36 research outputs found
ΠΠ»ΠΈΡΠ½ΠΈΠ΅ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΡΠ»Π΅ΠΊΡΡΠΎΠ»ΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΎΡΠ°ΠΆΠ΄Π΅Π½ΠΈΡ Π½Π° ΡΡΡΡΠΊΡΡΡΡ ΠΈ ΠΌΠΈΠΊΡΠΎΠΌΠ΅Ρ Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΠΏΠ»Π΅Π½ΠΎΠΊ NiβFe
The correlation between the synthesis modes, chemical composition, crystal structure, surface microstructure, and also the mechanical properties of thin nanostructured Ni β Fe films has been studied. Thin NiβFe films on the Si with Au sublayer were obtained using electrolyte deposition with different current modes: direct current and three pulsed modes with pulse duration of 1 s, 10β3 and 10β5 s. It is shown that a decrease in the pulse duration to 10β5 s leads to an increase in the film elastic modulus and the hardness due to the small grain size and a large number of grain boundaries with increased resistance to plastic deformation. The effect of heat treatment at 100, 200, 300, and 400 Β°C on the surface microstructure and micromechanical properties of the films was investigated. An increase in grain size from 6 to 200 nm was found after heat treatment at 400 Β°C which, in combination with interfusion processes of the half-layer material, led to a significant decrease in hardness and elastic modulus. NiβFe films with improved mechanical properties can be used as coatings for microelectronic body for their electromagnetic protection.ΠΡΠΎΠ²Π΅Π΄Π΅Π½Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΠΊΠΎΡΡΠ΅Π»ΡΡΠΈΠΈ ΠΌΠ΅ΠΆΠ΄Ρ ΡΠ΅ΠΆΠΈΠΌΠ°ΠΌΠΈ ΡΠΈΠ½ΡΠ΅Π·Π°, Ρ
ΠΈΠΌΠΈΡΠ΅ΡΠΊΠΈΠΌ ΡΠΎΡΡΠ°Π²ΠΎΠΌ, ΠΊΡΠΈΡΡΠ°Π»Π»ΠΈΡΠ΅ΡΠΊΠΎΠΉ ΡΡΡΡΠΊΡΡΡΠΎΠΉ ΠΈ ΠΌΠΈΠΊΡΠΎΡΡΡΡΠΊΡΡΡΠΎΠΉ ΠΏΠΎΠ²Π΅ΡΡ
Π½ΠΎΡΡΠΈ, Π° ΡΠ°ΠΊΠΆΠ΅ ΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΡΠ²ΠΎΠΉΡΡΠ²Π°ΠΌΠΈ ΡΠΎΠ½ΠΊΠΈΡ
Π½Π°Π½ΠΎΡΡΡΡΠΊΡΡΡΠΈΡΠΎΠ²Π°Π½Π½ΡΡ
ΠΏΠ»Π΅Π½ΠΎΠΊ NiβFe. Π’ΠΎΠ½ΠΊΠΈΠ΅ ΠΏΠ»Π΅Π½ΠΊΠΈ NiβFe Π±ΡΠ»ΠΈ ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ Π² ΡΠ°Π·Π»ΠΈΡΠ½ΡΡ
ΡΠ΅ΠΆΠΈΠΌΠ°Ρ
ΡΠ»Π΅ΠΊΡΡΠΎΠ»ΠΈΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΎΡΠ°ΠΆΠ΄Π΅Π½ΠΈΡ: Π² ΡΠ΅ΠΆΠΈΠΌΠ΅ ΠΏΠΎΡΡΠΎΡΠ½Π½ΠΎΠ³ΠΎ ΡΠΎΠΊΠ° ΠΈ Π² ΠΈΠΌΠΏΡΠ»ΡΡΠ½ΡΡ
ΡΠ΅ΠΆΠΈΠΌΠ°Ρ
Ρ Π΄Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΡΡ ΠΈΠΌΠΏΡΠ»ΡΡΠ° 1 Ρ, 10β3 ΠΈ 10β5 Ρ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΡΠΌΠ΅Π½ΡΡΠ΅Π½ΠΈΠ΅ Π΄Π»ΠΈΡΠ΅Π»ΡΠ½ΠΎΡΡΠΈ ΠΈΠΌΠΏΡΠ»ΡΡΠ° Π΄ΠΎ 10β5 Ρ ΠΏΡΠΈΠ²ΠΎΠ΄ΠΈΡ ΠΊ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΡ ΠΌΠΎΠ΄ΡΠ»Ρ ΡΠΏΡΡΠ³ΠΎΡΡΠΈ ΠΈ ΡΠ²Π΅ΡΠ΄ΠΎΡΡΠΈ ΠΏΠ»Π΅Π½ΠΎΠΊ Π±Π»Π°Π³ΠΎΠ΄Π°ΡΡ ΠΌΠ°Π»ΠΎΠΌΡ ΡΠ°Π·ΠΌΠ΅ΡΡ Π·Π΅ΡΠ½Π° ΠΈ, ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²Π΅Π½Π½ΠΎ, Π±ΠΎΠ»ΡΡΠΎΠΌΡ ΠΊΠΎΠ»ΠΈΡΠ΅ΡΡΠ²Ρ Π³ΡΠ°Π½ΠΈΡ Π·Π΅ΡΠ΅Π½ Ρ ΠΏΠΎΠ²ΡΡΠ΅Π½Π½ΡΠΌ ΡΠΎΠΏΡΠΎΡΠΈΠ²Π»Π΅Π½ΠΈΠ΅ΠΌ ΠΏΠ»Π°ΡΡΠΈΡΠ΅ΡΠΊΠΎΠΉ Π΄Π΅ΡΠΎΡΠΌΠ°ΡΠΈΠΈ. ΠΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΎ Π²Π»ΠΈΡΠ½ΠΈΠ΅ ΡΠ΅ΡΠΌΠΈΡΠ΅ΡΠΊΠΎΠΉ ΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΏΡΠΈ T = 100, 200, 300 ΠΈ 400 Β°Π‘ Π½Π° ΠΌΠΈΠΊΡΠΎΡΡΡΡΠΊΡΡΡΡ ΠΏΠΎΠ²Π΅ΡΡ
