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Spin-driven ordering of Cr in the equiatomic high entropy alloy NiFeCrCo

Spin-driven ordering of Cr in the equiatomic high entropy alloy NiFeCrCo
Spin-driven ordering of Cr in the equiatomic high entropy alloy NiFeCrCo

Spin-driven ordering of Cr in the equiatomic high entropy alloy NiFeCrCo

C. Niu, A. J. Zaddach, A. A. Oni, X. Sang, J. W. Hurt III, J. M. LeBeau, C. C. Koch, and

D. L. Irving

Citation: Applied Physics Letters 106, 161906 (2015); doi: 10.1063/1.4918996

View online: https://www.sodocs.net/doc/d84800171.html,/10.1063/1.4918996

View Table of Contents: https://www.sodocs.net/doc/d84800171.html,/content/aip/journal/apl/106/16?ver=pdfcov

Published by the AIP Publishing

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Spin-driven ordering of Cr in the equiatomic high entropy alloy NiFeCrCo

C.Niu,1A.J.Zaddach,1A.A.Oni,1X.Sang,1J.W.Hurt III,2J.M.LeBeau,1C.C.Koch,1and

D.L.Irving 1,a)

1

Department of Materials Science and Engineering,North Carolina State University,Raleigh,North Carolina 27695,USA 2

Department of Physics,Furman University,Greenville,South Carolina 29613,USA

(Received 13February 2015;accepted 13April 2015;published online 23April 2015)

Spin-driven ordering of Cr in an equiatomic fcc NiFeCrCo high entropy alloy (HEA)was predicted by ?rst-principles calculations.Ordering of Cr is driven by the reduction in energy realized by sur-rounding anti-ferromagnetic Cr with ferromagnetic Ni,Fe,and Co in an alloyed L12structure.The fully Cr-ordered alloyed L12phase was predicted to have a magnetic moment that is 36%of that for the magnetically frustrated random solid solution.Three samples were synthesized by milling or casting/annealing.The cast/annealed sample was found to have a low temperature magnetic moment that is 44%of the moment in the milled sample,which is consistent with theoretical pre-dictions for ordering.Scanning transmission electron microscopy measurements were performed and the presence of ordered nano-domains in cast/annealed samples throughout the equiatomic

NiFeCrCo HEA was identi?ed.V

C 2015AIP Publishing LLC .[https://www.sodocs.net/doc/d84800171.html,/10.1063/1.4918996]High entropy alloys (HEAs)are an exciting new class of

materials and several systems have exhibited desirable com-binations of properties not commonly exhibited by conven-tional alloys.HEAs are composed of at least four to ?ve principal elements that are present in high concentrations of 5–35at.%.1,2Alloys with equiatomic ratios have the highest con?gurational entropy contribution to the free energy.Equiatomic NiFeCrCoMn,which is a fcc random solid solu-tion (RSS),has a good combination of mechanical properties in hardness,3,4tensile strength,4–6ductility,4,6and fracture resistance at cryogenic temperatures.5Its balanced perform-ance in strength and ductility was attributed to a low stacking fault energy.3Non-equiatomic NiFeCrCoMn HEAs were also reported to remain a fcc RSS,which provides promising opportunities in the future for compositional engineering of the mechanical property combinations in this system.3,7,8

Structurally,HEAs form solid-solutions on simple lattices (e.g.,fcc,bcc,and hcp).This is in contrast to other multicom-ponent alloys,such as bulk metallic glasses (BMG),which are structurally amorphous or conventional alloys with high solute concentrations,which tend to segregate into secondary or multiple phases.Whether an alloy forms as a BMG vs.HEA has been attributed to a balance between entropy,enthalpy,and relative atomic size.9Many HEAs tend to have a near-zero enthalpy and are also composed of atomic species of sim-ilar metallic radius.The small enthalpy is believed to allow the entropy to stabilize these as a RSS at relatively low tem-peratures (i.e.,room temperature).

Recent work by Otto et al.further demonstrated the deli-cate balance between enthalpy and entropy in stabilizing a sin-gle phase RSS.10Starting with the established single phase HEA,equiatomic NiFeCrCoMn,the authors prepared ?ve alloys that each substituted one host element at a time with a replacement element following the Hume-Rothery criteria.It was found that all ?ve alloys became multiphase.The authors attributed this to the increased enthalpies between the

substitutional and host elements and their results clearly dem-onstrated that the entropy will not always dominate the free energy when enthalpic contributions become more signi?cant.

What remains unclear is the local or long range atomic distributions in HEAs.NiFeCrCoMn is one of the few sys-tems that remained a single fcc phase during the investiga-tion of Otto et al.,but the elements do not share a common bulk crystal or magnetic structure.Ni,Fe,and Co are ferro-magnetic (FM),while Cr and Mn are anti-ferromagnetic (A-FM).Klaver et al.investigated the relative energetics of mixing an A-FM solute (Cr)into a FM solvent (Fe)and found that Cr solutes had an energetic preference to spatially separate in the FM host due to a process called magnetic frustration (signi?cant scatter in the local moment of Cr that leads to a rise in total energy).11This was found to be most signi?cant for Cr atoms sitting in their own ?rst nearest-neighbor (1NN)shell and the effect diminished gradually as the distance between Cr atoms increased.Brif et al.recently performed x-ray spectroscopy measurements using scanning electron microscopy and demonstrated that Cr was uniformly distributed throughout the NiFeCrCo alloy.12At the resolu-tion of the technique,however,atomic level ordering would not be resolved.Lucas et al.searched for long range order in NiFeCrCo,which contains FM and A-FM elements,using x-ray and neutron diffraction and found none.13The authors noted,however,that this did not completely rule out any chance for local ordering.

