The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz<= f<=25000 Hz and 0.1 T< =Bm <=1.0 T for three main original magnetic states in five sorts of Fe-base...The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz<= f<=25000 Hz and 0.1 T< =Bm <=1.0 T for three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys. The measured and calculated results showed that the total power loss per cycle clearly exhibited a nonlinear behavior in the range below 3 kHz~5 kHz depending on both the magnetic state and the value of Dm, whereas it showed a quasi-linear behavior above this range. The total loss was decomposed into hysteresis loss, classical eddy current loss and excess loss, the obvious nonlinear behavior has been confirmed to be completely determined by the dependence of the excess loss on frequency. It has been indicated that the change rate of the excess loss per cycle with respect to frequency sharp decreases with increasing frequency in the range below about 3 kHz~5 kHz, wherease the rate of change slowly varies above this range, thus leading to the quasilinear behavior of the total loss per cycle. In this paper, some linear expressions of the total loss per cycle has been given in a wider medium-frequency segment, which can be used for roughly estimating the total loss.展开更多
The dependences of the power loss per cycle on frequency f and amplitude flux density Bm have been investigated for the three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloy...The dependences of the power loss per cycle on frequency f and amplitude flux density Bm have been investigated for the three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys in the ranges of 10 Hz<=f<=1000 Hz and 0.4 T<= Bm <=1.0 T. The total loss P is decomposed into the sum of the hysteresis loss Physt, the classical eddy current loss Pel and the excess loss Pexc. Physt has been found to be proportional to Bm^2 and f. The behavior of Pexc/f vs f being equivalent to P/f vs f clearly exhibits nonlinearity in the range not more than about 120 Hz, whereas the behavior of P/f vs f roughly shows linearity in the range far above 100 Hz and not more than 1000 Hz. In the range up to 1000 Hz, Physt is dominant in the original high permeability state and the state of low residual flux density, whereas Pexc in the state of high residual flux density is dominant in the wider range above about 100 Hz. The framework of the statistical theory of power loss has been used for representing the behavior of Pexc/f vs f. It has been found that the number n of the simultaneously active 'Magnetic Objects' linearly varies as n = n0 + Hexc/H0 as a function of the dynamic field Hexc in the range below about 120 Hz, whereas n approximately follows a law of the form n = n0 + (Hexc/H0)^m with 1 < m < 2 in the range far above 100 Hz and not more than 1000 Hz. The values of the field HO in principle related to the microstructure and the domain structure have been calculated for the three states.展开更多
In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range fr...In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range from 10 kHz to 200 kHz and at Bm = 0. 1 T,the P(f) has the fractal structure P (f) = Po, and with the increasing of induced anisotropy energy Ku, the fractal dimension Dfrises, thus the total power loss at high frequency increases and the frequency characteristic of P(f) becomes worse.展开更多
The rapid development of information technology leads a demand for high frequency soft magnetic materials with ex-ceptional radar wave absorption properties.A new magnetic material with superior radar wave absorption ...The rapid development of information technology leads a demand for high frequency soft magnetic materials with ex-ceptional radar wave absorption properties.A new magnetic material with superior radar wave absorption is explored in this paper.we explored the preparation of Y_(2)Co_(17)-xFex(x=0.0,1.0,2.0,3.0)alloy powders using yttrium oxide as a raw material by a low-cost and short preparation cycle reduction-diffusion process.The crystal structure,intrinsic magnetic properties,high frequency magnetism and radar wave absorption of Y_(2)Co_(17)-xFex(x=0.0,1.0,2.0,3.0)were investigated.These compounds have a perfect magnetic repair of Y_(2)Co_(17) and enable the improvement of the overall magnetic properties of Y_(2)Co_(17)-xFex(x=0.0,1.0,2.0,3.0)compounds.The Y_(2)Co_(17)-xFex/Polyurethane(PU)(x=0.0,1.0,2.0,3.0)absorbers were divided in detail using the zero-reflection mechanism.The results show that all Y_(2)Co_(17)-xFex/PU(x=0.0,1.0,2.0,3.0)absorbers have excellent absorption performance(reflection loss RL is less than-85 dB);in addition,Y_(2)Co_(15)Fe_(2)/PU absorbers and Y_(2)Co_(14)Fe_(3)/PU absorbers are superior candidates for S-band materials.In particular,the perfectly matched frequency fp of the modulated Y_(2)Co_(14)Fe_(3)/PU absorber is shifted to the L-band(1–2 GHz)where early warning radars are located.The Y_(2)Co_(14)Fe_(3)/PU absorber has an effective absorption bandwidth of 300 MHz(1.5–1.8 GHz)at a thickness of 5.230 mm.It can also absorb the full L-band at-4 dB,which has rarely been reported.展开更多
