机械合金化过程中Fe70B30粉末晶粒尺寸和微观应变的研究

用Ｘ射线和电镜研究了Ｆｅ＿（７０）Ｂ＿（３０）粉末经不同时间高能球磨后晶粒尺寸和微观应力的变化。在机械合金化过程中，粉末的Ｘ射线衍射谱的宽度随球磨时间的增加逐渐加宽，这是晶粒细化和内部微观应力共同作用的结果。Ｘ射线衍射结果表明：随着机械合金化的进行，粉末的晶粒尺寸逐渐减小，球磨初期晶粒尺寸下降较快，经１５ｈ球磨，晶粒尺寸为２５ｎｍ，机械合金化进行到一定时间后晶粒尺寸下降缓慢，８０ｈ球磨后晶粒尺寸可达５ｎｍ。在机械合金化过程中球磨所造成的微观应变不大，球磨初期粉末的内应力随球磨时间增加而增加，当粉末粒子尺寸很小时，随球磨的进行粉末中的微观应变显著下降。     

超微晶Fe_（73．5）Cu_1Nb_3Si_（13．5）B_9形成过程的等温

利用热重法（ＴＧ）研究了超微晶Ｆｅ＿（７３．５）Ｃｕ＿１Ｎｂ＿３Ｓｉ＿（１３．５）Ｂ＿９形成的等温晶化动力学过程，由Ｊ－Ｍ－Ａ方程求出了晶化动力学常数ｎ（ｘ）和Ｅ＿ｃ（ｘ）对ｘ的曲线。晶化形核过程中这些曲线的变化关系可以很好的由Ｃｕ的作用来说明。同时与等温ＤＳＣ的结果比较表明ＴＧ更能给出晶化初期的形核信息。     

Mechanical Alloying of Fe_(100-x)B_x

The formation of nonequilibrium phase by mechanical alloying (MA) of Fe and B powders in a high energy vibration ball mill has been made for Fe100-xBx system with x=15. 30, 35, 45,55 and 70. By using the X-ray diffraction, magnetic measurement and M6ssbauer spectrummethods, it was revealed that the structure of the MA product varies with milling time and B contents.     

草酸-硝酸盐低热固相反应法制备(Ni_(0.58)Cu_(0.2)Zn_(0.22))Fe_(1.96)O_4铁氧体

以草酸和金属硝酸盐为原料,用低热固相反应法合成了纳米(Ni0.58Cu0.2Zn0.22)Fe1.96O4尖晶石型铁氧体,借助FT-IR、DSC-TG、XRD、TEM以及SEM等技术对固相反应过程和样品进行了研究及表征.FT-IR研究表明,草酸和金属硝酸盐在研磨过程中发生低热固相反应,生成金属草酸盐前驱体;FT-IR和XRD分析表明,前驱体经不同温度焙烧后得到单一尖晶石相的NiCuZn铁氧体粉末;依据TEM和SEM表征证明,前驱体在450℃分解1h后铁氧体粒径约为30～40nm,铁氧体于900℃烧结为陶瓷体后,晶粒约为2～4μml,烧结致密,磁谱测量表明,900℃烧结样品的磁导率为210,截止频率为28MHz.     

Fe73.5Cu1Nb3Si13.5B9粉体晶化和显微分析

FeCuNbSiB非晶薄带进行淬火处理,将脆化后的薄带球磨.将非晶粉体在不同温度下,进行晶化处理,最后进行粉体的显微分析.分析显示,当温度T=550℃,保温时间t=0.5h时,粉体结晶效果最佳;显微分析说明钛酸酯偶联剂的处理对粉体的流动性、分散性起到了明显的改善作用,降低了粉体颗粒的二次团聚.     

Structural and Magnetic Properties of Mechanically Alloyed Nd_(15)Fe_(70)T_(15)N_δ(T=V, Mo) Magnets

Structural and magnetic properties of Nd15Fe70T15Nδ(T=V, Mo) alloys, made by mechanical alloying (MA) followed by heat-treatment and nitriding, have been investigated systematically.Effects of annealing temperature on the structure and magnetic properties of the materials were studied by means of X-ray diffraction, AC susceptibility and high field magnetization measurements. Under pure argon atmosphere, the optimum temperatures for the heat treatment are found to be 75 and 850℃ for Nd15Fe7015Nδ and Nd15Fe70Mo15Nδ respectively. Correspondingly, the following magnetic properties are achieved : (1) Nd15Fe70V15Nδ:Br=0.63 T,,HC=8.01kA/cm (10.1 kOe), (BH )max=50.3 kJ/m3 (6 32 MGOe), (2) Nd15Fe70Mo15Nδ :Br=0.42 T. iHc=5.6 kA/cm (7.4 kOe), (BH )max=26.6 kJ/m3 (3.34 MGOe)     

