32 research outputs found
The influence of multilayer metal-carbon coatings composition with different arrangement of functional layers on their surface morphology
This research was supported by the grants of Belarussian Republican Foundation for Fundamental Research BRFFR β T17KIG-009
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
Friction coefficient obtained using AFM as a criterion of changes in the surface properties after low-temperature plasma treatment
This research was supported by the grant of Belarussian Republican Foundation for Fundamental Research BRFFR No.F17-118
ΠΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΡ ΠΈΠ·Π»ΡΡΠ°ΡΡΠ΅ΠΉ ΠΊΠ°ΡΡΡΠΊΠΈ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠ½ΠΎ-Π°ΠΏΠΏΠ°ΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ° Π΄Π»Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠΊΡΠ°Π½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π½ΠΈΠ·ΠΊΠΎΡΠ°ΡΡΠΎΡΠ½ΠΎΠ³ΠΎ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΡ
Optimization of the radiation coil of the hardware-software complex for studying the effectiveness of shielding of low-frequency electromagnetic radiation will make it possible to assess the effectiveness of shielding coatings at a higher level. This fact will make it possible to develop coatings with improved characteristics. The purpose of this work was to determine the optimal characteristics of the emitting coil which will ensure its stable operation and magnetic field strength in the frequency range up to 100 kHz.The parameters of the manufactured samples, such as inductance (L), active (R) and total resistance (Z), were obtained using an MNIPI E7-20 emittance meter. In practice, the coils with the optimal parameters calculated theoretically were connected to a current source and amplifier. To detect electromagnetic radiation, a multilayer inductor connected to a UTB-TREND 722-050-5 oscilloscope was used as a signal receiver.The results of measurements showed that the resistance of multilayer coils is approximately 1000 times higher than that of single-layer coils. Also, for multilayer coils, an avalanche-like increase in total resistance is observed starting from a frequency of 10 kHz, while for single-layer coils there is a uniform increase in total resistance over the entire frequency range up to 100 kHz.The paper presents results of research on the correlation of the performance of single-layer and multilayer inductors depending on their parameters in the frequency range from Β 20 Hz Β to Β 100 kHz. Values of the voltage required to provide the magnetic field strength of 1, 5, 20 Oe at 25 Hz and 100 kHz have been calculated. After analyzing the data obtained, the optimal parameters of the inductor were found which ensure stable performance in the frequency range up to 100 kHz.ΠΠΏΡΠΈΠΌΠΈΠ·Π°ΡΠΈΡ ΠΈΠ·Π»ΡΡΠ°ΡΡΠ΅ΠΉ ΠΊΠ°ΡΡΡΠΊΠΈ ΠΏΡΠΎΠ³ΡΠ°ΠΌΠΌΠ½ΠΎ-Π°ΠΏΠΏΠ°ΡΠ°ΡΠ½ΠΎΠ³ΠΎ ΠΊΠΎΠΌΠΏΠ»Π΅ΠΊΡΠ° Π΄Π»Ρ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΡ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ ΡΠΊΡΠ°Π½ΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π½ΠΈΠ·ΠΊΠΎΡΠ°ΡΡΠΎΡΠ½ΠΎΠ³ΠΎ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΡ ΠΏΠΎΠ·Π²ΠΎΠ»ΠΈΡ Π½Π° Π±ΠΎΠ»Π΅Π΅ ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅Π½Π½ΠΎΠΌ ΡΡΠΎΠ²Π½Π΅ ΠΎΡΠ΅Π½ΠΈΠ²Π°ΡΡ ΡΡΡΠ΅ΠΊΡΠΈΠ²Π½ΠΎΡΡΡ ΡΠΊΡΠ°Π½ΠΈΡΡΡΡΠΈΡ