Π½ΠΎΡΡΠΈ ΠΈ ΠΌΠΈΠΊΡΠΎΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΠ΅ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΠΏΠ»Π΅Π½ΠΎΠΊ. ΠΠΎΡΠ»Π΅ ΡΠ΅ΡΠΌΠΎΠΎΠ±ΡΠ°Π±ΠΎΡΠΊΠΈ ΠΏΡΠΈ 400 Β°Π‘ Π½Π°Π±Π»ΡΠ΄Π°Π»ΠΎΡΡ ΡΠ²Π΅Π»ΠΈΡΠ΅Π½ΠΈΠ΅ ΡΠ°Π·ΠΌΠ΅ΡΠ° Π·Π΅ΡΠ½Π° ΠΎΡ 6 Π΄ΠΎ 200 Π½ΠΌ, ΡΡΠΎ Π² ΡΠΎΡΠ΅ΡΠ°Π½ΠΈΠΈ Ρ ΠΏΡΠΎΡΠ΅ΡΡΠ°ΠΌΠΈ Π²Π·Π°ΠΈΠΌΠΎΠ΄ΠΈΡΡΡΠ·ΠΈΠΈ ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»Π° ΠΏΠΎΠ΄ΡΠ»ΠΎΡ ΠΈ ΠΏΠ»Π΅Π½ΠΊΠΈ ΠΏΡΠΈΠ²Π΅Π»ΠΎ ΠΊ Π·Π½Π°ΡΠΈΡΠ΅Π»ΡΠ½ΠΎΠΌΡ ΡΠ½ΠΈΠΆΠ΅Π½ΠΈΡ ΡΠ²Π΅ΡΠ΄ΠΎΡΡΠΈ ΠΈ ΠΌΠΎΠ΄ΡΠ»Ρ ΡΠΏΡΡΠ³ΠΎΡΡΠΈ. ΠΠ»Π΅Π½ΠΊΠΈ NiβFe Ρ ΡΠ»ΡΡΡΠ΅Π½Π½ΡΠΌΠΈ ΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΈΠΌΠΈ ΡΠ²ΠΎΠΉΡΡΠ²Π°ΠΌΠΈ ΠΌΠΎΠ³ΡΡ Π±ΡΡΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π½Ρ ΠΊΠ°ΠΊ ΠΏΠΎΠΊΡΡΡΠΈΡ ΠΊΠΎΡΠΏΡΡΠΎΠ² ΠΌΠΈΠΊΡΠΎΡΠ»Π΅ΠΊΡΡΠΎΠ½ΠΈΠΊΠΈ Π΄Π»Ρ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠΉ ΠΈΡ
Π·Π°ΡΠΈΡΡ
Electrochemical behaviour of Ti/Al2O3/Ni nanocomposite material in artificial physiological solution: Prospects for biomedical application
Inorganic-based nanoelements such as nanoparticles (nanodots), nanopillars and nanowires, which have at least one dimension of 100 nm or less, have been extensively developed for biomedical applications. Furthermore, their properties can be varied by controlling such parameters as element shape, size, surface functionalization, and mutual interactions. In this study, Ni-alumina nanocomposite material was synthesized by the dc-Ni electrodeposition into a porous anodic alumina template (PAAT). The structural, morphological, and corrosion properties were studied using x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and electrochemical techniques (linear sweep voltammetry). Template technology was used to obtain Ni nanopillars (NiNPs) in the PAAT nanocomposite. Low corrosion current densities (order of 0.5 ΞΌA/cm2) were indicators of this nanocomposite adequate corrosion resistance in artificial physiological solution (0.9% NaCl). A porous anodic alumina template is barely exposed to corrosion and performs protective functions in the composite. The results may be useful for the development of new nanocomposite materials technologies for a variety of biomedical applications including catalysis and nanoelectrodes for sensing and fuel cells. They are also applicable for various therapeutic purposes including targeting, diagnosis, magnetic hyperthermia, and drug delivery. Therefore, it is an ambitious task to research the corrosion resistance of these magnetic nanostructures in simulated body fluid. Β© 2020 by the authors. Licensee MDPI, Basel, Switzerland.Government Council on Grants, Russian FederationBelarusian Republican Foundation for Fundamental Research,Β BRFFR: Π€18Π-00720163522Funding: The work was performed with support of State Scientific and Technical Program βNanotechβ (ΠΠΠ¦ No 20163522), Belarusian Republican Foundation for Fundamental Research (Grant No. Π€18Π-007), Act 211 of Government of Russian Federation (contract No. 02.A03.21.0011). Additionally, the work was partially supported by the Grant of World Federation of Scientists (Geneva, Switzerland)
Efficiency of Magnetostatic Protection Using Nanostructured Permalloy Shielding Coatings Depending on Their Microstructure
