Pub Date : 2023-01-01DOI: 10.30791/1028-978x-2023-1-46-54
N. Kolchugina, N. A. Dormidontov, P. A. Prokofev, Y. Milov, A. S. Andreenko, I. A. Sipin, A. G. Dormidontov, A. Bakulina
The hard magnetic (Sm,Zr)(Co,Fe,Cu)z alloys intended for the application as powder filler in bonded magnets are considered. The microstructure and intrinsic coercive force of the Sm0.87Zr0.13(Co0.702Cu0.088Fe0.210)6.7, Sm0.81Zr0.19(Co0.702Cu0.088Fe0.210)6.3, and Sm0.85Zr0.15(Co0.690Cu0.070Fe0.240)6.8 alloys, the structural and magnetic states of which were prepared at different aging temperatures and cooling rates, are studied. The formation of the high coercive force and adequate squareness of the magnetic hysteresis loop for alloy powders under study was observed at grain and subgrain sizes of the 2:17 phase of 10 – 20 μm. It is shown that the anisotropic powders of the Sm0.87Zr0.13(Co0.702Cu0.088Fe0.210)6,7 alloy can be prepared for manufacturing bonded magnets with a coercive force of 14 – 20 kOe and higher, which are intended for the application in electric machines.
{"title":"Structure and magnetic properties of (Sm,Zr)(Co,Fe,Cu)z alloy powders for bonded magnets","authors":"N. Kolchugina, N. A. Dormidontov, P. A. Prokofev, Y. Milov, A. S. Andreenko, I. A. Sipin, A. G. Dormidontov, A. Bakulina","doi":"10.30791/1028-978x-2023-1-46-54","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-1-46-54","url":null,"abstract":"The hard magnetic (Sm,Zr)(Co,Fe,Cu)z alloys intended for the application as powder filler in bonded magnets are considered. The microstructure and intrinsic coercive force of the Sm0.87Zr0.13(Co0.702Cu0.088Fe0.210)6.7, Sm0.81Zr0.19(Co0.702Cu0.088Fe0.210)6.3, and Sm0.85Zr0.15(Co0.690Cu0.070Fe0.240)6.8 alloys, the structural and magnetic states of which were prepared at different aging temperatures and cooling rates, are studied. The formation of the high coercive force and adequate squareness of the magnetic hysteresis loop for alloy powders under study was observed at grain and subgrain sizes of the 2:17 phase of 10 – 20 μm. It is shown that the anisotropic powders of the Sm0.87Zr0.13(Co0.702Cu0.088Fe0.210)6,7 alloy can be prepared for manufacturing bonded magnets with a coercive force of 14 – 20 kOe and higher, which are intended for the application in electric machines.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89935659","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 : 2023-01-01DOI: 10.30791/1028-978x-2023-6-24-32
P. Evdokimov, A. Kiseleva, D. Larionov, E. Novoseletskaya, A. Efimenko, I. M. Scherbakov, G. A. Shipunov, V. Dubrov, V. Putlayev
The behavior of mesenchymal stem cells depending on different pore sizes of ceramic materials based on tricalcium phosphate was studied. The effect of the emulsifier on the rheological characteristics of calcium phosphate-based photosensitive emulsions was investigated. The dependence of the conditions of photosensitive emulsions on the pore size in ceramic materials based on Ca3(PO4)2 has been demonstrated. Studies on the biocompatibility of macroporous bioceramics in medical and biological tests in vitro were carried out.