ΠΏΠΎΠΊΡΡΡΠΈΠΉ. ΠΠ°Π½Π½ΡΠΉ ΡΠ°ΠΊΡ Π΄Π°ΡΡ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡΡ ΡΠ°Π·ΡΠ°Π±Π°ΡΡΠ²Π°ΡΡ ΠΏΠΎΠΊΡΡΡΠΈΡ Ρ ΡΠ»ΡΡΡΠ΅Π½Π½ΡΠΌΠΈ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠ°ΠΌΠΈ. Π¦Π΅Π»ΡΡ Π΄Π°Π½Π½ΠΎΠΉ ΡΠ°Π±ΠΎΡΡ ΡΠ²Π»ΡΠ»ΠΎΡΡ ΠΎΠΏΡΠ΅Π΄Π΅Π»Π΅Π½ΠΈΠ΅ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΡΡ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊ ΠΈΠ·Π»ΡΡΠ°ΡΡΠ΅ΠΉ ΠΊΠ°ΡΡΡΠΊΠΈ, ΠΊΠΎΡΠΎΡΡΠ΅ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ°Ρ Π΅Ρ ΡΡΠ°Π±ΠΈΠ»ΡΠ½ΡΡ ΡΠ°Π±ΠΎΡΡ ΠΈ Π½Π°ΠΏΡΡΠΆΡΠ½Π½ΠΎΡΡΡ ΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ»Ρ Π² ΡΠ°ΡΡΠΎΡΠ½ΠΎΠΌ Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ Π΄ΠΎ 100 ΠΊΠΡ.ΠΠ°ΡΠ°ΠΌΠ΅ΡΡΡ ΠΈΠ·Π³ΠΎΡΠΎΠ²Π»Π΅Π½Π½ΡΡ
ΠΎΠ±ΡΠ°Π·ΡΠΎΠ², ΡΠ°ΠΊΠΈΠ΅ ΠΊΠ°ΠΊ ΠΈΠ½Π΄ΡΠΊΡΠΈΠ²Π½ΠΎΡΡΡ, Π°ΠΊΡΠΈΠ²Π½ΠΎΠ΅ ΠΈ ΠΎΠ±ΡΠ΅Π΅ ΡΠΎΠΏΡΠΎΡΠΈΠ²Π»Π΅Π½ΠΈΠ΅, Π±ΡΠ»ΠΈ ΠΏΠΎΠ»ΡΡΠ΅Π½Ρ, ΠΈΡΠΏΠΎΠ»ΡΠ·ΡΡ ΠΈΠ·ΠΌΠ΅ΡΠΈΡΠ΅Π»Ρ ΠΈΠΌΠΌΠΈΡΠ°Π½ΡΠ° ΠΠΠΠΠ E7-20. ΠΠ° ΠΏΡΠ°ΠΊΡΠΈΠΊΠ΅ ΠΊΠ°ΡΡΡΠΊΠΈ Ρ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΡΠΌΠΈ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠ°ΠΌΠΈ, Π²ΡΡΠΈΡΠ»Π΅Π½Π½ΡΠΌΠΈ ΡΠ΅ΠΎΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΈ, Π±ΡΠ»ΠΈ ΠΏΠΎΠ΄ΠΊΠ»ΡΡΠ΅Π½Ρ ΠΊ ΠΈΡΡΠΎΡΠ½ΠΈΠΊΡ ΠΈ ΡΡΠΈΠ»ΠΈΡΠ΅Π»Ρ ΡΠΎΠΊΠ°. ΠΠ»Ρ Π΄Π΅ΡΠ΅ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΡΠ»Π΅ΠΊΡΡΠΎΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΈΠ·Π»ΡΡΠ΅Π½ΠΈΡ Π² ΠΊΠ°ΡΠ΅ΡΡΠ²Π΅ ΠΏΡΠΈΡΠΌΠ½ΠΈΠΊΠ° ΡΠΈΠ³Π½Π°Π»Π° ΠΈΡΠΏΠΎΠ»ΡΠ·ΠΎΠ²Π°Π»Π°ΡΡ ΠΌΠ½ΠΎΠ³ΠΎΡΠ»ΠΎΠΉΠ½Π°Ρ ΠΊΠ°ΡΡΡΠΊΠ° ΠΈΠ½Π΄ΡΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ, ΠΏΠΎΠ΄ΠΊΠ»ΡΡΡΠ½Π½Π°Ρ ΠΊ ΠΎΡΡΠΈΠ»Π»ΠΎΠ³ΡΠ°ΡΡ UTB-TREND 722-050-5.Π Π΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΠ·ΠΌΠ΅ΡΠ΅Π½ΠΈΠΉ ΠΏΠΎΠΊΠ°Π·Π°Π»ΠΈ, ΡΡΠΎ ΡΠΎΠΏΡΠΎΡΠΈΠ²Π»Π΅Π½ΠΈΠ΅ ΠΌΠ½ΠΎΠ³ΠΎΡΠ»ΠΎΠΉΠ½ΡΡ
ΠΊΠ°ΡΡΡΠ΅ΠΊ ΠΏΡΠΈΠ±Π»ΠΈΠ·ΠΈΡΠ΅Π»ΡΠ½ΠΎ Π² 1000 ΡΠ°Π· Π±ΠΎΠ»ΡΡΠ΅ ΡΠΎΠΏΡΠΎΡΠΈΠ²Π»Π΅Π½ΠΈΡ ΠΎΠ΄Π½ΠΎΡΠ»ΠΎΠΉΠ½ΡΡ
. Π’Π°ΠΊΠΆΠ΅ Ρ ΠΌΠ½ΠΎΠ³ΠΎΡΠ»ΠΎΠΉΠ½ΡΡ
ΠΊΠ°ΡΡΡΠ΅ΠΊ Π½Π°Π±Π»ΡΠ΄Π°Π΅ΡΡΡ Π»Π°Π²ΠΈΠ½ΠΎΠΎΠ±ΡΠ°Π·Π½ΡΠΉ ΡΠΎΡΡ ΠΎΠ±ΡΠ΅Π³ΠΎ ΡΠΎΠΏΡΠΎΡΠΈΠ²Π»Π΅Π½ΠΈΡ, Π½Π°ΡΠΈΠ½Π°Ρ Ρ ΡΠ°ΡΡΠΎΡΡ 10 ΠΊΠΡ, Π² ΡΠΎ Π²ΡΠ΅ΠΌΡ ΠΊΠ°ΠΊ Ρ ΠΎΠ΄Π½ΠΎΡΠ»ΠΎΠΉΠ½ΡΡ
ΠΊΠ°ΡΡΡΠ΅ΠΊ ΠΏΡΠΎΠΈΡΡ
ΠΎΠ΄ΠΈΡ ΡΠ°Π²Π½ΠΎΠΌΠ΅ΡΠ½ΡΠΉ ΡΠΎΡΡ ΠΎΠ±ΡΠ΅Π³ΠΎ ΡΠΎΠΏΡΠΎΡΠΈΠ²Π»Π΅Π½ΠΈΡ Π½Π° Π²ΡΡΠΌ Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ ΡΠ°ΡΡΠΎΡ Π΄ΠΎ 100 ΠΊΠΡ. ΠΡΠ΅Π΄ΡΡΠ°Π²Π»Π΅Π½Ρ ΡΠ΅Π·ΡΠ»ΡΡΠ°ΡΡ ΠΈΡΡΠ»Π΅Π΄ΠΎΠ²Π°Π½ΠΈΠΉ ΠΊΠΎΡΡΠ΅Π»ΡΡΠΈΠΈ ΡΠ°Π±ΠΎΡΠΈΡ
Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊ Β ΠΎΠ΄Π½ΠΎΡΠ»ΠΎΠΉΠ½ΡΡ
Β ΠΈ ΠΌΠ½ΠΎΠ³ΠΎΡΠ»ΠΎΠΉΠ½ΡΡ
Β ΠΊΠ°ΡΡΡΠ΅ΠΊΒ ΠΈΠ½Π΄ΡΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈΒ Π²Β Π·Π°Π²ΠΈΡΠΈΠΌΠΎΡΡΠΈΒ ΠΎΡΒ ΠΈΡ
