热处理温度对FeCoSiB薄膜及FeCoSiB/Cu/FeCoSiB三明治膜应力阻抗效应的影响

采用DC磁控溅射法在玻璃基片上制备了FeCoSiB薄膜和FeCoSiB/Cu/FeCoSiB 三明治膜,并进行磁场退火热处理以消除残余应力和形成磁织构,提高薄膜的应力阻抗效应。薄膜的磁性能采用振动样品磁强计(VSM)进行测试,采用HP4275A 型阻抗分析仪在200kHz~10MHz频率范围内测试薄膜的应力阻抗效应。结果表明,磁场退火热处理可形成感生磁各向异性,改善薄膜的软磁性能、提高薄膜的应力阻抗效应。在温度低于300℃时,随着退火温度的增加,薄膜的应力阻抗效应增大;当退火温度超过300℃时,薄膜的应力阻抗效应随退火温度增加而降低。与Fe CoSiB单层膜相比, FeCoSiB/Cu/FeCoSiB 三明治膜应力阻抗效应较大。10MHz测试频率下,在基片末端位移为450μm时,经300℃热处理的三明治膜达到了8.3%,而单层膜仅有1.86%。当测试频率较高为10和4MHz时,薄膜的应力阻抗效应变化不大,当测试频率下降到低于1MHz时,薄膜的应力阻抗效应显著降低。     

Co—Fe—Si—B非晶丝的巨磁阻抗效应研究

用旋转水中纺丝法制成几种不同直径的（Ｃｏ０．９４Ｆｅ０．０６）７２．５Ｓｉ１２．５Ｂ１５非晶丝,对丝进行张力退火后,测试了非晶丝热处理前后的磁阻抗性能。结果表明制成的非晶丝具有明显的巨磁阻抗效应,且巨磁阻抗效应随电流频率不同而表现出正磁阻抗和负磁阻抗两种规律。张力退火对正磁阻抗效应有明显改善,而且对直径小的试样,阻抗对轴向外磁场变化的灵敏度更高。实验得到的最大灵敏度为１２４％／Ｏｅ。     

