiconductor material, thin films were obtained using the centrifugation method. The method of preparation, synthesis, microscopy of the surface, as well as the method of measuring the temperature dependences of the electrical properties of the obtained thin films are described. The temperature measurement range ranged from 270 to 330 K. The energy levels of the lowest unoccupied molecular orbital and the highest occupied molecular orbital were determined using cyclic voltammetry. The activation energy calculated from linear approximations of the current-voltage characteristics in Arrhenius coordinates was 0.65 eV. Analysis of the current-voltage characteristics of the ITO – PBAL – Al structure showed that they correspond to the typical characteristics of Schottky diodes with a charge mobility of ~ 1,18·10–11 cm2·V–1·s–1.To study the mechanisms of charge transfer, the C – V characteristics of the samples were investigated at a frequency of 1 kHz. The concentration of charge carriers was calculated using the Mott – Schottky relationship.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78703619","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 : 2022-01-01DOI: 10.30791/1028-978x-2022-10-52-63
A. Afzal, E. A. Trusova, A. Konovalov
A technologically promising method for obtaining nanostructured graphene/ZrO2 has been proposed. Its main idea is to use suspensions of graphene and nano-ZrO2 and create conditions for the interaction of graphene sheets and ZrO2 crystallites to form a hybrid nanostructured powder without the formation of new chemical bonds. The oxygen-free graphene sheets with thickness of several nanometers were obtained by sonochemical method in N,N-dimethyloctylamine-aqua emulsion. Nano-ZrO2 powder with average crystallite size of 8.1 nm was synthesized by sol-gel method. The morphology and phase composition of all synthesized objects (nano-ZrO2, graphene, composite) were studied by using a set of instrumental methods (transmission electron microscopy (TEM) and electron diffraction, x-ray diffraction (XRD), electron energy loss spectroscopy (EELS), nitrogen adsorption-desorption, diffusion aerosol spectrometry (DAS) and elemental analysis). It was shown that the proposed method allows obtain chemically homogeneous mesoporous hybrid powders consisting of graphene sheets and ZrO2 crystallites with a size of 8 – 13 nm fixed on them. We investigated an effect of duration of ultrasonic impact to graphite on the morphology of the hybrid and the mechanism of its formation. According to the results of a comprehensive analysis of the obtained data, the mechanisms for the formation of graphene suspension in emulsion and a nanostructured hybrid during the interaction of crystalline ZrO2 and oxygen-free graphene sheets in an aqueous-organic medium was proposed. The developed hybrid nanostructures are highly demanded innovative raw-products in the production of (photo)catalysts for a wide range of processes, sensor, ceramic and electrical materials, and materials for medical and biological purposes.
{"title":"Obtaining hybrid nanostructures based on graphene and nano-ZrO2","authors":"A. Afzal, E. A. Trusova, A. Konovalov","doi":"10.30791/1028-978x-2022-10-52-63","DOIUrl":"https://doi.org/10.30791/1028-978x-2022-10-52-63","url":null,"abstract":"A technologically promising method for obtaining nanostructured graphene/ZrO2 has been proposed. Its main idea is to use suspensions of graphene and nano-ZrO2 and create conditions for the interaction of graphene sheets and ZrO2 crystallites to form a hybrid nanostructured powder without the formation of new chemical bonds. The oxygen-free graphene sheets with thickness of several nanometers were obtained by sonochemical method in N,N-dimethyloctylamine-aqua emulsion. Nano-ZrO2 powder with average crystallite size of 8.1 nm was synthesized by sol-gel method. The morphology and phase composition of all synthesized objects (nano-ZrO2, graphene, composite) were studied by using a set of instrumental methods (transmission electron microscopy (TEM) and electron diffraction, x-ray diffraction (XRD), electron energy loss spectroscopy (EELS), nitrogen adsorption-desorption, diffusion aerosol spectrometry (DAS) and elemental analysis). It was shown that the proposed method allows obtain chemically homogeneous mesoporous hybrid powders consisting of graphene sheets and ZrO2 crystallites with a size of 8 – 13 nm fixed on them. We investigated an effect of duration of ultrasonic impact to graphite on the morphology of the hybrid and the mechanism of its formation. According to the results of a comprehensive analysis of the obtained data, the mechanisms for the formation of graphene suspension in emulsion and a nanostructured hybrid during the interaction of crystalline ZrO2 and oxygen-free graphene sheets in an aqueous-organic medium was proposed. The developed hybrid nanostructures are highly demanded innovative raw-products in the production of (photo)catalysts for a wide range of processes, sensor, ceramic and electrical materials, and materials for medical and biological purposes.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90466001","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 : 2022-01-01DOI: 10.30791/1028-978x-2022-11-16-28
V. Kapustin, I. Li, N. E. Kozhevnikova
The electronic and crystal structures of oxide-nickel compositions based on ternary barium-calcium-strontium carbonates containing nickel nanoparticles and nanocrystals of barium carbonate have been studied by electron spectroscopy and precision X-ray structural analysis. It was found that nickel nanoparticles have a significant effect on the parameters of the electronic structure of barium oxide crystallites formed in these compositions during their heat treatment. It is shown that X-ray diffraction analysis can be used as the basis for the method of quality control of ternary carbonates for their effective use in the composition of oxide-nickel cathodes.