Β ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΎΠ²Β Π²Β ΡΠ°ΡΡΠΎΡΠ½ΠΎΠΌΒ Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ ΠΎΡ 20 ΠΡ Π΄ΠΎ 100 ΠΊΠΡ. Π Π°ΡΡΡΠΈΡΠ°Π½Ρ Π·Π½Π°ΡΠ΅Π½ΠΈΡ Π½Π°ΠΏΡΡΠΆΠ΅Π½ΠΈΡ, Π½Π΅ΠΎΠ±Ρ
ΠΎΠ΄ΠΈΠΌΠΎΠ³ΠΎ Π΄Π»Ρ ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠ΅Π½ΠΈΡ Π½Π°ΠΏΡΡΠΆΡΠ½Π½ΠΎΡΡΠΈ ΠΌΠ°Π³Π½ΠΈΡΠ½ΠΎΠ³ΠΎ ΠΏΠΎΠ»Ρ 1, 5, 20 Π ΠΏΡΠΈ 25 ΠΡ ΠΈ 100 ΠΊΠΡ. ΠΡΠΎΠ°Π½Π°Π»ΠΈΠ·ΠΈΡΠΎΠ²Π°Π² ΠΏΠΎΠ»ΡΡΠ΅Π½Π½ΡΠ΅ Π΄Π°Π½Π½ΡΠ΅, Π½Π°ΠΉΠ΄Π΅Π½Ρ ΠΎΠΏΡΠΈΠΌΠ°Π»ΡΠ½ΡΠ΅ ΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΡ ΠΊΠ°ΡΡΡΠΊΠΈ ΠΈΠ½Π΄ΡΠΊΡΠΈΠ²Π½ΠΎΡΡΠΈ, ΠΎΠ±Π΅ΡΠΏΠ΅ΡΠΈΠ²Π°ΡΡΠΈΠ΅ ΡΡΠ°Π±ΠΈΠ»ΡΠ½ΡΠ΅ ΡΠ°Π±ΠΎΡΠΈΠ΅ Ρ
Π°ΡΠ°ΠΊΡΠ΅ΡΠΈΡΡΠΈΠΊΠΈ Π² Π΄ΠΈΠ°ΠΏΠ°Π·ΠΎΠ½Π΅ ΡΠ°ΡΡΠΎΡ Π΄ΠΎ 100 ΠΊΠΡ
Temperature induced structural and polarization features in BaFe12O19
We report the observation of a peculiar polarization behavior of BaFe12O19 in electric field where the linear polarization is detected at temperatures below 150 K whereas at higher temperatures a hysteresis-like polarization response is observed. At the same time, the performed neutron diffraction analysis shows no variations in crystal or magnetic structures with temperature. Based on the results of ab initio calculations we suggest the mechanism able to explain the experimentally observed behavior. We show that specific Fe atoms do not occupy the positions formally assigned to them by the conventional centrosymmetric P63/mmc (#194) space group (z = 0.25; 0.75) as these positions correspond to local energy maxima. Instead, these Fe atoms are shifted along the z-axis to positions z = 0.259 (0.241) and z = 0.759 (0.741), which correspond to local energy minima. To an inversion center move between these minima Fe atoms need to overcome an energy barrier. This barrier is rather insignificant for smaller volumes but it becomes larger for expanded volumes due to coupling between the displacements of these Fe atoms. Additionally, our analysis suggests that the non-centrosymmetric and polar P63mc (#186) space group could be appropriate for the description of the BaFe12O19 structure
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
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»
Magnetic Properties of the Densely Packed Ultra-Long Ni Nanowires Encapsulated in Alumina Membrane
High-quality and compact arrays of Ni nanowires with a high ratio (up to 700) were obtained by DC electrochemical deposition into porous anodic alumina membranes with a distance between pores equal to 105 nm. The nanowire arrays were examined using scanning electron microscopy, X-ray diffraction analysis and vibration magnetometry at 300 K and 4.2 K. Microscopic and X-ray diffraction results showed that Ni nanowires are homogeneous, with smooth walls and mostly single-crystalline materials with a 220-oriented growth direction. The magnetic properties of the samples (coercivity and squareness) depend more on the length of the nanowires and the packing factor (the volume fraction of the nanowires in the membrane). It is shown that the dipolar