The effect of microstructure on the efficiency of shielding or shunting of the magnetic fluxby permalloy shields was investigated in the present work. For this purpose, the FeNi shieldingcoatings with different grain structures were obtained using stationary and pulsed electrodeposition.The coatingsβ composition, crystal structure, surface microstructure, magnetic domain structure, andshielding efficiency were studied. It has been shown that coatings with 0.2β0.6ΞΌm grains have adisordered domain structure. Consequently, a higher value of the shielding efficiency was achieved,but the working range was too limited. The reason for this is probably the hindered movement of thedomain boundaries. Samples with nanosized grains have an ordered two-domain magnetic structurewith a permissible partial transition to a superparamagnetic state in regions with a grain size of lessthan 100 nm. The ordered magnetic structure, the small size of the domain, and the coexistenceof ferromagnetic and superparamagnetic regions, although they reduce the maximum value ofthe shielding efficiency, significantly expand the working range in the nanostructured permalloyshielding coatings. As a result, a dependence between the grain and domain structure and theefficiency of magnetostatic shielding was found
Combined Effect of Microstructure, Surface Energy, and Adhesion Force on the Friction of PVA/Ferrite Spinel Nanocomposites
Nanocomposite films based on spinel ferrite (Mg0.8Zn0.2Fe1.5Al0.5O4) in a PVA matrix were obtained. An increase in the spinel concentration to 10 wt.% caused an avalanche-like rise in roughness due to the formation of nanoparticle agglomerates. The lateral mode of atomic force microscopy (AFM) allowed us to trace the agglomeration dynamics. An unexpected result was that the composite with 6 wt.% of filler had a low friction coefficient in comparison with similar composites due to the successfully combined effects of low roughness and surface energy. The friction coefficient decreased to 0.07 when the friction coefficient of pure PVA was 0.72. A specially developed method for measuring nano-objectsβ surface energy using AFM made it possible to explain the anomalous nature of the change in tribological characteristics. Β© 2022 by the authors. Licensee MDPI, Basel, Switzerland.National University of Science and Technology,Β MISISAlex V. Trukhanov thanks NUST MISIS for support within the framework of the Β«Priority 2030Β»
Electrochemical behaviour of Ti/Al2O3/Ni nanocomposite material in artificial physiological solution: Prospects for biomedical application
Inorganic-based nanoelements such as nanoparticles (nanodots), nanopillars and nanowires, which have at least one dimension of 100 nm or less, have been extensively developed for biomedical applications. Furthermore, their properties can be varied by controlling such parameters as element shape, size, surface functionalization, and mutual interactions. In this study, Ni-alumina nanocomposite material was synthesized by the dc-Ni electrodeposition into a porous anodic alumina template (PAAT). The structural, morphological, and corrosion properties were studied using x-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), and