Effect of ZrO2 on phase transformation of Al2O3

材料专业英文词汇（全）来源：李硕的日志化学元素（elements）化学元素，简称元素，是化学元素周期表中的基本组成，现有113种元素，其中原子序数从93到113号的元素是人造元素。

物质(matter)物质是客观实在，且能被人们通过某种方式感知和了解的东西,是元素的载体。

材料(materials)材料是能为人类经济地、用于制造有用物品的物质。

化学纤维(man-made fiber, chemical fiber)化学纤维是用天然的或合成的高聚物为原料，主要经过化学方法加工制成的纤维。

可分为再生纤维、合成纤维、醋酯纤维、无机纤维等。

芯片（COMS chip）芯片是含有一系列电子元件及其连线的小块硅片，主要用于计算机和其他电子设备。

光导纤维（optical waveguide fibre）光以波导方式在其中传输的光学介质材料，简称光纤。

激光(laser)（light amplification by stimulated emission of radiation简写为：laser）激光是利用辐射计发光放大原理而产生的一种单色（单频率）、定向性好、干涉性强、能量密度高的光束。

超导(Superconduct)物质在某个温度下电阻为零的现象为超导，我们称具有超导性质的材料为超导体。

仿生材料(biomimetic matorials)仿生材料是模仿生物结构或功能，人为设计和制造的一类材料。

材料科学(materials science)材料科学是一门科学，它从事于材料本质的发现、分析方面的研究，它的目的在于提供材料结构的统一描绘，或给出模型，并解释这种结构与材料的性能之间的关系。

材料工程(materials engineering)材料工程属技术的范畴，目的在于采用经济的、而又能为社会所接受的生产工艺、加工工艺控制材料的结构、性能和形状以达到使用要求。

材料科学与工程(materials science and engineering)材料科学与工程是研究有关材料的成份、结构和制造工艺与其性能和使用性能间相互关系的知识及这些知识的应用，是一门应用基础科学。

第22卷第3期半导体光电Vol.22No.3 2001年6月Semiconductor Optoelectronics June2001文章编号：1001-5868（2001）03-0181-03利用制备参数的改变调整VO2薄膜的电阻温度系数卢勇，林理彬（四川大学物理系辐射物理及技术教育部重点实验室，四川成都610064）摘要：利用真空还原方法，通过合理控制时间和真空退火温度，制备出具有优良热致相变特性的VO2薄膜，并对不同真空还原时间、真空退火温度和衬底条件下制备的VO2薄膜结构和半导体相的电阻温度系数进行了研究。

结果表明，不同制备参数对所得薄膜的结构和价态有显著影响，从而对VO2的电阻温度系数产生较大调整。

关键词：VO2薄膜；热致相变；电阻温度系数中图分类号：TO135.1；TN215文献标识码：AModulation of TCR for VO2Thin Film byChanging Preparation ParametersL Yong，LIN Li-bin（Irradiation Physics and Technology Key Lab.of NationalEducation Ministry，Dept.of Physics，Sichuan University，Chengdu610064，China）Abstract：Measurements on electrical property for VO2thin films prepared under different conditions is performed.The effect of preparation conditions on the change of electrical property is studied.The results show that different preparation conditions can not only produce VO2thin films with good thermal induced phase transition property but can also modulate the temperature coefficient of resistance（TCR）for VO2thin films.The cause of the vorriation of TCR is also discussed.Key words：VO2thin film；thermal induced phase transition property；TCR1引言VO2是一种典型的过渡金属氧化物，它在68!C左右发生低温半导体态到高温金属态的一级相变，同时伴随有电导和光透过率的突变。

基于B酸与L酸协同催化的乙酰丙酸酯化反应柳晨露;刘颖;武书彬【摘要】将甘蔗渣以碳化-磺化的方法制备出B酸催化剂(C-SO3 H),并与L酸CrCl3协同催化乙酰丙酸(LA)和乙醇的酯化反应,通过单因素实验和正交实验优化乙酰丙酸酯化反应,探究最佳反应条件.结果表明,在B酸与L酸质量比为1:1,反应摩尔比(LA:EtOH)为1:5,反应时间为8 h,反应温度为90℃的条件下,乙酰丙酸乙酯(ELA)的得率达89.7％.另外,对照组实验的结果说明,B酸与L酸在酯化反应中有一定的协同作用,提高了乙酰丙酸乙酯的得率.【期刊名称】《应用化工》【年(卷),期】2019(048)002【总页数】4页(P361-364)【关键词】甘蔗渣;B酸与L酸;乙酰丙酸乙酯;正交实验【作者】柳晨露;刘颖;武书彬【作者单位】华南理工大学制浆造纸与工程国家重点实验室,广东广州 510641;华南理工大学制浆造纸与工程国家重点实验室,广东广州 510641;华南理工大学制浆造纸与工程国家重点实验室,广东广州 510641【正文语种】中文【中图分类】TQ35随着能源消耗的剧增，全球不可再生能源资源日益枯竭，人类对可再生能源的开发和利用引起了越来越多的关注。

乙酰丙酸酯是一类非常有潜力的新能源化学品，具有广泛的工业应用价值[1-2]。

用于催化乙酰丙酸酯生成的催化剂主要包括无机酸[3-4]和固体酸[5-7]。

磺化碳催化剂因其显著的催化效果，可回收使用的优势而被广泛研究；其可通过纤维素[8-9]、木材[10-11]等碳化-磺化制备所得，应用于各类酸的酯化反应[12-13]。

