Pub Date : 2023-01-01DOI: 10.30791/1028-978x-2023-3-43-48
A. Akhmetov, Z. Eremeeva
In this work, a study was made of the change in the microstructure of a hot-pressed billet from a powder mixture of high-speed steel grade R6M5K5 containing a diffusion-alloyed additive based on tungsten, molybdenum, cobalt and iron after heat treatment processes: quenching in oil at a temperature of 1230 °C and double high tempering at 550 °C for 60 min. The study was carried out using electron microscopy and energy dispersive X-ray spectroscopy. After quenching, dissolution of small-sized carbides in the matrix is observed, and after two-fold tempering, secondary carbides of the M6C and MC types are already precipitated. The second type of carbides is formed from a separate structural component — a phase based on ferrovanadium, whose powder was used as a source of vanadium. Also, cobalt is unevenly distributed in the matrix, which is concentrated in a separate phase based on a diffusion-alloyed additive. These phases practically do not dissolve, and are quite stable under these conditions of hot pressing and heat treatment. It is shown that the hardness of blanks changes from 63.1 HRA after hot pressing to 67.2 HRA after quenching and up to 66.3 HRA after double tempering.
{"title":"Changes in the microstructure and hardness after heat treatment of a billet made of powder high-speed steel R6M5K5 containing a diffusion-alloyed additive","authors":"A. Akhmetov, Z. Eremeeva","doi":"10.30791/1028-978x-2023-3-43-48","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-3-43-48","url":null,"abstract":"In this work, a study was made of the change in the microstructure of a hot-pressed billet from a powder mixture of high-speed steel grade R6M5K5 containing a diffusion-alloyed additive based on tungsten, molybdenum, cobalt and iron after heat treatment processes: quenching in oil at a temperature of 1230 °C and double high tempering at 550 °C for 60 min. The study was carried out using electron microscopy and energy dispersive X-ray spectroscopy. After quenching, dissolution of small-sized carbides in the matrix is observed, and after two-fold tempering, secondary carbides of the M6C and MC types are already precipitated. The second type of carbides is formed from a separate structural component — a phase based on ferrovanadium, whose powder was used as a source of vanadium. Also, cobalt is unevenly distributed in the matrix, which is concentrated in a separate phase based on a diffusion-alloyed additive. These phases practically do not dissolve, and are quite stable under these conditions of hot pressing and heat treatment. It is shown that the hardness of blanks changes from 63.1 HRA after hot pressing to 67.2 HRA after quenching and up to 66.3 HRA after double tempering.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"124 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87897830","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-2023-4-5-30
P. Tyubaeva, A. Popov, A. A. Olkhov
This thematic review considers the principles of creating biomedical materials based on biopolymers and their compositions for various medical needs. The direction of creating materials with antimicrobial activity is especially emphasized using the example of polyhydroxyalkanoates. These biopolymers and composites based on them occupy leading positions in the production of medical devices. Polyhydroxyalkanoates as a class of biopolymers, as well as polyhydroxybutyrate, the most suitable representative of this class for biomedical products, were analyzed from the point of view of increasing resistance to microorganisms. Progress in this direction has been reported in recent years. The influence of the supramolecular and molecular structure of materials on the ability to biodegrade in the environment and in a living organism is considered in sufficient detail. The advantage of mixtures of biopolymers for achieving high degradation rates compared to the original polymers was noted. Promising antiseptics based on porphyrin metal complexes in combination with biopolymer nonwoven fibrous matrices have been demonstrated. Features of preclinical tests of antiseptic materials are considered. Based on this review of research papers, it can be concluded that the structural organization of a polymeric material or composite determines the level of intermolecular interactions during the formation of the material and thereby programs the complex of functional properties and the degradation mechanism under the influence of aggressive external factors.