electrochemical techniques (linear sweep voltammetry). Template technology was used to obtain Ni nanopillars (NiNPs) in the PAAT nanocomposite. Low corrosion current densities (order of 0.5 ΞΌA/cm2) were indicators of this nanocomposite adequate corrosion resistance in artificial physiological solution (0.9% NaCl). A porous anodic alumina template is barely exposed to corrosion and performs protective functions in the composite. The results may be useful for the development of new nanocomposite materials technologies for a variety of biomedical applications including catalysis and nanoelectrodes for sensing and fuel cells. They are also applicable for various therapeutic purposes including targeting, diagnosis, magnetic hyperthermia, and drug delivery. Therefore, it is an ambitious task to research the corrosion resistance of these magnetic nanostructures in simulated body fluid. Β© 2020 by the authors. Licensee MDPI, Basel, Switzerland.Government Council on Grants, Russian FederationBelarusian Republican Foundation for Fundamental Research,Β BRFFR: Π€18Π-00720163522Funding: The work was performed with support of State Scientific and Technical Program βNanotechβ (ΠΠΠ¦ No 20163522), Belarusian Republican Foundation for Fundamental Research (Grant No. Π€18Π-007), Act 211 of Government of Russian Federation (contract No. 02.A03.21.0011). Additionally, the work was partially supported by the Grant of World Federation of Scientists (Geneva, Switzerland)
ΠΠ»ΠΈΡΠ½ΠΈΠ΅ Π³Π°Π±Π°ΡΠΈΡΠ½ΡΡ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² ΡΠΈΠ»ΠΈΠ½Π΄ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΊΡΠ°Π½Π° Π½Π° ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΡΠΊΡΠ°Π½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ
Study of dimensional parametersΚΌ influence on shielding properties of cylindrical shields will allow to optimise the fusion process, as well as to reduce production costs by reducing the material used. The purpose of this work was to compare results of theoretical calculation of shielding effectiveness of an infinite cylindrical shield with the data obtained in real conditions.A cylindrical Ni-Fe shield was synthesised by electrochemical deposition with length of 32 cm, diameter of 4.5 cm and shielding thickness of β 100 Β΅m. The cylinder length was then reduced from 32 cm to 6 cm in 4 cm increments and for each cylinder length shielding effectiveness was measured using three-coordinate Helmholtz field-forming system.The measurement results show that the calculation of shielding effectiveness of infinite cylindrical shield is valid for cylinder lengths l β₯ 18β20 cm. Shielding effectiveness is markedly reduced at values of l Λ 15 cm.Analysis of data obtained allowed to conclude that it is necessary to determine the correction factor when calculating a cylindrical screen shielding efficiencyΠΠ·ΡΡΠ΅Π½ΠΈΠ΅ Π²Π»ΠΈΡΠ½ΠΈΡ Π³Π°Π±Π°ΡΠΈΡΠ½ΡΡ
ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ² Π½Π° ΡΠΊΡΠ°Π½ΠΈΡΡΡΡΠΈΠ΅ ΡΠ²ΠΎΠΉΡΡΠ²Π° ΡΠΈΠ»ΠΈΠ½Π΄ΡΠΈΡΠ΅ΡΠΊΠΈΡ