Here,we implement two complementary ?rst principles approaches to predict the relative energetics of chemical ordering within the NiFeCrCo system.NiFeCrCo is selected because it is the base alloy for many other 5telement HEAs.Similar ?ndings are anticipated for NiFeCoMn but they are not explored here.We demonstrate that Cr has a strong energy preference for not sitting within its own 1NN shell.In this equiatomic alloy,Cr can only escape to the sec-ond nearest neighbor shell,which creates an alloyed L12structure.This alloyed L12is predicted to have a smaller total magnetic moment as compared to the RSS.To compare

a)

Electronic mail:dlirving@https://www.sodocs.net/doc/d84800171.html,

0003-6951/2015/106(16)/161906/4/$30.00V

C 2015AIP Publishing LLC 106,161906-1

APPLIED PHYSICS LETTERS 106,161906

(2015)

with predictions,we synthesized equiatomic NiFeCrCo under equilibrium and non-equilibrium approaches.The temperature dependence of the magnetic properties of all samples are measured.Cast alloys have a signi?cantly smaller low temper-ature magnetic moment than ball milled samples.Cold working cast alloys is found to increase the measured low temperature moment.Finally,we apply advanced electron microscopy to identify ordered nanodomains in this alloy.

There are a number of challenges in the prediction of properties of RSS alloys,so two theoretical approaches using the generalized gradient approximation of the exchange-correlation functional as determined by Perdew,Burke,and Ernzerhof (GGA-PBE)14,15were implemented here.The ?rst was the well established Vienna ab initio simulation package (VASP)16,17with atomic centers approximated with projector-augmented wave (PAW)pseudo-potentials.18,19A k-point mesh was selected based on the convergence of the enthalpy to 1meV/atom.Special quasi random structures (SQS),which best represent the targeted alloy within the con?nes of the periodic unit cell,20were generated through a Monte Carlo algorithm.21For an equiatomic alloy,the identity of the atom at each lattice site is not uniquely determined during SQS gen-eration.Therefore,24permutations exist for the four compo-nent RSS SQS.We tested the convergence of enthalpy for 24,64,and 120atom SQSs with all possible permutations.We ?nd that the average enthalpy of the formation for these RSSs are 0.30960.023,0.30260.009,and 0.30260.007eV per

formula unit,respectively.Through averaging the permuta-tions,even the small 24-atom SQS leads to a relatively con-verged enthalpy,albeit with more scatter.The second method implemented was the Exact Muf?n-Tin Orbital combined with Coherent Potential Approximation (EMTO-CPA).22,23The screening parameter for these calculations was set to 0.9and a k-point mesh was selected based on the convergence of the enthalpy to 1meV/atom.The CPA technique averages the Green’s function to attain the randomness of atoms in a RSS.This one-site approximation neglects lattice distortions and also loses information on local chemical structure.

The local magnetic moments of each element as a func-tion of the average magnetic moment, m

NN ,of 1NN atoms for all permutations in the 24-and 120-atom SQS structures are plotted in Figures 1(a)and 1(b),respectively.FM Fe,Ni,and Co generally have positive moments,while the A-FM Cr atoms have a distribution of both positive and negative moments.Notably,Cr scatters signi?cantly and is most neg-ative when its neighbors have the largest positive moment,corresponding to when Cr is surrounded by a majority of FM neighbors.The magnetic moment of Cr becomes less nega-tive as the average moment of the neighbors becomes smaller,which is a product,in part,of having more Cr in the 1NN shell.This strong dependence of the local moment is a result of magnetic frustration of the central Cr atom;similar to the trends identi?ed in Ref.11for Fe-Cr alloys.

In binary Fe-Cr,there is a substantial repulsion when Cr resides in its own 1NN shell.This repulsion weakens as the distance between Cr atoms increases.For the equiatomic NiFeCrCo HEA,each element makes up 25at.%of the sys-tem and,assuming no preferential segregation,Cr can only avoid sitting in its own 1NN shell by forming an alloyed L12structure.In the alloyed L12structure,one element occupies the cubic corner (CC)sites,while the face centered (FC)sites contain a RSS of the other three elements.Any displacements of the atom occupying the CC site will move it back into its own 1NN shell.Formation of the alloyed L12structure also results in a reduction in con?gurational entropy as compared to the RSS and this penalty needs to be accounted for when comparing the relative energy of the RSS to the alloyed L12.

The relative energies of ordering one element (Ni,Fe,Co,or Cr)from the RSS to the CC site of the alloyed L12are plot-ted in Figure 2(a).The EMTO-CPA allows for a continuous

FIG.2.(a)Free energy (enthalpy of formation and con?gurational entropy contribution at 300K)of equiatomic NiFeCrCo.Four possible L12structures are considered by ordering each element to the CC.(Left)EMTO-CPA free energy for the RSS to the alloyed L12as a function of the long range order parameter of the selected element in the CC site.Long range order parameter determined as described in Ref.24.(Right)The VASP 24-atom SQS is compared to results from EMTO-CPA for the RSS and all four L12structures.(b)Atomic magnetic moment vs.the average magnetic moment of 12nearest neighbors from VASP calculations using a 24-atom L12SQS with ordered

Cr.

FIG.1.Atomic magnetic moment vs.the average magnetic moment of 12?rst nearest-neighbors from all 24permutations of the 24-atom SQS (a)and 120-atom SQS (b).

change in composition of each lattice site in the transition between the RSS and L12(Figure 2(a,left)),while the SQS structures are only evaluated at the end points (Figure 2(a,right)).VASP and EMTO results are all spin-polarized.Cr is predicted as non-magnetic by EMTO,which contributes to dif-ferences in predicted enthalpies between the two methods.For comparison of trends,we align the enthalpies of the EMTO to those of VASP for the RSS only.No other constraints are applied other than this alignment of the RSS.Differences between the two electronic structure methods is found to be small.In addition to the enthalpy of formation,the plotted val-ues also include con?gurational entropy as determined for an ideal solution at a temperature of 300K.Con?gurational en-tropy is given by S config ?P c i ln c i ,where c i is the ratio of the number of atoms of a disordered component over the total num-ber of disordered atoms.In the case of a partially ordered L12phase,a convenient way of calculating con?gurational entropy

is S config ?S CC –site config tS FC –site

config .Full estimates of the free energy requires contributions from the vibrational,magnetic,and elec-tronic entropy,which are not included here.From the data pre-sented in Figure 2,the most favorable ordering occurs through moving Cr to the CC site.

Figure 2(b)presents the magnetic moment for each element

as a function of the average magnetic moment, m

NN ,of the 121NN atoms in the six possible permutations of the alloyed L12structure.In comparing these results to the similar data in Figures 1(a)and 1(b),the magnetic frustration is avoided as evi-denced by the small scatter in the moments of each element.Fe,Co,and Ni all have aligned and positive magnetic moments,while Cr has a magnetic moment opposite of all its FM neigh-bors.This results in a reduction of the bulk magnetic moments when moving from the RSS (m RSS ?2:5960:99l B )to the alloyed Cr L12(m L12?0:9460:14l B ).The uniform magnetic alignment also leads to an extremely small scatter on the order of 2meV per formula unit in the predicted enthalpy of the alloyed L12structure.