{"title":"Traditional and new approaches to the creation of biomedical materials based on polyhydroxyalkanoates with antimicrobial activity","authors":"P. Tyubaeva, A. Popov, A. A. Olkhov","doi":"10.30791/1028-978x-2023-4-5-30","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-4-5-30","url":null,"abstract":"This thematic review considers the principles of creating biomedical materials based on biopolymers and their compositions for various medical needs. The direction of creating materials with antimicrobial activity is especially emphasized using the example of polyhydroxyalkanoates. These biopolymers and composites based on them occupy leading positions in the production of medical devices. Polyhydroxyalkanoates as a class of biopolymers, as well as polyhydroxybutyrate, the most suitable representative of this class for biomedical products, were analyzed from the point of view of increasing resistance to microorganisms. Progress in this direction has been reported in recent years. The influence of the supramolecular and molecular structure of materials on the ability to biodegrade in the environment and in a living organism is considered in sufficient detail. The advantage of mixtures of biopolymers for achieving high degradation rates compared to the original polymers was noted. Promising antiseptics based on porphyrin metal complexes in combination with biopolymer nonwoven fibrous matrices have been demonstrated. Features of preclinical tests of antiseptic materials are considered. Based on this review of research papers, it can be concluded that the structural organization of a polymeric material or composite determines the level of intermolecular interactions during the formation of the material and thereby programs the complex of functional properties and the degradation mechanism under the influence of aggressive external factors.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78964767","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-2023-5-22-34
I. Arutyunyan, A. Dunaev, E. M. Trifanova, M. Khvorostina, A. Elchaninov, A. Soboleva, T. Fatkhudinov, V. Popov
The biocompatibility of polylactic-co-glycolic acid (PLGA) scaffolds for tissue engineering constructions can be significantly improved by autologous mesenchymal stem cells (MSCs) colonization. However, the features of the cell colonization procedure can generally affect the changes in the physical and mechanical properties of these scaffolds, which are mostly determined by their architectonics. To study this issue, in this work, we have formed and investigated three types of experimental PLGA samples: 1). molded monolithic blocks; 2). porous scaffolds formed by plasticization in supercritical CO2 followed by foaming; and 3). electrospun fibrous non-woven scaffolds. The quantitative XTT test showed the nontoxicity of all studied samples, as well as the greater efficiency of the dynamic cell colonization method compared to the static one. After 48 hours of samples incubation with cell cultures, their physical and mechanical properties were noted to change both at macro- and microlevels. These changes, in our opinion, occur due to the processes of hydrolytic and enzymatic PLGA hydrolysis, as well as the effect of adhered MSCs on the scaffold internal structure and surface morphology. Similar transformations of certain physical, mechanical and structural properties of scaffolds based on other biodegradable polymers or their compositions can also occur as a result of their colonization with various cell cultures, which should be taken into account when applying the scaffolds to develop tissue engineering constructions.
{"title":"Effects of mesenchymal stem cells on the physical and mechanical properties of polyester scaffolds of different architectonics","authors":"I. Arutyunyan, A. Dunaev, E. M. Trifanova, M. Khvorostina, A. Elchaninov, A. Soboleva, T. Fatkhudinov, V. Popov","doi":"10.30791/1028-978x-2023-5-22-34","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-5-22-34","url":null,"abstract":"The biocompatibility of polylactic-co-glycolic acid (PLGA) scaffolds for tissue engineering constructions can be significantly improved by autologous mesenchymal stem cells (MSCs) colonization. However, the features of the cell colonization procedure can generally affect the changes in the physical and mechanical properties of these scaffolds, which are mostly determined by their architectonics. To study this issue, in this work, we have formed and investigated three types of experimental PLGA samples: 1). molded monolithic blocks; 2). porous scaffolds formed by plasticization in supercritical CO2 followed by foaming; and 3). electrospun fibrous non-woven scaffolds. The quantitative XTT test showed the nontoxicity of all studied samples, as well as the greater efficiency of the dynamic cell colonization method compared to the static one. After 48 hours of samples incubation with cell cultures, their physical and mechanical properties were noted to change both at macro- and microlevels. These changes, in our opinion, occur due to the processes of hydrolytic and enzymatic PLGA hydrolysis, as well as the effect of adhered MSCs on the scaffold internal structure and surface morphology. Similar transformations of certain physical, mechanical and structural properties of scaffolds based on other biodegradable polymers or their compositions can also occur as a result of their colonization with various cell cultures, which should be taken into account when applying the scaffolds to develop tissue engineering constructions.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"72 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88236543","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-2023-4-31-41
V. Perinsky, I. Perinskaya, I. Rodionov, L. Kuts
The results of a study of the formation of a silver-containing porous layer on the surface of single-crystal silicon KEF-4,5 by ion-beam alloying are presented. A computer simulation of the process of ion doping of silicon with KEF-4,5, high-energy helium and silver ions was carried out using the TRIM/SRIM software package in order to determine the dose and energy neighborhoods of helium and silver ions necessary and sufficient in the experiment. The relief of the porous surface, the density of quasi-pores on the surface of implanted silicon, the elemental composition of the obtained porous composite silver-containing layers, taking into account the effect of intermediate heat treatment on it, are studied. The ion-beam formation of a silver-containing coating ensures the creation of a developed surface relief at the nanoscale with high reproducibility and controllability inherent in the ion doping method, which contributes to an increase in the yield of usable solar cell products. The technological modes of high reproducibility and controllability inherent in the ion doping method are determined based on the experimental data obtained for studying the relief of a porous surface and the density of quasi-pores on the surface of implanted silicon from the energy and dose of helium ions. Based on the study of the elemental composition of the quasi-porous composite silver-containing layer obtained by implantation of silver ions, the recommended parameters of implantation of silver ions have been established.
