Amorphous powder cores based on spherical （Fe0.76Si0.09B0.1P0.05）99Nb1 amorphous powder and their SiO2 layer prepared by in situ coating insulation process were investigated in detAll. These cores were characterized...Amorphous powder cores based on spherical （Fe0.76Si0.09B0.1P0.05）99Nb1 amorphous powder and their SiO2 layer prepared by in situ coating insulation process were investigated in detAll. These cores were characterized by scanning electron microscopy and X-ray diffraction analyses, and the results revealed that the surface layer of the amorphous powder was composed of SiO2 with uniform surface coverage. The thickness of the SiO2 insulating layer could be controlled by adjusting the tetraethyl orthosilicate （TEOS） content. By cold-pressing with epoxy resin under a pressure of 1800 MPa, a ring powder core with an outer diameter of 20.3 ram, inner diameter of 12.7 mm, and height of 5.3 mm was prepared. The FeSiBPNb composite core showed its best properties when the TEOS content was 2 mL/g （the volume of TEOS for each gram of （Fe0.76Si0.09B0.1P0.05）99Nb1 amorphous powder, mL/g）, which showed good relative permeability in the high-frequency range of up to 10 MHz and a low core loss of 320 W/kg under the maximum magnetic flux density of 0.1 T and frequency of 100 kHz.展开更多
In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux densi...In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.展开更多
To fully release the potential of wide bandgap(WBG)semiconductors and achieve high energy density and efficiency,a carbonyl iron soft magnetic composite(SMC)with an easy plane-like structure is prepared.Due to this st...To fully release the potential of wide bandgap(WBG)semiconductors and achieve high energy density and efficiency,a carbonyl iron soft magnetic composite(SMC)with an easy plane-like structure is prepared.Due to this structure,the permeability of the composite increases by 3 times(from 7.5 to 21.5)at 100 MHz compared with to the spherical carbonyl iron SMC,and the permeability changes little at frequencies below 100 MHz.In addition,the natural resonance frequency of the composite shifts to higher frequencies at 1.7 GHz.The total core losses of the composites at 10,20,and 30 m T are80.0,355.3,and 810.7 m W/cm^(3),respectively,at 500 k Hz.Compared with the spherical carbonyl iron SMC,the core loss at500 k Hz is reduced by more than 60%.Therefore,this kind of soft magnetic composite with an easy plane-like structure is a good candidate for unlocking the potential of WBG semiconductors and developing the next-generation power electronics.展开更多
With a pressing need for high efficiency, low power consumption, and miniaturization of electronics, soft magnetic composites(SMCs) show great potential, especially for applications in key electronic component. Howeve...With a pressing need for high efficiency, low power consumption, and miniaturization of electronics, soft magnetic composites(SMCs) show great potential, especially for applications in key electronic component. However, core loss is still the focused issue for SMCs that hinders their sustainable development and widespread applications. In the present study, high-performance SMCs were fabricated by novel Fe_(74)B_(7)C_(7)P_(7)Si_(3)Mo_(1)Cr_(1) powders with spherical shape and a fully glassy structure, which were successfully prepared by a gas atomization method. The microstructure and high-frequency magnetic properties of these SMCs were studied in detail. To enhance the soft ferromagnetism, the effects of annealing temperature(T_a) and powder size on their performance were clarified. Increasing T_a up to 703 K not only helps to effectively release internal stress in the powders, but also improves the integrity of the insulation layer structure, which is conducive to decreasing the core loss. In addition, reducing the powder size contributes to the overall performance enhancement. Prepared from the powders with the smallest mean particle size and annealed at 703 K, the SMC exhibits optimum property combination of a stable effective permeability of 26.2 up to 1 MHz, a total core loss of 883 kW m^(–3)(100 kHz, 100 mT), and a DC-Bias performance of 79.3% under 100 Oe field, which is even comparable to those of the most prominent SMCs reported so far. These results are meaningful for potentially stimulating the development and application of new low-loss SMCs.展开更多
Fe-Ni-Y2O3 nanocomposites with uniform distribution of fine oxide particles in the gamma Fe Ni matrix were successfully fabricated via solution combustion followed by hydrogen reduction. The morphological characterist...Fe-Ni-Y2O3 nanocomposites with uniform distribution of fine oxide particles in the gamma Fe Ni matrix were successfully fabricated via solution combustion followed by hydrogen reduction. The morphological characteristics and phase transformation of the combusted powder and the Fe-Ni-Y2O3 nanocomposites were characterized by XRD, FESEM and TEM.Porous Fe-Ni-Y2O3 nanocomposites with crystallite size below 100 nm were obtained after reduction. The morphology, phases and magnetic property of Fe-Ni-Y2O3 nanocomposites reduced at different temperatures were investigated. The Fe-Ni-Y2O3 nanocomposite reduced at 900 °C has the maximum saturation magnetization and the minimum coercivity values of 167.41 A/(m2·kg)and 3.11 k A/m, respectively.展开更多
基金The work was with the support from the National Key Research and Development Program of China （Grant No. 2017YFB0903902）, National Natural Science Foundation of China （Grant Nos. 51601205, 51671035, 51071034, and 51671206）, and Ningbo Municipal Nature Science Foundation （Grant No. 2017A610036）.