To test the predictions made by ?rst principles methods,samples were prepared in three ways for analysis by SQUID-VSM.One sample was prepared by ball milling pure elemental powders in high-purity argon in a stainless steel vial using a SPEX 8000mixer mill for 24h at room temperature.Two other samples were prepared by melting pure elemental metals in high purity argon atmosphere using an electric arc melter.Each arc melted sample was then cast into a water-cooled cop-per mold and annealed in Ar-2%H 2at 1273K for 24h.One sample was tested after annealing and the other was cold rolled to 80%rolling reduction before testing.SQUID-VSM meas-urements were conducted with a Quantum Design MPMS using an applied ?eld of 198.9kA ám à1from 1.8to 390K at a rate of 0.08K ás à1.

Magnetization as a function of temperature for all of the samples is presented in Figure 3.At 1.8K,the highly disor-dered sample produced by ball milling exhibits the largest magnetization.Cast samples with low temperature moments are 44%of those measured for ball milled samples.A large difference in moments is expected from the results shown in Figures 1and 2(b),as the contribution from Cr is much more negative in the ordered state,while the contributions from the other elements remain nearly constant.While there are slight compositional differences between the cast and milled

samples,none were signi?cant enough to explain the differ-ence in magnetic properties.A smaller,yet still signi?cant increase in magnetization is seen after cold working,which would disrupt order in the cast/annealed sample.

Local atomic and chemical structure were also explored through scanning transmission electron microscopy (STEM).Samples for electron microscopy were prepared from the cast HEA using a standard twinjet electropolisher.High-angle annular dark ?eld (HAADF)STEM images were acquired using a probe-corrected FEI Titan G260–300kV operated at 200kV.Further details of the sample preparation and imaging conditions can be found in Ref.25.The revolv-ing STEM (RevSTEM)method was employed to remove drift distortion from the STEM images.26Forty 1024?1024pixel frames were acquired with a dwell time of 2l s/pixel.A 90 rotation angle step was introduced between each suc-cessive frame.

Figure 4(a)shows a representative RevSTEM image of the cast HEA.The seemingly uniform intensity distribution results from small difference in the atomic number of con-stituent elements (Z Cr ?24,Z Fe ?26,Z Co ?27,and Z Ni ?28),making it dif?cult to unambiguously distinguish ordering by visual inspection.Highlighting intensity varia-tions in the image,we calculate the ratio of each atom col-umn intensity to the average intensity of the four nearest neighbors through peak ?tting and converting the STEM image to a matrix representation.27The ratio map for the RevSTEM image is shown in Figure 4(b)where local regions of modulating large (red)and small (blue)ratios are evident.To further quantify this local ordering,we compare each block of 5?5neighbors to a completely ordered pat-tern,which is then used to calculate a correlation coef?cient (Figure 4(c))for each block.A perfectly ordered structure with alternating intensity would result in a correlation coef?-cient of unity,while a disordered structure would have zero correlation.The correlation coef?cient reaches a maximum of approximately 0.67,which,according to a p-value test generated through comparing these correlations to those of a simulated RSS,is inconsistent with the null hypothesis (p ?7?10à8).Therefore,the result strongly suggests the presence of ordered 2–3nm domains in the bulk HEA.

We have demonstrated that magnetic frustration of Cr exists in NiFeCrCo random solid-solutions,which leads to signi?cant scattering of the local magnetic moment.Ordering of Cr provides a way to eliminate the magnetic frustration and also leads to a reduction of free energy.

FIG.3.Magnetization of three equiatomic NiFeCrCo samples (milled for 24h,cast,and cast followed by cold working,respectively)as a function of temperature from SQUID measurements.

Temperature dependent SQUID measurements indicate that this alloy has a ?nite magnetic moment at low temperatures,which is sensitive to synthesis approach.The equilibrium approach leads to a smaller magnetic moment,consistent with the theoretical predictions.RevSTEM measurements identi?ed ordered nanodomains present throughout the sam-ple.Although nanodomains were found here,future studies that explore a variety of annealing procedures may be war-ranted to ultimately achieve long range ordering.

C.N.,A.J.Z.,C.C.K.,and

D.L.I.acknowledge support for this work from the National Science Foundation from the Metals and Metallic Nanostructures program under Grant No.DMR-1104930.A.A.,X.S.,and J.M.L.acknowledge support from the Air Force Of?ce of Scienti?c Research (Grant No.FA9550-12-1-0456)and the Analytical Instrumentation Facility (AIF)at North Carolina State University,which was supported by the State of North Carolina and the National Science Foundation.D.L.I.acknowledges support for J.W.H.from the NSF REU on Advanced Materials for Environmental Sustainability under Grant No.EEC-1156762.D.L.I.and C.N.would also like to acknowledge Levente Vitos for sharing his EMTO-CPA code,version 5.7,for work on this project.C.N.and D.L.I.thank M.C.Gao for sharing 64atom SQS.

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FIG.4.(a)A representative HAADF-STEM image acquired along the [110]zone axis of the HEA.Circles are plotted around each atom column with different colors representing (b)intensity ratio and (c)correlation coef?cient.The ratio range in (b)is clipped to [0.981.02]to better highlight the presence of ordering.