Precipitation strengthening is an effective approach to enhance the strength of soft magnetic alloys for applications at high temperatures,while inevitably results in deterioration in coercivity due to the pinning eff...Precipitation strengthening is an effective approach to enhance the strength of soft magnetic alloys for applications at high temperatures,while inevitably results in deterioration in coercivity due to the pinning effect on the domain wall movement.Here,we realize a good combination of high-temperature strength and ductility(ultimate tensile strength of 564 MPa and elongation of~20%,respectively)as well as low coercivity(6.97 Oe)of FeCo-2V-0.3Cr-0.2Mo soft magnetic alloy through introducing high-density magnetic nanoprecipitates.The magnetic nanoprecipitates are characterized by FeCo-based phase with disordered body-centered cubic structure,which enables the alloy to have a low coercivity.In addition,these nanoprecipitates can impede the dislocation motion and suppress the brittle fracture,which lead to a high tensile strength and ductility.This work provides a guideline to enhance strength and ductility while maintaining low coercivity in soft magnetic alloys via magnetic nanoprecipitates.展开更多
Annealing temperatures and applied magnetic fields are two important parameters for the performance modification of magnetic alloys.This article investigated the effect of different annealing temperatures on crystalli...Annealing temperatures and applied magnetic fields are two important parameters for the performance modification of magnetic alloys.This article investigated the effect of different annealing temperatures on crystallization condition,magnetic properties and thermal stability of the amorphous magnetic alloy Co_(36)Fe_(36)Si_(4.8)B1_(9.2)Nb_(4)(at%).Results indicate that the annealing temperature can significantly affect the size and content of precipitated nanocrystals in the amorphous alloy,and the precipitation of nanocrystalline phases can result in the distinct change of magnetic properties and Curie temperature.When the annealing was performed at 595 ℃ for 30 min under an applied transverse external magnetic field of 9550.0A·m^(-1),the amorphous alloy shows excellent soft magnetic properties with the saturation magnetization of alloy reaching 110.00 mA·m^(2)·g^(-1),the residual magnetic induction intensity of 4 × 10^(-6) T and the coercivity as low as57.3 A·m^(-1).Furthermore,the Curie temperature of the field-annealed samples can reach up to 440 0C,approximately 58℃ higher than that of the as-quenched species.展开更多
The core loss spectrum P(f) of Fe-B-Si amorphous soft magnetic alloy has been studied.It is found that P(f) has the fractal structure.The effect of heat treatment on the fractal dimension Df is discussed.
文摘The dependences of the power loss per cycle on frequency have been investigated in the ranges of 100 Hz<= f<=25000 Hz and 0.1 T< =Bm <=1.0 T for three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys. The measured and calculated results showed that the total power loss per cycle clearly exhibited a nonlinear behavior in the range below 3 kHz~5 kHz depending on both the magnetic state and the value of Dm, whereas it showed a quasi-linear behavior above this range. The total loss was decomposed into hysteresis loss, classical eddy current loss and excess loss, the obvious nonlinear behavior has been confirmed to be completely determined by the dependence of the excess loss on frequency. It has been indicated that the change rate of the excess loss per cycle with respect to frequency sharp decreases with increasing frequency in the range below about 3 kHz~5 kHz, wherease the rate of change slowly varies above this range, thus leading to the quasilinear behavior of the total loss per cycle. In this paper, some linear expressions of the total loss per cycle has been given in a wider medium-frequency segment, which can be used for roughly estimating the total loss.
基金National Amorphous and Nanocrystalline Alloy Engineering Researeh Cease
文摘The dependences of the power loss per cycle on frequency f and amplitude flux density Bm have been investigated for the three main original magnetic states in five sorts of Fe-based nanocrystalline soft magnetic alloys in the ranges of 10 Hz<=f<=1000 Hz and 0.4 T<= Bm <=1.0 T. The total loss P is decomposed into the sum of the hysteresis loss Physt, the classical eddy current loss Pel and the excess loss Pexc. Physt has been found to be proportional to Bm^2 and f. The behavior of Pexc/f vs f being equivalent to P/f vs f clearly exhibits nonlinearity in the range not more than about 120 Hz, whereas the behavior of P/f vs f roughly shows linearity in the range far above 100 Hz and not more than 1000 Hz. In the range up to 1000 Hz, Physt is dominant in the original high permeability state and the state of low residual flux density, whereas Pexc in the state of high residual flux density is dominant in the wider range above about 100 Hz. The framework of the statistical theory of power loss has been used for representing the behavior of Pexc/f vs f. It has been found that the number n of the simultaneously active 'Magnetic Objects' linearly varies as n = n0 + Hexc/H0 as a function of the dynamic field Hexc in the range below about 120 Hz, whereas n approximately follows a law of the form n = n0 + (Hexc/H0)^m with 1 < m < 2 in the range far above 100 Hz and not more than 1000 Hz. The values of the field HO in principle related to the microstructure and the domain structure have been calculated for the three states.
文摘In order to check the traditional core loss formula, the core loss spectrum P(f) of Co-based amorphous soft magnetic alloy with constant permeability has been studied. It is found that within a high frequency range from 10 kHz to 200 kHz and at Bm = 0. 1 T,the P(f) has the fractal structure P (f) = Po, and with the increasing of induced anisotropy energy Ku, the fractal dimension Dfrises, thus the total power loss at high frequency increases and the frequency characteristic of P(f) becomes worse.