ΡΠΊΡΠ°Π½ΠΎΠ² ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΡ ΠΎΠΏΡΠΈΠΌΠΈΠ·ΠΈΡΠΎΠ²Π°ΡΡ ΠΏΡΠΎΡΠ΅ΡΡ ΡΠΈΠ½ΡΠ΅Π·Π°, Π° ΡΠ°ΠΊΠΆΠ΅ ΡΠ½ΠΈΠ·ΠΈΡΡ Π·Π°ΡΡΠ°ΡΡ Π½Π° ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΡΡΠ²ΠΎ, Π·Π° ΡΡΡΡ ΡΠΌΠ΅Π½ΡΡΠ΅Π½ΠΈΡ ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΠ΅ΠΌΠΎΠ³ΠΎ ΠΌΠ°ΡΠ΅ΡΠΈΠ°Π»Π°. Π¦Π΅Π»ΡΡ Π΄Π°Π½Π½ΠΎΠΉ ΡΠ°Π±ΠΎΡΡ Π±ΡΠ»ΠΎ ΡΡΠ°Π²Π½Π΅Π½ΠΈΠ΅ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΠΎΠ² ΡΠ΅ΠΎΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠ°ΡΡΡΡΠ° ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠΊΡΠ°Π½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π±Π΅ΡΠΊΠΎΠ½Π΅ΡΠ½ΠΎΠ³ΠΎ ΡΠΈΠ»ΠΈΠ½Π΄ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΊΡΠ°Π½Π° ΠΈ Π΄Π°Π½Π½ΡΡ
, ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ
Π² ΡΠ΅Π°Π»ΡΠ½ΡΡ
ΡΡΠ»ΠΎΠ²ΠΈΡΡ
.ΠΠ΅ΡΠΎΠ΄ΠΎΠΌ ΡΠ»Π΅ΠΊΡΡΠΎΡ
ΠΈΠΌΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΠΎΡΠ°ΠΆΠ΄Π΅Π½ΠΈΡ Π±ΡΠ» ΡΠΈΠ½ΡΠ΅Π·ΠΈΡΠΎΠ²Π°Π½ ΡΠΈΠ»ΠΈΠ½Π΄ΡΠΈΡΠ΅ΡΠΊΠΈΠΉ ΡΠΊΡΠ°Π½ Ni-Fe, Π΄Π»ΠΈΠ½Π° ΠΊΠΎΡΠΎΡΠΎΠ³ΠΎ ΡΠΎΡΡΠ°Π²ΠΈΠ»Π° 32 ΡΠΌ, Π΄ΠΈΠ°ΠΌΠ΅ΡΡ 4,5 ΡΠΌ, ΡΠΎΠ»ΡΠΈΠ½Π° ΡΠΊΡΠ°Π½ΠΈΡΡΡΡΠ΅Π³ΠΎ ΠΏΠΎΠΊΡΡΡΠΈΡ ΡΠΎΡΡΠ°Π²ΠΈΠ»Π°β 100 ΠΌΠΊΠΌ. ΠΠ°ΡΠ΅ΠΌ Π΄Π»ΠΈΠ½Π° ΡΠΈΠ»ΠΈΠ½Π΄ΡΠ° ΡΠΌΠ΅Π½ΡΡΠ°Π»Π°ΡΡ ΠΎΡ 30 Π΄ΠΎ 6 ΡΠΌ Ρ ΡΠ°Π³ΠΎΠΌ Π² 4 ΡΠΌ, Π΄Π»Ρ ΠΊΠ°ΠΆΠ΄ΠΎΠΉ Π΄Π»ΠΈΠ½Ρ ΡΠΈΠ»ΠΈΠ½Π΄ΡΠ° Π±ΡΠ»Π° ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½Π° ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΡΠΊΡΠ°Π½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ Ρ ΠΏΠΎΠΌΠΎΡΡΡ ΠΏΠΎΠ»Π΅ΠΎΠ±ΡΠ°Π·ΡΡΡΠ΅ΠΉ ΡΠΈΡΡΠ΅ΠΌΡ ΡΡΡΡ
ΠΊΠΎΠΎΡΠ΄ΠΈΠ½Π°ΡΠ½ΡΡ
ΠΊΠ°ΡΡΡΠ΅ΠΊ ΠΠ΅Π»ΡΠΌΠ³ΠΎΠ»ΡΡΠ°.Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠΉ ΠΏΠΎΠΊΠ°Π·Π°Π»ΠΈ, ΡΡΠΎ ΡΠ°ΡΡΡΡ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠΊΡΠ°Π½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π±Π΅ΡΠΊΠΎΠ½Π΅ΡΠ½ΠΎΠ³ΠΎ ΡΠΈΠ»ΠΈΠ½Π΄ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΊΡΠ°Π½Π° ΡΠΏΡΠ°Π²Π΅Π΄Π»ΠΈΠ² ΠΏΡΠΈ Π΄Π»ΠΈΠ½Π΅ ΡΠΈΠ»ΠΈΠ½Π΄ΡΠ° l β₯ 18β20 ΡΠΌ. ΠΡΠΈ Π·Π½Π°ΡΠ΅Π½ΠΈΡΡ
l Λ 15 ΡΠΌ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΡΠΊΡΠ°Π½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π·Π°ΠΌΠ΅ΡΠ½ΠΎ ΡΠ½ΠΈΠΆΠ°Π΅ΡΡΡ.ΠΠ½Π°Π»ΠΈΠ· ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΡ
Π΄Π°Π½Π½ΡΡ
ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΠ» ΡΠ΄Π΅Π»Π°ΡΡ Π²ΡΠ²ΠΎΠ΄ ΠΎ Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎΡΡΠΈ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΡ ΠΏΠΎΠΏΡΠ°Π²ΠΎΡΠ½ΠΎΠ³ΠΎ ΠΊΠΎΡΡΡΠΈΡΠΈΠ΅Π½ΡΠ° ΠΏΡΠΈ ΡΠ°ΡΡΡΡΠ°Ρ
ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠΊΡΠ°Π½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠΈΠ»ΠΈΠ½Π΄ΡΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΠΊΡΠ°Π½Π°
Correlation of the chemical composition, phase content, structural characteristics and magnetic properties of the Bi-substituted M-type hexaferrites