各类无机盐催化剂，在酯化反应中表现突出，但不易回收。

为了探究B酸与L酸在酯化反应中的协同作用，本文通过单因素实验和正交实验获得乙酰丙酸(LA)与乙醇(EtOH)酯化生成乙酰丙酸乙酯(ELA)的最佳反应条件。

1 实验部分1.1 试剂与仪器蔗渣，取自蔗糖加工厂；乙酰丙酸、乙醇、甲苯、硫酸、氯化铬等均为分析纯。

第26卷第5期 硅　酸　盐　通　报 Vol .26　No .5　2007年10月 BULLETI N OF THE CH I N ESE CERAM I C S OC I ETY Oct ober,2007　Zr O 2对L i 2O 2A l 2O 32S i O 2微粉析晶行为的影响吴松全,刘宇艳,王福平,孙德智(哈尔滨工业大学,哈尔滨　150001)摘要:采用高分子网络凝胶法成功地制备出L i 2O 2A l 2O 32Si O 22Zr O 2(LASZ )微晶玻璃粉,探讨了添加不同含量Zr O 2对LASZ 微晶玻璃的析晶行为和相转变的影响。

研究表明:热处理温度在700～1200℃时,LASZ 微粉先形成六方晶系的β2石英固溶体,随热处理温度的升高,逐渐转变为稳定的四方晶系β2锂辉石固溶体。

Zr O 2含量增加,降低了β2石英固溶体的结晶温度,延迟了β2石英固溶体向β2锂辉石固溶体的转变。

当Zr O 2的物质的量分数从0增加到4.0%时,析晶活化能从304.6kJ /mol 降低到248.9kJ /mol 。

所获得的LASZ 粉末晶粒大小为20～60n m,晶粒尺寸随温度的升高而增大,随Zr O 2的增加而下降。

本实验所制备的LASZ 微晶玻璃的热膨胀系数为(4～14)×10-7/℃。

关键词:高分子网络凝胶法;L i 2O 2A l 2O 32Si O 2微晶玻璃;Zr O 2;β2石英;β2锂辉石中图分类号:T Q171.733 文献标识码:A 文章编号:100121625(2007)0520845206Effect of ZrO 2on the Cryst a lli za ti on Behav i or of L i 2O 2A l 2O 32S i O 2Gl a ss 2Ceram i c PowdersWU Song 2quan,L I U Yu 2yan ,WAN G Fu 2ping,SUN D e 2zhi(Harbin I nstitute of Technol ogy,Harbin 150001,China )Abstract:By using polyacryla m ide gel method and sintering at high te mperature,L i 2O 2A l 2O 32Si O 22Zr O 2(LASZ )glass 2cera m ic po wders were p repared .The effects of Zr O 2additi on on the crystallizati on and phase transfor mati on p r ocess in LASZ syste m were investigated .W hen heating the dried gels fr om 700℃t o 1200℃f or 2h,hexagonal β2quartz s olid 2s oluti on first crystallized and then gradually transf or med int o tetragonal β2s podumene s olid 2s oluti on with increasing te mperature .The crystallizati on of β2quartz s olid 2s oluti on was enhanced and the transf or mati on fr om β2quartz s olid 2s oluti on t o β2s podu mene s olid 2s oluti on was increasingly restricted as more Zr O 2was added in the studied LASZ glasses .The activati on energy decreased fr o m 304.6kJ /mol t o 248.9kJ /mol as the Zr O 2content changed fr om 0mol%t o 4.0mol%.The average particle size of the LASZ powders is 20260nm and has a tendency t o increase with the increasing of calcined te mperature and decrease obvi ously with the increasing of Zr O 2additi on .The ther mal expansi on coefficient of LASZ glass 2cera m ic made fr o m LASZ powders by the polyacryla m ide gelmethod is about (4214)×10-7/℃.Key words:polyacryla m ide gel method;L i 2O 2A l 2O 32Si O 2glass cera m ic;Zr O 2;β2quartz;β2s podu mene 作者简介:吴松全(19722),男,博士,副教授.主要从事微晶玻璃的研究.E 2mail:wus ongquan@hit .edu .cn1　引　言锂铝硅(L i 2O 2A l 2O 32Si O 2,LAS )系微晶玻璃(如β2石英固溶体或β2锂辉石固溶体)具有极低的热膨胀系846　专题论文硅酸盐通报 第26卷数、优异的抗热震性能和较高的机械性能,在烹调灶面板、大型天文望远镜镜坯、激光管的腔体等方面得到了广泛应用[1,2]。