{"title":"Ion-beam formation of a silver-containing surface of porous silicon","authors":"V. Perinsky, I. Perinskaya, I. Rodionov, L. Kuts","doi":"10.30791/1028-978x-2023-4-31-41","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-4-31-41","url":null,"abstract":"The results of a study of the formation of a silver-containing porous layer on the surface of single-crystal silicon KEF-4,5 by ion-beam alloying are presented. A computer simulation of the process of ion doping of silicon with KEF-4,5, high-energy helium and silver ions was carried out using the TRIM/SRIM software package in order to determine the dose and energy neighborhoods of helium and silver ions necessary and sufficient in the experiment. The relief of the porous surface, the density of quasi-pores on the surface of implanted silicon, the elemental composition of the obtained porous composite silver-containing layers, taking into account the effect of intermediate heat treatment on it, are studied. The ion-beam formation of a silver-containing coating ensures the creation of a developed surface relief at the nanoscale with high reproducibility and controllability inherent in the ion doping method, which contributes to an increase in the yield of usable solar cell products. The technological modes of high reproducibility and controllability inherent in the ion doping method are determined based on the experimental data obtained for studying the relief of a porous surface and the density of quasi-pores on the surface of implanted silicon from the energy and dose of helium ions. Based on the study of the elemental composition of the quasi-porous composite silver-containing layer obtained by implantation of silver ions, the recommended parameters of implantation of silver ions have been established.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"6 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75804745","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-2023-1-80-88
P. N. Petrova, M. Markova, A. Fedorov
This paper presents the results of research on the development of technology for plastic deformation of polymer blanks based on polytetrafluoroethylene (PTFE) and carbon fibers of the UVIS-AK-P brand in order to increase their strength and creep resistance. The dependence of the physico-mechanical and tribotechnical characteristics of the obtained composites is investigated and compared with a composite of the same composition, but obtained using a previously developed technology. It is established that the use of plastic deformation technology for the properties of PCM based on PTFE and carbon fibers of the brand UVIS-AK-P is an effective solution for obtaining high-strength, wear-resistant composites, characterized by increased resistance to tensile loads. The developed composites obtained using plastic deformation are characterized by 3 times increased tensile strength and 22 – 29 times reduced creep compared to the original PTFE obtained by standard technology. Structural studies of the technology of plastic deformation of polymer blanks have shown that this technology leads to the orientation of the carbon fiber (CF) in the direction of the flow of the material and a change in the spiral conformation of macromolecules with a transition to a more stable conformation, which favorably affects its operational properties. The use of this method will make it possible to obtain high-strength polymer materials with increased resistance to deformation, promising for use for loading schemes with high tensile loads.