{"title":"Effect of porosity of tricalcium phosphate-based materials on the behavior of mesenchymal stem cells","authors":"P. Evdokimov, A. Kiseleva, D. Larionov, E. Novoseletskaya, A. Efimenko, I. M. Scherbakov, G. A. Shipunov, V. Dubrov, V. Putlayev","doi":"10.30791/1028-978x-2023-6-24-32","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-6-24-32","url":null,"abstract":"The behavior of mesenchymal stem cells depending on different pore sizes of ceramic materials based on tricalcium phosphate was studied. The effect of the emulsifier on the rheological characteristics of calcium phosphate-based photosensitive emulsions was investigated. The dependence of the conditions of photosensitive emulsions on the pore size in ceramic materials based on Ca3(PO4)2 has been demonstrated. Studies on the biocompatibility of macroporous bioceramics in medical and biological tests in vitro were carried out.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"107 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80686404","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 : 2023-01-01DOI: 10.30791/1028-978x-2023-2-62-76
N. Melekhin, M. Boldin, А. Popov, А. Bragov, А. R. Filippov, S. Shotin, A. Murashov, A. Nokhrin, V. Chuvil’deev, N. Tabachkova
The results of dynamic compressive testing of alumina samples with different grain sizes sintered from nano and fine α-Al2O3 powders are presented. The ceramics were obtained by spark plasma sintering (SPS). The effect of heating rate (Vh), sintering temperature (Ts), holding time (ts), cooling rate (Vc) on hardness, fracture toughness, dynamic strength stress (σY) of Al2O3 has been studied. An amorphous layer of nanometer thickness was present on the surface of nanopowders in the initial state. After sintering, the grain boundaries of the ceramics had a crystalline structure; no inclusions of the amorphous phase were found. It has been suggested that during the SPS process, an amorphous structure containing an excess free volume is transformed into a crystalline phase with the formation of dislocation-type defects at the grain boundaries, which create long-range internal stress fields. It is shown that nanopores less than 50 – 100 nm in size are present at the grain boundaries of sintered ceramics. It is shown that the nonmonotonic nature of the dependence of σY on the temperature and time of the SPS is due to the simultaneous change in the density, the nonequilibrium state of the grain boundaries, and the grain size of the ceramic. It is shown that a decrease in the degree of nonequilibrium of the grain boundaries of alumina due to an increase in the SPS temperature or an increase in the holding time makes it possible to increase the dynamic strength of alumina. It has been established that an increase in the cooling rate leads to the formation of compressive residual stresses and a slight increase in σY of ceramics. The maximum dynamic strength (σY = 1755 MPa) for alumina ceramics with average grain size 1.6 – 2 µm obtained by SPS (Vh = 50 °С/min, Ts = 1520 °С, ts = 50 min).
{"title":"Dynamic strength of fine-grained alumina ceramics obtained by Spark Plasma Sintering","authors":"N. Melekhin, M. Boldin, А. Popov, А. Bragov, А. R. Filippov, S. Shotin, A. Murashov, A. Nokhrin, V. Chuvil’deev, N. Tabachkova","doi":"10.30791/1028-978x-2023-2-62-76","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-2-62-76","url":null,"abstract":"The results of dynamic compressive testing of alumina samples with different grain sizes sintered from nano and fine α-Al2O3 powders are presented. The ceramics were obtained by spark plasma sintering (SPS). The effect of heating rate (Vh), sintering temperature (Ts), holding time (ts), cooling rate (Vc) on hardness, fracture toughness, dynamic strength stress (σY) of Al2O3 has been studied. An amorphous layer of nanometer thickness was present on the surface of nanopowders in the initial state. After sintering, the grain boundaries of the ceramics had a crystalline structure; no inclusions of the amorphous phase were found. It has been suggested that during the SPS process, an amorphous structure containing an excess free volume is transformed into a crystalline phase with the formation of dislocation-type defects at the grain boundaries, which create long-range internal stress fields. It is shown that nanopores less than 50 – 100 nm in size are present at the grain boundaries of sintered ceramics. It is shown that the nonmonotonic nature of the dependence of σY on the temperature and time of the SPS is due to the simultaneous change in the density, the nonequilibrium state of the grain boundaries, and the grain size of the ceramic. It is shown that a decrease in the degree of nonequilibrium of the grain boundaries of alumina due to an increase in the SPS temperature or an increase in the holding time makes it possible to increase the dynamic strength of alumina. It has been established that an increase in the cooling rate leads to the formation of compressive residual stresses and a slight increase in σY of ceramics. The maximum dynamic strength (σY = 1755 MPa) for alumina ceramics with average grain size 1.6 – 2 µm obtained by SPS (Vh = 50 °С/min, Ts = 1520 °С, ts = 50 min).","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"253 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76579727","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 : 2023-01-01DOI: 10.30791/1028-978x-2023-3-49-56