Effect of supercritical CO 2on phase structure of PEO/PVAc blendsevaluated from SAXS absolute intensity measurementYeong-Tarng Shieh a,*,Yen-Gu Lin a ,Hsin-Lung Chen baDepartment of Chemical Engineering,National Yunlin University of Science and Technology,123University Road,Section 3,Touliu,Yunlin 640,Taiwan,ROCbDepartment of Chemical Engineering,National Tsing Hua University,Hsin-Chu 300,Taiwan,ROCReceived 11December 2001;received in revised form 25February 2002;accepted 27February 2002AbstractThe effect of supercritical CO 2on the morphological structure of crystalline/amorphous PEO/PVAc blends was investigated by means of SAXS with the measurement of absolute scattering intensity.The morphological structure of PEO/PVAc exhibited a considerable change upon CO 2treatment as demonstrated by the drastic increase of scattering intensity,or the enhancement of electron density contrast between the crystalline and amorphous layers in the lamellar stacks,resulting from the swelling of amorphous PEO via the incorporation of CO 2into the interlamellar (IL)regions and/or the expulsion of PVAc from the IL regions.Upon CO 2treatment,the crystal and amorphous layer thickness (l c and l a ,respectively)were both pared with the increase of l a ,the increase of l c was relatively signi®cant and was attributed to the occurrence of melting and recrystallization during CO 2treatment leading to thicker PEO crystals via a depression of equilibrium melting temperature and/or an increase of crystal fold surface free energy.The measured electron density contrast revealed that the distance of segregation in PEO/PVAc blends involved the extralamellar segregation before CO 2treatments and the swelling of inter-lamellar region dominated the drastic increase of scattering intensity after CO 2treatments.The ®nding of extralamellar morphology was consistent with the magnitude of volume fraction of lamellar stacks in the blends.The lamellar size distribution appeared to be broader and the lamellar stacks more disorganized for the blends after CO 2treatments according to SAXS one-dimensional correlation function pro®les.q 2002Elsevier Science Ltd.All rights reserved.Keywords :Crystallization;Phase segregation;Lamellar1.IntroductionCrystallization of a melt-miscible crystalline/amorphous blend involves the segregation of amorphous diluent.Depending upon the distance of segregation,various types of morphology may be created.These segregation types include (1)interlamellar (IL)segregation,where segrega-tion of the diluent occurs at lamellar level,so that the diluent is located in the IL regions;(2)inter®brillar (IF)segrega-tion,where the diluent is segregated by a larger distance to the regions between the lamellar bundles in spherulites;and (3)interspherulitic (IS)segregation,where the diluent is segregated by the largest distance to the regions between spherulites [1,2].The latter two types characterized by the longer segregation distance are also termed as `extralamel-lar segregations'.These morphological patterns represent the diluent dispersion from nanoscopic scale for IL segrega-tion to micrometer scale for IS segregation.Different scales of segregation may lead to different properties.A blend system does not necessarily exhibit only one type of morphology.Different types of morphology may coexist leading to multiple locations for the amorphous diluent [3±7].Keith and Padden [8]suggested that the distance over which uncrystallizable diluent may be segregated is determined by the interplay between the diffusion coef®-cient (D )of impurity molecules and the crystal growth rate (G ).If the diffusion of diluent is relatively slow compared to the crystal growth,the diluent molecules may be trapped inside the IL regions.If diluent diffusion is faster,on the other hand,extralamellar segregation is generated.The interplay between D and G is de®ned by the parameter,d D =G :d has the unit of length and thus provides a quali-tative measure of segregation distance.d may depend on the composition,temperature,molecular weight,and polymer±polymer interaction of the blend.Poly(ethylene oxide)(PEO)/poly(vinyl acetate)(PVAc)Polymer 43(2002)3691±36980032-3861/02/$-see front matter q 2002Elsevier Science Ltd.All rights reserved.PII:S0032-3861(02)00190-8/locate/polymer*Corresponding author.Tel.:1886-5-534-2601;fax:1886-5-531-2071.E-mail address:shiehy@.tw (Y.-T.Shieh).crystalline/amorphous blends have been known to be compatible by both theoretical prediction and experimental results[9±16].Segregation morphology of PEO/PVAc blends has been studied.Martuscelli and Silvestre and coworkers[11,12]examined the segregation morphology by small angle X-ray scattering(SAXS)and found that PVAc was incorporated into the IL regions of PEO crystals. Segregation of the amorphous diluent was found to strongly depend on T g and molecular weight[17].Runt and co-workers[18]found that segregation of the weakly interact-ing polymer pairs(e.g.PEO/poly(methyl methacrylate) (PMMA)and PEO/PVAc)was largely dependent on glass transition temperatures(T g)of the amorphous diluent.The high-T g diluent(e.g.PMMA)was found to reside exclusively in IL regions whereas the low-T g diluent(e.g. PVAc)was excluded at least partially into IF regions.The introduction of strong intermolecular interactions between the crystallizable and amorphous components resulted in signi®cantly reduced crystal growth rates and promoted diluent segregation over greater length scales,regardless of diluent mobility at the crystallization temperature. Although diluent mobility contributed to diluent segrega-tion,the growth of the PEO crystals,and the factors that in¯uenced the growth rate,dominated the length scale of diluent segregation.SAXS has been a powerful tool for probing the detailed microstructure of crystalline/amorphous blends in our previous reports[19±24].The morphological parameters in the lamellar level such as the long period(L),crystal layer thickness(l c),and amorphous layer thickness(l a)can be deduced from the one-dimensional correlation function or the interphase distribution function.Close examination on the composition variation of l a may reveal the existence of IL segregation[25±27].The volume fraction of lamellar stacks(f s)given by the ratio of volume fraction of bulk crystallinity(f c)to the volume fractional crystallinity within the lamellar stacks(f cs),i.e.f s f c=f cs;could serve as a measure for the extent of IL segregation[24]. When the absolute scattering intensity is available,the perturbation of intensity upon blending or treatment may be connected with the change of phase structure of crystal-line/amorphous blends.Supercritical CO2¯uids or compressed CO2gases or liquids have recently drawn much attention because the environmentally friendly CO2(especially the supercritical state CO2)is a potential candidate to be an alternative to substitute for organic chemicals used in modi®cation and processing of polymers,such as being used as a foaming agent to prepare microcellular foams[28±31],a processing aid to reduce melt viscosity in injection molding[32±35],a nucleating agent to induce crystallization[36±38].Upon treatment of the supercritical¯uids,the phase structure of polymers may be perturbed and hence the properties could be modi®ed