The work provides the results of the one-step formation of boron-containing coatings on an Mg–Mn–Ce alloy by plasma electrolytic oxidation. The results of studies of the composition, structure and morphology of hete...The work provides the results of the one-step formation of boron-containing coatings on an Mg–Mn–Ce alloy by plasma electrolytic oxidation. The results of studies of the composition, structure and morphology of heteroxide coatings are presented. It was established that the boron is contained in the coating mainly in the form of B or B_(2)O_(3). The introduction of B changes the color of coatings, and also helps to increase their porosity. The method of determining the full cross section of the interaction of thermal neutron absorption efficiency by samples material using the installation of neutron-activation analysis based on ^(252)Cf was developed. It was shown that the introduction of boron into the formed coatings allows to increase the macroscopic cross-section of the interaction of samples with thermal neutrons by 3.8 times. This effect opens the potential for the use of synthesized material in the field of nuclear technologies and aerospace industry.展开更多
The high corrosion rate of magnesium and its alloys in chloride-containing solution significantly reduces the potential of this material for diverse applications.Therefore,the formation of a smart protective coating w...The high corrosion rate of magnesium and its alloys in chloride-containing solution significantly reduces the potential of this material for diverse applications.Therefore,the formation of a smart protective coating was achieved in this work to prevent degradation of the MA8 magnesium alloy.A porous ceramic-like matrix was obtained on the material by plasma electrolytic oxidation(PEO).Further surface functionalization was performed using layered double hydroxides(LDH) served as nanocontainers for the corrosion inhibitor.Several methods of LDH intercalation with benzotriazole(BTA) were proposed.The composition and morphology of the formed coating were studied using SEM-EDX analysis,XRD,XPS,and Raman microspectroscopy.The corrosion behavior of the coated samples was evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization.The corrosion rate was estimated using volumetry and gravimetry methods.The formed composite coating provides the Mg alloy with the lowest corrosion activity(|Z|_(f)=0.1 Hz)=8.48·10^(5) Ω·cm^(2),I_(c)=1.4·10^(-8)A/cm^(2),P_(H)=0.21 mm/year) and improves the protective properties of the PEO-coated sample(|Z|_(f)=0.1 Hz)=8.37·10^(3) Ω·cm^(2),I_(c)=4.1·10^(-7)A/cm^(2),P_(H)=0.31 mm/year).The realization of the self-healing effect of the inhibitor-containing LDH/PEO-coated system was studied using localized electrochemical methods(SVET and SIET) with two artificial defects on the surface.A mechanism involving three stages for the active corrosion protection of the alloy was proposed.These findings contribute to the follow-up work of developing modified LDH/PEO-based structures that promote the Mg alloy with high corrosion resistance,superior electrochemical performance for applications in various fields of industry and medicine.展开更多
The electrochemical behaviour of biodegradable magnesium alloy Mg-0.8Ca was evaluated in a mammalian cell culture medium(MEM)and Na Cl solutions(0.9 wt.%, 0.3 wt.%) using traditional(EIS, PDP, OCP) and local scanning ...The electrochemical behaviour of biodegradable magnesium alloy Mg-0.8Ca was evaluated in a mammalian cell culture medium(MEM)and Na Cl solutions(0.9 wt.%, 0.3 wt.%) using traditional(EIS, PDP, OCP) and local scanning electrochemical(SVET, SIET with p H-selective microelectrode) methods at the micro-and meso-level. Corrosion rates of samples in two different media were determined using weight loss tests. The influence of testing media components, alloy composition and microstructure on the material’s degradation process was determined.The SVET/SIET test parameters were optimized for in vitro investigation of the bioresorbable material surface. The mechanism of the alloy’s bioresorption was suggested. The effect of microsized phases on the corrosion behaviour of the alloy was proved using complementary in situ monitoring and SKPFM measurements. The rapid degradation rate of the alloy is related to the presence of local microgalvanic cells formed by cathodic α-magnesium matrix and anodic Mg_(2)Ca phase. The highest corrosion activity was revealed in the first 12 min of sample exposure to MEM, followed by stabilization of corrosion process due to the material’s passivation. Using SEM-EDX analysis, micro-Raman spectroscopy and XPS analysis the composition of the corrosion products was determined. Degradation in MEM proceeds with a formation of magnesium-and-carbonate substituted hydroxyapatite-containing film on the sample’s surface. The low possibility of application of Mg-0.8Ca alloy without coating protection in implant surgery was highlighted.展开更多