基金supported by the National Key Research and Development Program of China(Grant No.2021YFB3501302)the National Natural Science Foundation of China(Grant No.51731001)the Fund from the State Key Laboratory of Baiyunobo Rare Earth Resource Researches and Comprehensive Utilization’s Key Research and Development Projects.
文摘The rapid development of information technology leads a demand for high frequency soft magnetic materials with ex-ceptional radar wave absorption properties.A new magnetic material with superior radar wave absorption is explored in this paper.we explored the preparation of Y_(2)Co_(17)-xFex(x=0.0,1.0,2.0,3.0)alloy powders using yttrium oxide as a raw material by a low-cost and short preparation cycle reduction-diffusion process.The crystal structure,intrinsic magnetic properties,high frequency magnetism and radar wave absorption of Y_(2)Co_(17)-xFex(x=0.0,1.0,2.0,3.0)were investigated.These compounds have a perfect magnetic repair of Y_(2)Co_(17) and enable the improvement of the overall magnetic properties of Y_(2)Co_(17)-xFex(x=0.0,1.0,2.0,3.0)compounds.The Y_(2)Co_(17)-xFex/Polyurethane(PU)(x=0.0,1.0,2.0,3.0)absorbers were divided in detail using the zero-reflection mechanism.The results show that all Y_(2)Co_(17)-xFex/PU(x=0.0,1.0,2.0,3.0)absorbers have excellent absorption performance(reflection loss RL is less than-85 dB);in addition,Y_(2)Co_(15)Fe_(2)/PU absorbers and Y_(2)Co_(14)Fe_(3)/PU absorbers are superior candidates for S-band materials.In particular,the perfectly matched frequency fp of the modulated Y_(2)Co_(14)Fe_(3)/PU absorber is shifted to the L-band(1–2 GHz)where early warning radars are located.The Y_(2)Co_(14)Fe_(3)/PU absorber has an effective absorption bandwidth of 300 MHz(1.5–1.8 GHz)at a thickness of 5.230 mm.It can also absorb the full L-band at-4 dB,which has rarely been reported.
基金This work was supported financially by the Science Fund from Natural Science Foundation of Hebei Province(No.E2020202088)the Creative Research Groups(No.61271043)+1 种基金the National Natural Science Foundation of China(No.51771201 and 52002109)the Joint Research Fund Liaoning-Shenyang National Laboratory for Materials Science(No.20180510059)。
文摘Precipitation strengthening is an effective approach to enhance the strength of soft magnetic alloys for applications at high temperatures,while inevitably results in deterioration in coercivity due to the pinning effect on the domain wall movement.Here,we realize a good combination of high-temperature strength and ductility(ultimate tensile strength of 564 MPa and elongation of~20%,respectively)as well as low coercivity(6.97 Oe)of FeCo-2V-0.3Cr-0.2Mo soft magnetic alloy through introducing high-density magnetic nanoprecipitates.The magnetic nanoprecipitates are characterized by FeCo-based phase with disordered body-centered cubic structure,which enables the alloy to have a low coercivity.In addition,these nanoprecipitates can impede the dislocation motion and suppress the brittle fracture,which lead to a high tensile strength and ductility.This work provides a guideline to enhance strength and ductility while maintaining low coercivity in soft magnetic alloys via magnetic nanoprecipitates.
基金financially supported by National S&T Major Project of China (No.2018ZX10301201)the National Natural Science Foundation of China (No.51371018)the Fundamental Research Funds for the Central Universities (No. FRF-BR-14-001B)。
文摘Annealing temperatures and applied magnetic fields are two important parameters for the performance modification of magnetic alloys.This article investigated the effect of different annealing temperatures on crystallization condition,magnetic properties and thermal stability of the amorphous magnetic alloy Co_(36)Fe_(36)Si_(4.8)B1_(9.2)Nb_(4)(at%).Results indicate that the annealing temperature can significantly affect the size and content of precipitated nanocrystals in the amorphous alloy,and the precipitation of nanocrystalline phases can result in the distinct change of magnetic properties and Curie temperature.When the annealing was performed at 595 ℃ for 30 min under an applied transverse external magnetic field of 9550.0A·m^(-1),the amorphous alloy shows excellent soft magnetic properties with the saturation magnetization of alloy reaching 110.00 mA·m^(2)·g^(-1),the residual magnetic induction intensity of 4 × 10^(-6) T and the coercivity as low as57.3 A·m^(-1).Furthermore,the Curie temperature of the field-annealed samples can reach up to 440 0C,approximately 58℃ higher than that of the as-quenched species.
文摘The core loss spectrum P(f) of Fe-B-Si amorphous soft magnetic alloy has been studied.It is found that P(f) has the fractal structure.The effect of heat treatment on the fractal dimension Df is discussed.