The best linear fit of Hc(T)/Ms(T) vs 2k1(T)/0Ms2(T) infers that Hc is determined by a nucleation process in nanocrystalline twophase magnet. The condition of the grain shapes is improved after adding Hf and Ga, but t...The best linear fit of Hc(T)/Ms(T) vs 2k1(T)/0Ms2(T) infers that Hc is determined by a nucleation process in nanocrystalline twophase magnet. The condition of the grain shapes is improved after adding Hf and Ga, but the surfaces are deteriorated by some precipitates on the boundary. Taking into account the values of , Neff, the results of TEM, and Moessbauer spectroscopy, the magnetic field heattreatment not only induces grain refinement but also causes a uniform distribution of the soft and hard phases. It is one recommendable method to improve the condition of the microstructure. Both the remanence and energy product values are increased by 20 %-30 % for all ribbons after annealing with magnetic field. The magnetic interaction in Nd2Fe14B/Fe3B+Fe based nanocrystalline twophase magnets is studied using M plots in this paper. It is found that the exchangecoupled interaction is greatly enhanced in the sample annealed with magnetic heattreatment, specially, Nd4Fe76Co3Hf0.5Ga0.5B16 which achieves the highest energy product (BH)max=126.4 kJ/m3.展开更多
研究了不同磁场强度热处理工艺对铁基纳米晶合金带材磁性能的影响。结果表明:铁基纳米晶合金带材的综合磁性能优劣受热处理磁场强度的影响很大。磁场强度为100 m T热处理后的铁基纳米晶合金磁芯矫顽力Hc、剩余磁感应强度Br和动态磁滞损...研究了不同磁场强度热处理工艺对铁基纳米晶合金带材磁性能的影响。结果表明:铁基纳米晶合金带材的综合磁性能优劣受热处理磁场强度的影响很大。磁场强度为100 m T热处理后的铁基纳米晶合金磁芯矫顽力Hc、剩余磁感应强度Br和动态磁滞损耗Ps同时达到最小值,分别为0.45 A/m、0.12 T、9.60 W/kg;并且在3MHz的高频条件下仍保持有3μH的较高电感量;在保证较高磁导率的同时,合金获得具有低损耗、低剩磁、低矫顽力,即具有良好的高频磁性能。展开更多
Fe基纳米晶软磁合金自1988年被发现以来,因其低矫顽力、高磁导率、低铁损、低磁致伸缩系数等优异特性,尤其是高频下突出的软磁性能一直受到广泛的关注;其中,Finemet合金已作为高频变压器等设备的铁心材料在工业生产中得到了应用。近年来...Fe基纳米晶软磁合金自1988年被发现以来,因其低矫顽力、高磁导率、低铁损、低磁致伸缩系数等优异特性,尤其是高频下突出的软磁性能一直受到广泛的关注;其中,Finemet合金已作为高频变压器等设备的铁心材料在工业生产中得到了应用。近年来,一系列高饱和磁感应强度的新型纳米晶软磁合金的研发,将进一步促进电子、电力设备的小型化和节能化。Fe基纳米晶软磁合金通常是由其前驱体非晶带材经退火处理结晶化制备获得。在热处理过程中带材会产生脆性,这不仅增加了铁心加工成形的难度,也使得铁心在实际工况下易失效,严重制约了其在工业生产中的广泛应用。因此,材料工作者对其退火脆性问题展开了研究,并取得了一系列成果。Fe基纳米晶软磁合金的退火脆化产生可分为两个阶段,即非晶前驱体在低于初始结晶化温度下退火导致结构弛豫引起的韧-脆性转变,以及结晶化后由α-Fe相析出引起的合金脆性增加。目前,评价带材的韧-脆性主要采用相对断裂应变(Relative strain at fracture,εf)和临界应力强度因子(KQ)这两个参量。