玻璃纤维制品知识

制品工艺 第一节玻璃纤维纺织制品概述 (一)分类定义: 玻璃纤维纺织制品的国际标准名称为Textile Glass。标准定义是“以连续玻璃纤维或定长玻璃纤维为基材制成的纺织制品的通称”。玻璃纤维制品总体分为无纺制品和纺织制品两大类。(我公司目前生产的玻纤制品属于无纺制品类) 按产品形态划分可分为纱线和织物两大类别。其中纱线类制品又分为无碱玻璃纤维无捻粗纱和无碱连续玻璃纤维纱。 (二)纱织制品分类表:

第二节细纱 (一)电子纱和工业纱 1. 定义:纤维直径小于10微米的细纱,因其工业用途不同分为电子纱和工业纱。 2. 用途:电子纱最终用于电子元件印刷线路板。 工业纱用于工业织物,如防火帘、模建筑、同步带、帘子线、编制套管等。 3.生产工艺流程(拉丝工艺起): 4.细纱主要质量控制标准: 外观质量、号数(TEX值)、含水率、可燃物含量、捻度、硬挺度、硬度、断裂强度等。 5. 细纱成品代号表示: 纱管类型4.0KG左右 Y1 ---- 浸润剂类型 0.7Z ---- 0.7捻/25mm (28捻/米) Z向 1/0 ---- 单股加捻 75 ---- 每磅纤维的百码数(7500码/磅) 单纤维直径为9微米的玻纤长丝 捻度–纱线加捻程度,公制单位:捻/100cm,英制单位:捻/英寸(1英寸=2.54cm)。 捻向--表示捻度的方向,分为S和Z两个方向。 6.细纱产品简介 (1) 电子纱 a.G75Y1/Y4系列 规格代号 TEX中心值直径(μm) G75Y1/Y4 68.7±1.7 9 b.E225系列 规格代号 TEX中心值直径(μm) E225Y3 22.5±0.7 7 c.D450系列 规格代号 TEX中心值直径(μm) D450Y5 11.2±0.5 5 (2) 工业纱 a.G37系列 规格代号 TEX中心值直径(μm) G37Y1 136±4.0 9 b.D225系列 规格代号 TEX中心值直径(μm) D225Y5 2.5±0.9 5 c.G25R/N系列

聚酯玻纤布介绍-聚酯玻纤布施工工艺

聚酯玻纤布介绍,聚酯玻纤布施工工艺聚酯玻纤布(又称聚脂玻纤布,玻纤聚酯布)是由玻璃纤维和聚酯纤维复合而成的高性能路面裂缝处理材料。其独特结构组合了玻纤和聚脂纤维的优点,就是聚脂纤维的柔韧性和玻璃纤维的强度。它通过吸收沥青材料后形成的一个有效的结构防水层,其与沥青混合料层复合后明显提高其低温抗裂性、抗疲劳、抗反射性能,起到应力分散和防水的作用,有效的提高面层的抗疲劳性,降低裂缝扩展和延缓反射裂纹的产生,从而延长路面的使用寿命。 聚酯玻纤布在生活中的应用也是非常广泛,具体有以下几点: 1、新建及道路拓宽改造等工程。 2、旧水泥混凝土路面加铺沥青面层。 3、沥青路面面层裂缝的修补,旧沥青道路维修。 4、半刚性基层收缩裂缝的修补。 关于聚酯玻纤布的施工工艺是怎样的呢?给大家来介绍一下具体的步骤有哪些: 1、在将要铺装聚酯玻纤布的路面上进行清洁工作:除去污物、碎石以及尘土,保证沥青粘结效果。 2、当基础路面有较大的裂缝(6mm以上)、坑或破损时,应该进行修补填平。 3、使用的粘结油层要是热沥青,不可以使用乳化沥青,否则聚酯玻纤布的粘结效果降低。 4、粘结沥青的温度为163-204℃。

5、粘结沥青撒布后要在沥青未失去流动性以前铺撞聚酯玻纤布,否则布体难以浸透沥青,降低聚酯玻纤布的防水性能。 6、铺装聚酯玻纤布施工的环境温度要在4℃以上。为了取得好的效果,在铺装聚酯玻纤布时还要注意以下几个方面: 7、聚酯玻纤布要在热沥青上进行安装施工.我们推荐以下的沥 青.AC-20;PG64-22;AR8000; 或者刺入等级为60-80的沥青.对高温的夏季施工,推荐采用粘度比较高的沥青,以下沥青比较适合夏季施 工:AC-30;PG67-22;AR8000;或者刺如等级为40-60的沥青. 8、沥青使用比例为1.1升/平方米,但是依据安装路面的实际情况和预计的迭合量,该使用比例会有一个范围:1.0-1.3升/平方米.我们不推荐将运输车中 的沥青加热到204℃以上,因为这样操作会妨碍液体沥青的预成熟 9、在装卸聚酯玻纤布时一定要小心谨慎.如果布卷从运输车辆上掉落下来,会损伤聚酯玻纤布,从而造成应用问题. 10、如果安装中出现了条纹,任何在铺装方向上出现的大于2.5厘米的条纹都要被割开并迭合起来,并且手工将迭合处浸渍在沥青层中. 聚酯玻纤布要使用辊压或刷子刷,以保证它与路面的充分接触并除去气泡.热沥青的涂覆宽度要在聚酯玻纤布的宽度上再加4英寸. 聚酯玻纤布在曲线面上不易弯曲或伸展.在曲面上安装施工时可以将布截短,可以机械或手工进行安装. 11、聚酯玻纤布安装时可以使用拖拉机或卡车拖动的带有金属辊的机构进行,该金属辊的作用是保证将聚酯玻纤布平整地铺展在路面上.在安装辊后面要安装有一排刷子,保证将聚酯玻纤布压紧在沥青涂层中. 聚酯玻纤布的接头中要保证在长度方向有5.1厘米的迭合层,在宽度方向上有10.2厘米的迭合层.上面的横向接头要沿着铺装的方向,所有的接头都要搭接在一起. 12、铺路机械或其它车辆在聚酯玻纤布安装中在其上面转向一定要逐渐展开,并且一定要保证尽可能地少转向,以避免可能对布的损害。在铺展施工中,设备轮胎要附着于布面,布面上尽可能少撒沙子以免被粘附。不要为了减小粘附轮胎而减少沥青的铺覆量。应该是在迭合部位进行撒布。 13、铺设完成的道路在合同方或安装工程师确定后可以开放交通。

The way常见用法

The way 的用法 Ⅰ常见用法: 1)the way+ that 2)the way + in which(最为正式的用法) 3)the way + 省略(最为自然的用法) 举例:I like the way in which he talks. I like the way that he talks. I like the way he talks. Ⅱ习惯用法: 在当代美国英语中,the way用作为副词的对格,“the way+ 从句”实际上相当于一个状语从句来修饰整个句子。 1)The way =as I am talking to you just the way I’d talk to my own child. He did not do it the way his friends did. Most fruits are naturally sweet and we can eat them just the way they are—all we have to do is to clean and peel them. 2)The way= according to the way/ judging from the way The way you answer the question, you are an excellent student. The way most people look at you, you’d think trash man is a monster. 3)The way =how/ how much No one can imagine the way he missed her. 4)The way =because