interaction changes the demagnetizing field during a reversal magnetization of the Ni nanowires, and the general effective field of magnetostatic uniaxial shape anisotropy. The effect of magnetostatic interaction between ultra-long nanowires (with an aspect ratio of >500) in samples with a packing factor of β₯37% leads to a reversal magnetization state, in which a βcurlingβ-type model of nanowire behavior is realized. Β© 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: An.T. (Andrei Turutin) acknowledges the financial support of the Russian Science Foundation (Grant No. 19-79-30062) in part of the experimental work. A.K. (Alexander Kislyuk) and I.K. (Ilya Kubasov) acknowledge the financial support of the Ministry of Science and Higher Education of the Russian Federation as a part of the State Assignment (basic research, Project No. 0718-2020-0031 βNew magnetoelectric composite materials based on oxide ferroelectrics having an ordered domain structure: production and propertiesβ) in part of the XRD study
Magnetic Properties of the Densely Packed Ultra-Long Ni Nanowires Encapsulated in Alumina Membrane
High-quality and compact arrays of Ni nanowires with a high ratio (up to 700) were obtained by DC electrochemical deposition into porous anodic alumina membranes with a distance between pores equal to 105 nm. The nanowire arrays were examined using scanning electron microscopy, X-ray diffraction analysis and vibration magnetometry at 300 K and 4.2 K. Microscopic and X-ray diffraction results showed that Ni nanowires are homogeneous, with smooth walls and mostly single-crystalline materials with a 220-oriented growth direction. The magnetic properties of the samples (coercivity and squareness) depend more on the length of the nanowires and the packing factor (the volume fraction of the nanowires in the membrane). It is shown that the dipolar interaction changes the demagnetizing field during a reversal magnetization of the Ni nanowires, and the general effective field of magnetostatic uniaxial shape anisotropy. The effect of magnetostatic interaction between ultra-long nanowires (with an aspect ratio of >500) in samples with a packing factor of β₯37% leads to a reversal magnetization state, in which a βcurlingβ-type model of nanowire behavior is realized. Β© 2021 by the authors. Licensee MDPI, Basel, Switzerland.Funding: An.T. (Andrei Turutin) acknowledges the financial support of the Russian Science Foundation (Grant No. 19-79-30062) in part of the experimental work. A.K. (Alexander Kislyuk) and I.K. (Ilya Kubasov) acknowledge the financial support of the Ministry of Science and Higher Education of the Russian Federation as a part of the State Assignment (basic research, Project No. 0718-2020-0031 βNew magnetoelectric composite materials based on oxide ferroelectrics having an ordered domain structure: production and propertiesβ) in part of the XRD study
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