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。     

几种新型铁基纳米晶软磁合金的磁性能

用较便宜的元素Mo、W、V和Cr部分或全部代替较昂贵的Nb,我们发展了一些新的铁基纳米晶软磁合金,它们仍象Fe-Cu-Nb-Si-B纳米晶合金那样具有优良的综合软磁性能。本文扼要地报道新开发的5种铁基纳米晶合金的直流和交流磁性能,并与已报道的Fe-Cu-Nb-Si-B合金和功率Mn-Zn铁氧体H_(74)的性能做了比较。特别是新发展的Fe-Cu-Cr-V-Si-B合金的高频铁损已达到P_(2/100k)=171kW/m~3,P_(2/100k)=395kW/m~3和P_(2/200k)=579kW/m~3的水平,这明显优于Fe-Cu-Nb-Si-B的水平。     

Investigation of Nanocrystalline Fe-Cu-Nb-Mo-Si-B Alloy

The soft magnetic properties are reported for newly-developed nanocrystalline Fe72.7Cu1Nb1.8-Mo2Si13B9.5 and Fe73Cu1Nb1.5Mo2Si13B9.5. The high frequency core losses of the new alloys are as follows: P3/100K=473 kW·m-3, P2/200K=750 kW·m-3, P2/500K=3400 kW·m-3,P0.5/1000K=680 kW·m-3, which are clearly lower than those of the early-developed Fe-Cu-Nb-Si-B nanocrystalline alloys and the superior power MnZn ferrite H7.4. The dependences ofcore loss on frequency and amplitude magnetic flux density have been analysed. The temperature relations of initial susceptibility have been examined for as-quenched and different annealedFe72.7Cu1Nb1.8Mo2Si13B9.5 alloy and interpreted by using the phenomenological theory.     

Magnetic Properties and Applications of Newly-developed Fe_(73.5)Cu_1Nb_(1.5)V_(1.5)Si_(13.5)B_9 Alloy

The synthetical soft magnetic properties including d.c. and a.c. magnetic properties and pulse magnetic property are reported for a newly-developed nanocrystalline Fe73.5Cu1 Nb1.5V1.5Si13.5B9 alloy The new alloy possesses high d.c. relative initial permeability of 12.5×104 and low coerciv ity of 0.54 A/m. Under the conditions of Bm=0.3 T, f=100 kHz and Bm=0.2 T, f=200 kHz the core losses of the new alloy are 543 kW·m-3 and 834 kW.m-3, respectively which can be compa rable with those of nanocrystalline Fe73.5Cu1Nb3Si13.5B9 alloy. The analyses of core losses have been carried out in the wider range of f=20～104 kHz and Bm=0.0025～0.8 T and the approxi mate expression P(kW·m-3)=1.803 B:f1.77 has been obtained. The analyses of core losses in the range of f=20～104 kHz and Bmf=(10～40)×103(T.Hz) have shown that the core loss and the corresponding amplitude permeability roughly vary as P = 2.347×10-6(Bmf)1.97f-0.2231 and μa = 9.56× 105f-0.7464, respectively for the given product B.f. Some practical applica tions have also been mentioned.     

Structures and Properties of Nanocrystalline Nd4.5Fe75Co1Si1B18.5Composite Magnets

1. IntroductionImprovement of hard magnetic properties, simplification of processing, and reduction of cost havebeen the principal motivating factors for much ofthe research on Nd-Fe-B permanent magnet materials since they were discovered. According to traditional Stoner-Wohlfarth model, the biggest Jr/Jsof hard magnetic materials with coarser microstructures is 0.sit]. When the grain size of Nd-Fe--B magnets is small enough, exchange coupled interactionwould be produced between soft and h…     

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…     

Influence of annealing on the crystallographic structure and some magnetic properties of the Fe73.5Cu1Nb3-xUxSi13.5B9 nanocrystalline alloys

The influence of annealing on the structure and some magnetic properties of Fe73.5Cu1Nb3-xUxSi13.5B9 (x=1, 2, 3) alloys has been studied. The results confirmed the nanocrystalline character of these alloys in the temperature range 550–650 °C. The influence of the uranium content on the structural stability has been observed for annealing treatment at high temperature, i.e. at about 700 °C. The coercive field strongly depended both on the annealing temperature and on the uranium content. A minimum value of Hc was observed after annealing at 550 °C. Core losses of all alloys in the nanocrystalline state decreased with increasing uranium content. © 1998 Kluwer Academic Publishers     

Relations among High-frequency Magnetic Properties and Frequency in Nanocrystalline Fe72.5Cu1Nb2V2Si13.5B9 Alloy