文摘Amorphous powder cores based on spherical （Fe0.76Si0.09B0.1P0.05）99Nb1 amorphous powder and their SiO2 layer prepared by in situ coating insulation process were investigated in detAll. These cores were characterized by scanning electron microscopy and X-ray diffraction analyses, and the results revealed that the surface layer of the amorphous powder was composed of SiO2 with uniform surface coverage. The thickness of the SiO2 insulating layer could be controlled by adjusting the tetraethyl orthosilicate （TEOS） content. By cold-pressing with epoxy resin under a pressure of 1800 MPa, a ring powder core with an outer diameter of 20.3 ram, inner diameter of 12.7 mm, and height of 5.3 mm was prepared. The FeSiBPNb composite core showed its best properties when the TEOS content was 2 mL/g （the volume of TEOS for each gram of （Fe0.76Si0.09B0.1P0.05）99Nb1 amorphous powder, mL/g）, which showed good relative permeability in the high-frequency range of up to 10 MHz and a low core loss of 320 W/kg under the maximum magnetic flux density of 0.1 T and frequency of 100 kHz.
文摘In many situations such as the cores of a rotating electrical machine and the T joints of a multiphase transformer, the local flux density varies with time in terms of both magnitude and direction, i.e. the flux density vector is rotating. Therefore, the magnetic properties of the core materials under the rotating flux density vector excitation should be properly measured, modeled and applied in the design and analysis of these electromagnetic devices. This paper presents an extensive review on the development of techniques and apparatus for measuring the rotational core losses of soft magnetic materials based on the experiences of various researchers in the last hundred years.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11574122 and 51731001)Joint Fund of Equipment Pre-Research and Ministry of Education,China(Grant No.6141A02033242)。
文摘To fully release the potential of wide bandgap(WBG)semiconductors and achieve high energy density and efficiency,a carbonyl iron soft magnetic composite(SMC)with an easy plane-like structure is prepared.Due to this structure,the permeability of the composite increases by 3 times(from 7.5 to 21.5)at 100 MHz compared with to the spherical carbonyl iron SMC,and the permeability changes little at frequencies below 100 MHz.In addition,the natural resonance frequency of the composite shifts to higher frequencies at 1.7 GHz.The total core losses of the composites at 10,20,and 30 m T are80.0,355.3,and 810.7 m W/cm^(3),respectively,at 500 k Hz.Compared with the spherical carbonyl iron SMC,the core loss at500 k Hz is reduced by more than 60%.Therefore,this kind of soft magnetic composite with an easy plane-like structure is a good candidate for unlocking the potential of WBG semiconductors and developing the next-generation power electronics.
基金supported by the National Key Research and Development Program of China (Grant Nos.2022YFB3804100,and 2022YFB4200800)the National Natural Science Foundation of China (Grant No.52271148)。
文摘With a pressing need for high efficiency, low power consumption, and miniaturization of electronics, soft magnetic composites(SMCs) show great potential, especially for applications in key electronic component. However, core loss is still the focused issue for SMCs that hinders their sustainable development and widespread applications. In the present study, high-performance SMCs were fabricated by novel Fe_(74)B_(7)C_(7)P_(7)Si_(3)Mo_(1)Cr_(1) powders with spherical shape and a fully glassy structure, which were successfully prepared by a gas atomization method. The microstructure and high-frequency magnetic properties of these SMCs were studied in detail. To enhance the soft ferromagnetism, the effects of annealing temperature(T_a) and powder size on their performance were clarified. Increasing T_a up to 703 K not only helps to effectively release internal stress in the powders, but also improves the integrity of the insulation layer structure, which is conducive to decreasing the core loss. In addition, reducing the powder size contributes to the overall performance enhancement. Prepared from the powders with the smallest mean particle size and annealed at 703 K, the SMC exhibits optimum property combination of a stable effective permeability of 26.2 up to 1 MHz, a total core loss of 883 kW m^(–3)(100 kHz, 100 mT), and a DC-Bias performance of 79.3% under 100 Oe field, which is even comparable to those of the most prominent SMCs reported so far. These results are meaningful for potentially stimulating the development and application of new low-loss SMCs.
基金Project(51104007)supported by the National Natural Science Foundation of ChinaProject(2132046)supported by Beijing Natural Science Foundation,China
文摘Fe-Ni-Y2O3 nanocomposites with uniform distribution of fine oxide particles in the gamma Fe Ni matrix were successfully fabricated via solution combustion followed by hydrogen reduction. The morphological characteristics and phase transformation of the combusted powder and the Fe-Ni-Y2O3 nanocomposites were characterized by XRD, FESEM and TEM.Porous Fe-Ni-Y2O3 nanocomposites with crystallite size below 100 nm were obtained after reduction. The morphology, phases and magnetic property of Fe-Ni-Y2O3 nanocomposites reduced at different temperatures were investigated. The Fe-Ni-Y2O3 nanocomposite reduced at 900 °C has the maximum saturation magnetization and the minimum coercivity values of 167.41 A/(m2·kg)and 3.11 k A/m, respectively.
