V部分替代Nb对含Co FINEMET型合金磁性的影响

研究了含Co的Finemet型（Fe.．5Co0．5）73．5Nb3Si13．5B9Cu1和（Fe0.5Co0．5）73．5Nb2V1Si13．5B9Cu1合金在不同温度纳米晶化后的磁性．结果表明,用V部分替代Nb对淬态（Fe0.5Co0．5）73．5Nb2V1Si13.5B9Cu1非晶合金的居里温度没有明显的影响,但是形成（Fe0．5Co0．5）7a．5Nb2V1Si13．589Cu1纳米晶合金使剩余非晶中Co的含量降低,导致初始磁导率在高温下快速衰减;用V部分替代Nb使（Fe0．5Co0.5）73．5Nb2ViSi13．5B9Cu1纳米晶合金中的晶体相含有更多的Co,增大了材料的饱和磁感应强度B8并显著提高了初始磁导率．     

Fe基非晶和纳米晶合金的热膨胀

将非晶Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９和Ｆｅ９１Ｚｒ７Ｂ２合金经退火制成纳米晶合金，测量了淬火态和退火态样品的热膨胀曲线，研究了退火温度对热膨胀的影响，结果表明，纳米晶粒的形成导致居里温度Ｔｃ以下的热膨胀系数急剧增加，而Ｔｃ以上的热膨胀系数几乎不随退火温度变化。     

Corrosion behaviors of amorphous and nanocrystalline Fe-based alloys in NaCl solution

Amorphous Fe(73.5)Si(13.5)B9Nb3Cu1 alloy was prepared by the chill block melt-spinning process and nanocrystalline Fe(73.5)Si(13.5)B9Nb3Cu1 alloy was obtained by annealing. The crystallization behaviors were analysed by DSC, XRD and TEM. The electrochemical corrosion behaviors in different annealed states were performed by linear polarization method and electrochemical impedance spectroscopy in 3.5% NaCl solution. The results show that the crystallization of amorphous alloy occurs in the two steps. Some nanometer crystals appear when annealing in 550 degrees C and 600 degrees C, respectively with grain size 13 nm and 15 nm. The nanocrystalline alloy has a tendency to passivation and lower anodic current density than amorphous alloy. It indicates that nanocrystalline alloy has a higher corrosion resistance. Amorphous Fe(73.5)Si(13.5)B9Nb3Cu1 alloy consisted of only single semi-circle. When the alloy was annealed in 600 degrees C, its EIS consisted of two time constants, i.e., high frequency and low frequency capacitive loops. The charge transfer reaction resistances increases as annealing temperature rises.     

Cu和Nb对非晶态Fe—Si—B合金等温晶化过程的影响

采用示差扫描量热卡计（ＤＳＣＩ）得到了非晶态Ｆｅ－Ｓｉ－Ｂ合金加入Ｃｕ和Ｎｂ后的等温晶化放热曲线，结合Ｘ射线衍射（ＸＲＤ）分析，明确了Ｃｕ和Ｎｂ在形成纳米α－Ｆｅ（Ｓｉ）晶体相时的作用。此外，非晶态Ｆｅ７６．５Ｓｉ１３．５Ｂ９Ｃｕ１Ｎｂ３等温化的α－Ｆｅ（Ｓｉ）放热峰呈明显的非对称形状。     

Ordering of the α-Fe(Si) Crystallization Phase in Annealed Fe_(73.5)Cu_1Mo_3Si_(13.5)B_9 Alloy

The ordering of the α-Fe(Si) crystallization phase in annealed Fe73.5Cu1Mo3Si13.5B9 alloy has been studied using XRD method. The α-Fe(Si) phase in Fe73.5Cu1Mo3Si13.5B9 alloy annealed at 460℃ for 1 h consists of the DO3-type ordered region with spherical shape and disordered region. The size of DO3 ordered region increases with the annealing temperature. When the annealing temperature is 560℃, the size of the ordered region in the α-Fe(Si) grain is 14.0nm,which is nearly as large as that of the α-Fe(Si) grain (14.2 nm) and the degree of order of the α-Fe(Si) phase is about 0.78. When Fe73.5Cu1 Mo3Si13.5B9 amorphous alloy is annealed at 520℃, with the increment of the annealing time, the shape of the DO3 ordered region in the α-Fe(Si) phase is spheroidal at the beginning of the annealing and becomes spherical and has asize of 12.8 nm when the annealing time is 60 min. In addition, the DO3 superlattice lines of the α-Fe(Si) phase will vanish if Fe73.5Cu1Mo3Si13.5 B9 amorphous alloy is annealed for 1 h at 750℃.     