1-IntroductionBypartlyreplacingNbbyVintheearly-deve-lopedtypicalnanocrystallineFe73.5Cu1Nb3Sil3.5B9alloyll],anewnanocrystallineFe72.5Cu1Nb2V2Sil3.5B9alloyhavingsuperiorsoftmagneticpropertiescomparabletothoseofFe73.5Cu1Nb3Si13.5B9alloyhasbeensuccessfullydeveloped.Thecostofthenewalloyisreducedanditsamorphousribboncaneasilybepre-paredascomparedwithFe73.5Cu1Nb3Sil3.5B9alloy.ThenewaIloyhasbeenappliedinseveralaspects,suchastoroidalcoreinmaintransformerofswitch-ingmodepowersupplywithlargero…     

Magnetic Properties and Structure of Nanocrystalline Nd4.5Fe76Co1B18.5 Alloys

In this paper, the technology, structures and magnetic properties of Nd4.5Fe76Co1B18.5 nanocomposite magnets were investigated. The effect of crystallizing treatment temperature and time on structures and magnetic properties of Nd4.5Fe76Co1B18.5 amorphous ribbons was studied. The results show that Nd4.5Fe76Co1B18.5 containing more analogue metals is easy to form a morphous. The magnetic properties of 16 m/s quenched ribbon for 710 degrees Cx900 s crystallizing treatment reach H-i(c)=242.1 kA/m, B-r=0.9410 T and (BH)(max)=59.64 kJ/m(3). The even grain size is about D-Fe3B=34 nm and D-Nd2Fe14B=23 nm.     

宽过冷液相区铁基非晶合金的形成和磁性

用熔体急冷法制备出具有明显的玻璃转变和较宽的过冷液相区的Fe-Co-(Nb)-Zr-B非晶合金,研究了热稳定性和软磁性能。结果表明,在Fe-Co-Zr-B四元合金中添加适量的Nb可以显著扩大过冷液相区,提高合金的热稳定性。当冷却速率降低时,急冷合金具有非晶和纳米晶的复相结构。非晶合金的饱和磁化强度随Nb含量的增加而减小。不同Nb含量的非晶合金的饱和磁致伸缩系数均较低。在低于晶化温度的温度下退火可以有效地降低矫顽力,改善软磁性能。晶化导致软磁性能降低。     

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．     

纳米晶复合Nd9.5Fe81-xCoxZr3B6.5永磁材料磁性能的研究

采用熔体快淬及晶化退火工艺制备了Nd9.5Fe81-xCoxZr3B6.5(x=0、2、5、8、10)纳米晶合金条带,研究了Co的添加对快淬合金磁性能和居里温度的影响.结果表明,适量Co元素的添加能够有效降低各相晶粒的尺寸,增强了软、硬磁相晶粒的交换耦合作用,从而提高了合金的磁性能.Co含量为5%(原子分数)的合金,经670℃/4min的晶化处理后所得到的最佳磁性能为`Br=0.90T,jHc=588kA/m,(BH)max=117kJ/m3.     

Anisotropic Magnetoresistance Effect in Amorphous and Nanocrystalline Fe(Cu,Nb)-Si-B Alloys

1. IntroductionRecent works on the properties of Fe-basednanocrystalline alloys have generated considerable interest in the filed of materials because of their excellent soft magnetic characteristi.s[1'21. As a newlydeveloped material, the origin of the excellent softmagnetic characteristics was not clear yet. H..z.r[3]et al. have suggested that smaller magnetic crystallineanisotropy is one of the most important factors whichdominate the excellent soft magnetic characteristics,but the explanat…     

FeCuNbVSiB纳米晶软磁合金及其在电力电子技术领域中的应用

报道了新开发的Ｆｅ７３．２Ｃｕ０．８Ｎｂ２Ｖ１．５Ｓｉ１．５Ｂ１１纳米晶合金的主要磁性能：μ０≥８×１０＾４,ＢＳ＝１．４０Ｔ,Ｐ０．５／２０ｋ≤１９Ｗ／ｋｇ,Ｐ０．５／５０ｋ≤９０Ｗ／ｋｇ。以μ（ｋ）ｔ Ｐ０．５／２０ｋ为参数,研究了合金的温度稳定性。研究表明,与２５℃时全金性能相比,在－５０℃和＋５０℃时合金性能的相对变化率不超过５％。介绍了合金在中、高频功率变压器、传感器、电感器等电力电子技     

Co47.6Fe20.4B21.9Si5.1Nb5-xZrx(x=0~5)合金的非晶形成能力和磁性能

采用铜模吸铸法制备了直径d为2~5mm的Co_(47.6)Fe_(20.4)B_(21.9)Si_(5.1)Nb_(5-x)Zr_x(x=0~5)合金。利用X射线衍射(XRD)、差示扫描量热仪(DSC)、振动样品磁强计(VSM)和显微硬度计分析合金的非晶形成能力(GFA)、磁性能及显微硬度。结果表明:该合金体系具有较好的GFA,随着Zr含量的增加,其GFA呈逐渐降低的趋势。Zr含量为0~2%(原子分数)时,能制得d为3mm的非晶合金;Zr含量为0~3%(原子分数)时,可制得d为2mm的非晶合金。直径2mm的棒状非晶合金(Zr含量为0~3%(原子分数))表现为明显的软磁性,饱和磁化强度Ms趋于一定值。该体系非晶合金均具有很高的显微硬度,Zr含量为3%(原子分数)时达到1420HV。     