{"title":"The role of nanostructures in the formation of the emission properties of oxide-nickel cathodes","authors":"V. Kapustin, I. Li, N. E. Kozhevnikova","doi":"10.30791/1028-978x-2022-11-16-28","DOIUrl":"https://doi.org/10.30791/1028-978x-2022-11-16-28","url":null,"abstract":"The electronic and crystal structures of oxide-nickel compositions based on ternary barium-calcium-strontium carbonates containing nickel nanoparticles and nanocrystals of barium carbonate have been studied by electron spectroscopy and precision X-ray structural analysis. It was found that nickel nanoparticles have a significant effect on the parameters of the electronic structure of barium oxide crystallites formed in these compositions during their heat treatment. It is shown that X-ray diffraction analysis can be used as the basis for the method of quality control of ternary carbonates for their effective use in the composition of oxide-nickel cathodes.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85957934","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 : 2022-01-01DOI: 10.30791/1028-978x-2022-8-48-60
E. Neskoromnaya, A. Melezhyk, E. S. Mkrtchan, A. Memetova, A. Babkin
The paper presents an easy-to-implement and cheap technology for the synthesis of an effective sorption material based on graphene oxide, carboxymethylcellulose and iron nanoparticles. The synthesized nanocomposite is a partially ordered structure corresponding to the reduced graphene oxide, superficially modified with a layer of carboxymethyl cellulose (CMC). Iron nanoparticles of various structures and sizes have been identified in the structure of the synthesized material. The structures of the resulting composite and the raw materials were studied using the methods of SEM, TEM, XRD, and IR-Fourier spectroscopy. The presence of iron particles in the structure of the material in various forms (Fe2O3, FeO, Fe0) was shown. Sorption properties of the synthesized nanocomposite have been studied. The effect of the pH of the solution and the weight of the adsorbent suspension on its sorption activity during the extraction of Pb and Zn ions from aqueous solutions has been studied. The synthesized material demonstrates the greatest sorption activity at pH = 6 and the weight of the sample m = 1 mg. During the experimental analysis of the kinetics of the process, high values of the sorption activity of the synthesized material were established (for Pb ions — 680 mg·g–1, Zn ions — 387 mg·g–1). The obtained kinetic curves are best described by a pseudo-second-order model. The synthesized composite material can be successfully used for the adsorption of heavy metals from polluted aqueous media.
{"title":"Composite material carboxymethylcellulose – graphene oxide decorated with iron nanoparticles for sorption removal of heavy metal ions from polluted aqueous media","authors":"E. Neskoromnaya, A. Melezhyk, E. S. Mkrtchan, A. Memetova, A. Babkin","doi":"10.30791/1028-978x-2022-8-48-60","DOIUrl":"https://doi.org/10.30791/1028-978x-2022-8-48-60","url":null,"abstract":"The paper presents an easy-to-implement and cheap technology for the synthesis of an effective sorption material based on graphene oxide, carboxymethylcellulose and iron nanoparticles. The synthesized nanocomposite is a partially ordered structure corresponding to the reduced graphene oxide, superficially modified with a layer of carboxymethyl cellulose (CMC). Iron nanoparticles of various structures and sizes have been identified in the structure of the synthesized material. The structures of the resulting composite and the raw materials were studied using the methods of SEM, TEM, XRD, and IR-Fourier spectroscopy. The presence of iron particles in the structure of the material in various forms (Fe2O3, FeO, Fe0) was shown. Sorption properties of the synthesized nanocomposite have been studied. The effect of the pH of the solution and the weight of the adsorbent suspension on its sorption activity during the extraction of Pb and Zn ions from aqueous solutions has been studied. The synthesized material demonstrates the greatest sorption activity at pH = 6 and the weight of the sample m = 1 mg. During the experimental analysis of the kinetics of the process, high values of the sorption activity of the synthesized material were established (for Pb ions — 680 mg·g–1, Zn ions — 387 mg·g–1). The obtained kinetic curves are best described by a pseudo-second-order model. The synthesized composite material can be successfully used for the adsorption of heavy metals from polluted aqueous media.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84326987","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 : 2022-01-01DOI: 10.30791/1028-978x-2022-9-64-76
