Amorphous ribbons of the alloy Fe73.5 Si13.5B9Cu1Nb1V2 were prepared by the standard single copper wheel melt spinning technique in the air atmosphere. The crystallization kinetics of amorphous ribbons was analyzed by...Amorphous ribbons of the alloy Fe73.5 Si13.5B9Cu1Nb1V2 were prepared by the standard single copper wheel melt spinning technique in the air atmosphere. The crystallization kinetics of amorphous ribbons was analyzed by non-isothermal differential scanning calorimetry （DSC） measurements. The crystallization activation energies of amorphous ribbons calculated by using Kissinger model were 364 and 337 kJ/mol for the first and the second crystallization, respectively. The Avrami exponent n was calculated from the Johnson- Mehl-Avrami （ MA） equation. The value of the Avrami exponent showed that the crystallization mechanism in the non-isothermal primary crystallization of amorphous ribbons was all shapes growing from small dimensions controlled by diffusion at decreasing nuclectcn rate. The variation of soft magnetic properties of nanocrystalline Fe73.5 Si13.5B9Cu1Nb1V2 alloy powder cores s a tunction of milling times has been investigated. It is found that the effective permeability of the cores shows high frequency stability and decreases with the increase of milling times. The quality factor increases with increasing frequency in lower frequency range, and reaches a maximum at the frequency of 80 kHz then decreases gradually with increasing frequency.展开更多
Two silicon resins with excellent thermal stability,JH1123 and JH7102,are used as the insulated agents and binders for the gas-atomized FeSiAl powder,and corresponding magnetic powder cores(MPCs)are fabricated.The ins...Two silicon resins with excellent thermal stability,JH1123 and JH7102,are used as the insulated agents and binders for the gas-atomized FeSiAl powder,and corresponding magnetic powder cores(MPCs)are fabricated.The insulation capability and application prospects of the two silicon resins are evaluated by comparing the magnetic properties of the coated powder and MPCs.The scanning electron microscopy,energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy results show that uniform insulation layers are both formed on the powder surfaces.JH1123 has stronger binding ability,and the JH1123-coated powder exhibits severe agglomeration,with d50(average particle size)approximately twice that of the JH7102-coated powder.Both as-prepared MPCs exhibit outstanding soft magnetic properties.Wherein,the permeability of FeSiAl@JH1123 is up to 74.0,which is 35.5%higher than that of FeSiAl@JH7102 because JH1123 can further improve the density of the MPCs.As for FeSiAl@JH7102,it has better direct current bias and lower core loss of 716.9 mW cm^(−3) at 20 mT and 1000 kHz due to its lower coercivity and greater anti-magnetic saturation ability.A comprehensive comparison shows that FeSiAl@JH1123 is suitable for medium and high frequency applications,while FeSiAl@JH7102 is more suitable for high frequency applications.This indicates that the use of JH1123 and JH7102 silicon resins for binding and insulated coating not only simplifies the preparation process of MPCs,but also enables the controlled production of MPCs for different applications.展开更多
The FeSiBC amorphous powder cores were fabricated using powders of the FeSiBC amorphous ribbons which were mechanically crushed for a short time, and the relationship between magnetic properties and powder particle si...The FeSiBC amorphous powder cores were fabricated using powders of the FeSiBC amorphous ribbons which were mechanically crushed for a short time, and the relationship between magnetic properties and powder particle sizes was evaluated. The saturation magnetization Bs of the amorphous Fe82Si2B15C1 alloy was 1.62 T, which provided a superior dc-bias property for the powder cores. Meanwhile, a stable permeability up to high frequency range over 10 MHz and the low core loss of 400 kW/ma at f=50 kHz and Bm =0.1 T were obtained. These excellent high-frequency magnetic properties of the FeSiBC amorphous powder cores could be attributed to the effective electrical insulation between the FeSiBC amorphous powders made by mechanical crushing.展开更多