Natural Passivity of Amorphous Fe_(40)Ni_(40)P_(14)B_6 and Fe_(54.6)Ni_(38)Si_(4.1)B_(2.3)V_1 Alloys

The natural passive films forrned on Fe_(40)Ni_(40)P_(14)B_6 and Fe_(54.6)Ni_(38)Si_(4.1)B_(2.3)V_1 amorphous alloys long-term exposed in air have been studied by X-ray photoelectron spectroscopy (XPS) and Auger electron (including Ar+ ion depth profiling) spectroscopy (AES). The following aspects have been investigated: (1) chemical states of the elements in the films. binding energies and the chemical shifts measured by XPSf (2) structure and composition of the films fand (3) thickness of the passive films determined by AES depth profiling and XPS analysis.     

Structural Modification of Al_(6)5Cu_(16.5)Ti_(18.5) Amorphous Powder through Annealing and Post Milling:Improving Thermal Stability

To improve thermal stability of the Al65Cu16.5Ti18.5 amorphous powder,structural modification of the amorphous powder was performed through annealing and post milling.Annealing above the crystallization temperature(Tx) not only induced nanoscale intermetallics to precipitate in the amorphous powder,but also increased Cu atomic percentage within the residual amorphous phase.Post milling induced the amorphization of the nanocrystal intermetallics and the formation of Cu9Al4 from the residual amorphous phase.Thus,a mixed structure consisting of amorphous phase and Cu9Al4 was obtained in the powder after annealing and post milling(the APMed powder).The phase constituent in the APMed powder did not change during the post annealing,which exhibited significantly improved thermal stability in comparison with the as-milled amorphous powder.     

Fe73.5Cu1Nb3Si13.5B9非晶合金的晶化动力学

用ＤＴＡ结合ＸＲＤ了Ｆｅ７３．５Ｃｕ１Ｎｂ３Ｓｉ１３．５Ｂ９晶合金的晶化动力学。表明，该事金在５００℃时析出α－Ｆｅ（Ｓｉ）相。晶化初期激活能最小为２４２ｋＪ／ｍｏｌ，它随晶化量的增加，在ＸＣ为０．４－０．８时，呈极大值为５２０ｋＪ／ｍｏｌ。在６２４℃时析出Ｆｅ２Ｂ相。     

Structure and Thermal Stability of Co60Ge40 Prepared by Mechanical Alloying

The phase composition and structure of Co₆₀Ge₄₀ prepared by mechanical alloying followed by heat treatment are studied by x-ray diffraction, x-ray microanalysis, differential scanning calorimetry, and scanning electron microscopy. The results indicate that milling a 60 : 40 mixture of Co and Ge for 2 h leads to the formation of phase-pure, nanocrystalline -Co₅Ge₃ (B8₂ structure). This phase is chemically inhomogeneous and metastable. On heating to 720°C, it transforms into a homogeneous, equilibrium phase of -Co₅Ge₃. The transformation into the stable phase occurs through a two-phase state, involving the formation of the orthorhombic phase Co₂Ge. At t 630°C, Co₂Ge dissolves in -Co₅Ge₃.     

Fe73.5Cu1Mo3Si13.5B9非晶合金的晶化动力学

用ＤＴＡ，结合ＸＲＤ，ＴＥＭ研究了Ｆｅ７３．５Ｃｕ１Ｍｏ３Ｓｉ１３．５Ｂ９软磁非晶合金的晶化动力学，结果表明，该合金在４７８℃时析出ａ－Ｆｅ相，晶化初期激活能量最小（１４８ｋＪ．ｍｏｌ＾－１），它随晶化学量的增加而增大，在ＸＣ为５０－７８％时，呈极大值（５１０ｋＪ．ｍｏｌ＾－１）随退火温度的升高，α－Ｆｅ相的数目增多，但尺寸基本不变。为１４－１６ｍｍ。     

机械合金化制备NiAl(Cr,Nb)粉体

采用机械合金化的方法制备NiAl(Cr,Nb)金属间化合物粉末。以Ni、Al、Cr和Nb的粉末为原料,按原子分数Ni-38Al-5Nb-5Cr配比,研究其机械合金化过程,并采用XRD,SEM,DSC等分析手段对粉末的结构、颗粒形貌及热稳定性能等进行表征。结果表明:复合粉末在球磨10h后初步合成了NiAl(Cr,Nb),随球磨时间的延长,粉末有细化的趋势,最终产物多为规则的近球形。     

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.     

