Tensile stress annealing(TSA)is an effective strategy for tailoring magnetic anisotropy and high-frequency performance in nanocrystalline soft magnetic alloys.Here,we systematically investigate the influence of TSA on...Tensile stress annealing(TSA)is an effective strategy for tailoring magnetic anisotropy and high-frequency performance in nanocrystalline soft magnetic alloys.Here,we systematically investigate the influence of TSA on the microstructure,magnetic domain evolution,and permeability stability of Fe_(69.5)Co_(3)Nb_(2)Mo_(1.5)Si_(14)B_(9)Cu_(1)nanocrystalline alloys.Across all applied stresses(0-300 MPa),the alloys retain an ultrafine grain size(≤11 nm),yet the induced uniaxial anisotropy constant(K_(u))rises sharply from 22.5 to 665 J/m^(3).This increase in K u refines the magnetic domain structure,reducing average domain width from 110 to 36μm,and shifts the magnetization mechanism from domain-wall displacement to rotation-dominated reversal.Quantitative correlation between K u,domain structure,and effective permeability(μ_(e))reveals that higher stress suppressesμ_(e)at low frequencies but yields exceptional frequency stability:μ_(e)≈2330 is maintained up to 1 MHz at 50 MPa,andμ_(e)≈585 remains constant from1 kHz to 10 MHz at 300 MPa.These findings demonstrate thatstress-induced anisotropy is a decisive factor in governinghigh-frequency magnetic response,offering both mechanisticinsight and a practical framework for designing next-generation soft magnetic materials for precision current transformers,EMC filters,and MHz-class power electronics.展开更多
Fluorite Ce0.8Sm0.2O2-δ（SDC） nanopowder with a crystallite size of 15 nm was synthesized by a co-precipitation method. An SDC porous layer was coated onto a BaCo0.7Fe0.2Nb0.1O3-δ（BCFN） mixed conductor to improve...Fluorite Ce0.8Sm0.2O2-δ（SDC） nanopowder with a crystallite size of 15 nm was synthesized by a co-precipitation method. An SDC porous layer was coated onto a BaCo0.7Fe0.2Nb0.1O3-δ（BCFN） mixed conductor to improve its oxygen transport behavior. The results show that the SDC-coated BCFN membrane exhibits a remarkably higher oxygen permeation flux（JO2） than the uncoated BCFN in the partial oxidation of coke oven gas（COG）. The maximum JO2 value of the SDC-coated BCFN is 18.28 mL ·min^-1·cm^-2 under a COG/air flux of 177 mL ·min^-1/353 mL ·min^-1 at 875℃ when the thickness of the BCFN membrane is 1 mm; this JO2 value is 23% higher than that of the uncoated BCFN membrane. This enhancement is likely because of the higher oxygen ionic conductivity of SDC, which supplies oxygen vacancies and accelerates oxygen exchange on the membrane/coating layer/gas three-phase boundary.展开更多
基金supported by the National Key R&D Program of China(2022YFB3804100)the National Natural Science Foun-dation of China(52231005)+3 种基金the Natural Science Foundation of Jiangsu Province(BK20221474)the Laboratory of Advanced Metallic Materials,Southeast University(AMM2025A01,AMM2024A02,and AMM2023B05)the Science Technology Development Program of Yixing(C2024002)the Center for Fundamental and Interdisciplinary Sciences of Southeast University for the support in magnetic domain measurement。
文摘Tensile stress annealing(TSA)is an effective strategy for tailoring magnetic anisotropy and high-frequency performance in nanocrystalline soft magnetic alloys.Here,we systematically investigate the influence of TSA on the microstructure,magnetic domain evolution,and permeability stability of Fe_(69.5)Co_(3)Nb_(2)Mo_(1.5)Si_(14)B_(9)Cu_(1)nanocrystalline alloys.Across all applied stresses(0-300 MPa),the alloys retain an ultrafine grain size(≤11 nm),yet the induced uniaxial anisotropy constant(K_(u))rises sharply from 22.5 to 665 J/m^(3).This increase in K u refines the magnetic domain structure,reducing average domain width from 110 to 36μm,and shifts the magnetization mechanism from domain-wall displacement to rotation-dominated reversal.Quantitative correlation between K u,domain structure,and effective permeability(μ_(e))reveals that higher stress suppressesμ_(e)at low frequencies but yields exceptional frequency stability:μ_(e)≈2330 is maintained up to 1 MHz at 50 MPa,andμ_(e)≈585 remains constant from1 kHz to 10 MHz at 300 MPa.These findings demonstrate thatstress-induced anisotropy is a decisive factor in governinghigh-frequency magnetic response,offering both mechanisticinsight and a practical framework for designing next-generation soft magnetic materials for precision current transformers,EMC filters,and MHz-class power electronics.
基金financially supported by the National Natural Science Foundation of China (Nos. 51472156, 51072112, and 51311130110)the Innovation Foundation of Shanghai University (No. sdcx2012033)the Training Funding Project for Young College Teachers of Shanghai
文摘Fluorite Ce0.8Sm0.2O2-δ（SDC） nanopowder with a crystallite size of 15 nm was synthesized by a co-precipitation method. An SDC porous layer was coated onto a BaCo0.7Fe0.2Nb0.1O3-δ（BCFN） mixed conductor to improve its oxygen transport behavior. The results show that the SDC-coated BCFN membrane exhibits a remarkably higher oxygen permeation flux（JO2） than the uncoated BCFN in the partial oxidation of coke oven gas（COG）. The maximum JO2 value of the SDC-coated BCFN is 18.28 mL ·min^-1·cm^-2 under a COG/air flux of 177 mL ·min^-1/353 mL ·min^-1 at 875℃ when the thickness of the BCFN membrane is 1 mm; this JO2 value is 23% higher than that of the uncoated BCFN membrane. This enhancement is likely because of the higher oxygen ionic conductivity of SDC, which supplies oxygen vacancies and accelerates oxygen exchange on the membrane/coating layer/gas three-phase boundary.