R. Romanov, D. Fominski, V. Nevolin, V. A. Kasianenko, V. Fominski
The possibility of forming new solid-lubricating thin-film coatings consisting of nanosized layers of WS2, MoS2 and amorphous carbon (a-C) with improved antifriction properties has been studied. To control the tribological properties of coatings, the conditions for obtaining layers of 2Н-WS2 and 2Н-MoS2 with a thickness of 5 – 20 nm with a crystalline laminar structure with a basal orientation to the substrate were determined. Nanolayers were created by reactive pulsed laser deposition from metal and metal oxide targets in hydrogen sulfide at elevated temperatures. It is shown that when alternating the processes of selected films deposition, no noticeable solid-phase reactions were observed at the interfaces. Tribological tests were carried out at room temperature using the method of sliding a steel ball over a coated disk without lubrication in an atmosphere enriched with nitrogen (~ 9 % relative humidity). The structural state of the coatings before and after the tribotests was studied by Raman spectroscopy. The lowest friction coefficient ~ 0,015 was found for the WS2 coatings deposited at 500 °C. The tribological properties of the MoS2 coatings turned out to be much worse. The coating, consisting of the WS2 and carbon nanolayers, showed a slightly higher friction coefficient (0,021), but it had the enhanced wear resistance.
{"title":"Component selection and nano-structuring of WS2/MoS2/a-C thin-film coatings for effective friction reduction in difficult conditions of sliding","authors":"R. Romanov, D. Fominski, V. Nevolin, V. A. Kasianenko, V. Fominski","doi":"10.30791/1028-978x-2022-9-64-76","DOIUrl":"https://doi.org/10.30791/1028-978x-2022-9-64-76","url":null,"abstract":"The possibility of forming new solid-lubricating thin-film coatings consisting of nanosized layers of WS2, MoS2 and amorphous carbon (a-C) with improved antifriction properties has been studied. To control the tribological properties of coatings, the conditions for obtaining layers of 2Н-WS2 and 2Н-MoS2 with a thickness of 5 – 20 nm with a crystalline laminar structure with a basal orientation to the substrate were determined. Nanolayers were created by reactive pulsed laser deposition from metal and metal oxide targets in hydrogen sulfide at elevated temperatures. It is shown that when alternating the processes of selected films deposition, no noticeable solid-phase reactions were observed at the interfaces. Tribological tests were carried out at room temperature using the method of sliding a steel ball over a coated disk without lubrication in an atmosphere enriched with nitrogen (~ 9 % relative humidity). The structural state of the coatings before and after the tribotests was studied by Raman spectroscopy. The lowest friction coefficient ~ 0,015 was found for the WS2 coatings deposited at 500 °C. The tribological properties of the MoS2 coatings turned out to be much worse. The coating, consisting of the WS2 and carbon nanolayers, showed a slightly higher friction coefficient (0,021), but it had the enhanced wear resistance.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82659215","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 : 2022-01-01DOI: 10.30791/1028-978x-2022-12-62-75
G. Dzhardimalieva, I. Uflyand, V. Zhinzhilo, E. Drogan, V. Burlakova
In the present work, complexes of zirconium(IV) oxyacrylate with polypyridine ligands 2,2’-bipyridine, 1,10-phenanthroline, and 4’-phenyl-2,2’:6’,2’’-terpyridine were obtained for the first time and characterized by elemental analysis, IR spectroscopy, thermogravimetry and differential scanning calorimetry. Thermolysis of these complexes at 600 °C made it possible to obtain nanosized zirconium oxides, which were studied by X-ray diffraction analysis, scanning electron microscopy, high-resolution transmission electron microscopy, and atomic force microscopy. The average crystallite size of the obtained zirconium oxide nanoparticles is 5.63 – 6.06 nm. Zirconium oxide nanoparticles are characterized by spherical and oval shapes. The products have been tested as anti-wear additives in lubricating oils. The optimal concentrations of nanoparticles were determined, at which the antiwear properties of the lubricant are best manifested.
