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1、第26卷第3期Vol126,No13西 华 大 学 学 报 自 然 科 学 版Journal of Xihua UniversityNatural Science2007年5月May 2007文章编号:16732159X(2007)0320001203 收稿日期:2006212216 基金项目:武器装备预研基金资助项目(No151481260105SC0301)作者简介:赵 平(19542),男,四川省南溪县人,教授,博士,主要从事特种材料制备技术,高性能结构材料研究。E2mail:zp661 氢化锆表面氢渗透阻挡层形貌和组织分析赵 平1,彭 倩2,孔祥巩2,邹从沛2(11 西华大学材料科学与
2、工程学院,四川 成都610039;21 中国核动力研究设计院核燃料及材料国家重点实验室,四川 成都610041)摘 要:用氧化预处理和电镀法在氢化锆表面生成Cr2C镀层,经过400、10h预加热得到氢渗透阻挡层并对试样进行加热至700、保温10h的氢渗透试验。用XRD对氢渗透阻挡层的组成物进行了分析,用SEM对氢渗透试验后的阻挡层表面和截面进行观察和微区成分分析。分析结果表明,该阻挡层中存在Cr2O3、金属Cr、O和C,阻挡层与基体之间存在一个由baddeleyite结构的ZrO2组成的致密的过渡层;阻挡层基本致密。关键词:氢化锆表面;baddeleyite结构的ZrO2过渡层;氢渗透阻挡层
3、中图分类号:TG11112 文献标识码:A0 引言氢化锆可以在小型核反应堆中作为中子慢化剂使用,但其中的氢在工作温度下极易从基体中渗透出来,影响氢化锆慢化剂的慢化能力,所以阻止氢化锆中氢的渗透就成了必须解决的一个关键问题。国内外对氢渗透的研究很多,但是目前公开报道的研究和应用都集中于防止氢及其同位素的渗透,其主要的方法是在容器表面形成氧化物、碳化物和氮化物等126。关于阻挡氢渗透的机理,文献4认为表面层中的C的悬链可以捕获氢而起到阻挡或减缓氢渗透的作用;Y1S1Li等人5,6对金箔上制备的厚度分别为10!和26!,经过等离子体处理和加热后的Zr氧化膜进行了XPS分析后,认为在该氧化膜中存在Zr
4、O2以及ZrOx(x 2)和ZrOy(x y 2),这种Zr氧化物及其与ZrO2的界面可能起到捕捉氢而生成2OH原子团的作用。总之,比较一致的观点是,含有C或O的膜层是良好的氢渗透阻挡层。对于在氢化锆表面建立氢渗透阻挡层的研究,能见到的公开报导较少。文献729 讨论了用CO2氧化法在氢化锆表面制备氧化锆阻挡层的工艺并分析了该阻挡层的结构,文献10 介绍了用电镀法在氢化锆表面制备Cr2C2O氢渗透阻挡层的工艺。本文的目的在于对用电镀+适度氧化法制备的氢渗透阻挡层的组织结构进行比较深入的分析,以便能够系统地描述其结构,以证明所用制备方法能否得到氢渗透阻挡层所具有的组成和结构。1 实验方法与实验结果
5、试验所用氢化锆结构为ZrH11801,即H/Zr原子比约为11801。按照文献10介绍的制备工艺,首先将6621 mm氢化锆试样进行氧化预处理,然后在含有有机酸的镀液中电镀得到一层Cr2C镀层(以后简称为镀层),再将试样在普通电阻炉中在空气中进行预加热(4005,保温10 h),即得到如文献10所介绍的氢渗透阻挡层(以后简称为阻挡层)。氧化预处理后的试样表面XRD分析结果如图1所示,图2为镀层的XRD分析结果;图3为400 加热后的阻挡层XRD分析谱图。图1 氧化预处理一氢化锆表面XRD分析图2 氢化锆表面电镀层XRD分析图3 氢化锆表面氢渗透阻挡层XRD分析对经过400预加热后的试样进行氢渗
6、透试验:放入真空烧结炉中,抽真空至7191023Pa、升温至700,保温10h,然后随炉冷却至室温。对氢渗透试验后的阻挡层进行XRD分析得到的谱图与图3基本一致,在此没有列出;再仔细地磨去表面阻挡层作XRD分析,其结果如图4所示。图4 氢渗透试验后阻挡层XRD分析图5 氢渗透阻挡层表面SEM形貌在扫描电镜下观察经过氢渗透试验后的阻挡层表面,其形貌如图5所示。另外取试样的横截面磨成金相样在扫描电镜下观察阻挡层及其与基体的结合层形貌并进行微区成分分析,图6为截面形貌的SEM照片和微区分析的位置,表1是微区分析结果。图6 氢渗透阻挡截面SEM形貌表1 试样截面微区成分分析数据NO.iTEMZrOCC
7、ra%at2912770173%wt7012329177b%at3817261128%wt7812721173c%at100%wt100d%at151246616118115%wt121274012547148e%at1815181149%wt41999510412 分析与讨论从图1可以看到,经过氧化预处理的氢化锆试样部分氧化为baddeleyite结构的ZrO2,其余X射线能够检测到的仍然为ZrH11801结构的氢化锆。电镀以后,从XRD分析结果(见图2)可以看到,镀层中有金属Cr出现,但可能是量少的原因,没有发现C或C的化合物。而谱图中的baddeleyite结构的ZrO2,应该是预处理的
8、产物。经过400加热得到的阻挡层中不仅仍然有金属Cr,并出现了Cr2O3(见图3)。同样由于X射线穿透了阻挡层,谱图中出现了baddeleyite结构的ZrO2峰。经过氢渗透试验后的XRD谱图与图3一致,即阻挡层的基本结构没有受到明显影响。图4是将试样表面阻挡层磨去后得到的谱图,由图可看出仍然是baddeleyite结构的ZrO2和基体。2西华大学学报 自然科学版2007年用SEM观察经过700加热的阻挡层表面,可以看到,阻挡层表面不是完全平整(如图5所示)。从试样的截面形貌(见图6)也可以看到,阻挡层表面确实不平整,其中还有少量的没有连接贯通的孔隙。同时可以看到,阻挡层与基体之间存在明显的过
9、渡层(如图6中的a点所示),而这一过渡层是连续、致密的并且与基体和阻挡层均紧密地结合在一起。仔细观察可看到,过渡层向基体中生长出了许多分枝(如图6中的b点)。根据表1的微区分析数据能够知道,这一过渡层和深入基体的分枝均由Zr和O组成,结合XRD分析结果可认为该过渡层为baddeleyite结构的ZrO2。由微区成分分析数据可知,过渡层以外是阻挡层,其组成为Cr、C、O,但对阻挡层不同区域的微区成分分析可知,其组成不一致,如c点为Cr,d点为Cr、O和C,e点为Cr、C。同时微区成分分析数据也可认定,阻挡层中有C存在,说明在镀液中配有机酸得到含C阻挡层的目的达到了,这也和文献11介绍的用含有有机
10、酸的镀液进行电镀可得到Cr2C镀层的结果相符。过渡层由Zr和O组成以及阻挡层中既含有O又含有C,而目前多数研究报告认为,氢渗透阻挡层中的C或O可以捕捉H而大幅度地降低其扩散速率,因此可认为,本试验所得到的阻挡层具备有效地降低氢的渗透速率而成为氢渗透阻挡层的条件。3 结论(1)本试验采用的制备工艺基本没有影响氢化锆试样的基体。(2)本试验采用的制备工艺可在氢化锆试样表面得到baddeleyite结构的ZrO2过渡层和Cr2C2O阻挡层。参 考 文 献1 I.Tazhibaeva,A.Klepikov,O.G.Romanenko,et al.Hydro2gen Permeation Through