A new method of the formation of composite coatings with the function of active corrosion protection of magnesium alloys was developed using the plasma electrolytic oxidation(PEO) method. Susceptibility of PEO-layers ...A new method of the formation of composite coatings with the function of active corrosion protection of magnesium alloys was developed using the plasma electrolytic oxidation(PEO) method. Susceptibility of PEO-layers to pitting formation was evaluated using localized electrochemical methods(SVET/SIET). The morphological features and electrochemical properties of composite coatings were studied using SEM/EDX, XRD, micro-Raman spectroscopy and EIS/PDP measurements, respectively. The effect of surface layers impregnation with corrosion inhibitor on their protective properties in a corrosive environment was established. Additional protection was achieved using controllable coating pore sealing with polymer. It was found that the polymer treatment of the PEO-layer does not reduce the inhibitor’s efficiency. The formed protective composite inhibitor-and-polymer-containing layers decrease the corrosion current density of a magnesium alloy in a 3 wt.% Na Cl solution to three orders of magnitude. This predetermines the prospect of new smart coatings formation that significantly expand the field of application of electrochemically active materials. The mechanism of smart composite coating corrosion degradation was established. The antibacterial activity of the inhibitor-containing coatings against S. aureus methicillin-resistant strain was proved using the in vitro model. These protective layers are promising for reducing the incidence of implant-associated infections.展开更多
This paper presents a method of the formation of composite polymer-containing coatings on a Mg–Mn–Ce magnesium alloy by forming a ceramic-like layer using plasma electrolytic oxidation(PEO)and subsequent spraying su...This paper presents a method of the formation of composite polymer-containing coatings on a Mg–Mn–Ce magnesium alloy by forming a ceramic-like layer using plasma electrolytic oxidation(PEO)and subsequent spraying superdispersed polytetrafluoroethylene suspension.The coating composition and their morphological features were studied by SEM,EDS,GDOES,and XRD.The presented data confirm the embedding of fluoropolymer in the PEO coating.The evaluation of the corrosion properties of the formed composite polymer-containing coatings indicates a decrease in the corrosion current density by more than 3 orders of magnitude in comparison with the base PEO coating.The incorporation of a fluoropolymer in a PEO layer by more than 32%increases the load value at which abrasion of the coating to the substrate occurs and reduces the wear of the coating by more than 27 fold in comparison with the PEO layer.It has been established that composite coatings possess hydrophobic properties:the value of the contact angle attains 152°.展开更多
In this study, the biocompatible protective coating was formed using plasma electrolytic oxidation(PEO) on bioresorbable Mg-0.8Ca alloy. The composition of the formed coating was studied using XRD, SEM-EDX analysis, a...In this study, the biocompatible protective coating was formed using plasma electrolytic oxidation(PEO) on bioresorbable Mg-0.8Ca alloy. The composition of the formed coating was studied using XRD, SEM-EDX analysis, and micro-Raman spectroscopy. The uniform distribution of hydroxyapatite over the thickness of protective PEO-layer was established. Using traditional(EIS, PDP, OCP) and local scanning electrochemical methods(SVET, SIET with H^(+)-selective microelectrode), the level of protective properties of PEO-layer in a biological environment(mammalian cell culture medium, MEM) was determined. It was established that modification of Mg-0.8Ca alloy surface by PEO contributes to a significant increase in the corrosion resistance of the surface layer, making it possible to control the process of material‘s biodegradation. The maximum local electrochemical activity was recorded after 72 h of testing, while for the uncoated sample,intense corrosion degradation was recorded in the first 12 min of exposure to the cell culture medium. Formation of the PEO-coating results in a twofold decrease in the corrosion current density(2.8·10^(-6)A cm^(-2)) and an increase in the impedance modulus measured at a low frequency(1.7·10^(4)Ω cm^(2)) in comparison with the uncoated material(9.5·10^(-6)A cm^(-2);8.1·10^(3)Ω cm^(2)). The mechanism of material bioresorption was established and a model for biodegradation process of Mg-0.8Ca alloy with hydroxyapatite-containing PEO-coating in MEM was proposed. Analysis of these results and comparing with others obtained by various scientific groups indicate the prospects for application of biocompatible PEO-coating on Mg-Ca alloy in implant surgery.展开更多