accordingly;it is thus important to reveal the effect of supercritical CO2on the phase structure of a polymer before the supercritical CO2can be practically used in applications of the polymer.In the present study, we probe the morphological structure of crystalline/amor-phous PEO/PVAc blends treated by supercritical CO2by means of SAXS.It will be seen that the morphological structure of PEO/PVAc exhibits a signi®cant change upon CO2treatment as demonstrated from the drastic perturbation of scattering intensity.In addition,with the absolute inten-sity,the electron density contrast between the crystalline and amorphous layers in the lamellar stacks can be evalu-ated very conveniently from the simple geometric analysis of the correlation function proposed by Strobl and Schneider [39].The measured electron density contrast will be used to investigate the effect of supercritical CO2on the phase structure of crystalline/amorphous PEO/PVAc blends.2.Experimental section2.1.Materials and sample preparationsPEO with M v 900;000was acquired from Aldrich Chemical Company(Milwaukee,WI)and PVAc with M w 104;000and M w=M n 2:0was obtained from Chang Chun Plastics Corporation(Taipei,Taiwan). Uniform®lm samples of neat PEO or its blends with PVAc were prepared by dissolving0.2g neat PEO or the blends in15ml chloroform,followed by casting and drying at room temperature for2days.Specimens for CO2 treatments were ca.0.3mm thick.2.2.CO2TreatmentsThe CO2treatments were performed in a supercritical extractor supplied by ISCO(Lincoln,Nebraska)with a model SFX2±10which was equipped with a syringe pump with a model260D.The polymer®lms for the CO2 treatments were put in a10cm3cell located inside the extractor pressurized by the equipped syringe-type pump at5000psi and controlled at328C.The treatment time was1h.A preliminary test showed that1h of treatment time was able to reach the equilibrium solubility of CO2 in the®lm sample.After the treatment,the cell was depres-surized to ambient pressure in less than20s.The sample after the CO2treatment showed a negligible weight change, indicating that neither CO2resided inside the®lm sample nor any part of the sample was dissolved away.The uniform PEO and PEO/PVAc®lms looked translucent and colorless before CO2treatments but turned into an opaque,milk white,collapsed®lm upon CO2treatments.The change in ®lm appearance indicated that the melting and recrystalliza-tion of PEO had occurred upon CO2treatments.2.3.Bulk crystallinity measurementsVolume fraction of bulk crystallinities(f c)of semicrys-talline PEO/PVAc were calculated from mass fraction of bulk crystallinity(v c)which was determined by dividingY.-T.Shieh et al./Polymer43(2002)3691±3698 3692the heat of fusion of a sample by the heat of fusion of perfectly crystalline PEO.The heat of fusion in J/g of a sample was measured by a differential scanning calorimeter (DSC 2010)of TA Instruments (New Castle,DE).The heat of fusion of perfectly crystalline PEO is 205J/g [40].2.4.SAXS measurementsAll SAXS measurements were performed at room temperature.The X-ray source was operated at 200mA and 40kV and was generated by a 18kW rotating anode X-ray generator (Rigaku)with a rotating anode Cu target.The incident X-ray beam was monochromated by pyrolytic graphite and a set of three pinhole inherent collimators was used so that the smearing effects inherent in slit-collimated small-angle X-ray cameras can be avoided.The sizes of the ®rst and second pinhole are 1.5and 1.0mm,respectively,and the size of the guard pinhole before the sample is 2.0mm.The scattered intensity was detected by a two-dimensional position sensitive detector (Ordela Model 2201X,Oak Ridge Detector Laboratory Inc.)with 256£256channels (active area 20£20cm 2with ,1mm resolution).The sample to detector distance is 4000mm long.The beam stop is around lead disk of 18mm in diameter.All data were corrected by the background (dark current and empty beam scattering)and the sensitivity of each pixel of the area detector.The area scattering pattern has been radially averaged to increase the ef®ciency of data collection compared with one-dimensional linear detector.Data were acquired and processed on an IBM-compatible personal computer.3.Results and discussionFrom DSC measurements for T g of the PEO/PVAc blends prepared by solution casting from chloroform,a single composition-dependent T g is identi®ed over the entire composition range,indicating that PEO is miscible with PVAc in the amorphous region.The T g of the blend is between those of pure PEO and PVAc being 265and 328C,respectively,and increases with increasing PVAc content.The composition variation of T g of the PEO/PVAc blends suggests that the amorphous regions of the blends are rubbery at the 328C of CO 2treatment tempera-ture in this study.Fig.1shows the Lorentz-corrected SAXS pro®les of neat PEO and its blends with PVAc prior to supercritical CO 2treatments.The scattering intensity decreases with increas-ing incorporation of PVAc due to decreasing electron density contrast D h h c 2h a between the crystalline and amorphous layers.The electron densities of crystalline PEO,amorphous PEO,and PVAc calculated from their mass densities (1.24,1.12,and 1.19g/cm 3,respectively)are 0.676,0.612,and 0.636mol/cm 3,respectively.The scattering intensity contrast decreases with increasing PVAc content,suggesting that the electron density of theIL regions is increased due to incorporation of PVAc into IL regions,as this would decrease the electron density contrast between the crystalline and amorphous layers.A second-order peak near q 0.32nm 21can be roughly identi®ed,indicating that a fairly well lamellar stacking in the samples.Fig.2compares the Lorentz-corrected SAXS pro®les of the samples between before and after supercritical CO 2treatments.Neat PEO and the blends after CO 2treatmentsY.-T.Shieh et al./Polymer 43(2002)3691±36983693Fig.1.Lorentz-corrected SAXS pro®les of neat PEO and its blends with various amount of PVAc before CO 2treatments.Fig.2.Lorentz-corrected SAXS pro®les of PEO/PVAc 100/0,90/10,80/20,and 70/30.In each graph,rectangular and triangular symbols stand for samples for before and after CO 2treatments,respectively.apparently show much stronger scattering intensity than those before CO 2treatments due to an increased electron density contrast between the crystalline and amorphous layers caused by the supercritical CO 2.For neat PEO the scattering intensity is increased upon CO 2treatment suggesting that the electron density of amorphous PEO in the IL regions is decreased due to decreasing mass density through the swelling by CO 2,as this would increase the electron density contrast between the crystalline and amor-phous layers.This suggestion is based on the observation of appearance of the sample changing from a uniform,trans-lucent,and colorless ®lm to a collapsed,opaque,and milk white ®lm upon CO 2treatments due to the presence of voids in the CO 2treated sample.These voids include big and small ones.Big voids existing outside the lamellar stacks are apparently responsible for the milk white appearance for samples whereas small voids existing in the IL regions are responsible for the drastic increase of SAXS intensity and would disorganize the lamellar stacks as will be demon-strated later by