D. Ponomareva, E. I. Timoshchuk, R. E. Shirokov, E. Vasilyeva, I. I. Lyapin, V. Y. Takhtin
The template synthesis of glassy carbon foams was used in the work and the influence of the initial template cell size, the concentration of the solution, and the number of impregnation stages on the macrostructural and strength characteristics of the obtained materials was studied. As a carbon precursor was used the solution of Novolac resin grade SFP-012A2, the coke residue of which is more than 57 wt. %. It was shown that increasing the number of impregnation stages makes it possible to improve strength characteristics while maintaining open porosity at the level of 90 %, while glassy carbon foam based on a polyurethane template with a porosity of 60 pores per inch and 4 stages of impregnation with a solution with a concentration of 30 wt. % has the best set of properties due to the uniform wall thickening in the material volume. The value of compressive strength was 1.12 MPa, which is 2 times higher than the value of foreign analogues, while the open porosity was 91 %. It has been established that a decrease in the size of the cells of the initial template can lead to embrittlement of the material due to the formation of a cluster of overlapped cells. Increasing the mechanical strength of glassy carbon foams while maintaining an open-cell structure expands the field of application of this class of materials.
{"title":"Influence of the number of impregnation stages on the macrostructural and strength characteristics of glassy carbon foams","authors":"D. Ponomareva, E. I. Timoshchuk, R. E. Shirokov, E. Vasilyeva, I. I. Lyapin, V. Y. Takhtin","doi":"10.30791/1028-978x-2023-3-49-56","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-3-49-56","url":null,"abstract":"The template synthesis of glassy carbon foams was used in the work and the influence of the initial template cell size, the concentration of the solution, and the number of impregnation stages on the macrostructural and strength characteristics of the obtained materials was studied. As a carbon precursor was used the solution of Novolac resin grade SFP-012A2, the coke residue of which is more than 57 wt. %. It was shown that increasing the number of impregnation stages makes it possible to improve strength characteristics while maintaining open porosity at the level of 90 %, while glassy carbon foam based on a polyurethane template with a porosity of 60 pores per inch and 4 stages of impregnation with a solution with a concentration of 30 wt. % has the best set of properties due to the uniform wall thickening in the material volume. The value of compressive strength was 1.12 MPa, which is 2 times higher than the value of foreign analogues, while the open porosity was 91 %. It has been established that a decrease in the size of the cells of the initial template can lead to embrittlement of the material due to the formation of a cluster of overlapped cells. Increasing the mechanical strength of glassy carbon foams while maintaining an open-cell structure expands the field of application of this class of materials.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78419477","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 : 2023-01-01DOI: 10.30791/1028-978x-2023-5-5-21
K. Povarova, A. Drozdov, A. Samokhin, O. Skachkov, A. Fadeev, A. A. Dorofeev, V. Sirotinkin, A. Ashmarin, M. A. Bulakhtin, A. V. Antonova, A. Morozov
The article discusses the possibilities of preparing high-quality powder materials from heat-resistant light alloys based on refractory monoaluminides of nickel β-NiAl and ruthenium β-RuAl for the manufacture of compact samples/products of complex shape using additive technologies with minimal final machining. Additive technologies are based on the use of spherical precursor micro-powders with a regulated granulometric composition, good fluidity and an oxide-free surface. The possibilities of obtaining precursors from RuAl-based alloys by plasma spheroidization of powders obtained by crushing mixtures from scrap samples of alloys based on RuAl with various additives are considered.