稀土La改性铁基非晶带材组织结构与软磁性能研究

主要研究掺杂了不同含量稀土La后的铁基非晶带材Fe73.5Cu1Nb3Si13.5B9非晶带材组织结构与软磁性能.结果表明,随着稀土La掺杂含量的增加,Fe73.5Cu1Nb3Si13.5B9非晶带材的Fe-Si相的析出温度下降,而Fe-B相的析出温度则升高,一方面,非晶的热稳定性下降,另一方面,有利于控制Fe73.5...     

电脉冲快速退火Fe73.5Cu1Mo3Si13.5B9合金的组织与磁性能

采用电脉冲快速退火实现了非晶合金Ｆｅ７３．５Ｃｕ１Ｍｏ３Ｓｉ１３．５的纳米晶化。显微组织分析与磁性能测定结果表明,该合金经适当工艺的脉冲电流处理可得到较常规法晶粒密度更高、晶粒尺寸更小、软磁性能更优的纳米晶材料。基于随机无规磁各向异性模型,阐明了该合金的软磁性能与其显微结构的关系。     

电脉冲快速退火Fe_(73.5)Cu_1Mo_3Si_(13.5)B_9合金的组织与磁性能

采用电脉冲快速退火实现了非晶合金Ｆｅ７３．５Ｃｕ１Ｍｏ３Ｓｉ１３．５Ｂ９的纳米晶化。显微组织分析与磁性能测定结果表明,该合金经适当工艺的脉冲电流处理可得到较常规法晶粒密度更高、晶粒尺寸更小、软磁性能更优的纳米晶材料。基于随机无规磁各向异性模型,阐明了该合金的软磁性能与其显微结构的关系     

Nb和Si元素对提高纳米晶带材抗氧化能力研究

采用SEM和XRD等手段分析了Fe82Cu1B12Si4 Nb1与Fe73.5 Cu1 B7 Si15.5 Nb3纳米晶合金带材在空气中灼烧后的晶化产物和氧化产物;通过降低Nb和Si元素含量,提高Fe和B元素的含量,虽然使Fe82Cu1 B12 Si4 Nb1纳米晶合金具有高饱和磁感应强度和低的矫顽力,但却降低了它的非晶形成和抗氧化能力。根据K.Hono等采用原子探针法观察到的在晶化过程中各元素分布情况,提出了一个晶化过程模型,通过模型分析了纳米晶合金的抗氧化能力的原因;随着晶化过程推进,残余非晶相中Nb元素含量增加,使得残余非晶相区的晶化温度提高,同时发挥限制晶体长大的作用。     

Microstructure and Stability of Fe73.5Cu1Nb3Si13.5B9 Alloy at Different Stages of Phase Transformation

1. IntroductionStability of magnetic materials is very importals for application. It has been known that themagnetic stability and structural stability are closelyconnected. An effectual method for studying thendcrostructure instability is to measure magneticaftereffect (MAE)l'~']. There is a difference inthe MAE between the amorphous and the crystalline ferromagnetic materials, revealing distinctionof their microstructure. In this work, the MAE andthe microstructure were studied at differ…     

Si含量对纳米晶Fe_(87-x)Cu_1Nb_3Si_xB_9合金磁性能的影响

研究了Si含量对Fe87-xCu1Nb3SixB9合金经不同方式退火后磁性能的影响。结果表明:随Si含量的增加,Fe87-xCu1Nb3SixB9合金经普通退火后软磁性能逐渐得到优化;经磁退火后可感生出单轴磁各向异性,且磁退火特征随Si含量的增加而逐渐明显。根据横磁退火实验结果计算出的感生磁各向异性值Ku,则由26.7J/m3(Si=9.5at%)降低至14.1J/m3(Si=13.5at%)。由实验数据的分析认为Fe87-xCu1Nb3SixB9合金在高Si含量时经普通退火或纵磁退火后呈现优异的软磁特性,归因于析出的α-Fe(Si)相晶粒具有小的磁晶各向异性K1,从而导致合金具有更低的有效磁各向异性常数K所至。     