the one-dimensional correlation function pro®les in Fig.7.For the blends upon CO 2treatment,the enhanced scattering intensity may be somewhat due to the expulsion of PVAc from the IL regions in addition to the swelling effect as described earlier,since the electron density of PVAc is higher than that of amorphous PEO and hence the expulsion of PVAc from IL regions would increase the electron density contrast between the crystalline and amorphous layers of the lamellar stacks.The inference of the expulsion of PVAc from IL regions is based on infrared spectroscopy evidence that the carbonyl groups in PVAc exhibit speci®c interactions with CO 2of Lewis acid-base nature [41].These interactions might give rise to the expul-sion of PVAc from IL regions during depressurizing of CO 2.The weight-average long period associated with the lamellar stacks can be calculated from the peak maximum of the Lorentz-corrected SAXS pro®les using the Bragg's equation,L 2p =q max :Fig.3shows the composition variation of long period for the blends before and after CO 2treatments.The long periods of neat PEO and theblends before CO 2treatments exhibit a roughly constant value at near 39nm with an insigni®cant composition dependence.The long periods for samples after CO 2treat-ments exhibit a signi®cantly increased long period falling in the range 56±62nm depending on the blend composition.In the lamellar stack model with sharp phase boundary,the long period represents the sum of the crystal thickness (l c )and the amorphous layer thickness (l a ).Rise in long period may thus stem from the thickening of crystal layer or the swelling of amorphous layer.Two approaches may be utilized to determine the average thickness of the two layers,namely,the one-dimensional correlation function and the interphase distribution function.The one-dimensional correlation function was utilized to deconvolute long period into the thickness of these two types of layers.The correla-tion function,K z ;de®ned by Strobl and Schneider,adopts the following form [39]:K z 12p 2 10I q q 2cos qz d q 1 where I q is the absolute scattering intensity obtained from the SAXS measurement,q 4p =l sin u =2 (u scattering angle),and z is the direction along which the electron density is measured.K z is different from the correlation function,g z ;de®ned by Vonk,where normalization by the invariant was introduced for g z [42,43].Since the experimentally accessible q range is ®nite,extrapolation of intensity to both low and high q is necessary for the integrations.Extrapolation to zero q was accom-plished by the Debye±Bueche model [44,45],I q A11a 2c q2ÀÁ22where A is a constant and a c is the correlation length.A anda c can be determined from the plot of I q 21=2vs.q 2using the intensity data at low q region.Extension to large q can be performed using the Porod±Ruland model [46],I q K p exp 2d 2q 2q 41I fl3where K p is the Porod constant,d is a parameter related to the thickness of crystal/amorphous interphase,and I ¯is the background intensity arising from thermal density ¯uctua-tion.The values of K p ,d ,and I ¯were obtained by curve ®tting the intensity pro®le at high q region.Fig.4shows the representative plot of K z :Assuming the corresponding two-phase model,l c and l a can be estimated via simple geometric analysis of K z :The thickness of the thinner layers (l 1)is given by the intersection between the straight line extended from the self-correlation triangle and the baseline given by 2A .The average thickness of the thicker layer is then given by l 2 L 2l 1:The assignment of l 1and l 2is governed by the magnitude of the linear crys-tallinity within the lamellar stacks (f cs ),where f cs l c = l c 1l a :When f cs ,0.5,the crystals contribute to theY.-T.Shieh et al./Polymer 43(2002)3691±3698position variation of long period of semicrystalline PEO/PVAc.Filled circle (X )and ®lled square (B )stand for samples for before and after CO 2treatments,respectively.smaller thickness,thus l 1 l c and l 2 l a :The inverse is true for f cs .0.5.f cs is related to the volume fraction of bulk crystallinity,f c ,byf c f s f cs 4where f s is the volume fraction of lamellar stacks in the sample.Since f s #1,Eq.(4)prescribes that f c cannot be higher than f cs .As a result,the assignment of l 1and l 2would be rather straightforward for f c .0.5,because l 1in this case must correspond to l a and l 2to l c .From the DSC measurements,f c of neat PEO and the blends containing 10and 20%PVAc lie above 0.5(Table 1),l 1and l 2were thus assigned to l a and l c ,respectively.l a and l c of these three samples before CO 2treatment are thus near 7and 32nm,respectively,from the corresponding one-dimensional correlation function pro®les (Fig.5).Although f c of the blend containing 30%PVAc is below 0.5,l 1can still be reasonably assigned to l a and l 2to l c for this blend because a big difference between l a and l c is present for neat PEO and the blends containing 10and 20%PVAc.This big difference between l a and l c is not likely to lead to an opposite assign-ment for l a and l c for the blend with f c below 0.5.Fig.6shows plots of l c and l a as a function of the weight fraction of PVAc (W PVAc ).Like the long period,l c and l a of samples before CO 2treatments are insigni®cantly varied with W PVAc .The thickness of crystal layer (l c )being weakY.-T.Shieh et al./Polymer 43(2002)3691±36983695Table 1The heats of fusion (D H ,J/g),melting temperatures (T m ,8C),volume frac-tional bulk crystallinities (f c ),and crystal layer thickness (l C ,nm)of PEO/PVAc blends for before and after CO 2treatments PEO/PVAcBefore CO 2treatment After CO 2treatmentD H 1T m1f C1l C1D H 2T m2f C2l C2100/0151.259.90.6831.8152.363.10.6943.590/10128.760.60.5831.6132.062.50.5943.580/20113.860.60.5131.8121.362.30.5443.770/3094.460.80.4231.884.461.50.3749.1Fig.5.One-dimensional correlation function of (a)neat PEO,(b)PEO/PVAc 90/10,(c)PEO/PVAc 80/20,(d)PEO/PVAc 70/30before CO 2treatments.Fig.4.Schematic plot of Strobl-Schneider's one-dimensional correlation function pro®le.Determinations of the lamellar layer thickness and the invariant assuming the corresponding two-phase model are demonstrated in the®gure.position variations of l c and l a of PEO/PVAc for (a)before,and (b)after CO 2treatments.functions of W PVAc can be associated with the assumption of corresponding two-phase model in deriving l c and l a from K z ;where the thickness of the crystal±amorphous inter-phase (l i )is `included'into the values of l c and l a .The interphase thickness can be estimated from the deviation from the self-correlation triangle near z 0(Figs.4,5and 7).The values of l i thus obtained are tabulated in Table 2.The interphase thickness for samples for both before and after CO 2treatment appears to be ,1nm,which is much smaller than l c or l a .These small l i values may be responsible for the observed weak functions of W PVAc for l c of samples before CO 2treatment.The thickness of amorphous layer (l a )being weak functions of W PVAc before CO 2treatment indi-cates that increasing PVAc does not swell the IL regions.This suggests that the increased PVAc content forms an extralamellar morphology.This result is not similar to what was obtained in Martuscelli and coworkers'work [11]having a ®nding of only IL