{"title":"Synthesis of zirconium(IV) oxyacrylate complexes with polypyridine ligands and their use as precursors of nanomaterials with antiwear properties","authors":"G. Dzhardimalieva, I. Uflyand, V. Zhinzhilo, E. Drogan, V. Burlakova","doi":"10.30791/1028-978x-2022-12-62-75","DOIUrl":"https://doi.org/10.30791/1028-978x-2022-12-62-75","url":null,"abstract":"In the present work, complexes of zirconium(IV) oxyacrylate with polypyridine ligands 2,2’-bipyridine, 1,10-phenanthroline, and 4’-phenyl-2,2’:6’,2’’-terpyridine were obtained for the first time and characterized by elemental analysis, IR spectroscopy, thermogravimetry and differential scanning calorimetry. Thermolysis of these complexes at 600 °C made it possible to obtain nanosized zirconium oxides, which were studied by X-ray diffraction analysis, scanning electron microscopy, high-resolution transmission electron microscopy, and atomic force microscopy. The average crystallite size of the obtained zirconium oxide nanoparticles is 5.63 – 6.06 nm. Zirconium oxide nanoparticles are characterized by spherical and oval shapes. The products have been tested as anti-wear additives in lubricating oils. The optimal concentrations of nanoparticles were determined, at which the antiwear properties of the lubricant are best manifested.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81946485","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 : 2022-01-01DOI: 10.30791/1028-978x-2022-4-40-52
Е. Lantsev, А. Nokhrin, V. Chuvil’deev, M. Boldin, Yu. V. Blagoveshchenskiy, P. Andreev, K. Smetanina, A. Murashov, N. Isaeva, A. V. Terentev
The mechanism of high-temperature creep deformation during compression tests of binderless tungsten carbide specimens with different initial particle size was studied. Tungsten carbide samples with high relative density (96.1 – 99.2 %) were obtained by high-speed spark plasma sintering (SPS) from nano-, submicron-, and micron-sized α-WC powders. The creep tests were carried out in two modes: isothermal soaking at different temperatures (1300 – 1375 °C) at a given stress, allowing to estimate the activation energy of creep, and tests by “stress jumps” at 1325 °C, allowing to estimate the value of the coefficient n in the creep equation. It is shown that the value of creep activation energy in ultrafine grained tungsten carbide with grain size ~ 0.15 µm sintered from plasma chemical nanopowders is ~ 31 kTm. This value is 1.5 – 2 times higher than the creep activation energy in fine-grained tungsten carbide samples obtained by SPS from submicron (~ 0.8 μm) and micron (~ 3 μm) industrial powders. It was found that the value of the coefficient n varies from 2.4 to 3.1, which corresponds to the case of motion of lattice dislocations in the field of uniformly located point obstacles. It has been suggested that one of the reasons for the increase in creep activation energy in tests of tungsten carbide is an increased volume fraction of W2C low carbide particles formed during high-speed sintering of plasma-chemical α-WC nanopowders with an increased concentration of adsorbed oxygen.
{"title":"Study of high-temperature deformation features of binderless tungsten carbide with various initial particle size","authors":"Е. Lantsev, А. Nokhrin, V. Chuvil’deev, M. Boldin, Yu. V. Blagoveshchenskiy, P. Andreev, K. Smetanina, A. Murashov, N. Isaeva, A. V. Terentev","doi":"10.30791/1028-978x-2022-4-40-52","DOIUrl":"https://doi.org/10.30791/1028-978x-2022-4-40-52","url":null,"abstract":"The mechanism of high-temperature creep deformation during compression tests of binderless tungsten carbide specimens with different initial particle size was studied. Tungsten carbide samples with high relative density (96.1 – 99.2 %) were obtained by high-speed spark plasma sintering (SPS) from nano-, submicron-, and micron-sized α-WC powders. The creep tests were carried out in two modes: isothermal soaking at different temperatures (1300 – 1375 °C) at a given stress, allowing to estimate the activation energy of creep, and tests by “stress jumps” at 1325 °C, allowing to estimate the value of the coefficient n in the creep equation. It is shown that the value of creep activation energy in ultrafine grained tungsten carbide with grain size ~ 0.15 µm sintered from plasma chemical nanopowders is ~ 31 kTm. This value is 1.5 – 2 times higher than the creep activation energy in fine-grained tungsten carbide samples obtained by SPS from submicron (~ 0.8 μm) and micron (~ 3 μm) industrial powders. It was found that the value of the coefficient n varies from 2.4 to 3.1, which corresponds to the case of motion of lattice dislocations in the field of uniformly located point obstacles. It has been suggested that one of the reasons for the increase in creep activation energy in tests of tungsten carbide is an increased volume fraction of W2C low carbide particles formed during high-speed sintering of plasma-chemical α-WC nanopowders with an increased concentration of adsorbed oxygen.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77580054","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 : 2022-01-01DOI: 10.30791/1028-978x-2022-7-14-24