Bi-substituted M-type hexaferrites, BaFe12-xBixO19 (0.1 β€ x β€ 1.2), or Bi-BaM, were produced by the solid-state reactions. The correlation between the phase content, chemical composition, crystal structure features, and peculiarities of the magnetic properties of Bi-BaM was established using XRD (X-ray diffraction), SEM (scanning electron microscopy), and VSM (vibrational sample magnetometry). XRD phase analysis made it possible to establish the limit of substitution of Fe3+ ions by Bi3+ ions. It was shown that at a low substitution level (x β€ 0.3), no impurity phases were detected, and the samples are characterized by a single-phase state with the space group (SG) P63/mmc. As the degree of substitution (x β₯ 0.6) increases, the formation of impurity phases was observed, which can be explained by the difficulties of ion diffusion in the process of solid-phase synthesis as well as the formation of defects in the magnetoplumbite structure due to the large ionic radius of Bi3+. As impurity phases in the studied compositions (x β₯ 0.6) the following were noted: BiFeO3 (SG: Pnma); BiO2 (SG: Fm-3m); BaBi2O6 (SG: R-3); and Ba0.5Bi1.5O2.16 (SG: Im-3m). The content of the main phase (SG: P63/mmc) decreases from 95.11 to 88.27 vol% with an increase in x from 0.6 to 1.2, respectively. Analysis of SEM images showed the growth of particles up to 10 ΞΌm, depending on the concentration of bismuth oxide during hexaferrite synthase. The Bi-BaM magnetic characteristics were examined using VSM in the range of 3 T at 300 K. Due to the magnetic structure's frustration, with increased x a decrease in saturation magnetization (Ms) was found. There were two concentration diapasons with different speeds of Ms decrease. In the first diapason, the main contribution belong to the magnetic structure frustration in the frame of the main phase (P63/mmc) due to the long-range Fe-O-Fe exchange interaction weakening (under Bi substitution). In the second diapason, the main contribution belong to the impurity phase formation and decrease of the main magnetic phase concentration in samples
The effect of heat treatment on the microstructure and mechanical properties of 2d nanostructured au/nife system
Nanostructured NiFe film was obtained on silicon with a thin gold sublayer via pulsed electrodeposition and annealed at a temperature from 100 to 400β¦C in order to study the effect of heat treatment on the surface microstructure and mechanical properties. High-resolution atomic force microscopy made it possible to trace stepwise evolving microstructure under the influence of heat treatment. It was found that NiFe film grains undergo coalescence twiceβat ~100 and ~300Β°Cβin the process of a gradual increase in grain size. The mechanical properties of the Au/NiFe nanostructured system have been investigated by nanoindentation at two various indentation depths, 10 and 50 nm. The results showed the opposite effect of heat treatment on the mechanical properties in the near-surface layer and in the material volume. Surface homogenization in combination with oxidation activation leads to abnormal strengthening and hardening-up of the near-surface layer. At the same time, a nonlinear decrease in hardness and Youngβs modulus with increasing temperature of heat treatment characterizes the internal volume of nanostructured NiFe. An explanation of this phenomenon was found in the complex effect of changing the ratio of grain volume/grain boundaries and increasing the concentration of thermally activated diffuse gold atoms from the sublayer to the NiFe film. Β© 2020 by the authors. Licensee MDPI, Basel, Switzerland.Funding: The work was supported by Act 211 Government of the Russian Federation, contract β 02.A03.21.0011