{"title":"High-strength fluoroplastic composites with increased resistance to deformation under load","authors":"P. N. Petrova, M. Markova, A. Fedorov","doi":"10.30791/1028-978x-2023-1-80-88","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-1-80-88","url":null,"abstract":"This paper presents the results of research on the development of technology for plastic deformation of polymer blanks based on polytetrafluoroethylene (PTFE) and carbon fibers of the UVIS-AK-P brand in order to increase their strength and creep resistance. The dependence of the physico-mechanical and tribotechnical characteristics of the obtained composites is investigated and compared with a composite of the same composition, but obtained using a previously developed technology. It is established that the use of plastic deformation technology for the properties of PCM based on PTFE and carbon fibers of the brand UVIS-AK-P is an effective solution for obtaining high-strength, wear-resistant composites, characterized by increased resistance to tensile loads. The developed composites obtained using plastic deformation are characterized by 3 times increased tensile strength and 22 – 29 times reduced creep compared to the original PTFE obtained by standard technology. Structural studies of the technology of plastic deformation of polymer blanks have shown that this technology leads to the orientation of the carbon fiber (CF) in the direction of the flow of the material and a change in the spiral conformation of macromolecules with a transition to a more stable conformation, which favorably affects its operational properties. The use of this method will make it possible to obtain high-strength polymer materials with increased resistance to deformation, promising for use for loading schemes with high tensile loads.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79953190","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-2023-6-34-41
I. Fadeeva, A. A. Forysenkova, V. A. Volchenkova, A. Fomina, V. B. Smirnova, S. Barinov
The dependence of the (Zn, Cu, Co, Ni, Mn)-substituted calcium phosphates’ composition on the water synthesis method has been studied. Cation-substituted tricalcium phosphates and hydroxyapatites were obtained by precipitation from an aqueous solution and by the mechanical activation’ method. The reaction products were dried, calcined at 400°C and investigated by ICP AES and flame AAS. The content of Zn, Cu, Co, Ni, Mn in samples and mother liquors was quantitatively determined. It has been established that the content of Cu2+, Zn2+, Co2+, Ni2+ ions in phosphates is greatly reduced compared to the calculated amounts. At the same time, for tricalcium phosphate, precipitation and the mechanical activation’ method gave comparable results for the content of dopant ions. At the same time, the mechanical activation’ method increase the content of the dopant ion in the substituted hydroxyapatites up to ≈ 48 %.
{"title":"Dopant ions’ behavior in solution synthesis of substituted calcium phosphates","authors":"I. Fadeeva, A. A. Forysenkova, V. A. Volchenkova, A. Fomina, V. B. Smirnova, S. Barinov","doi":"10.30791/1028-978x-2023-6-34-41","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-6-34-41","url":null,"abstract":"The dependence of the (Zn, Cu, Co, Ni, Mn)-substituted calcium phosphates’ composition on the water synthesis method has been studied. Cation-substituted tricalcium phosphates and hydroxyapatites were obtained by precipitation from an aqueous solution and by the mechanical activation’ method. The reaction products were dried, calcined at 400°C and investigated by ICP AES and flame AAS. The content of Zn, Cu, Co, Ni, Mn in samples and mother liquors was quantitatively determined. It has been established that the content of Cu2+, Zn2+, Co2+, Ni2+ ions in phosphates is greatly reduced compared to the calculated amounts. At the same time, for tricalcium phosphate, precipitation and the mechanical activation’ method gave comparable results for the content of dopant ions. At the same time, the mechanical activation’ method increase the content of the dopant ion in the substituted hydroxyapatites up to ≈ 48 %.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"296 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75419848","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-2023-3-64-74
T. I. Devyatkina, R. V. Taranets, V. V. Rogozhin, V. Isaev
A comparative analysis of the influence of the structure of azo compounds (on the example of methyl red (MKR) and nitroso-p-salt (NRS)) was carried out during copper plating of anodized aluminum alloys, on the microstructure, micro-roughness and quality of deposited copper coatings. It is shown that the choice of azo dye significantly depends on the charge of the surface of the oxide film in the solutions used. It is shown that the dyes used should have at least two functional groups in their composition, one of which should ensure the formation of complexes with copper ions, and the other – their adhesion to the surface of the oxide film due to the forces of electrostatic interaction. The adsorption of azo compounds changes the structure of the double electric layer at the film – electrolyte interface, which affects the speed of the copper plating process. At the same time, the mobility of the formed complexes in the adsorption layer increases, which leads to a better opening of the film surface. The studied indicators (dyes) positively affected the structure of the copper coating (eliminated defects and made it fine-crystalline), and also significantly smoothed the surface of the copper coating. The advantage of using the NRS over the MKR was revealed, which allowed not only to obtain a high-quality coating, but also to significantly intensify the copper plating process. A new composition of copper sulfuric acid electrolyte for coating anodized aluminum alloys at elevated cathode current densities with preservation of fine-crystalline structure and smoothed surface is proposed.
