共查询到18条相似文献,搜索用时 187 毫秒
1.
根据用原子力显微镜对Fe基纳米晶Fe73.5Cu1Nb3Si13.5B9合金薄带的介观结构和巨磁阻抗效应的实验研究结果,提出了纳米晶软磁合金巨磁阻抗效应受其介观结构影响的理论模型.该模型成功地解释了低频对纳米晶软磁合金巨磁阻抗效应的影响,反映了现有“三明治”理论的主要特征,并弥补了它的不足;同时指出了纳米晶粒电导率σ、磁导率μ对合金巨磁阻抗效应有影响.
关键词:
铁基纳米晶合金
介观结构
巨磁阻抗效应
介观模型 相似文献
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从非晶态合金的晶化出发,介绍了最近发展起来的新型优质软磁材料──纳米晶软磁合金.其中包含:(1)非晶态合金的晶化概念以及微晶析出对非晶态合金磁性的影响;(2)纳米晶软磁材料的发现及其具有的优良的综合磁性能;(3)分析了该合金优良磁性能的来源,介绍了目前理论上的解释.最后展望了该合金的发展趋势. 相似文献
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根据实验研究成果提出纳米晶合金软磁性能受其介观结构影响的观点,建立了Fe基纳米晶合金的球状介观结构模型,分别求出只有交变磁场或交变磁场和静磁场作用时纳米晶粒球的频率函数——D函数.分析表明,两种D函数都是复变函数,其实部Re(D)为纳米晶电感性质和电容性质的反映,虚部Im(D)为纳米晶电阻性质的反映,据此建立了Fe基纳米晶合金介观结构的等效RLC并联模型.由该模型求得合金产生极值巨磁电阻的条件为vextGMI=v|Re(D)=0,决定因素有μ,σ,ω,R和Hex及微观磁结构.
关键词:
Fe基纳米晶合金
等效RLC并联模型
球状介观结构模型
频率函数 相似文献
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根据用原子力显微镜对在不同温度下晶化的Fe基非晶合金薄带三维介观结构的观察,结合X射线衍射、Mssbauer谱等前人已有的实验结果并在目前已有的理论研究基础上,对Fe基非晶合金薄带在不同温度下的晶化过程进行了系统的分析、研究,提出了两种Nb-B框架介观结构、团聚相和单位体积纳米晶粒平均数等新概念,建立了Fe基纳米晶合金的晶化机理假说,提出了描述Fe基非晶合金晶化过程的介观织构模型.这个模型能够演化成二相结构模型和三相互套结构模型,还可以合理地解释现有的实验结果以及500—600℃退火中Fe基纳米晶巨磁阻
关键词:
Fe基纳米晶合金
晶化机理
两种Nb-B框架介观结构
团聚相 相似文献
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超微晶软磁合金的磁性和结构 总被引:6,自引:0,他引:6
简要介绍了新型超微晶软磁合金Finemet的发展现状及应用,介绍了蜚 晶态合金的晶化概念以及微昌析出对非晶态合金磁性的影响,分析了Finemet的性能和结构的关系,并探索了Finemet优异软磁特性的根源。 相似文献
10.
对纳米晶Fe73.5Cu1Mo3Si13.5B9合金的原始制备态和各退火态样品进行了室温Mossbauer谱研究,结果表明晶化态的合金存在α-Fe(Si)微晶相和晶界的非晶相。晶相和非晶相内场和面积随退火温度的变化是退火时Cu,Mo,B等成分的扩散和在各相中的再分配引起的。最佳磁性能对应非晶相中的铁量占合金铁总量的30%左右,超微晶合金的双相无规各向异性模型表明,一定量的非晶相对保持纳米晶优异的软
关键词: 相似文献
11.
在CO2激光功率为50—300W、扫描速度为20mm/s、激光散光斑为20mm照射条件下 ,诱导非 晶Fe735Cu1Nb3Si135B9带中发生结构重组,产生定量纳米α-F e(Si)晶相形成双相组织结构材料. 利用穆斯堡尔谱研究了非晶Fe735C u1Nb3Si135B9合金激光纳米化的 超精细结构. 实验结果表明,激光诱导非晶 Fe735Cu1Nb3Si135B 9纳米化后,其超精细磁场的分布随 着激光功率变 化由单峰向双峰变化,在高功率辐照时, 出现了双峰分布,并且峰位向高场移动. 高激光 功率辐照非晶Fe735Cu1Nb3Si135 sub>B9合金纳米晶化相有四种超精细结 构,即2个超精细磁场较小的初晶相和2个超精细磁场较大的纳米晶化相. 其中超精细磁场较 大(17—25MA/m)的α-Fe(Si)相为DO3结构.
