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
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
Magnetic nanocomposite material has been widely focused for the potential to become the next generation of magnetic material.In this paper,two kinds of chemical coating methods were used to prepare SmCo_(5)/Co nanocom...Magnetic nanocomposite material has been widely focused for the potential to become the next generation of magnetic material.In this paper,two kinds of chemical coating methods were used to prepare SmCo_(5)/Co nanocomposite particles which were further characterized and compared.The two methods were carried out by using different materials and at different temperatures.In Method I,oleylamine(OAm),oleic acid and Ca(acac)2 were used and the reaction was carried out at the temperature of 300℃.In MethodⅡ,anhydrous isopropanol,polyvinylpyrrolidone(PVP),N_(2)H_(4)·H_(2)O and CoCl_(2)·6 H_(2)O were used and the reaction temperature was~55℃.It was found that by using the two methods,the growth and the crystal structure of the Co nanoparticles(NPs)are different.In Method I,epitaxial growth on the surface of SmCo_(5) NPs was observed and the Co NPs were in a facecentered close packing crystal structure.While in Method II,the coated Co NPs were self-nucleated with a crystal structure of hexagonal close packing.Using MethodⅡwith the addition of surfactant,anisotropic nanocomposite particles were achieved with an enhanced saturated magnetization of 84.2 A·m^(2)·kg^(-1).And the coercivity change of the NPs illustrates that a nonmagnetic interlayer between the hard and soft magnetic phase is beneficial to maintain the coercivity.展开更多
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.
基金financially supported by the National Key R&D Program of China(No.2018YFB2003901)National Natural Science Foundations of China(NSFC)(No.51520105002)。
文摘Magnetic nanocomposite material has been widely focused for the potential to become the next generation of magnetic material.In this paper,two kinds of chemical coating methods were used to prepare SmCo_(5)/Co nanocomposite particles which were further characterized and compared.The two methods were carried out by using different materials and at different temperatures.In Method I,oleylamine(OAm),oleic acid and Ca(acac)2 were used and the reaction was carried out at the temperature of 300℃.In MethodⅡ,anhydrous isopropanol,polyvinylpyrrolidone(PVP),N_(2)H_(4)·H_(2)O and CoCl_(2)·6 H_(2)O were used and the reaction temperature was~55℃.It was found that by using the two methods,the growth and the crystal structure of the Co nanoparticles(NPs)are different.In Method I,epitaxial growth on the surface of SmCo_(5) NPs was observed and the Co NPs were in a facecentered close packing crystal structure.While in Method II,the coated Co NPs were self-nucleated with a crystal structure of hexagonal close packing.Using MethodⅡwith the addition of surfactant,anisotropic nanocomposite particles were achieved with an enhanced saturated magnetization of 84.2 A·m^(2)·kg^(-1).And the coercivity change of the NPs illustrates that a nonmagnetic interlayer between the hard and soft magnetic phase is beneficial to maintain the coercivity.