morphology for the PEO/PVAc blends due to different sample preparations and/or molecular weight of PEO used between the previous work and this work.Samples used in the earlier work were subjected to heating and cooling treatments whereas samples studied in this work were prepared by solvent cast-ing without being subjected to heating and cooling treat-ments.Moreover,according to Runt and coworkers'work [18],factors that would reduce crystal growth rates could promote diluent segregation over greater length scales regardless of the diluent mobility at the crystallization temperature.PEO used in this work has a very high mole-cular weight that might have a reduced crystal growth rate.It is thus not unreasonable that the extralamellar morphol-ogy is obtained in this work.Since the purpose of this work is to investigate the effect of CO 2treatments on the phase structure of the blends,the disparity on the segregation morphology of the blends between the previous work and this work is not examined further here.Variation of l a and l c with PVAc composition for samples after CO 2treatment is also displayed in Fig.6.l a and l c of samples exhibit signi®cant increases upon CO 2treatment.After CO 2treatment,the amorphous and crystal layer thick-ness of neat PEO is raised by about 6and 12.6nm,respec-tively,which are much larger than the magnitude of l i .The swelling of l a is attributed to the incorporation of CO 2into the IL regions and thus the mass density is decreased,which is consistent with the enhancement of scattering intensity after CO 2treatment observed in Fig.2.The increased amor-phous layer thickness upon CO 2treatment exhibits an insig-ni®cant dependence on composition suggesting that the swelling of amorphous PEO in IL regions dominates the increase of the amorphous layer thickness.The signi®cant increase in l c of neat PEO upon CO 2treat-ment is associated with the occurrence of melting and recrystallization during CO 2treatment that leads to thicker PEO crystals via a depression of equilibrium melting temperature and/or an increase of crystal fold surface free energy.It has been reported that the crystal fold surface free energy can be increased by CO 2treatments for PET and sPS [47].According to the secondary nucleation theory,the initial crystal thickness is given by [48,49]l p g2s e T 0m 0f0m c ÀÁ1d l 5where s e is the fold surface free energy and D h 0f is the bulk enthalpy of melting per unit volume.At low to moderateY.-T.Shieh et al./Polymer 43(2002)3691±36983696Fig.7.One-dimensional correlation function of (a)neat PEO,(b)PEO/PVAc 90/10,(c)PEO/PVAc 80/20,(d)PEO/PVAc 70/30after CO 2treatments.Table 2Thickness of crystal-amorphous interphase (l i )estimated from K z of PEO/PVAc blends for before and after CO 2treatments PEO/PVAc Before CO 2treatment l i (nm)After CO 2treatment l i (nm)100/00.730.9890/100.730.9880/200.910.9870/300.910.98degree of supercooling,d l is small.Eq.(5)thus reduces to l p gù2s e T 0m D h 0fT 0m 2T c ÀÁ 6The ®nal crystal thickness,according to the notation of Hoffman and Weeks [48,49],is g times the initial thickness,i.e.l c g l p g7where g is the so-called lamellar thickness factor.Eq.(6)prescribes that the initial crystal thickness is inversely proportional to the degree of supercooling.Thus,a depres-sion of T 0m upon CO 2treatment that would lower the degree of supercooling at a given T C can lead to the formation of thicker crystals.As can be also known from Eq.(6),an increased crystal fold surface free energy during CO 2treat-ment can also give rise to the increase of l c .From Fig.6(b),l c increases with increasing W PVAc due to the depression of equilibrium melting temperature of PEO upon blending with PVAc [11].It is noted that the values of l a and l c determined from K z could face a large uncertainty because the broad lamellar size distribution could shift the position of the baseline (2A )[39].On the other hand,the electron density contrast,D h ,can be determined from K z with better con®dence in that D h is much less sensitive to the perturbation of baseline position for the samples with intermediate crystallinity 0:3,f cs ,0:7 :As shown in Fig.4,the invariant (Q )of the corresponding two-phase model for a sample (as in Figs.5and 7)is obtained by extrapolation from the self-correlation triangle to z 0[39].The invariant is related to the electron density contrast by [39]Q f s f cs 12f cs D h 28where f cs is the crystallinity within the lamellar stacks given byf csQ A 1Q9and f s is given by f c /f cs from Eq.(4).f c ,as tabulated in Table 1,is volume fraction of bulk crystallinity and is calcu-lated from weight fraction of crystallinity (v c )measured by DSC according to Eq.(10).f c v cr cv c r c 1 12v c r a v c v c 1r c r a 12v c 10 The weight fraction of crystallinity (v c )is determined by dividing the heat of fusion,D H ,in J/g of a sample by D H 0,which is 205J/g for perfectly crystalline PEO [40].r c (1.24g/cm 3)and r a (ca 1.12g/cm 3)are mass densities of crystal and amorphous component,respectively.D h can be calculated by Eq.(8)with the knowledge of Q ,f cs ,and f c .Table 3tabulated the D h values obtained from the measuredinvariant as a function of W PVAc for both before and after CO 2treatments.D h msd.1and D h msd.2are used to denote those measured D h values for before and after CO 2treatments,respectively.The plots of D h msd.1and D h msd.2as a function of W PVAc are shown in Fig.8.As can be seen in Table 3and Fig.8,the D h msd.1is insigni®cantly varied with W PVAc suggesting that the amount of incorporation of PVAc into IL regions does not increase with increasing W PVAc and thus the distance of segregation in PEO/PVAc blends involves the extralamellar paring between D h msd.1and D h msd.2for neat PEO,the CO 2treatment can cause an enhancement in elec-tron density contrast resulting from the swelling of IL regions by CO 2.This enhancement decreases with increas-ing W PVAc up to 0.2,indicating that below 0.2W PVAc the swelling of the IL regions by CO 2decreases with increasing W PVAc .The measured electron density contrast for the blend containing 30%PVAc is higher than that containing 20%PVAc,indicating that the expulsion of PVAc from IL regions has occurred upon CO 2treatment.These results are supported by the observation of the composition variation of appearance of ®lm samples after CO 2treatments.The presence of extralamellar morphology in the prepared blends can be demonstrated by the measured f s values of less than unity.Fig.9shows these measured f s values (f s1and f s2for before and after CO 2treatments,respectively)plotting as a function of W PVAc .As can be seen in Fig.9,for neat PEO,the f s1is less than unity,suggesting that the extralamellar segregation of PEO forms before blending with PVAc.The f s1decreases with increasing W PVAc ,suggesting that the segregation distance increases with increasing W PVAc .Upon CO 2treatment,theY.-T.Shieh et al./Polymer 43(2002)3691±36983697Table 3The measured D h ( h c 2h a )values of PEO/PVAc blends for before (D h msd.1)and after (D h msd.2)CO 2treatments PEO/PVAc D h msd.1D h msd.2100/00.0710.11290/100.0700.08680/200.0690.06970/300.0680.075parison between composition variation of the measured D h values for before (D h msd.1)and after (D h msd.2)CO 2treatments.。