Formation and corrosion properties of Ni-based composite material in the anodic alumina porous matrix
Ni nanopillars (Ni NPs) composite material formation technology embedded in porous anodic alumina by electrochemical deposition is presented in this paper. The morphological and structural properties of the composite material were investigated using scanning electron microscopy, atomic force microscopy, X-ray diffraction. The corrosion resistance of the nanocomposite materials has been studied by potentiodynamic polarization curves analysis and polarization resistance method. The composite represents the array of vertically ordered Ni NPs with the identical size in alumina matrix. XRD investigation indicates that Ni NPs are polynanocrystalline material with 18β―nm crystallite size. It has been shown that Ni NPs and the composite material have sufficient corrosion resistance in a 0.9% aqueous NaCl solution. Porous alumina is the neutral and protective component of the composite. These nanocomposite materials can be excellent candidates for practical use in electronics, sensorics, biomedicine
Isostatic Hot Pressed WβCu Composites with Nanosized Grain Boundaries: Microstructure, Structure and Radiation Shielding Efficiency against Gamma Rays
Abstract: The WβCu composites with nanosized grain boundaries and high effective density were fabricated using a new fast isostatic hot pressing method. A significantly faster method was proposed for the formation of WβCu composites in comparison to the traditional ones. The influence of both the high temperature and pressure conditions on the microstructure, structure, chemical composition, and density values were observed. It has been shown that WβCu samples have a polycrystalline well-packed microstructure. The copper performs the function of a matrix that surrounds the tungsten grains. The WβCu composites have mixed bcc-W (sp. gr. Im 3 m) and fcc-Cu (sp. gr. Fm 3 m) phases. The W crystallite sizes vary from 107 to 175 nm depending on the sintering conditions. The optimal sintering regimes of the WβCu composites with the highest density value of 16.37 g/cm3 were determined. Tungstenβcopper composites with thicknesses of 0.06β0.27 cm have been fabricated for the radiation protection efficiency investigation against gamma rays. It has been shown that WβCu samples have a high shielding efficiency from gamma radiation in the 0.276β1.25 MeV range of energies, which makes them excellent candidates as materials for radiation protection. Β© 2022 by the authorsLicensee MDPI, Basel, Switzerland.Ministry of Education and Science of the Russian Federation,Β Minobrnauka: 075-15-2020-926Funding: M.V.S. acknowledges financial support from the Ministry of Science and Higher Education of the Russian Federation within the framework of state support for the creation and development of World-Class Research Centers βDigital Biodesign and Personalized Healthcareβ No. 075-15-2020-926