Influence of Magnetic Field Intensity on the Shape of the μ—T Curves for Fe73.5Cu1Nb3Si13.5B9 Alloy

Under different magnetic field intensities,the dependence of the permeability μon temperature T(μ-T curve) for the Fe73.5Cu1Nb3Si13.5B9 alloy annealed at 350-620℃ was investigated.The results showed that the magnetic field intensity had a remarkable influence on the shape of μ-T curves.For amorphous alloy,the sharp Hopkinson peak of μ-T curve disappeared gradually with the increase of magnetic field intensity.     

Giant Stress—impedance Effect in Amorphous and Current Annealed Fe73.5Cu1Nb3Si13.5B9 Ribbons

The giant stress-impedance(GSl) effect in amorphous and current annealed Fe73.5Cu1Nb3Si13.5B9 ribbons has been investigated .The results showed that the GSl effect changed drastically with annealing techniques and the maximum stress impedance ratio of 350% was obtained after optimal conditions of current annealing .The behaviors of the stress impedance vary with densities of annealing current and the stress longitudinally applied during current annealing.The maximum change of stress impedance existed in the sample annealed by high-current-density electropulsing under applied stress of 100MPa.     

不同退火温度下铁基薄带介观结构的AFM研究

用原子力显微镜(AFM)观测了铁基合金(Fe73.5Cu1Nb3Si13.5B9)薄带断口的介观结构.通过对310℃退火样品的观测,可以发现薄带的贴辊面区(SRFA)和自由面区(FFA)存在着非常明显的结构差异;而540℃退火样品的AFM观测结果则显示这种差异并不明显.将310℃和540℃退火的样品在HF酸溶液中进行腐蚀,获得不同腐蚀深度的腐蚀表面,再用AFM观测其表面形貌,则发现:在310℃退火样品的腐蚀表面,自由面和贴辊面形貌各自随腐蚀深度的变化而变化,并且两表面形貌之间在腐蚀前期有差异,但后期无明显不同;而540℃退火样品的两个腐蚀表面,则不存在这样的变化和差异.该观测结果与薄带断口观测到的介观结构相符合.造成这种结构差异的原因是经不同温度退火后,薄带内部残留的内应力不同.     

Co-Finemet非晶合金晶化动力学及其纳米晶粉芯的磁性

利用单辊熔体快淬法在大气环境中制备了Fe73.5-xCoxSi13.5B9Cu1Nb3(x=10,30,50)非晶薄带,利用差示扫描量热法(DSC)研究了非晶薄带的晶化动力学行为。采用Kissinger和Ozawa方法计算了非晶薄带的晶化表观激活能,计算结果表明:随着Co含量的增加,一次晶化的表观激活能降低而二次晶化的表观激活能升高。利用Johnson-Mehl-Avrami(JMA)模型计算了非晶薄带一次晶化的局域Avrami指数m,计算结果表明非晶薄带一次晶化的机理在不同的晶化阶段是不一样的,晶化初期为扩散控制的三维形核和晶粒生长的整体晶化,晶化中后期为一维形核和晶粒生长的表面晶化,形核率近似为零。研究了Fe63.5Co10Si13.5B9Cu1Nb3纳米晶粉芯的磁性与球磨时间之间的关系,结果表明:纳米晶粉芯的有效磁导率表现出较好的频率稳定性,而且随着球磨时间的增加而减小,品质因子在低频范围内随着频率的增加而增加,在约80 kHz达到峰值,然后随着频率的进一步增加而逐渐减小。     

Structure and Magnetic Properties of Fe_(76.5)Si_(13.5)B_9Cu_1 Alloy with Nanoscale Grain Size