ZrO2纳米粒子的水热合成贾祥非;侯近龙;陈尔跃【摘要】以锆酸四丁酯（Zr（OBu）4为原料，利用溶胶-水热法制备了ZrO2纳米粒子，分别用XRD，SEM，TEM对合成的样品进行了表征。

结果表明，用水热法合成的ZrO2纳米粒子的粒径较小且均一，并且含有单斜相（Monoclinic）和四方相（Tetragonal）2种结构。

%In this paper, we sythensis ZrO2 nanoparticles with Zr（OBu）4. Then characterize our samples with XRD, SEM and TEM. Results show that, sol-hydrothermal ZrO2 nanoparticles are monoclinic and tetragonal crystal.【期刊名称】《齐齐哈尔大学学报（自然科学版）》【年(卷),期】2012(028)001【总页数】3页(P69-71)【关键词】ZrO2;纳米粒子;水热合成【作者】贾祥非;侯近龙;陈尔跃【作者单位】齐齐哈尔大学化学与化学工程学院,黑龙江齐齐哈尔161006;齐齐哈尔大学化学与化学工程学院,黑龙江齐齐哈尔161006;齐齐哈尔大学化学与化学工程学院,黑龙江齐齐哈尔161006【正文语种】中文【中图分类】TQ134.12二氧化锆（ZrO2）纳米粒子是一种重要的宽带隙半导体纳米材料，其带隙能为5.0 eV。

由于ZrO2纳米粒子具有高的离子传导率，较大的介电常数，较强的表面酸性，耐高温，耐腐蚀等性质，被广泛应用于光、电、磁和热学等领域，例如固体电解质，催化剂载体，陶瓷材料和光敏材料等[1-3]。

二氧化锆晶体具有3种晶相结构，1 200 ℃以下为单斜相结构（Monoclinic），在1 200 ℃～2 370 ℃之间为四方晶相（Tetragonal），2 370 ℃以上为立方相结构（Cube）。