Fe73. 5 Cu1 Nb3 Si15.5B7 nanocrystalline powder cores with different particle sizes ranging from 10 to 125 9m were fabricated by cold-pressing techniques. The cores exhibited increased core loss P cv and decreased ini...Fe73. 5 Cu1 Nb3 Si15.5B7 nanocrystalline powder cores with different particle sizes ranging from 10 to 125 9m were fabricated by cold-pressing techniques. The cores exhibited increased core loss P cv and decreased initial permea- bility μi with addition of fine powders below 50 μm in size, and the content should be less than 40 mass%. It was thought to be closely related to the high coercive force H c due to the stresses generated during the crushing process and high demagnetization fields of small powders. Furthermore, modifying the alloy compositions by adding defined amount of Ni could improve the soft magnetic properties, including superior characteristics of permeability under high direct current （DC） bias field and comparable low core loss at high frequency.展开更多
Toroidal shape FeCuNbSiB nanocrystalline alloy powder cores were prepared by cold pressing using me- chanically crushed and ball-milled powders, respectively. The morphologies and their effects on the magnetic proper-...Toroidal shape FeCuNbSiB nanocrystalline alloy powder cores were prepared by cold pressing using me- chanically crushed and ball-milled powders, respectively. The morphologies and their effects on the magnetic proper- ties of the compacted cores were investigated. Compared with ball-milled powders, mechanically crushed ones have more regular shapes and rounder edges, which lead to better inter-particle insulation. FeCuNbSiB nanocrystalline al- loy powder cores fabricated from mechanically crushed powders exhibit remarkably lower core loss of about 248.2 kW/m3 at 100 kHz for maximum flux density Bm 0.1 T, and more stable permeability up to 10 MHz. Moreover, the dc-bias property could be improved significantly using mechanically crushed powders.展开更多
The influence of micro-structure on magnetic properties of amorphous powder core was investigated.The results show that the amorphous powders of the powder core become crystallized with the increase of annealing tempe...The influence of micro-structure on magnetic properties of amorphous powder core was investigated.The results show that the amorphous powders of the powder core become crystallized with the increase of annealing temperature,and the permeability decreases from 60 to 12,the core loss increases from 0.2 to 0.3 W·cm^(-3),DC-bias characteristic was improved with further increase of annealing temperature,and the magnetic properties become deteriorated due to decrease of permeability and enhancement of coercive force resulting from the crystallization of amorphous powder.展开更多
High-entropy alloys(HEAs),which are composed of 3d transition metals such as Fe,Co,and Ni,exhibit an exceptional combination of magnetic and other properties;however,the addition of non-ferromagnetic elements always n...High-entropy alloys(HEAs),which are composed of 3d transition metals such as Fe,Co,and Ni,exhibit an exceptional combination of magnetic and other properties;however,the addition of non-ferromagnetic elements always negatively affects the saturation magnetization strength(M s).Co_(4)Fe_(2)Al_(x)Mn_(y) alloys were designed and investigated in this study to develop a novel HEA with excellent soft magnetic properties.The Co_(4)Fe_(2)Al_(1.5)Mn_(1.5) HEA possesses the highest M s of 161.3 emu g^(-1) thus far reported for magnetic HEAs,a low coercivity of 1.9 Oe,a high electrical resistivity of 173μΩ cm,a superior thermal stability up to 600℃,which originates from the novel microstructure of B2 nanoparticles distributed in a DO_(3) matrix phase,and the crucial transition of Mn from antiferromagnetism to ferromagnetism with the assistance of Al.The Co_(4)Fe_(2_)Al_(1.5)Mn_(1.5) HEA was selected to produce micron-sized powder and soft magnetic powder cores(SMPCs)for application in the exploration field.The SMPCs exhibit a high stable effective perme-ability of 35.9 up to 1 MHz,low core loss of 38.1 mW cm^(-3)(@100 kHz,20 mT),and an excellent direct current(DC)bias performance of 87.7%at 100 Oe.This study paves the way for the development of soft magnetic HEAs with promising applications as magnetic functional materials.展开更多