高导磁非晶软磁合金磁退火效应的初步研究

本文介绍高导磁Fe-Co-Si-B和Fe-Ni-Co-Si-B非晶软磁合佥的磁场热处理效应,并将其效应与晶态Fe-Ni系软磁合金的磁场热处理效应相比较,探讨非晶软磁合金磁场热处理效应的特殊性。我们做了两种磁场退火试验：即纵向磁场热处理和横向磁场热处理。在做此实验前首先测定了它们的比重(d),居里温度(Tc),电阻率(ρ)和结晶化温度(Tcr)等有关性能参数。纵向磁退火选了5个温度：300℃,330℃,375℃,400℃及420℃, (此合金Tcr约480℃,Tc约420℃)。横向磁退火只选用了1个温度(330℃)。磁退火前后测试它们的交、直流磁特性,性能测试采用环样,交流磁性测试时,样品是用绝缘纸绝缘的。根据试验结果,并将其与晶态Fe-Ni系软磁合金比较,我们总结了以下几点：1．这两种高导磁非晶软磁合金经磁退火后具有与晶态软磁合金类似的效果：即纵向磁退火后μmax成倍提高,Hc大大下降,矩形比Br／Bs明显增加,横向磁退火后磁导率在一定磁场范围内恒定。这说明磁场热处理同样可使非晶软磁合金产生明显的感生磁各向异性(Ku),它可能是来源于原子的方向有序或空位的方向有序。2．从磁退火前后性能提高的幅度来看,本试验所用的两种非晶软磁的磁场热处理效应不如晶态软磁合金的效应大。为此,我们测定了非晶磁退火后的Ku,其值约为1．2×103erg／cm3,它比晶态1J65的Ku小一倍多,这可能是由于非晶软磁的磁退火温度受到Tcr的限制而不能很高,以致影响原子扩散过程,方向有序的形成也不很理想。再者我们发现Fe-Co-Si-B非晶软磁经退火处理后磁导率下降,这可能是在退火中消除了原有的由制造带来的应力各向异性,这样在经磁退火的过程中,虽然由于磁场的作用产生了方向有序使性能提高,同时又由于消除了应力的备向异性而使性能下降,综合作用的结果表现出经磁退火后性能的提高幅度不如晶态软磁的大。因为晶态软磁合金在遇火时性能也是提高的,经磁退火性能提高的幅度就更大了。这一点还可以从非晶的最佳磁退火温度不是在Tc附近,而是在低于Tc几十度这一点得到证明。3．磁退火前后这两种非晶软磁合金的交流损耗曲线(P／f-f曲线)的走向不同。非晶软磁淬火态的损耗曲线很特殊,在低频段,每周损耗P／f随频率的增加而增加,在2KHz-v4KHz频率范围内,每周损耗反常地随频率增加是减少的,并出现一个最小值,然后在4KHz之后又随频率的增加而增加,但增加的量不很大。非晶合金经磁场热处理后损耗曲线的走向又趋正常,与晶态软磁的损耗曲线一致。这可能与非晶态软磁合金在磁退火前的畴结构特殊有关,据文献介绍,非晶软磁合金在淬火态的畴结构远不同于晶态软磁,主要是迷宫畴,而磁退火后磁畴主要为180°畴,这样使淬火态的非晶软磁在损耗曲线上表现出反常现象,而磁退火使非晶磁畴结构变得与晶态软磁类似了。4．本试验所用的两种非晶软磁合金经磁退火后其总损耗有所下降,但仍略大于晶态1J79软磁合金的总损耗。根据非晶软磁合金有较高的磁导率和较大的电阻率,应比晶态1J79的总损耗小,然而试验结果却与预想的相反。经损耗分离证明,非晶态软磁合金的经典涡流损耗和磁滞损耗占总损耗的比份较小,而反常涡流损耗占比份很大,可达70％；而晶态1J79的反常涡流损耗占的比份很小,只有6％左右,这种大的反常涡流损耗致使非晶的总损耗偏大。非晶反常涡流损耗大的原因,可能是由于它在磁退火后得到的巨大磁畴有关,根据文献介绍,非晶磁退火后的畴可比晶态的磁畴大几十倍。巨大的畴结构必然带来一些经典涡流损耗中没有包括的内容,如微观涡流损耗等。     

硅橡胶表面状态的非晶带材压磁性能的研究

采用4284A阻抗分析仪,在0～1MHz频率范围内,研究了不同测试温度和退火条件下硅橡胶表面状态的非晶Fe73.5Cu1Nb3Si13.5B9带材的压磁性能.结果表明,非晶带材的阻抗变化|ΔZ|随着压应力和频率的增加而增加,对0.1MPa以下的微应力变化非常敏感;在13～37℃测试温度范围内,随着温度的升高,非晶带材压磁灵敏度增加,37℃时压磁性能最好;退火温度低于300℃时,非晶带材经300℃×0.5h退火处理后,其压磁性能最好.     

低温应力退火Fe基合金薄带巨磁阻抗特性的研究

通过同步辐射X射线衍射技术,观测Fe73.5Cu1Nb3Si13.5B9非晶薄带经过不同温度和不同应力退火60 min后样品的微观结构,利用HP4294A型阻抗分析仪测量相应样品的巨磁阻抗比与磁各向异性。研究结果表明,在450℃下施加不同应力退火的样品仍然处于非晶结构状态,并且在应力为112.1 MPa的条件下产生优异的磁性能,样品的最大巨磁阻抗比达到了1818.7%,是自由退火条件下最大巨磁阻抗比的1.9倍,同时能够改变巨磁阻抗曲线的形状,使Fe基合金薄带的巨磁阻抗曲线具有宽线性的特性。对实验数据进行拟合后发现,样品的最大巨磁阻抗比和磁各向异性场与外加应力都具有线性关系,磁感灵敏度与外加应力具有负指数关系。通过探究发现具有非晶结构的Fe基合金薄带的磁学性能对应力敏感,可以作为研究非晶纳米晶合金材料应力敏感问题的另一个新方向。     