The structure and magnetic properties of Fe76.5Si13.5B9Cu1 alloys with a nanocrystalline (NC) bcc Fe(Si) phase trom about 23 to 46 nm in diameter, which were first formed into amorphous ribbons and then annealed at various temperatures between 703 and 773 K, have been investigated. At annealing temperatures from 703 to 748 K, the single NC bcc(Si) phase is obtained in the crystallized alloys. The grain size and the Si-content in the NC bcc Fe(Si) phase for the alloys annealed at different temperatures are presented. The soft magnetic properties and the saturation magnetostriction for the alloys with the NC bcc Fe(Si) phase are also measured. The results show that, the saturation magnetizotion and the permeability are improved for the alloys with only the NC bcc Fe(Si) phase and become better with decreasing of the NC bcc phase size, and the saturation magnetostriction declines for the alloys with increasing Si-content in the NC bcc Fe(Si) phase.     

Nanocrystallization in Fe73.5Si13.5B9Cu1Nb1X2 (X = Nb,Mo and V) alloys studied by X-ray synchrotron radiation

The influence of partial substitution of Nb by refractory elements (Mo and V) on the nanocrystallization process of a FeSiB-CuNb alloy was studied by in situ X-ray diffraction, using a synchrotron radiation source. The crystalline volume fraction, the mean grain size of the crystallites and the nanophase Si content were estimated to describe the microstructural evolution and the kinetics of the process. For the studied alloys, the volume fraction of the Fe,Si nanophase after annealing at the same condition increases in the order Nb < Mo < V. The mean grain size of the Fe,Si nanocrystals also increases in the sequence Nb < Mo < V. Transformation kinetics is described in terms of Johnson-Mehl-Avrami kinetics (JMA) and the obtained values for the overall Avrami exponent are slightly below 1, as usually found for Finemet alloys.     

Hopkinson Effect in Soft Magnetic Materials

1. IntroductionIt is well known that the initial permeability ofmany ferromagnetic materials increases with increasing temperature and appears a sharp peak just before the Curie point, and then drops off to a verysmall value. The peak is called the Hopkinson peakand the phenomenon is normally called the Hopkinson effectll]. Since this effect is valid for all the ferromagnetic materials, it has been used as a methodto measure the Curie temperature. However, in ourresearch work of nanocrystall…     

退火工艺对铁基非晶薄带磁感应效应的影响

研究了频率、磁场强度以及退火工艺对Fe73.5Cu1Nb3Si13.5B9非晶薄带磁感应效应变化幅度的影响.研究结果表明:磁感应效应变化幅度随着磁场强度的增大而增大,随着频率的升高呈现先增大后减小的趋势;与淬火态非晶薄带相比,退火可以提高磁感应效应变化幅度,且经300℃×1h退火后的磁感应效应变化幅度最大.     

Crystallization of amorphous Fe73.5Si13.5B9Nb3Cu1

A study is reported on the devitrification behaviour of the amorphous alloy Fe73.5Si13.5B9Nb3Cu1. Samples of the studied glass underwent isothermal and non-isothermal heat treatments in a thermal analysis apparatus. In addition some samples were very rapidly heated to very high temperatures by means of a laser beam. In this way a large temperature range was explored and information was obtained on the overall thermal evolution of the studied amorphous alloy. The experimental results suggest that, as recently proposed in the literature, nanocrystallization can be linked to a rate limiting Nb diffusion stage in the crystal growth process. However topological short range ordering (TSRO) and chemical short range ordering (CSRO) also affect the devitrification behaviour. In the case of the studied alloy, three temperature ranges can be defined. At low temperature only TSRO occurs. Above a temperature that lies approximately in the range 450–500°C, glass in glass phase separation occurs up to a temperature that lies approximately in the range 700–750°C, above which it appears to be very limited. The occurrence of glass in glass phase separation appears to be necessary to obtain a fine microstructure, because Nb concentrates in the boron depleted, iron rich glassy phase. The occurrence of TSRO prior to demixing should be avoided if nanocrystallization is desired. All this appears to be satisfied by isothermally treating the sample at a temperature of 555°C. This revised version was published online in November 2006 with corrections to the Cover Date.