{"title":"Study of the conditions for obtaining precursors intended for 3D technologies from a heat-resistant alloy based on RuAl","authors":"K. Povarova, A. Drozdov, A. Samokhin, O. Skachkov, A. Fadeev, A. A. Dorofeev, V. Sirotinkin, A. Ashmarin, M. A. Bulakhtin, A. V. Antonova, A. Morozov","doi":"10.30791/1028-978x-2023-5-5-21","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-5-5-21","url":null,"abstract":"The article discusses the possibilities of preparing high-quality powder materials from heat-resistant light alloys based on refractory monoaluminides of nickel β-NiAl and ruthenium β-RuAl for the manufacture of compact samples/products of complex shape using additive technologies with minimal final machining. Additive technologies are based on the use of spherical precursor micro-powders with a regulated granulometric composition, good fluidity and an oxide-free surface. The possibilities of obtaining precursors from RuAl-based alloys by plasma spheroidization of powders obtained by crushing mixtures from scrap samples of alloys based on RuAl with various additives are considered.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78474835","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 : 2023-01-01DOI: 10.30791/1028-978x-2023-7-57-64
T. Pereverzeva, E. Y. Efremova, N. Chernousova, O. Kozhevnikova, A. Dedov
The compressibility of composite materials obtained by impregnation with water dispersion of polyurethane of webs made of polyethylene terephthalate fibers with a diameter of 20 µm and a mixture of these fibers with polyethylene terephthalate fibers with a diameter of 42 µm is investigated. The influence of the composition on the formation of the structure of canvases and composite materials based on them is shown. In the process of heat treatment, the volume of webs made of fibers with a diameter of 20 µm increases and decreases for webs based on a mixture of fibers of different diameters. Compared with canvases, with a degree of impregnation less than 1.0, the water permeability of materials of various compositions increases by 1.5 – 2.0 times. A model is proposed to predict the degree of compressibility of composite materials from the degree of impregnation and load. It is established that compressibility of composite materials decreases when using a web as a fibrous filler in which the fibers are oriented perpendicular to the surface of the web. Less effective for reducing compressibility is the use of a web made of a mixture of fibers of different diameters as a fibrous filler.
{"title":"Compressibility of composite materials based on fibrous filler of various compositions","authors":"T. Pereverzeva, E. Y. Efremova, N. Chernousova, O. Kozhevnikova, A. Dedov","doi":"10.30791/1028-978x-2023-7-57-64","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-7-57-64","url":null,"abstract":"The compressibility of composite materials obtained by impregnation with water dispersion of polyurethane of webs made of polyethylene terephthalate fibers with a diameter of 20 µm and a mixture of these fibers with polyethylene terephthalate fibers with a diameter of 42 µm is investigated. The influence of the composition on the formation of the structure of canvases and composite materials based on them is shown. In the process of heat treatment, the volume of webs made of fibers with a diameter of 20 µm increases and decreases for webs based on a mixture of fibers of different diameters. Compared with canvases, with a degree of impregnation less than 1.0, the water permeability of materials of various compositions increases by 1.5 – 2.0 times. A model is proposed to predict the degree of compressibility of composite materials from the degree of impregnation and load. It is established that compressibility of composite materials decreases when using a web as a fibrous filler in which the fibers are oriented perpendicular to the surface of the web. Less effective for reducing compressibility is the use of a web made of a mixture of fibers of different diameters as a fibrous filler.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82269800","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 : 2023-01-01DOI: 10.30791/1028-978x-2023-3-14-23
A. Burkov, P. Chigrin, E. Sazonova, P. A. Ilchenko