{"title":"The influence of the structure of azo compounds on the deposition process and the quality of copper coatings on Anodized aluminum alloys","authors":"T. I. Devyatkina, R. V. Taranets, V. V. Rogozhin, V. Isaev","doi":"10.30791/1028-978x-2023-3-64-74","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-3-64-74","url":null,"abstract":"A comparative analysis of the influence of the structure of azo compounds (on the example of methyl red (MKR) and nitroso-p-salt (NRS)) was carried out during copper plating of anodized aluminum alloys, on the microstructure, micro-roughness and quality of deposited copper coatings. It is shown that the choice of azo dye significantly depends on the charge of the surface of the oxide film in the solutions used. It is shown that the dyes used should have at least two functional groups in their composition, one of which should ensure the formation of complexes with copper ions, and the other – their adhesion to the surface of the oxide film due to the forces of electrostatic interaction. The adsorption of azo compounds changes the structure of the double electric layer at the film – electrolyte interface, which affects the speed of the copper plating process. At the same time, the mobility of the formed complexes in the adsorption layer increases, which leads to a better opening of the film surface. The studied indicators (dyes) positively affected the structure of the copper coating (eliminated defects and made it fine-crystalline), and also significantly smoothed the surface of the copper coating. The advantage of using the NRS over the MKR was revealed, which allowed not only to obtain a high-quality coating, but also to significantly intensify the copper plating process. A new composition of copper sulfuric acid electrolyte for coating anodized aluminum alloys at elevated cathode current densities with preservation of fine-crystalline structure and smoothed surface is proposed.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"41 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85128647","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-2023-6-80-84
M. Alymov
The method of hot gas extrusion differs from other methods of metal pressure treatment in that the processed material is subjected to intense plastic deformation by extrusion under conditions of high isostatic pressure of inert gas and heating in the area of plastic deformation. The method makes it possible to process powder materials, while inevitably there is a need to control mechanical properties by controlling porosity and pressure inside the pores. The paper presents a method for calculating the pressure inside the pores from the minimum size of the closed pore. The pore pressure was evaluated on materials obtained by the consolidation of nickel nanopowders by hot gas extrusion. Quantitative processing of the material cross-section view images obtained by scanning electron microscopy showed that the minimum pore size is 220 nm. The formula for calculating the pore pressure is derived from the formula for calculating the critical pore radius. It takes into account the external impact pressure (the gas pressure during the extrusion process was equal to 400 MPa), the surface tension coefficient and the yield strength of nickel (at the extrusion start temperature of 910 °С), as well as the minimum pore radius. The proposed method for calculating the pressure inside a closed pore will allow us to evaluate the mechanical properties of materials obtained by various methods of powder metallurgy.
{"title":"Porosity of nickel nanopowder compacts consolidated by gas extrusion","authors":"M. Alymov","doi":"10.30791/1028-978x-2023-6-80-84","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-6-80-84","url":null,"abstract":"The method of hot gas extrusion differs from other methods of metal pressure treatment in that the processed material is subjected to intense plastic deformation by extrusion under conditions of high isostatic pressure of inert gas and heating in the area of plastic deformation. The method makes it possible to process powder materials, while inevitably there is a need to control mechanical properties by controlling porosity and pressure inside the pores. The paper presents a method for calculating the pressure inside the pores from the minimum size of the closed pore. The pore pressure was evaluated on materials obtained by the consolidation of nickel nanopowders by hot gas extrusion. Quantitative processing of the material cross-section view images obtained by scanning electron microscopy showed that the minimum pore size is 220 nm. The formula for calculating the pore pressure is derived from the formula for calculating the critical pore radius. It takes into account the external impact pressure (the gas pressure during the extrusion process was equal to 400 MPa), the surface tension coefficient and the yield strength of nickel (at the extrusion start temperature of 910 °С), as well as the minimum pore radius. The proposed method for calculating the pressure inside a closed pore will allow us to evaluate the mechanical properties of materials obtained by various methods of powder metallurgy.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"81 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85528597","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-2023-3-75-84
E. Ermakova, S. S. Strelnikova, A. Anokhin, A. A. Konovalov, О. S. Antonova, M. Chuvikina
The paper focuses on lanthanum cobaltite micropowders LaCoO3-δ (LCO) synthesized by the sol-gel method using polyvinylpyrrolidone (PVP) as gelling agent. The PVP content has been varied from 0.5 to 5.0 wt. % when ionic solutions of the soluble raw components were prepared. The gels were dried in a microwave oven at microwave power 90 W for 2 h to evaporate water. Xerogels were thermally treated in a muffle furnace at temperatures 800°C and 900°C, the maximum holding time was 10 h and 30 h. After heat treatment of Xerogels at 800°C for 10 h LCO micropowders were slightly aggregated and particle size were in the range from 0.24 to 0.38 µm as well as specific surface area was in the range from 2.60 to 4.10 m2/g. After heat treatment 900°C for 10 h the specific surface area range of LCO micropowders decreased from 1.00 to 3.20 m2/g, but particle size range slightly increased from 0.31 up to 1.0 µm. Xerogels heat treatment at temperature 900° C for 30 h resulted to particles size range growing from 0.50 to 1.25 μm, and the specific surface area was 2.00 m2/g for all LCO micropowders. There was no effect of PVP content in the ionic solution on phase composition for all heat treated LCO micropowders.