玻璃纤维

玻璃纤维 玻璃纤维应用知识 作者: 赵工来源: 聚和成日期: 2009-4-18 点击数: 74 第一部分:玻纤知识: 1、玻纤分类 从长度分类分可以分连续玻纤、短玻纤(定长玻纤)和长玻纤(LET),连续玻纤是国内目前应用最广的玻纤,就是通常说的“长纤”,代表厂家有巨石,泰山、兴旺等。定长玻纤就是通常说的“短纤”,一般是外资改性厂与国内部分企业在用,代表厂家有PPG,OCF及国内的CPIC,巨石泰山也有少部分,但质量不如人意。LET是最近在国内兴起的,代表厂家有PPG,CPIC及巨石,目前国内金发,浙江俊尔,南京聚隆产量较大。 从碱金属含量分可分为无碱,低中高,通常改性增强用无碱,也就是E玻纤,国内改性一般使用E玻纤。 2、玻纤的应用 玻纤增强塑料的原理主要是由于玻纤/树脂界面上连接必然是使作用到模塑件上的力传导到玻纤上,因此玻纤的长度被充分利用,起到树

脂增强的目的,但玻纤在树脂基体中长度必须满足一定的要求,这就是临界玻纤长度,玻璃纤维的临界纤维长度(即可将力从基材传递给纤维的最小长度)在0.3~0.6mm之间,临界长度只与剪切力与玻纤单丝直径有关,上面的临界长度是指玻纤在最终产品里的长度,如是果是塑料粒子里话,此长就就在0.6~0.8mm之间,从理论上讲,临界长度与玻纤的原始长度没有关系,如果增强产品把玻纤的长度都控制在这个范围的话,此时产品的力学性能与表面外观都是最好的,最平衡的,如果长度过长,力学性能上升,但制品表面会变粗糙与翘曲,如果长度过短,就会导致力学性能不足。要控制玻纤的长度应该从调整螺杆结构及转速入手,如果玻纤长径控制在400效果最佳。 3、评价玻纤好坏的主要指标 第一个指标:玻纤在拉丝过程中所使用的表面活性处理剂。表面活性处理剂也就是通常所说的浸润剂,浸润剂主要是偶联剂与成膜剂,另外还有一些润滑剂、抗氧剂、乳化剂、抗静电剂等,成膜剂的成分与其它助剂的种类对玻纤有决定性的影响,所以在选择玻纤时就根据基料与成品要求选择合适的玻纤。像PPG、CPIC等公司短纤牌号较多,就是因为表面浸润剂不一样,这样就针对性比较强。 第二个指标:单丝直径。以前介绍过临界玻纤长度只与剪切力和单丝直径有关,从理论上讲,如果单丝直径越小,产品的力学性能与表面外观越佳。目前国内玻纤直径一般都在10μm,13μm,像CPIC就有开发7μm的玻纤。 4、浮纤原因分析

The way的用法及其含义(二)

The way的用法及其含义(二) 二、the way在句中的语法作用 the way在句中可以作主语、宾语或表语: 1.作主语 The way you are doing it is completely crazy.你这个干法简直发疯。 The way she puts on that accent really irritates me. 她故意操那种口音的样子实在令我恼火。The way she behaved towards him was utterly ruthless. 她对待他真是无情至极。 Words are important, but the way a person stands, folds his or her arms or moves his or her hands can also give us information about his or her feelings. 言语固然重要,但人的站姿,抱臂的方式和手势也回告诉我们他(她)的情感。 2.作宾语 I hate the way she stared at me.我讨厌她盯我看的样子。 We like the way that her hair hangs down.我们喜欢她的头发笔直地垂下来。 You could tell she was foreign by the way she was dressed. 从她的穿著就可以看出她是外国人。 She could not hide her amusement at the way he was dancing. 她见他跳舞的姿势,忍俊不禁。 3.作表语 This is the way the accident happened.这就是事故如何发生的。 Believe it or not, that's the way it is. 信不信由你, 反正事情就是这样。 That's the way I look at it, too. 我也是这么想。 That was the way minority nationalities were treated in old China. 那就是少数民族在旧中

(完整版)the的用法

定冠词the的用法: 定冠词the与指示代词this ,that同源,有“那(这)个”的意思,但较弱,可以和一个名词连用,来表示某个或某些特定的人或东西. (1)特指双方都明白的人或物 Take the medicine.把药吃了. (2)上文提到过的人或事 He bought a house.他买了幢房子. I've been to the house.我去过那幢房子. (3)指世界上独一无二的事物 the sun ,the sky ,the moon, the earth (4)单数名词连用表示一类事物 the dollar 美元 the fox 狐狸 或与形容词或分词连用,表示一类人 the rich 富人 the living 生者 (5)用在序数词和形容词最高级,及形容词等前面 Where do you live?你住在哪? I live on the second floor.我住在二楼. That's the very thing I've been looking for.那正是我要找的东西. (6)与复数名词连用,指整个群体 They are the teachers of this school.(指全体教师) They are teachers of this school.(指部分教师) (7)表示所有,相当于物主代词,用在表示身体部位的名词前 She caught me by the arm.她抓住了我的手臂. (8)用在某些有普通名词构成的国家名称,机关团体,阶级等专有名词前 the People's Republic of China 中华人民共和国 the United States 美国 (9)用在表示乐器的名词前 She plays the piano.她会弹钢琴. (10)用在姓氏的复数名词之前,表示一家人 the Greens 格林一家人(或格林夫妇) (11)用在惯用语中 in the day, in the morning... the day before yesterday, the next morning... in the sky... in the dark... in the end... on the whole, by the way...