TiO_(2)-B/anatase nanotubes doped by vanadium have been synthesized through a facile one-step hydrothermal reaction.The material shows a mesoporous structure with a specific surface area of 179.1 m^(2)g^(-1).XPS data ...TiO_(2)-B/anatase nanotubes doped by vanadium have been synthesized through a facile one-step hydrothermal reaction.The material shows a mesoporous structure with a specific surface area of 179.1 m^(2)g^(-1).XPS data presume the presence of V^(3+),V^(4+),V^(5+),and Ti^(3+) in doped TiO2-B/anatase.As found by XRD and EIS investigations,the vanadium expands bronze titania crystal structure and enhances the conductivity of material by three orders of magnitude.When tested for lithium storage,the V-modified titania nanotubes show a specific capacity of 133 mA h g^(-1) after 100 charge/discharge cycles at the current density of 3000 mA g^(-1) with a Coulombic efficiency of around 98.9%,resulting in its good cycleability.The material still possesses a reversible capacity of 114 mA h g^(-1) at a very high current load of 6000 mA g^(-1),demonstrating superior rate characteristics for secondary lithium batteries.Furthermore,V-doped Ti O2-B/anatase mesoporous nanotubes show promise performance as anode material for sodium-ion batteries,delivering about 119 mA h g^(-1) and 101 m A h g^(-1) at the current loads of 10 and 1500 m A g^(-1),respectively.展开更多
基金The formation of coatings,as well as XRD,XPS,and OSP analyzes was supported by Russian Science Foundation Grant No.22-73-10149,https://rscf.ru/project/22-73-10149/The SEM,EDX analyzes and study of absorption of neutron radiation by coatings was supported by the Russian Science Foundation Grant No.23-13-00329,https://rscf.ru/ project/23-13-00329/。
文摘The work provides the results of the one-step formation of boron-containing coatings on an Mg–Mn–Ce alloy by plasma electrolytic oxidation. The results of studies of the composition, structure and morphology of heteroxide coatings are presented. It was established that the boron is contained in the coating mainly in the form of B or B_(2)O_(3). The introduction of B changes the color of coatings, and also helps to increase their porosity. The method of determining the full cross section of the interaction of thermal neutron absorption efficiency by samples material using the installation of neutron-activation analysis based on ^(252)Cf was developed. It was shown that the introduction of boron into the formed coatings allows to increase the macroscopic cross-section of the interaction of samples with thermal neutrons by 3.8 times. This effect opens the potential for the use of synthesized material in the field of nuclear technologies and aerospace industry.
基金supported by the Grant of Russian Science Foundation,Russia (project no.21-73-10148,https://rscf.ru/en/project/ 21-73-10148/)supported by the Grant of Russian Science Foundation,Russia (project no.20-13-00130,https://rscf.ru/en/ project/20-13-00130/)。
文摘The high corrosion rate of magnesium and its alloys in chloride-containing solution significantly reduces the potential of this material for diverse applications.Therefore,the formation of a smart protective coating was achieved in this work to prevent degradation of the MA8 magnesium alloy.A porous ceramic-like matrix was obtained on the material by plasma electrolytic oxidation(PEO).Further surface functionalization was performed using layered double hydroxides(LDH) served as nanocontainers for the corrosion inhibitor.Several methods of LDH intercalation with benzotriazole(BTA) were proposed.The composition and morphology of the formed coating were studied using SEM-EDX analysis,XRD,XPS,and Raman microspectroscopy.The corrosion behavior of the coated samples was evaluated using electrochemical impedance spectroscopy and potentiodynamic polarization.The corrosion rate was estimated using volumetry and gravimetry methods.The formed composite coating provides the Mg alloy with the lowest corrosion activity(|Z|_(f)=0.1 Hz)=8.48·10^(5) Ω·cm^(2),I_(c)=1.4·10^(-8)A/cm^(2),P_(H)=0.21 mm/year) and improves the protective properties of the PEO-coated sample(|Z|_(f)=0.1 Hz)=8.37·10^(3) Ω·cm^(2),I_(c)=4.1·10^(-7)A/cm^(2),P_(H)=0.31 mm/year).The realization of the self-healing effect of the inhibitor-containing LDH/PEO-coated system was studied using localized electrochemical methods(SVET and SIET) with two artificial defects on the surface.A mechanism involving three stages for the active corrosion protection of the alloy was proposed.These findings contribute to the follow-up work of developing modified LDH/PEO-based structures that promote the Mg alloy with high corrosion resistance,superior electrochemical performance for applications in various fields of industry and medicine.