BeCu/绝缘层/NiCoP复合结构丝巨磁阻抗效应的研究

利用化学镀方法制备了BeCu/绝缘层/NiCoP复合丝,对细丝在200℃进行热处理以改善铁磁层的磁性,并首次研究了巨磁阻抗效应.结果表明该复合丝在较低频率下有较大的巨磁阻抗效应,在1kHz时磁阻抗比为-3.32%,300kHz时磁阻抗比获得最大值108%.研究了样品退火前后的巨磁阻抗效应和镀层厚度对巨磁阻抗效应的影响.研究表明磁阻抗比不仅取决于△R/R和△X/X,还和R与X的比值相关.     

非晶FeCoSiB薄带的压磁性能研究

采用单辊法制备非晶FeCoSiB薄带,并进行退火处理以消除残余应力,提高薄带的压磁效应.采用4294A型阻抗分析仪在40Hz～100MHz频率范围内测试薄带的压磁效应.结果表明,退火可使薄带内部产生磁各向异性,消除内应力,提高薄带的压磁性能.在退火低于300℃时,薄带压磁效应随着退火温度的增加而增加;但当退火温度高于300℃后,薄带压磁效应随着退火温度的增加而降低.当温度为300℃时,退火时间也会对薄带的压磁性能产生影响,在退火时间低于1h时,薄带压磁效应随着退火时间的增加而增加;但当退火温度高于1h后,薄带压磁效应随着退火时间的增加而降低.非晶FeCoSiB薄带的经过300℃×1h退火后,测试频率为100MHz﹑压力为1.42MPa时,阻抗变化可达3.38Ω,压磁性能最佳.     

玻璃包裹Fe基纳米晶丝的高频巨磁阻抗效应

采用高频感应加热熔融拉引法制备玻璃包裹Fe73.0Cu1.0Nb1.5V2.0Si13.5B9.0纳米晶丝,细丝直径D约为3～20μm,玻璃层厚度d在1～2μm之间,其中玻璃层厚度占细丝总直径较小.研究结果发现,玻璃包裹Fe73.0Cu1.0Nb1.5V2.0Si13.5B9.0纳米晶细丝具有良好的高频巨磁阻抗效应,细丝磁阻抗的变化主要由电阻部分的变化决定,同时出现最大磁阻抗变化时对应的外磁场值Hm随频率的增加向高场方向移动.系统研究了不同条件细丝在趋肤效应开始明显时的起始频率f0变化情况,讨论了影响f0的各种可能因素.     

电流退火NiFeCoP/BeCu复合结构丝的巨磁阻抗效应和磁化特性

用化学镀的方法制备了镀NiFeCoP膜的复合结构丝,这种复合结构丝在较低频率下就有较好的磁阻抗效应.对样品进行电流退火处理,不同电流密度退火对复合结构丝磁阻抗效应特性的影响不同.利用复数磁导率探讨了该复合丝在不同电流密度退火后的磁化过程和磁化频率特性,较大电流密度退火后复合结构丝的畴壁运动被抑制,减弱了动态磁化过程,降低了相应的磁阻抗效应.     

不同退火过程对FeZrBCu软磁合金薄膜巨磁阻抗效应的影响

用射频溅射法制备了(Fe88Zr7B5)0.96Cu0.04非晶软磁合金薄膜.研究了不同退火条件对其巨磁阻抗(GMI)效应的影响.该样品在自然退火和电流退火热处理后,纵向GMI比下降,并随退火电流的增加而增加,在电流为800mA时达到最大值17%,磁场灵敏度相对于未退火样品的4%(kA/m)-1有所提高,达到7%(kA/m)-1.(Fe88Zr7B5)0.96Cu0.04薄膜经不同温度下纵向磁场退火处理后,样品的纵向和横向GMI比均有所提高,在250℃获得最大的GMI比,13MHz时,最大纵向磁阻抗比达到17.5%,表现为单峰;横向磁阻抗比曲线变为双峰结构,在±0.4kA/m的磁场下,出现峰值为17.8%。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...