基金Funded by the State Key Lab of Advanced Metals and Materials(No.2011-ZD03)The Hubei Provincial Department of Education(No.D20111103)
文摘Amorphous ribbons of the alloy Fe73.5 Si13.5B9Cu1Nb1V2 were prepared by the standard single copper wheel melt spinning technique in the air atmosphere. The crystallization kinetics of amorphous ribbons was analyzed by non-isothermal differential scanning calorimetry （DSC） measurements. The crystallization activation energies of amorphous ribbons calculated by using Kissinger model were 364 and 337 kJ/mol for the first and the second crystallization, respectively. The Avrami exponent n was calculated from the Johnson- Mehl-Avrami （ MA） equation. The value of the Avrami exponent showed that the crystallization mechanism in the non-isothermal primary crystallization of amorphous ribbons was all shapes growing from small dimensions controlled by diffusion at decreasing nuclectcn rate. The variation of soft magnetic properties of nanocrystalline Fe73.5 Si13.5B9Cu1Nb1V2 alloy powder cores s a tunction of milling times has been investigated. It is found that the effective permeability of the cores shows high frequency stability and decreases with the increase of milling times. The quality factor increases with increasing frequency in lower frequency range, and reaches a maximum at the frequency of 80 kHz then decreases gradually with increasing frequency.
基金supported by the Key R&D Program of Shandong Province,China(Grant No.2022CXGC020308).
文摘Two silicon resins with excellent thermal stability,JH1123 and JH7102,are used as the insulated agents and binders for the gas-atomized FeSiAl powder,and corresponding magnetic powder cores(MPCs)are fabricated.The insulation capability and application prospects of the two silicon resins are evaluated by comparing the magnetic properties of the coated powder and MPCs.The scanning electron microscopy,energy dispersive X-ray spectroscopy and Fourier transform infrared spectroscopy results show that uniform insulation layers are both formed on the powder surfaces.JH1123 has stronger binding ability,and the JH1123-coated powder exhibits severe agglomeration,with d50(average particle size)approximately twice that of the JH7102-coated powder.Both as-prepared MPCs exhibit outstanding soft magnetic properties.Wherein,the permeability of FeSiAl@JH1123 is up to 74.0,which is 35.5%higher than that of FeSiAl@JH7102 because JH1123 can further improve the density of the MPCs.As for FeSiAl@JH7102,it has better direct current bias and lower core loss of 716.9 mW cm^(−3) at 20 mT and 1000 kHz due to its lower coercivity and greater anti-magnetic saturation ability.A comprehensive comparison shows that FeSiAl@JH1123 is suitable for medium and high frequency applications,while FeSiAl@JH7102 is more suitable for high frequency applications.This indicates that the use of JH1123 and JH7102 silicon resins for binding and insulated coating not only simplifies the preparation process of MPCs,but also enables the controlled production of MPCs for different applications.
基金Item Sponsored by National Natural Science Foundation of China(51071050)
文摘The FeSiBC amorphous powder cores were fabricated using powders of the FeSiBC amorphous ribbons which were mechanically crushed for a short time, and the relationship between magnetic properties and powder particle sizes was evaluated. The saturation magnetization Bs of the amorphous Fe82Si2B15C1 alloy was 1.62 T, which provided a superior dc-bias property for the powder cores. Meanwhile, a stable permeability up to high frequency range over 10 MHz and the low core loss of 400 kW/ma at f=50 kHz and Bm =0.1 T were obtained. These excellent high-frequency magnetic properties of the FeSiBC amorphous powder cores could be attributed to the effective electrical insulation between the FeSiBC amorphous powders made by mechanical crushing.