Co对Nd-Fe-Al大块非晶合金的晶化行为和磁性能的影响

采用示差扫描量热法(DSC)，X射线衍射(XRD)和振动样品磁强计(VSM)研究了Co对Nd—Fe-Al大块非晶合金的非晶形成能力，晶化行为和磁性能的影响。结果表明：加入Co元素后可以显著提高Nd—Fe-Al大块非晶合金的非晶形成能力以及提高合金的居里温度。Nd60Fe30-xAl10Cox(z=0、5、10)大块非晶合金在室温有较高的内禀矫顽力，具有硬磁性。内禀矫顽力随着Co含量的增加变化不大．但是饱和磁化强度和剩磁则随着Co含量的增加有所下降。Nd60Fe3-xAl10Cox(x=0、5、10)大块非晶合金具有的硬磁性能来自于非晶相。合金少量晶化后，磁性能变化不大。完全晶化后合金的硬磁性迅速消失。     

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.     

Laser additive processing of functionally-graded Fe–Si–B–Cu–Nb soft magnetic materials

Laser additive manufacturing is a novel tool for processing compositionally-graded alloys that are challenging to process via a conventional route. This article discusses a novel combinatorial approach for assessing composition–microstructure–magnetic property relationships, using laser deposited compositionally-graded Fe–Si–B–Nb–Cu alloys (by changing the silicon to boron ratios). The microstructure of Fe–Si–B–Nb–Cu alloys with a lower Si to B ratio consists of dendritic α-Fe₃Si grains, with B and Nb partitioning to the inter-dendritic regions, resulting in the formation of Fe₃B grains. As the Si/B ratio increases, the (Fe, Nb) enriched eutectic phase was observed along with α-Fe₃Si grains; and no Fe₃B was observed. These microstructural changes with varying Si/B ratios significantly affect the magnetic properties of these laser-deposited soft magnetic alloys.     

放电等离子烧结制备Nb-Si-Ti-Al-Hf-Cr合金的显微组织及力学性能

以预合金化的粉末尺寸D50为3.3μm的NbSS固溶体相细粉末,粉末尺寸D50分别为22.1μm和23.5μm的Nb5Si3和Cr2Nb化合物粉末为原料,采用放电等离子烧结技术制备NbSS/Nb5Si3两相合金和NbSS/Nb5Si3/Cr2Nb三相合金,研究显微组织形貌、室温和高温力学性能及高温氧化性能。结果表明:两相合金的显微组织由NbSS基体和呈均匀岛状分布的Nb5Si3组成,三相合金中NbSS有相互连接成基体的趋势,而Nb5Si3和Cr2Nb相也以块状散布在NbSS中。NbSS/Nb5Si3两相合金和NbSS/Nb5Si3/Cr2Nb三相合金的室温断裂韧性值KQ分别达到15.1MPa·m1/2和11.3MPa·m1/2,室温下合金中NbSS相以韧窝型断裂为主,对Nb-Si基合金的室温断裂韧性有利,而Nb5Si3和Cr2Nb相为脆性断裂。1250℃时NbSS/Nb5Si3/Cr2Nb合金的压缩强度高于NbSS/Nb5Si3合金,但当温度上升到1350℃时两者强度出现反转。Cr2Nb相对合金高温抗氧化性能有利,1250℃下静态氧化100h时NbSS/Nb5Si3合金的氧化增重为233mg/cm2,大于NbSS/Nb5Si3/Cr2Nb合金的175mg/cm2。     

Microstructure and tensile properties of Ni3 (Si,Ti) alloys containing second phase dispersions

Abstract

The alloying behaviour, microstructure, and high temperature mechanical properties of quaternary polycrystalline Ni₃ (Si,Ti), which was alloyed with transition elements V, Nb, Zr, and Hf beyond their maximum solubility limits, were investigated. The solubility limits of the quaternary elements in the L1₂ Ni₃ (Si,Ti) phase were determined to be ranked in the sequence of Nb > V > Hf > Zr, and correlated with the size misfit parameter between Si and the quaternary element X, and with the difference in formation enthalpy between Ni₃ Si and Ni₃ X. The second phases (dispersions) formed beyond the solubility limit were identified as a face centred cubic type Ni solid solution for the V containing Ni₃ (Si,Ti) alloy and Ni₃ X type compounds of the Nb, Zr, and Hf containing Ni₃ (Si,Ti) alloys. The second phase dispersions in the L1₂ phase matrix resulted in strengthening over a wide range of temperatures. The high temperature tensile elongation was improved by the introduction of the second phase dispersions. Among the quaternary Ni₃ (Si,Ti) alloys observed in the present study, the Nb containing Ni₃ (Si,Ti) alloy with the Nb containing second phase dispersion was shown to have the most favourable mechanical properties.