“the way+从句”结构的意义及用法

“theway+从句”结构的意义及用法 首先让我们来看下面这个句子: Read the followingpassageand talkabout it wi th your classmates.Try totell whatyou think of Tom and ofthe way the childrentreated him. 在这个句子中,the way是先行词,后面是省略了关系副词that或in which的定语从句。 下面我们将叙述“the way+从句”结构的用法。 1.the way之后,引导定语从句的关系词是that而不是how,因此,<<现代英语惯用法词典>>中所给出的下面两个句子是错误的:This is thewayhowithappened. This is the way how he always treats me. 2.在正式语体中,that可被in which所代替;在非正式语体中,that则往往省略。由此我们得到theway后接定语从句时的三种模式:1) the way+that-从句2)the way +in which-从句3) the way +从句 例如:The way(in which ,that) thesecomrade slookatproblems is wrong.这些同志看问题的方法

不对。 Theway(that ,in which)you’re doingit is comple tely crazy.你这么个干法,简直发疯。 Weadmired him for theway inwhich he facesdifficulties. Wallace and Darwingreed on the way inwhi ch different forms of life had begun.华莱士和达尔文对不同类型的生物是如何起源的持相同的观点。 This is the way(that) hedid it. I likedthe way(that) sheorganized the meeting. 3.theway(that)有时可以与how(作“如何”解)通用。例如: That’s the way(that) shespoke. = That’s how shespoke.

玻璃纤维布介绍,玻璃纤维布作用

玻璃纤维布介绍,玻璃纤维布作用 玻璃纤维布是无捻粗纱平纹织物,是手糊玻璃钢重要基材。玻璃纤维布的强度主要在织物的经纬方向上,对于要求经向或纬向强度高的场合,也可以织成单向布,它可以在经向或纬向布置较多的无捻粗纱,单经向布,单纬向布。无捻粗纱roving是由平行原丝或平行单丝集束而成的。玻璃纤维布是制作玻璃钢产品的重要材料,它是一种性能优异的无机非金属材料,种类繁多,优点诸多,在抗腐蚀、耐热性、绝缘性非常好。 那么,玻璃纤维布在我们生活中有哪些用处呢?主要有以下几点: 1、玻璃纤维布通常用作复合材料中的增强材料,电绝缘材料和绝热保温材料,电路基板等国民经济各个领域。 2、玻璃纤维布多用于手糊成型工艺,玻璃纤维布主要是在船体、贮罐、冷却塔、船舶、车辆、槽罐等方面应用。 3、玻璃纤维布广泛应用于墙体增强、外墙保温、屋面防水等方面,还可以应用于水泥、塑料、沥青、大理石、马赛克等墙体材料的增强,是建筑行业理想的工程材料。 4、玻璃纤维布在工业上主要用于:隔热、防火、阻燃。该材料在遭到火焰燃烧时吸收大量热量并能阻止火焰穿过、隔绝空气。 那么,玻璃纤维布厂家哪家好呢? 南京道之尊复合材料有限公司是一家以高新技术为导向,集产、学、研为一体的专业从事玻璃纤维布开发、研制、生产、加工和销售现代土工材料的企业。

引进世界先进、功能齐全、性能优越的德国大型经编机,大型涂层机,分切机等生产设备。 我公司生产的产品涵盖防裂贴(抗裂贴),贴缝带,路用创可贴;聚酯玻纤布,高性能聚酯布,玻纤聚酯防裂布,经编复合增强防裂布,玻纤复合土工布,涤纶复合土工布,短纤针刺非织造无纺土工布,玻璃纤维土工格栅,涤纶土工格栅等土工复合材料。

way 用法

表示“方式”、“方法”,注意以下用法: 1.表示用某种方法或按某种方式,通常用介词in(此介词有时可省略)。如: Do it (in) your own way. 按你自己的方法做吧。 Please do not talk (in) that way. 请不要那样说。 2.表示做某事的方式或方法,其后可接不定式或of doing sth。 如: It’s the best way of studying [to study] English. 这是学习英语的最好方法。 There are different ways to do [of doing] it. 做这事有不同的办法。 3.其后通常可直接跟一个定语从句(不用任何引导词),也可跟由that 或in which 引导的定语从句,但是其后的从句不能由how 来引导。如: 我不喜欢他说话的态度。 正:I don’t like the way he spoke. 正:I don’t like the way that he spoke. 正:I don’t like the way in which he spoke. 误:I don’t like the way how he spoke. 4.注意以下各句the way 的用法: That’s the way (=how) he spoke. 那就是他说话的方式。 Nobody else loves you the way(=as) I do. 没有人像我这样爱你。 The way (=According as) you are studying now, you won’tmake much progress. 根据你现在学习情况来看,你不会有多大的进步。 2007年陕西省高考英语中有这样一道单项填空题: ——I think he is taking an active part insocial work. ——I agree with you_____. A、in a way B、on the way C、by the way D、in the way 此题答案选A。要想弄清为什么选A,而不选其他几项,则要弄清选项中含way的四个短语的不同意义和用法,下面我们就对此作一归纳和小结。 一、in a way的用法 表示:在一定程度上,从某方面说。如: In a way he was right.在某种程度上他是对的。注:in a way也可说成in one way。 二、on the way的用法 1、表示:即将来(去),就要来(去)。如: Spring is on the way.春天快到了。 I'd better be on my way soon.我最好还是快点儿走。 Radio forecasts said a sixth-grade wind was on the way.无线电预报说将有六级大风。 2、表示:在路上,在行进中。如: He stopped for breakfast on the way.他中途停下吃早点。 We had some good laughs on the way.我们在路上好好笑了一阵子。 3、表示:(婴儿)尚未出生。如: She has two children with another one on the way.她有两个孩子,现在还怀着一个。 She's got five children,and another one is on the way.她已经有5个孩子了,另一个又快生了。 三、by the way的用法

玻璃钢材质介绍

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玻璃钢简介

新型建材玻璃钢简介 玻璃钢,学名树脂基玻璃纤维增强塑料,简称FRP,起源于二十世纪三十年代的美国,至今已有70余年的发展历史,经历了由以军代民、军民结合、以民为主的发展过程。中国的玻璃钢行业始于1958年,发展于60年代,至今,玻璃钢以其优越的机械和化学性能逐步发展到交通运输、石油化工、建筑造船、环境保护、体育器械、机器电器、卫生洁具等领域,已形成了一个初具规模的新型工业部门,逐渐有取代碳素钢、不锈钢、木材、各种金属材料之势。 近几年来,新的成型工艺不断出现,玻璃钢由过去的单一手糊制品逐渐发展到缠绕、拉挤、模压、注射、离心、喷射等等诸多工艺种类,与此相适应,新的产品也层出不穷,诸多产品以各自独特的优越性能,打开了各自的市场。随着社会和经济事业的迅速发展,玻璃钢制品,迅速挤占市场份额,成为初具规模的新型建材产业。玻璃钢具有独特的优异性能和优势。下面就其性能对玻璃钢产品作一简介。 一、轻质高强。玻璃钢密度在1.4—2.2之间,仅为普通钢材的1/4,而强度跟普通碳素钢差不多,仅次于高级合金钢。例如玻璃钢梯子间(煤矿用)、玻璃钢高速公路护栏、玻璃钢钓鱼竿、跳高用撑竿、旅游船等等。 二、耐腐蚀性能好。玻璃钢对大气、水、一般浓度的酸、碱、盐、各种油类和溶剂具有良好的抵抗作用。例如各种化工场所用的