基金Sponsored by National High-tech Research and Development Program(863 Program)of China(2013AA030802)
文摘Fe73. 5 Cu1 Nb3 Si15.5B7 nanocrystalline powder cores with different particle sizes ranging from 10 to 125 9m were fabricated by cold-pressing techniques. The cores exhibited increased core loss P cv and decreased initial permea- bility μi with addition of fine powders below 50 μm in size, and the content should be less than 40 mass%. It was thought to be closely related to the high coercive force H c due to the stresses generated during the crushing process and high demagnetization fields of small powders. Furthermore, modifying the alloy compositions by adding defined amount of Ni could improve the soft magnetic properties, including superior characteristics of permeability under high direct current （DC） bias field and comparable low core loss at high frequency.
基金Sponsored by National High-tech Research and Development Program of China(2012AA030301)
文摘Toroidal shape FeCuNbSiB nanocrystalline alloy powder cores were prepared by cold pressing using me- chanically crushed and ball-milled powders, respectively. The morphologies and their effects on the magnetic proper- ties of the compacted cores were investigated. Compared with ball-milled powders, mechanically crushed ones have more regular shapes and rounder edges, which lead to better inter-particle insulation. FeCuNbSiB nanocrystalline al- loy powder cores fabricated from mechanically crushed powders exhibit remarkably lower core loss of about 248.2 kW/m3 at 100 kHz for maximum flux density Bm 0.1 T, and more stable permeability up to 10 MHz. Moreover, the dc-bias property could be improved significantly using mechanically crushed powders.
基金This work was financially supported by Beijing Municipal Science and Technology Program(No.D0405003040121).
文摘The influence of micro-structure on magnetic properties of amorphous powder core was investigated.The results show that the amorphous powders of the powder core become crystallized with the increase of annealing temperature,and the permeability decreases from 60 to 12,the core loss increases from 0.2 to 0.3 W·cm^(-3),DC-bias characteristic was improved with further increase of annealing temperature,and the magnetic properties become deteriorated due to decrease of permeability and enhancement of coercive force resulting from the crystallization of amorphous powder.
基金financially supported by Guangdong Major Project of Basic and Applied Basic Research,China (Grant No.2019B030302010)the National Natural Science Foundation of China (No.52301212,52071157,52071222)+1 种基金the National Key Research and Development Program of China (Grant No.2021YFA0716302)the open research fund of Songshan Lake Materials Laboratory (No.2022SLABFN11)。
基金supported by Youth Innovation Promotion Association CAS (Grant No.2021294)the S&T Innovation 2025 Major Special Program (Grant No.2021Z038)+1 种基金the 2022 Xinjiang Uygur Autonomous Region Postgraduate Innovation Research Program (Grand No.XJ2022G070)the Tianshan Innovation Team Program of Xinjiang Uygur Autonomous Region (Grand No.2020D14038).
文摘High-entropy alloys(HEAs),which are composed of 3d transition metals such as Fe,Co,and Ni,exhibit an exceptional combination of magnetic and other properties;however,the addition of non-ferromagnetic elements always negatively affects the saturation magnetization strength(M s).Co_(4)Fe_(2)Al_(x)Mn_(y) alloys were designed and investigated in this study to develop a novel HEA with excellent soft magnetic properties.The Co_(4)Fe_(2)Al_(1.5)Mn_(1.5) HEA possesses the highest M s of 161.3 emu g^(-1) thus far reported for magnetic HEAs,a low coercivity of 1.9 Oe,a high electrical resistivity of 173μΩ cm,a superior thermal stability up to 600℃,which originates from the novel microstructure of B2 nanoparticles distributed in a DO_(3) matrix phase,and the crucial transition of Mn from antiferromagnetism to ferromagnetism with the assistance of Al.The Co_(4)Fe_(2_)Al_(1.5)Mn_(1.5) HEA was selected to produce micron-sized powder and soft magnetic powder cores(SMPCs)for application in the exploration field.The SMPCs exhibit a high stable effective perme-ability of 35.9 up to 1 MHz,low core loss of 38.1 mW cm^(-3)(@100 kHz,20 mT),and an excellent direct current(DC)bias performance of 87.7%at 100 Oe.This study paves the way for the development of soft magnetic HEAs with promising applications as magnetic functional materials.