基金the Grant of Russian Science Foundation,Russia(project no.20–13–00130,https://rscf.ru/en/project/20–13–00130/)the Grant of Russian Science Foundation,Russia(project no.21–73–10148,https://rscf.ru/en/project/21–73–10148/)the government assignments from the Ministry of Science and Higher Education of the Russian Federation,Russia(project no.0205–2021–0003)。
文摘The electrochemical behaviour of biodegradable magnesium alloy Mg-0.8Ca was evaluated in a mammalian cell culture medium(MEM)and Na Cl solutions(0.9 wt.%, 0.3 wt.%) using traditional(EIS, PDP, OCP) and local scanning electrochemical(SVET, SIET with p H-selective microelectrode) methods at the micro-and meso-level. Corrosion rates of samples in two different media were determined using weight loss tests. The influence of testing media components, alloy composition and microstructure on the material’s degradation process was determined.The SVET/SIET test parameters were optimized for in vitro investigation of the bioresorbable material surface. The mechanism of the alloy’s bioresorption was suggested. The effect of microsized phases on the corrosion behaviour of the alloy was proved using complementary in situ monitoring and SKPFM measurements. The rapid degradation rate of the alloy is related to the presence of local microgalvanic cells formed by cathodic α-magnesium matrix and anodic Mg_(2)Ca phase. The highest corrosion activity was revealed in the first 12 min of sample exposure to MEM, followed by stabilization of corrosion process due to the material’s passivation. Using SEM-EDX analysis, micro-Raman spectroscopy and XPS analysis the composition of the corrosion products was determined. Degradation in MEM proceeds with a formation of magnesium-and-carbonate substituted hydroxyapatite-containing film on the sample’s surface. The low possibility of application of Mg-0.8Ca alloy without coating protection in implant surgery was highlighted.
基金supported by the Grant of Russian Science Foundation, Russia (project no. 21–73– 10148, https://rscf.ru/en/project/21–73–10148/)The study of material‘s structure, composition, and corrosion processes kinetics was supported by the Grant of Russian Science Foundation, Russia (project no. 20–13–00130, https://rscf.ru/en/project/20–13–00130/)Raman spectra were acquired under the government assignments from the Ministry of Science and Higher Education of the Russian Federation, Russia (project no. FWFN(0205)-2022–0003)。
文摘A new method of the formation of composite coatings with the function of active corrosion protection of magnesium alloys was developed using the plasma electrolytic oxidation(PEO) method. Susceptibility of PEO-layers to pitting formation was evaluated using localized electrochemical methods(SVET/SIET). The morphological features and electrochemical properties of composite coatings were studied using SEM/EDX, XRD, micro-Raman spectroscopy and EIS/PDP measurements, respectively. The effect of surface layers impregnation with corrosion inhibitor on their protective properties in a corrosive environment was established. Additional protection was achieved using controllable coating pore sealing with polymer. It was found that the polymer treatment of the PEO-layer does not reduce the inhibitor’s efficiency. The formed protective composite inhibitor-and-polymer-containing layers decrease the corrosion current density of a magnesium alloy in a 3 wt.% Na Cl solution to three orders of magnitude. This predetermines the prospect of new smart coatings formation that significantly expand the field of application of electrochemically active materials. The mechanism of smart composite coating corrosion degradation was established. The antibacterial activity of the inhibitor-containing coatings against S. aureus methicillin-resistant strain was proved using the in vitro model. These protective layers are promising for reducing the incidence of implant-associated infections.
基金supported by the Russian Science Foundation[Grant No.20-73-00280].