{"title":"Investigation of the polyvinylpyrrolidone amount as gelling agent to lanthanum cobaltite micropowders synthesize by sol-gel method","authors":"E. Ermakova, S. S. Strelnikova, A. Anokhin, A. A. Konovalov, О. S. Antonova, M. Chuvikina","doi":"10.30791/1028-978x-2023-3-75-84","DOIUrl":"https://doi.org/10.30791/1028-978x-2023-3-75-84","url":null,"abstract":"The paper focuses on lanthanum cobaltite micropowders LaCoO3-δ (LCO) synthesized by the sol-gel method using polyvinylpyrrolidone (PVP) as gelling agent. The PVP content has been varied from 0.5 to 5.0 wt. % when ionic solutions of the soluble raw components were prepared. The gels were dried in a microwave oven at microwave power 90 W for 2 h to evaporate water. Xerogels were thermally treated in a muffle furnace at temperatures 800°C and 900°C, the maximum holding time was 10 h and 30 h. After heat treatment of Xerogels at 800°C for 10 h LCO micropowders were slightly aggregated and particle size were in the range from 0.24 to 0.38 µm as well as specific surface area was in the range from 2.60 to 4.10 m2/g. After heat treatment 900°C for 10 h the specific surface area range of LCO micropowders decreased from 1.00 to 3.20 m2/g, but particle size range slightly increased from 0.31 up to 1.0 µm. Xerogels heat treatment at temperature 900° C for 30 h resulted to particles size range growing from 0.50 to 1.25 μm, and the specific surface area was 2.00 m2/g for all LCO micropowders. There was no effect of PVP content in the ionic solution on phase composition for all heat treated LCO micropowders.","PeriodicalId":20003,"journal":{"name":"Perspektivnye Materialy","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89749757","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-2023-2-77-86
N. V. Shadrinov, A. A. Borisova, A. R. Khaldeeva, K. P. Antoev
The results of a study of the influence of the mixing mode and curing system on the properties of low temperature and oil resistant rubber based on a composition of butadiene-nitrile rubber (BNKS-18AMN) and ultra-high molecular weight polyethylene (GUR 4113) are presented. Different ways of UHMWPE introducing into the rubber compound are considered: mixing before and after the introduction the main ingredients of the rubber compound at temperatures up to 80 °C (below the melting point of UHMWPE) and preliminary high-temperature (160 °C) mixing of rubber and UHMWPE. It was found that the preliminary high temperature mixing of rubber with UHMWPE leads to a decrease in the viscosity of the rubber compound, as well as a reduction in the scorch time and the achievement of an optimum vulcanization but does not lead to significant changes in the physical and mechanical properties and oil resistance of vulcanizates. The study of the influence of the curing system showed the effectiveness of using a combined sulfur-peroxide curing system, which is manifested in the improvement of the technical properties of vulcanizates, which is largely due to an increase in the density of rubber crosslinking through the formation of stronger and more heat-resistant C-C bonds. It has been shown that the best set of technical properties of vulcanizates, including high frost-resistance, physical and mechanical properties, resistance to hydrocarbon environment and retention of properties after thermal exposure, is achieved when using the sulfur-peroxide combination S/DCP – 1/2.
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