虽然εf值的离散性较大,但由于测定方法简便且能够定量地反映合金的脆化程度而被广泛应用于带材退火脆性的研究。通常合金的退火脆性随α-Fe相体积分数的增加而增大,而细化α-Fe晶粒则有利于抑制合金的退火脆性倾向。当合金中α-Fe相体积分数在70%以下时,合金的硬度随α-Fe相体积分数的增加呈线性增长,此时硬度也可以间接地反映合金脆化的程度。添加合金元素、优化热处理工艺以及采用新型热处理方法等均可以细化纳米晶合金的组织结构,从而在一定程度上抑制其退火脆性倾向。本文综述了近年来有关Fe基纳米晶软磁合金的退火脆化机制、韧-脆性评价方法,分析了合金成分、热处理工艺、组织结构、退火脆性间的关系,总结了抑制退火脆性的途径等方面的研究进展,并对存在的问题和今后的研究方向进行了探讨。展开更多
文摘The best linear fit of Hc(T)/Ms(T) vs 2k1(T)/0Ms2(T) infers that Hc is determined by a nucleation process in nanocrystalline twophase magnet. The condition of the grain shapes is improved after adding Hf and Ga, but the surfaces are deteriorated by some precipitates on the boundary. Taking into account the values of , Neff, the results of TEM, and Moessbauer spectroscopy, the magnetic field heattreatment not only induces grain refinement but also causes a uniform distribution of the soft and hard phases. It is one recommendable method to improve the condition of the microstructure. Both the remanence and energy product values are increased by 20 %-30 % for all ribbons after annealing with magnetic field. The magnetic interaction in Nd2Fe14B/Fe3B+Fe based nanocrystalline twophase magnets is studied using M plots in this paper. It is found that the exchangecoupled interaction is greatly enhanced in the sample annealed with magnetic heattreatment, specially, Nd4Fe76Co3Hf0.5Ga0.5B16 which achieves the highest energy product (BH)max=126.4 kJ/m3.
文摘Fe基纳米晶软磁合金自1988年被发现以来,因其低矫顽力、高磁导率、低铁损、低磁致伸缩系数等优异特性,尤其是高频下突出的软磁性能一直受到广泛的关注;其中,Finemet合金已作为高频变压器等设备的铁心材料在工业生产中得到了应用。近年来,一系列高饱和磁感应强度的新型纳米晶软磁合金的研发,将进一步促进电子、电力设备的小型化和节能化。Fe基纳米晶软磁合金通常是由其前驱体非晶带材经退火处理结晶化制备获得。在热处理过程中带材会产生脆性,这不仅增加了铁心加工成形的难度,也使得铁心在实际工况下易失效,严重制约了其在工业生产中的广泛应用。因此,材料工作者对其退火脆性问题展开了研究,并取得了一系列成果。Fe基纳米晶软磁合金的退火脆化产生可分为两个阶段,即非晶前驱体在低于初始结晶化温度下退火导致结构弛豫引起的韧-脆性转变,以及结晶化后由α-Fe相析出引起的合金脆性增加。目前,评价带材的韧-脆性主要采用相对断裂应变(Relative strain at fracture,εf)和临界应力强度因子(KQ)这两个参量。虽然εf值的离散性较大,但由于测定方法简便且能够定量地反映合金的脆化程度而被广泛应用于带材退火脆性的研究。通常合金的退火脆性随α-Fe相体积分数的增加而增大,而细化α-Fe晶粒则有利于抑制合金的退火脆性倾向。当合金中α-Fe相体积分数在70%以下时,合金的硬度随α-Fe相体积分数的增加呈线性增长,此时硬度也可以间接地反映合金脆化的程度。添加合金元素、优化热处理工艺以及采用新型热处理方法等均可以细化纳米晶合金的组织结构,从而在一定程度上抑制其退火脆性倾向。本文综述了近年来有关Fe基纳米晶软磁合金的退火脆化机制、韧-脆性评价方法,分析了合金成分、热处理工艺、组织结构、退火脆性间的关系,总结了抑制退火脆性的途径等方面的研究进展,并对存在的问题和今后的研究方向进行了探讨。