M. V. Tesakova, S. Kuzmin, V. Parfenyuk
Carbon-based materials are widespread and promising in areas such as electrochemical and electrocatalytic power generation and can be excellent choices for use as electrode substrates. To increase the efficiency of using carbonaceous materials, the surface of the electrodes is modified with metal complexes of phthalocyanines and porphyrins with electrocatalytic properties. In this work polyporphyrin coatings were obtained on a glassy carbon electrode based on individual metal complexes of 5,10,15,20-tetrakis(3-aminophenyl)porphyrin and a composite based on two metal complexes Fe and Mn. Polymerization was carried out by the electrochemical method in the region of positive values of the potential in the potentiodynamic mode. Electrodeposited polyporphyrin coatings have a developed surface and exhibit catalytic activity in the reaction of oxygen electroreduction. The results of evaluating the catalytic activity of polyporphyrins obtained by various methods are in good agreement with each other and indicate a higher catalytic activity of a composite based on two metal complexes compared to films of individual porphyrins, which suggests the presence of a synergistic effect. Based on the results of our research, we propose potential directions for the creation of electrodes based on glassy carbon modified with polyporphyrins for electrocatalytic oxygen reduction.
{"title":"Oxygen electrocatalytic reduction on glass-carbon electrodes coated with polyporphyrin films based on metal complexes of 5,10,15,20-tetrakis(3-aminophenyl)porphyrin","authors":"M. V. Tesakova, S. Kuzmin, V. Parfenyuk","doi":"10.30791/1028-978x-2022-7-14-24","DOIUrl":"https://doi.org/10.30791/1028-978x-2022-7-14-24","url":null,"abstract":"Carbon-based materials are widespread and promising in areas such as electrochemical and electrocatalytic power generation and can be excellent choices for use as electrode substrates. To increase the efficiency of using carbonaceous materials, the surface of the electrodes is modified with metal complexes of phthalocyanines and porphyrins with electrocatalytic properties. In this work polyporphyrin coatings were obtained on a glassy carbon electrode based on individual metal complexes of 5,10,15,20-tetrakis(3-aminophenyl)porphyrin and a composite based on two metal complexes Fe and Mn. Polymerization was carried out by the electrochemical method in the region of positive values of the potential in the potentiodynamic mode. Electrodeposited polyporphyrin coatings have a developed surface and exhibit catalytic activity in the reaction of oxygen electroreduction. The results of evaluating the catalytic activity of polyporphyrins obtained by various methods are in good agreement with each other and indicate a higher catalytic activity of a composite based on two metal complexes compared to films of individual porphyrins, which suggests the presence of a synergistic effect. Based on the results of our research, we propose potential directions for the creation of electrodes based on glassy carbon modified with polyporphyrins for electrocatalytic oxygen reduction.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74348557","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 : 2022-01-01DOI: 10.30791/1028-978x-2022-7-75-86
M. A. Sudarchikova
Composite materials based on aluminum alloy D16 and titanium alloy Ti – 10 Nb – 3 Mo with surface layers of titanium, titanium nitride and a multilayer composition consisting of alternating layers of titanium and titanium nitride for biomedical and tribological purposes by high-vacuum magnetron sputtering at direct current in inert and reactive media were obtained. The structure and phase composition were studied using SEM, AES, X-ray diffractometry and probe microscopy. The rate of formation of a surface layer of pure titanium on a substrate made of alloy D16 was 185 nm/min, and the rate of synthesis of a surface layer of titanium in a reactive medium was significantly slowed down and was no more than 70 nm/min due to nitrogen poisoning of the target. The transition layer formed as a result of the synthesis of a titanium layer on an aluminum alloy substrate had a thickness of about 600 nm, which is significantly greater than the thickness of the transition layer when titanium is obtained on a titanium alloy substrate. During the formation of titanium nitride on a titanium sublayer, a greater concentration of nitrogen was observed than during the formation of nitride on a substrate with the same deposition parameters. The intensity of the TiN phase reflexes in the X-ray diffractometry diagrams were weakly expressed in all variants of the applied ratios of working gases Ar/N2 during spraying. The speed of the titanium sublayer makes it possible to form a greater thickness of the titanium nitride layer than without the sublayer, as well as a more nitrogen–saturated surface layer - up to 38% by weight.
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