关键词:
激光
纳米晶α-Fe(Si)
735Cu1Nb< sub>3Si135B9')" href="#">非晶Fe735Cu1Nb< sub>3Si135B9
超精细结构
超精细磁场 相似文献
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在激光功率为40—160W、扫描速度为10mm/s、激光光斑为20mm照射条件下,用CO 2激 光辐照非晶Fe73.5Cu1Nb3Si13.5B9< /sub>产生微量晶化.利用透射穆斯堡尔谱 (TMS)技术分析了原始态和晶化后样品的超精细结构.确定了穆斯堡尔谱的基本参数——化 学位移(IS)、四极分裂(QS)、内磁场(Hhf)随激光功率变化的规律.分析表明,CO2关键词:
激光辐照
微量晶化
73.5Cu1Nb3 Si13.5B9')" href="#">非晶Fe73.5Cu1Nb3 Si13.5B9
穆斯堡尔谱 相似文献
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The influence of nanocrystallization conditions on the structure, magnetic properties, and temperature stability of nanocrystalline magnetically soft Fe73.5Cu1Nb1.5Mo1.5Si13.5B9 alloy is studied. It is found that preliminary low-temperature annealing exerts an influence on subsequent nanocrystallization of the alloy. In addition, preannealing followed by nanocrystallization considerably improves the magnetic properties of the alloy. It is shown that the magnetic properties of the material can be controlled by varying the frequency of a magnetic field used for thermal treatment causing nanocrystallization. It is established that the magnetic properties of nanocrystalline Fe73.5Cu1Nb1.5Mo1.5Si13.5B9 alloy offer a high temperature stability. 相似文献
15.
Anh-Tuan Le Chong-Oh Kim Nguyen Chau Nguyen Duy Cuong Nguyen Duc Tho Nguyen Quang Hoa Heebok Lee 《Journal of magnetism and magnetic materials》2006
In this paper, the effect of microstructural and surface morphological developments on the soft magnetic properties and giant magneto-impedance (GMI) effect of Fe73.5−xCrxSi13.5B9Nb3Au1 (x=1, 2, 3, 4, 5) alloys was investigated. It was found that the Cr addition causes slight decrease in the mean grain size of α-Fe(Si) grains. AFM results indicated a large variation of surface morphology of density and size of protrusions along the ribbon plane due to structural changes caused by thermal treatments with increasing Cr content. Ultrasoft magnetic properties such as the increase of magnetic permeability and the decrease of coercivity were observed in the samples annealed at 540 °C for 30 min. Accordingly, the GMI effect was also observed in the annealed samples. 相似文献
16.
Monica Sorescu Tianhong XuSteven Herchko 《Journal of magnetism and magnetic materials》2011,323(22):2859-2865
Differential scanning calorimetry, X-ray diffraction and room temperature Mössbauer spectrum measurements of Fe73.5Cu1Nb3Si13.5B9 (Finemet) alloy have been carried out in order to study its structural and magnetic properties as a function of annealing temperature. The DSC profile of as-quenched Finemet showed two exothermic peaks at 530 and 702 °C, corresponding to two crystallization processes. The Finemet alloy remains amorphous at 450 °C with one broad peak in XRD pattern and one broad sextet in Mössbauer spectrum. When the Finemet alloy was annealed at 550 °C, only well indexed body-center-cubic phase was detected. After being annealed at 650 and 750 °C, the XRD patterns showed the coexistence of α-Fe(Si) and Fe-B intermetallic phases with the increase in XRD peak intensities, indicating the growth of crystallites and the decomposition of Fe73.5Cu1Nb3Si13.5B9 alloy at elevated temperatures. The Mössbauer spectra of annealed Finemet alloy could be fitted with 4 or 5 sextets and one doublet at higher annealing temperatures, revealing the appearance of different crystalline phases corresponding to the different Fe sites above the crystallization temperature. The appearance of the nanocrystalline phases at different annealing temperatures was further confirmed by the recoilless fraction measurements. 相似文献
17.
The magnetic and the transport properties of the Fe73.5Si13.5B8CuNb2VAl nanocrystalline ribbon have been presented. The coercive field was found to increase from 0.24 to 1 Oe on lowering the temperature from 300 to 5 K. The irreversibility in the FC-ZFC was observed and the magnetization was found to follow T3/2 law. Magnetoresistance measurements were done along the length of the ribbon and the MR of −0.07% was observed at 300 K. Cluster glass behavior was predicted by the power law. 相似文献