Titanium alloy Ti6Al4V is the most common metal material in orthopaedics. However, it is characterized by high elasticity and bioinertness, which makes it difficult to osseointegrate on its surface and leads to aseptic loosening of the implant, has insufficient corrosion resistance and high wear, leading to the accumulation of metal ions and wear particles in the body of patients. To eliminate these shortcomings, a Ti – Al coating was prepared by electrospark processing of the Ti6Al4V alloy in an equimolar mixture of titanium and aluminum granules. The prepared TiAl coating consists of intermetallic phases: Ti3Al, TiAl, TiAl2, and TiAl3, which have higher tribological properties. Thus, the average value of the friction coefficient of the sample with a TiAl coating was 12% lower, and the reduced wear was 2.36 times less than the original Ti6Al4V alloy one in a simulating body fluid. In addition, the deposition of a TiAl coating on the Ti6Al4V alloy makes it possible to increase the corrosion resistance of its surface. Biomedical studies have shown that the deposition of a TiAl coating on a Ti6Al4V alloy increases the resistance of erythrocytes to the hemolytic agent action. Improving the biological activity of the alloy surface during ESA deposition of TiAl coating leads to normal growth of fibroblasts on it without signs of cytotoxity. Treatment of samples with adhered cell culture by a solution of trypsin-Versen led to a reduction in the density of cells in the coating by 42 %, while in the alloy by 60 %. This indicates a better fibroblast attachment to the surface of the Ti-Al coating, compared to the Ti6Al4V alloy.
{"title":"Biocompatibility of Ti – Al intermetallic coatings on titanium alloy Ti6Al4V","authors":"A. Burkov, P. Chigrin, E. Sazonova, P. A. Ilchenko","doi":"10.30791/1028-978x-2023-3-14-23","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-3-14-23","url":null,"abstract":"Titanium alloy Ti6Al4V is the most common metal material in orthopaedics. However, it is characterized by high elasticity and bioinertness, which makes it difficult to osseointegrate on its surface and leads to aseptic loosening of the implant, has insufficient corrosion resistance and high wear, leading to the accumulation of metal ions and wear particles in the body of patients. To eliminate these shortcomings, a Ti – Al coating was prepared by electrospark processing of the Ti6Al4V alloy in an equimolar mixture of titanium and aluminum granules. The prepared TiAl coating consists of intermetallic phases: Ti3Al, TiAl, TiAl2, and TiAl3, which have higher tribological properties. Thus, the average value of the friction coefficient of the sample with a TiAl coating was 12% lower, and the reduced wear was 2.36 times less than the original Ti6Al4V alloy one in a simulating body fluid. In addition, the deposition of a TiAl coating on the Ti6Al4V alloy makes it possible to increase the corrosion resistance of its surface. Biomedical studies have shown that the deposition of a TiAl coating on a Ti6Al4V alloy increases the resistance of erythrocytes to the hemolytic agent action. Improving the biological activity of the alloy surface during ESA deposition of TiAl coating leads to normal growth of fibroblasts on it without signs of cytotoxity. Treatment of samples with adhered cell culture by a solution of trypsin-Versen led to a reduction in the density of cells in the coating by 42 %, while in the alloy by 60 %. This indicates a better fibroblast attachment to the surface of the Ti-Al coating, compared to the Ti6Al4V alloy.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"22 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82911344","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 : 2023-01-01DOI: 10.30791/1028-978x-2023-3-57-63
E. V. Evstratov, A. S. Baikin, S. I. Averin
Mixtures of tungsten-copper powders (88.2 wt. % W + 11.8 wt. % Cu) with different granulometric composition after mechanical activation at different process times were studied. Before mechanical activation, W particles have a size of about 4 μm, and large agglomerates of tungsten particles are ~20 μm. The structures and elemental composition of W-Cu powder samples before and after mechanical activation (1, 3, 5, and 10 min) were studied by scanning electron microscopy and X-ray microanalysis. The strength (compression) tests of pressed samples in a cylindrical matrix 12 mm in diameter were carried out on an Instron 3382 testing machine. Powder compaction curves were obtained, the dependences of the pressing stress on density were plotted, and the dependence of the sample density on the mechanical activation time was determined. As a result of strength tests, the dependences of stress on strain were obtained. The highest density of the mixture is achieved when the duration of treatment in the mechanical activator is 5 min. A further increase in the processing time of the mixture leads to the grinding of the powder and the destruction of the agglomerates. The average particle size of the powder decreases, which leads to a deterioration in the compaction of the samples. At the same time, with an increase in the treatment time to 10 min, the distribution of copper particles over the sample improves simultaneously with a decrease in the size of its particles to 100 – 400 nm, which, apparently, affects the increase in strength.