11、 Steels and Alloys with Different ProtectiveCoatingsJ.Fusion Engineering and Design,2000,51252:1992205.2 Y.Yamada2Takamura,F.Koch,H.Maier,et al.HydrogenPermeation Barrier Performance Characterization of Vapor DepositedAmorphous Aluminum Oxide Films Using Coloration of Tungsten OxideJ.Surface and Coa
12、tings Technology.2002,153:1142118.3 Byung Hyuck Lim,Hyun Seon Hong,Kyung Sub Lee.Mea2surements of Hydrogen Permeation and Absorption in Zirconium OxideScalesJ.Journal of Nuclear Materials.2003,312:1342140.4王佩璇,王 宇,史宝贵.不锈钢表面沉积SiC作为氢渗透阻挡层的研究J.金属学报,1999,35(6):6542658.5 P.C.Wong,Y.S.Li,M.Y.Zhou,K.A.R.Mi
13、tchell.XPS In2vestigation of the Interactions of Hydrogen with Thin Films of Zirconi2um Oxide I.Hydrogen Treatment a 10!Thick FilmJ.Applied Sur2face Science,1995,89:2552261.6 Y.S.Li,P.C.Wong,K.A.R.Mitchell.XPS Investigationsof the Interactions of Hydrogen with Thin Films of Zirconium Oxide.Effects o
14、f Heating a 26!Thick Film after Treatment with a HydrogenPlasmaJ.Applied Surface Science,1995,89:2632269.7张华锋,杨启法,王振东,等.氢化锆高温抗氢渗透涂层研究J.原子能科学技术,2005,39(1):83287.8赵 平,彭 倩,孔祥巩,等.氢化锆表面CO2反应层结构分析J.核动力工程,2005,26(4):3772379,405.9刘庆生,秦丽娟,常 英,等.CO2反应法制备氢化锆表面氢渗透阻挡层的研究.表面技术,2005,34:32234.10秦丽娟,赵 平.氢化锆表面电镀铬制备氢渗
15、透阻挡层的研究J.材料开发与应用,2005,20(3):25227.11陈 亚.现代实用电镀技术M.北京:国防工业出版社,2003:2782284.(编校:周剑华)3第3期赵 平 等:氢化锆表面氢渗透阻挡层形貌和组织分析Vol126,No13Journal of Xihua UniversityNatural Science2007ABSTRACTSStudy on the Structure of Hydrogen PermeationBarrier on the Surface of Zirconium Hydride Sub2strateZHAO Ping(School of Mater
16、ials Science and Engineering,XihuaUniversity,Chengdu 610039 China),PENG Qian,et al.JOURNALOF XIHUA UNIVERSITY.v.26,no131PP1123,3/2007.(ISSN 16732159X;In Chinese)Abstract:A layer of chromium2carbon alloy film on thesurface of zirconium hydride substrate was fabricated by re2treatment of oxidation and
17、 electroplating,and then was re2heat2ed for 10 hours at a temperature of 400to obtain a hydrogenpermeation barrier film.Afterward the sample was heated at atemperature of 700for 10 hours,which is called hydrogenpermeation test.XRD is used to analyze the structure of thefilm,and SEM is employed to ob
18、serve the surface and the sec2tion of the film and to analyze the compositions on the section.Results indicate that there are Cr2O3,Cr,O and C in the film;and a transition2layer made up of ZrO2with a structure of bad2deleyite exists between the matrix and the film;the film seemsto be compacted.Key w
19、ords:zirconium hydride surface;interface of badde2leyite ZrO2;hydrogen permeation barrierSr3Al2O6:Eu2+White Light Phosphor Reducedwith the Aid of PWEI Wan2qiang(School of Materials Science and Engineering,Xi2hua University,Chengdu 610039 China),HE Yi,et al.JOURNALOF XIHUA UNIVERSITY.v.26,no131PP1425
20、,3/2007.(ISSN 16732159X;In Chinese)Abstract:By using solid reaction method at high tempera2ture,a new kind of Sr3Al2O6:Eu2+white light Phosphor issynthesized in the carbon thermal reduction atmosphere withthe aid of(NH4)3PO43H2O,which indicates that Sr3Al2O6:Eu2+is the main phase in the resultant,an