文摘This paper presents a method of the formation of composite polymer-containing coatings on a Mg–Mn–Ce magnesium alloy by forming a ceramic-like layer using plasma electrolytic oxidation(PEO)and subsequent spraying superdispersed polytetrafluoroethylene suspension.The coating composition and their morphological features were studied by SEM,EDS,GDOES,and XRD.The presented data confirm the embedding of fluoropolymer in the PEO coating.The evaluation of the corrosion properties of the formed composite polymer-containing coatings indicates a decrease in the corrosion current density by more than 3 orders of magnitude in comparison with the base PEO coating.The incorporation of a fluoropolymer in a PEO layer by more than 32%increases the load value at which abrasion of the coating to the substrate occurs and reduces the wear of the coating by more than 27 fold in comparison with the PEO layer.It has been established that composite coatings possess hydrophobic properties:the value of the contact angle attains 152°.
基金Local electrochemical tests,biocompatible coating formation and modeling the mechanism of the material degradation were supported by the Grant of Russian Science Foundation,Russia (project no.21-73-10148,https://rscf.ru/en/project/ 21-73-10148/)The study of material‘s structure,composition,and kinetics of the corrosion processes using traditional electrochemical methods was supported by the Grant of Russian Science Foundation,Russia (project no.20-13-00130,https://rscf.ru/en/project/20-13-00130/)XRD data were acquired under the government assignments from the Ministry of Science and Higher Education of the Russian Federation,Russia (project no.FWFN(0205)-2022-0003)。
文摘In this study, the biocompatible protective coating was formed using plasma electrolytic oxidation(PEO) on bioresorbable Mg-0.8Ca alloy. The composition of the formed coating was studied using XRD, SEM-EDX analysis, and micro-Raman spectroscopy. The uniform distribution of hydroxyapatite over the thickness of protective PEO-layer was established. Using traditional(EIS, PDP, OCP) and local scanning electrochemical methods(SVET, SIET with H^(+)-selective microelectrode), the level of protective properties of PEO-layer in a biological environment(mammalian cell culture medium, MEM) was determined. It was established that modification of Mg-0.8Ca alloy surface by PEO contributes to a significant increase in the corrosion resistance of the surface layer, making it possible to control the process of material‘s biodegradation. The maximum local electrochemical activity was recorded after 72 h of testing, while for the uncoated sample,intense corrosion degradation was recorded in the first 12 min of exposure to the cell culture medium. Formation of the PEO-coating results in a twofold decrease in the corrosion current density(2.8·10^(-6)A cm^(-2)) and an increase in the impedance modulus measured at a low frequency(1.7·10^(4)Ω cm^(2)) in comparison with the uncoated material(9.5·10^(-6)A cm^(-2);8.1·10^(3)Ω cm^(2)). The mechanism of material bioresorption was established and a model for biodegradation process of Mg-0.8Ca alloy with hydroxyapatite-containing PEO-coating in MEM was proposed. Analysis of these results and comparing with others obtained by various scientific groups indicate the prospects for application of biocompatible PEO-coating on Mg-Ca alloy in implant surgery.
文摘TiO_(2)-B/anatase nanotubes doped by vanadium have been synthesized through a facile one-step hydrothermal reaction.The material shows a mesoporous structure with a specific surface area of 179.1 m^(2)g^(-1).XPS data presume the presence of V^(3+),V^(4+),V^(5+),and Ti^(3+) in doped TiO2-B/anatase.As found by XRD and EIS investigations,the vanadium expands bronze titania crystal structure and enhances the conductivity of material by three orders of magnitude.When tested for lithium storage,the V-modified titania nanotubes show a specific capacity of 133 mA h g^(-1) after 100 charge/discharge cycles at the current density of 3000 mA g^(-1) with a Coulombic efficiency of around 98.9%,resulting in its good cycleability.The material still possesses a reversible capacity of 114 mA h g^(-1) at a very high current load of 6000 mA g^(-1),demonstrating superior rate characteristics for secondary lithium batteries.Furthermore,V-doped Ti O2-B/anatase mesoporous nanotubes show promise performance as anode material for sodium-ion batteries,delivering about 119 mA h g^(-1) and 101 m A h g^(-1) at the current loads of 10 and 1500 m A g^(-1),respectively.