Fe_（76．5－x）Cu_（1．0）Nb_xSi_（13．5）B_（9．0）

研究了Ｎｂ含量ｘ对Ｆｅ＿（７６．５－ｘ）Ｃｕ＿（１．０）Ｎｂ＿ｘＳｉ＿（１３．５）Ｂ＿（９．０）纳米软磁合金的结构与磁性影响。研究结果表明，当Ｎ６含量ｘ约为３ａｔ％时，合金的软用性能最高；随Ｎｂ含量ｘ的增加，最佳软磁性能下合金显微组织结构中的αＦｅ－Ｓｉ纳米晶晶粒尺寸Ｄ、Ｓｉ含量、体积分数Ｖ＿ｃ均呈下降趋势，非晶相的短程有序范围δ增大；合金的磁性除与αＦｅ－Ｓｉ纳米晶有关外，还与合金中非晶相密切相关。用新近提出的双相无规磁各向异性模型讨论了合金的磁性与结构的关系。     

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.     

机械合金化Fe50Ti50非晶的形成及球磨强度对它的影响

本文通过电子扫描和Ｘ衍射对机械合金人Ｆｅ５０Ｔｉ５０非晶粉末形成做了研究。研究发现：机械合金非晶形成可以大致地分为二个阶段－粉末的破碎阶段和非晶的形成阶段。另外，对球磨强度对非晶形成的影响进行了研究。结果表明：强度低时粉末需要较长的时间才能形成非晶，强度高时粉末形成非晶的时间大大缩短，但在随后的球磨中，粉末会重新晶化形成新相。     

Sm8Fe83Si2C5Cu0.5Nb1.5非晶合金的晶化动力学

用差热分析（ＤＴＡ）,结合Ｘ射线衍射（ＸＲＤ）研究了Ｓｍ８Ｆｅ８３Ｓｉ２Ｃ５Ｃｕ０．５Ｎｂ１．５非晶合金的晶化动力学。结果表明：温度在０￣１０００℃范围内,该合金的晶化相为α－Ｆｅ和Ｓｍ２（ＦｅＳｉ）１７Ｃｘ,α－Ｆｅ相的晶化表观激活能力３４９．５３ｋＪ／ｍｏｌ,Ｓｍ２（ＦｅＳｉ）１７Ｃｘ的晶化表观激活能力３１６．１９ｋＪ／ｍｏｌ,两相在晶化初期激活能量小,随晶化量（ｘｃ）的增加激活能增大,当α－     

非晶态Fe_（73．5）Cu_1Nb_3Si_（13．5）B_9合金的结构弛豫研

利用Ｍｓｓｂａｕｅｒ谱，同步辐射小角Ｘ射线散射和大角Ｘ射线衍射等实验技术对非晶态Ｆｅ（７３．５）Ｃｕ１Ｎｂ３Ｓｉ（１３．５）Ｂ９合金的结构弛豫行为进行了研究。结果表明：晶化前退火引起原子结构，磁畴结构，电子密度的一系列变化；自由体积不断减少，沿条带平面内的宽畴成分增加，表面优先晶化；晶化前在４００℃时形成了Ｃｕ的团簇结构，并引入了很大的电子密度不均匀性。     

Fe_（76．5－x）Cu_1Nb_xSi_（13．5）B_9纳米晶合金的结构和磁性研究

本文研究了Ｆｅ（７６．５－ｘ）Ｃｕ１ＮｂｘＳｉ（１３．５）Ｂ９纳米晶合金中Ｎｂ含量的变化（ｘ＝１－７）对结构和磁性的影响。结果表明，随ｘ值的增高，α－Ｆｅ（Ｓｉ）纳米晶相的尺寸减小，体积分数，含Ｓｉ量及其ＤＯ_３有序度降低。Ｎｂ含量对残余非晶相的结构有影响。合金的饱和磁致伸缩系数（λｓ）随ｘ值的增加而增大，在ｘ＝３时，合金的起始磁导率（μｉ）最大，矫顽力（Ｈｃ）最小。