{"title":"Effect of mechanical activation time on structure and mechanical properties of W-Cu powder composite","authors":"E. V. Evstratov, A. S. Baikin, S. I. Averin","doi":"10.30791/1028-978x-2023-3-57-63","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-3-57-63","url":null,"abstract":"Mixtures of tungsten-copper powders (88.2 wt. % W + 11.8 wt. % Cu) with different granulometric composition after mechanical activation at different process times were studied. Before mechanical activation, W particles have a size of about 4 μm, and large agglomerates of tungsten particles are ~20 μm. The structures and elemental composition of W-Cu powder samples before and after mechanical activation (1, 3, 5, and 10 min) were studied by scanning electron microscopy and X-ray microanalysis. The strength (compression) tests of pressed samples in a cylindrical matrix 12 mm in diameter were carried out on an Instron 3382 testing machine. Powder compaction curves were obtained, the dependences of the pressing stress on density were plotted, and the dependence of the sample density on the mechanical activation time was determined. As a result of strength tests, the dependences of stress on strain were obtained. The highest density of the mixture is achieved when the duration of treatment in the mechanical activator is 5 min. A further increase in the processing time of the mixture leads to the grinding of the powder and the destruction of the agglomerates. The average particle size of the powder decreases, which leads to a deterioration in the compaction of the samples. At the same time, with an increase in the treatment time to 10 min, the distribution of copper particles over the sample improves simultaneously with a decrease in the size of its particles to 100 – 400 nm, which, apparently, affects the increase in strength.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"34 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84316884","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 : 2023-01-01DOI: 10.30791/1028-978x-2023-7-65-72
S. Eremin, V. N. Anikin, D. Rudenko, A. M. Kolesnikova, Y. Sobolev, V. Kuzin, M. Fedorov, N. A. Revyakina
In the work, experiments were carried out on the production and testing of hard alloys from powders of the VK10KHOM and VRK15 grades coated with multigraphene obtained by the electrochemical method. Samples with multigraphene were sintered under standard conditions for grades VK10KHOM and VRK15. In the weight ratio, the amount of multigraphene was 0.1 wt. % for the VK10KHOM grade alloy and 0.1 wt. % and 0.5 wt. % for the VRK15 grade. Friction tests of VK10KhOM samples showed that the width of the wear areas of samples with multigraphene is 8 % less than in the original ones. At 0.1 wt. % graphene, the density of the VK10KHOM grade is 14.5 and VRK15 is 14.0, and the porosity is 0.02 % and 2 %, respectively. Comparative tests were carried out on cutting titanium grade VT-3. As a result of cutting, it was found that the coating of powders with multigraphene increases the resistance of carbide inserts of both grades. It is shown that for VRK15 the plate durability increased by 4 times, and for the VK10KHOM grade it was not possible to establish the plate failure time. The increase in wear resistance is presumably caused by a decrease in the coefficient of friction due to multigraphene, which, dissolving in the hard alloy, precipitates in the form of nanographite clusters.