压力容器和输送管道、风机组、中央空调机组、设备防腐、冷却塔、除尘净化塔、离子交换柱及卫生洁具等等。 三、热性能良好。导热系数低,室温下为0.3-0.4千卡/米.时.度,是金属材料的1/100—1/1000。可以用来做保温材料,例如保温套管等。 四、电性能良好。高温下仍有良好的介电性。微波透过性良好,已广泛用于天线雷达罩、电缆桥架、电表盒、电表箱等。 五、工艺性能优越。可根据产品的数量、形状、数量、技术要求及用途灵活的选择成型工艺;可以一次成型,尤其对数量少,形状复杂,不宜成型的产品,更突出他的工艺优越性。 六、可设计性好。可以灵活的设计产品结构,满足使用要求,也可以充分的选择材料,满足产品性能。例如输水管道,可以选择食品级树脂,来输送饮用水,也可采用耐腐树脂,来输送化工原料,可以采用无碱玻璃纤维,制成可以输送消防水的高压管道,也可以采用添加石英砂作成刚度达10000的夹砂地埋管。 七、颜色可随意调整,美观实用。玻璃钢通过在原材料中加入颜料(胶衣树脂糊)或喷涂等方式,制作出千变万化的颜色来,美观实用,不褪色。 随着市场经济的发展,人类社会的进步,这一被世界上公认的“绿色产品”,将在各领域得到广泛的应用,市场前景和潜力很大。

way 的用法

way 的用法 【语境展示】 1. Now I’ll show you how to do the experiment in a different way. 下面我来演示如何用一种不同的方法做这个实验。 2. The teacher had a strange way to make his classes lively and interesting. 这位老师有种奇怪的办法让他的课生动有趣。 3. Can you tell me the best way of working out this problem? 你能告诉我算出这道题的最好方法吗? 4. I don’t know the way (that / in which) he helped her out. 我不知道他用什么方法帮助她摆脱困境的。 5. The way (that / which) he talked about to solve the problem was difficult to understand. 他所谈到的解决这个问题的方法难以理解。 6. I don’t like the way that / which is being widely used for saving water. 我不喜欢这种正在被广泛使用的节水方法。 7. They did not do it the way we do now. 他们以前的做法和我们现在不一样。 【归纳总结】 ●way作“方法,方式”讲时,如表示“以……方式”,前面常加介词in。如例1; ●way作“方法,方式”讲时,其后可接不定式to do sth.,也可接of doing sth. 作定语,表示做某事的方法。如例2,例3;

国内玻璃纤维产品的应用及行业分析

玻璃纤维行业 玻璃纤维产业在我国属于朝阳产业,玻纤产品广阔的应用前景给玻纤产 业带来了良好的发展机遇,玻纤产业目前正逐渐由成熟期进入繁荣期。 我国玻璃纤维年产量平均增长速度超过世界玻璃纤维年产量平均增长速 度,2003 年达到47.3 万吨,占世界总产量的1/5,估计2004 年能达到 60 万吨。 我国玻纤产业的兴旺得益于池窑拉丝技术的成熟,池窑拉丝产品品质高, 能耗低,有利于企业进行规模扩张。2003 年池窑拉丝产量达到总产量的 58.1%,预计到2005 年能达到80%。 目前我国玻纤行业正在进入新一轮产能扩张浪潮中,2004 年新增产能 19.1 万吨,有8 条万吨级以上池窑玻纤生产纤点火投产。 2004 年上半年,我国玻纤行业首次实现贸易顺差5917.55 万美元,彻 底扭转了整个行业多年来的逆差局面,池窑拉丝产品已经成为出口的增 长支柱,估计2004 年可实现进出口贸易额10 亿美元以上,贸易顺差突 破1 亿美元。这一有利局面还将继续保持。 以浙江巨石、泰山玻纤、重庆国际为首的三大巨头在2003 年的产量集 中度达到60%,2004 年三者都加快了前进的步伐,目前各自有大型的 生产基地正在建设中,未来的三足鼎立之势已悄然展露。 玻璃纤维行业蕴藏着巨大的投资机会,建议关注浙江巨石的控股股东中 国玻纤和重庆国际的控股股东云天化,这两大玻纤巨头的良好业绩对其 控股上市公司的股价会起到强力支撑作用。 目录 国内玻璃纤维产品的应用 (3) 1、电子领域 (3) 2、交通领域 (3) 3、建筑领域 (3) 4、其他 (4) 我国玻璃纤维行业发展状况 (5) 我国玻璃纤维产量增速超过世界平均水平 (5) 先进的池窑法生产的玻纤产品比重直线上升 (6) 无碱玻纤产量占玻纤总产量比例呈稳步上升 (7) 我国玻璃纤维行业进出口状况分析 (8) 我国玻璃纤维行业价格走势分析 (9) 1、细纱市场 (9) 2、粗纱市场 (9) 未来我国玻纤行业企业将成三足鼎立态势 (10) 巨石集团有限公司 (11) 泰山玻璃纤维股份有限公司 (11) 重庆国际复合材料有限公司(CPIC) (12) 国外玻璃纤维行业企业在国内的基本发展情况 (13) 玻璃纤维行业研究Jan-2005 谨请参阅尾页重要申明及联合证券股票和行业评级规范。欢迎访问我们http:// 219.133.104.135/ibase。3/15