21、d the bright continu2ous luminescence can be obtained in the range of 380 nm and650 nm when the sample doped with 10%P excited by 250 nmultraviolet.Key words:Sr3Al2O6:Eu2+;solid reaction method;whitelight phosphor;phosphor aided reduceFormation and Crystallization of Ti2Al Alloy byMolecular Dynamics
22、 SimulationLIU Liu(School of Materials Science and Engineering,Xihua Uni2versity,Chengdu 610039 China),J IA Xing2wang,et al.JOURNALOF XIHUA UNIVERSITY.v.26,no131PP1628,3/2007.(ISSN 16732159X;In Chinese)Abstract:In this paper,the formation of amorphous Ti2Alalloy and its crystallization process were
23、studied by moleculardynamics simulation.The amorphous alloy was obtained byquenching under melting state.Through the quenching withdifferent cooling rate,the critical amorphous transition rate ofvarious concentration alloys was gained,which indicates thatthe alloy of 4090 at%Al has the lower transit
24、ion rate andtherefore is more capable of getting in amorphous state in cool2ing process.The conformation analysis shows that the amor2phous alloy is mainly composed of icosahedral and original crys2tal clusters.With the analysis of the crystallization,the mi2cromechanism of this process is,in fact,t
25、he decrease in the de2fect and the icosahedral clusters,on the other hand,the in2crease in the original crystal cluster in amount and volume.Key words:Ti2Al amorphous alloy;molecular dynamicssimulation;crystallizationPreparation of NiO Using Vacuum Treating andInvestigation into the Characteristics
26、of Super2Ca2pacitorLI Sheng(School of Materials Science and Engineering,Xihua Uni2versity,Chengdu 610039 China),DING Shi2hua,et al.JOURNAL OFXIHUA UNIVERSITY.v.26,no131PP19211,3/2007.(ISSN 16732159X;In Chinese)Abstract:Ni(NO3)2was used as material to prepareNi(OH)2by Sol2Gel method.Under the conditi
27、on of 91510-311510-2Pa,the Ni(OH)2was dealt in different tem2peratures with vacuum sintering oven to get NiO,which wasused to form unsymmetrical super2capacitor with AC.The un2symmetrical super2capacitor in charging and discharging pro2cessing with the different current densities was tested.Com2pari
28、son between charging and discharging value at 200 mA/gfor all the samples was conducted.The results gained show thatvacuum2treating at 300will get the highest specific capaci2tance,which reached to 361192 F/g.The contrasting researchon the influence of the two techniques on the specific capaci2tance
29、 in condensers indicates that NiO prepared using Ni(OH)2by vacuum2treating process will have higher specific capacitancethan those treated with tube2type resistor2oven.So,adoptingthe vacuum2treating to prepare NiO is an effective way to im2prove the electric capacity.Key words:super capacitor;vacuum treating;Sol2Gel;NiO;specific capacitancePrediction of Springback Value for U ShapedParts in the Stamping Process of Auto Body Panel