{"title":"Effect of multigraphene on the resistance of plates from hard alloys","authors":"S. Eremin, V. N. Anikin, D. Rudenko, A. M. Kolesnikova, Y. Sobolev, V. Kuzin, M. Fedorov, N. A. Revyakina","doi":"10.30791/1028-978x-2023-7-65-72","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-7-65-72","url":null,"abstract":"In the work, experiments were carried out on the production and testing of hard alloys from powders of the VK10KHOM and VRK15 grades coated with multigraphene obtained by the electrochemical method. Samples with multigraphene were sintered under standard conditions for grades VK10KHOM and VRK15. In the weight ratio, the amount of multigraphene was 0.1 wt. % for the VK10KHOM grade alloy and 0.1 wt. % and 0.5 wt. % for the VRK15 grade. Friction tests of VK10KhOM samples showed that the width of the wear areas of samples with multigraphene is 8 % less than in the original ones. At 0.1 wt. % graphene, the density of the VK10KHOM grade is 14.5 and VRK15 is 14.0, and the porosity is 0.02 % and 2 %, respectively. Comparative tests were carried out on cutting titanium grade VT-3. As a result of cutting, it was found that the coating of powders with multigraphene increases the resistance of carbide inserts of both grades. It is shown that for VRK15 the plate durability increased by 4 times, and for the VK10KHOM grade it was not possible to establish the plate failure time. The increase in wear resistance is presumably caused by a decrease in the coefficient of friction due to multigraphene, which, dissolving in the hard alloy, precipitates in the form of nanographite clusters.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83724516","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 : 2023-01-01DOI: 10.30791/1028-978x-2023-2-44-53
D. Mayorov, Yuriy O. Velyaev
Samples of amorphous silicon dioxide (SiO2) were obtained by acid decomposition of mineral raw materials (nepheline). Their physico-chemical, acid-base and structural-surface properties have been studied by methods of chemical analysis, Parks, BET, BJH, etc. It was found that in terms of the content of impurities, the pH of the aqueous extract, the pH values of the isoionic point and the zero charge point, the SiO2 samples obtained are almost identical to pyrogenic amorphous silicon dioxide obtained from reactive raw materials (pharmaceutical preparation “Polysorb PM”) and have an increased specific external surface compared to “Polysorb PM” (in 1.1 – 1.9 times) and specific pore volume (1.4 times). Based on the obtained values of the specific capacity of the adsorption monolayer of the surface of SiO2 samples and the change in Gibbs energy (ΔG0) during sorption, it is concluded that the method of their preparation does not significantly affect the physicochemical properties of their surfaces and the mechanism of nitrogen sorption. Based on the results obtained, an assumption is made about the prospects of using silicon dioxide, obtained on the basis of acid processing of mineral raw materials, as an enterosorbent in therapeutic practice.
{"title":"On the prospects of using silicon dioxide obtained from mineral raw materials as an enterosorbent","authors":"D. Mayorov, Yuriy O. Velyaev","doi":"10.30791/1028-978x-2023-2-44-53","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-2-44-53","url":null,"abstract":"Samples of amorphous silicon dioxide (SiO2) were obtained by acid decomposition of mineral raw materials (nepheline). Their physico-chemical, acid-base and structural-surface properties have been studied by methods of chemical analysis, Parks, BET, BJH, etc. It was found that in terms of the content of impurities, the pH of the aqueous extract, the pH values of the isoionic point and the zero charge point, the SiO2 samples obtained are almost identical to pyrogenic amorphous silicon dioxide obtained from reactive raw materials (pharmaceutical preparation “Polysorb PM”) and have an increased specific external surface compared to “Polysorb PM” (in 1.1 – 1.9 times) and specific pore volume (1.4 times). Based on the obtained values of the specific capacity of the adsorption monolayer of the surface of SiO2 samples and the change in Gibbs energy (ΔG0) during sorption, it is concluded that the method of their preparation does not significantly affect the physicochemical properties of their surfaces and the mechanism of nitrogen sorption. Based on the results obtained, an assumption is made about the prospects of using silicon dioxide, obtained on the basis of acid processing of mineral raw materials, as an enterosorbent in therapeutic practice.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"58 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87644598","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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