玻璃纤维增强塑料

玻璃纤维增强塑料(FRP)基础知识一.什么是复合材料 指一种材料不能满足使用要求,需要由两种或两种以上的才料,通过某种技术方法结合组成另一种能够满足人们需求的新材料,叫做复合材料。 二.什么是玻璃纤维增强塑料(FiberReinforcedPlastics)指用玻璃纤维增强,不饱和聚酯树脂(或环氧树脂;酚醛树脂)为基体的复合材料,称为玻璃纤维增强塑料。简称FRP 由于其强度相当于钢材,又含有玻璃纤维且具有玻璃那样的色泽;形体和耐腐蚀;电绝缘;隔热等性能,在我国被俗称为“玻璃钢”。这个名称是原中国建筑材料工业部部长赖际发在1958年提出的一直延用至今。 三.FRP的基本构成 基体(树脂)+增强材料+助剂+颜料+填料 1.基体(树脂):环氧树脂;酚醛树脂;乙烯基树脂;不饱和聚酯树脂;双酚A等

2.增强材料(纤维):玻璃纤维;碳纤维;硼纤维;芳纶纤维;氧化铝纤维;碳化硅纤维;玄武岩纤维等。 3.助剂:引发剂(固化剂);促进剂;消泡剂;分散剂;基材润湿剂;阻聚剂;触边剂;阻燃剂等。 4.颜料:氧化铁红;大红粉;炭黑;酞青兰;酞青绿等。多数为色浆状态。 5.填料:重钙;轻钙;滑石粉(400目以上);水泥等。PVC:聚氯乙烯,硬PVC和软PVC,硬PVC有毒。PPR:聚丙烯。 PUR:泡沫。 PRE:聚苯醚。 尼龙:聚酰胺纤维。 FRP的发展过程:无法确定发明人。 四.FRP材料的特点: 1.优点: (1)质轻高强:FRP的相对密度在1.5~2.0之间,只有碳钢的1/4~1/5但是拉伸强度却接近甚至超过碳素钢,而强度

可以与高级合金钢相比,被广泛的应用于航空航天;高压容器以及其他需要减轻自重的制品中。 (2)耐腐蚀性好:FRP是良好的耐腐蚀材料,对于大气;水和一般浓度的酸碱;盐及多种油类和溶剂都有较好的抵抗力,已经被广泛应用于化工防腐的各个方面。正在取代碳钢;不锈钢;木材;有色金属等材料。 (3)电性能好:FRP是优良的绝缘材料,用于制造绝缘体,高频下仍能保持良好的介电性,微波透过性良好,广泛应用于雷达天线罩;微波通讯等行业。 (4)热性能好:FRP导电率低,室温下为1.25~1.67KJ只有金属的1/100~1/1000是优良的绝热材料。在瞬间超高热情况下,是理想的热保护和耐烧蚀材料。 (5)可设计性好:可根据需求充分选择材料来满足产品的性能和结构等要求。 (6)工艺性能优良:可以根据产品的形状来选择成型工艺且工艺简单可以一次成型。 2.缺点:

E-CR玻璃纤维介绍

E-CR玻璃介绍 无硼玻璃纤维从20世纪70年代末到80年代初开始商业化生产,但直到90年代末才在世界各地大规模生产。由于玻璃和化学技术的发展、制造过程的改进,使无硼玻璃纤维进入商业领域,在增强塑料中,无硼玻璃纤维比传统的无碱玻璃纤维性质要好。 E-CR玻璃的发展和应用 在过去的30年期间,出于环保的考虑增多,导致一些限制性的污染标准出台,工作人员研究了一些减少污染的技术,比如,改变玻璃的组成成分,但是大多数人员选择在废气排到大气前,处理这些废气来减少污染,从而来控制E玻璃的污染。有一种减少环境污染的新方法,那就是改变E玻璃的组成来去除硼和氟的污染,这一技术的应用需要玻璃熔化技术和显微结构技术的发展,从而来解决由于玻璃组成的改变而带来的问题。改变玻璃的组成是非常重要的事情,它牵涉到大量的工作,尽管存在许多潜在的问题,一些工作人员仍在不断反复的做着改变E玻璃组成的试验。 在E玻璃中,B2O3和F2是挥发的成份,在玻璃熔化时,大量的挥发物会挥发出来,影响挥发的因素有熔化温度、熔化率和水分含量。B2O3挥发15%-25%,F2挥发50%生成SiF4未挥发出来的F2生成CaF2和Na2SiF6,在过去的几年中,B2O3已从8%降到5%,F2也由0.5%降到0.2%,B2O3能降低熔体的玻璃黏度,F2是一种助熔剂,起助熔作用,它还是一种还原剂,降F2后,需增加一些还原剂(如碳粉、矿渣、硫酸盐、亚硫酸盐等)。

E-CR玻璃的配方来源于加拿大的OCF,在其他国家也有应用,E-CR玻璃中不含硼和氟,该种玻璃在加拿大使用了25年无需任何废气处理设备,玻璃成分和含硼含氟的E玻璃成分相似,如果经过化学处理,其效果会更好一些,另外,一些特殊的原料和某些设备需要改进。 OCF在90年代末,开始向与E-CR玻璃相似的玻璃配方转变,该成份组成无硼无氟,价格昂贵的原料用的很少,新OCF波玻璃有较高的软化点,比E玻璃需要较高的熔化温度,并且组成也不同,传统的E玻璃软化点的变化范围在830℃—860℃之间,E-CR玻璃大约为880℃,新OCF玻璃大约在916℃,由于无硼无氟,所以不需要一些废气处理设备,正是这个原因,OCF领导着玻纤市场,E-CR玻璃被ASTMD578-00标准定义为改性玻璃:事实上,由于E-CR玻璃的多功能性几乎取代了E玻璃。 E玻璃纤维处在酸性环境中时,会受到酸性物质的侵蚀,在这个过程中,首先侵蚀CaO和MgO,并能破坏它的骨架组成,而E-CR 玻璃有耐酸侵蚀性,E-CR玻璃在合成隔热材料方面也比E玻璃有很多优点。 玻璃成分讨论 硼和氟是影响玻璃黏度和表面张力的两大重要成分,在玻璃纤维生产过程中,保持温度—黏度两者的稳定关系非常重要,玻璃的组成决定玻璃的黏度,拉丝黏度一般在102.8—103泊,E玻璃纤维碱金属氧化物含量在一定的范围内,Na2O、K2O和Li2O质量百分比小于1%。

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