第40卷第2期2021年2月硅㊀酸㊀盐㊀通㊀报BULLETIN OF THE CHINESE CERAMIC SOCIETY Vol.40㊀No.2February,2021t-ZrO 2相变提高搪玻璃抗拉强度的研究李志恒,徐坤山,许文友,薛洪喜,刘㊀杰(烟台大学化学化工学院,烟台㊀264005)摘要:采用添加四方相氧化锆(t-ZrO 2)的方式增强搪玻璃涂层的力学性能,通过三点弯曲试验研究搪玻璃表面应变变化情况,对断裂截面进行XRD㊁SEM㊁拉曼分析㊂结果表明,添加适量t-ZrO 2改善了搪玻璃的表面形貌,减少了气孔数量㊂在三点弯曲试验中,2%t-ZrO 2质量含量的搪玻璃承受的最大力值提高了7kN,在11kN 三点弯曲压力作用下出现裂纹,应变值提高约37%㊂含有t-ZrO 2搪玻璃试样的截面断裂前后发生t 相到m 相的相变,t-ZrO 2相与搪玻璃原始釉相的边界处出现裂纹的偏转,从而抑制裂纹扩展㊂关键词:搪玻璃;氧化锆相变;三点弯曲试验;应变分析;裂纹扩展中图分类号:TQ173㊀㊀文献标志码:A ㊀㊀文章编号:1001-1625(2021)02-0622-08Study on t-ZrO 2Phase Transition to Improve Tensile Strength of EnamelLI Zhiheng ,XU Kunshan ,XU Wenyou ,XUE Hongxi ,LIU Jie(College of Chemistry and Chemical Engineering,Yantai University,Yantai 264005,China)Abstract :The mechanical properties of the enamel coating were enhanced by adding tetragonal zirconium oxide (t-ZrO 2).The changes in the surface strain of the enamel were researched through a three-point bending experiment,and the fracture section is analyzed by XRD,SEM,and Raman.The results show that adding a proper amount of t-ZrO 2improves the surface morphology of the enamel and reduces the number of pores.In the three-point bending experiment,the maximum force of the enamel with 2%t-ZrO 2mass content increases by 7kN.Cracks appear under the action of 11kN three-point bending pressure,and the strain value increases by about 37%.The t-ZrO 2enamel sample has a phase transition from t-ZrO 2to m-ZrO 2before and after the fracture.The crack deflection occurs at the boundary between the t-ZrO 2phase and the original enamel phase,which restricts the crack propagate.Key words :enamel;zirconia phase transition;three-point bending experiment;strain analysis;crack propagate收稿日期:2020-08-24;修订日期:2020-09-16基金项目:国家自然科学基金(51971192),山东省高等学校科技计划(J18KB007);山东省自然科学基金(ZR2020ME132)作者简介:李志恒(1993 ),男,硕士研究生㊂主要从事搪玻璃压力容器㊁无损检测方面的研究㊂E-mail:q15317@通信作者:徐坤山,博士,讲师㊂E-mail:17911162@ 0㊀引㊀言搪玻璃是一种在钢板上喷涂玻璃质釉,经过高温烧制形成的具有耐高温㊁耐腐蚀等优点的复合材料,但搪玻璃在工业应用中面临着断裂韧性低㊁易爆瓷的问题㊂因搪玻璃使用过程中产生爆瓷现象所引起的设备报废造成了大量经济损失,因此,延长搪玻璃的使用寿命是迫切要解决的问题㊂为延长搪玻璃压力容器使用寿命,相关研究发现氧化锆可以有效增强陶瓷等脆性材料的力学性能,因此氧化锆成为目前研究较多的复合材料增强相之一[1-2]㊂当氧化锆从t-ZrO 2转变为m-ZrO 2时,体积发生7%的膨胀,抑制了裂纹的扩展,该过程可明显提高材料的力学性能,其机理是由应力诱导相变吸收能量和裂纹桥接发挥作用[3]㊂但纯t-ZrO 2无法在室温下稳定存在,通常在ZrO 2中加入氧化钇作为稳定剂[4-5]㊂在尖端裂纹的应力诱导下,氧化锆从t-ZrO 2向m-ZrO 2相变,且相变过程与温度㊁应力等有一定关系[6]㊂t-ZrO 2在应力诱导下发生相变时,晶粒尺寸越大相变量越大,力学性能提升越显著[7]㊂添加t-ZrO 2可增强烧结试样的致密度,充分发挥弥散强化作用,显著提高材料的抗弯强度㊂气孔率也是影响试样抗弯强度的重要因素,㊀第2期李志恒等:t-ZrO2相变提高搪玻璃抗拉强度的研究623 t-ZrO2提高了材料的相对密度并降低气孔率,进而提升其力学性能[8]㊂ZrO2能促进玻璃网格的形成,使得键合强度进一步提高[9]㊂在玻璃体系中,过多的ZrO2使材料整体结构稳定性和力学性能下降,ZrO2的加入对材料抗弯曲能力的提高具有重要意义,抗弯强度最高可达83.67MPa[10-11]㊂在防腐蚀方面,t-ZrO2和m-ZrO2均具有良好的耐酸㊁耐碱性能,可有效避免酸碱腐蚀[12]㊂目前关于t-ZrO2相变对搪玻璃增韧性能的研究较少,特别是采用应变片评价搪玻璃弯曲性能的研究鲜见报道㊂本文针对搪玻璃易出现爆瓷的问题,基于t-ZrO2相变增韧搪玻璃力学性能的机理,设计了三点弯曲试验,研究了搪玻璃在外力作用下涂层表面裂纹扩展过程㊂采用应变仪测量搪玻璃在载荷作用下的变形情况,通过XRD㊁拉曼分析研究裂纹前后t-ZrO2相变情况㊂研究结果对于从机理上提高搪玻璃抗拉强度㊁发展新的搪玻璃断裂评价方法乃至延长搪玻璃使用寿命具有重要参考价值㊂1㊀实㊀验1.1㊀原材料钢板选用Q345R钢材,弹性模量209GPa,屈服应力460MPa,抗拉强度604MPa㊂厚度(5ʃ0.2)mm,宽度(50ʃ0.2)mm,三点弯曲试验跨距50mm㊂搪玻璃基础釉粉配方主要成分如表1所示,添加使用氧化钇(质量分数为5.36%)稳定的t-ZrO2,其颗粒直径为50μm㊂表1㊀搪玻璃釉粉成分Table1㊀Enamel powder ingredientsChemical composition SiO2Na2O Al2O3K2O CaO MnO F Co2O3NiO Other Mass fraction/%68.4210.648.74 3.42 2.41 1.61 1.130.980.84 1.811.2㊀制㊀样钢板喷砂除锈,将t-ZrO2均匀地混合在基础釉粉中,釉水比6ʒ4调制,喷涂搪玻璃釉,通风阴凉处24h晾干,使用马弗炉890ħ控温烧制,所有试样烧制后厚度控制在(0.6ʃ0.05)mm,取出后使用丙酮擦拭搪玻璃表面,划线定位,粘贴应变片,将应变片与应变仪和万能拉伸试验机连接进行三点弯曲试验㊂1.3㊀性能测试及表征三点弯曲试验采用WAW-600D型电液伺服万能试验机进行;喷砂使用GT-9060A型喷砂机进行;氧化锆晶型采用BX43型拉曼光谱仪检测;物相利用Smart LabⅢX型X射线衍射仪测定,扫描范围5ʎ~80ʎ,波长λ=0.15406nm;样品形貌利用JSM-7900F型扫描电镜㊁BMM-202E型金相显微镜观察;使用扫描电镜对搪玻璃的元素进行EDS分析㊂2㊀结果与讨论2.1㊀氧化锆含量对表面形貌影响对加入不同质量分数(下同)的t-ZrO2搪玻璃表面观察发现,不含t-ZrO2的表面有较多气孔,低t-ZrO2含量(t-ZrO2ɤ2%)的搪玻璃表面相对光滑,气孔和凹坑较少㊂t-ZrO2含量在0%~2%范围内,随着t-ZrO2含量的增加,搪玻璃力学性能得到提高,且气孔数量大量减少[13]㊂搪玻璃气孔主要是在450~650ħ烧制过程中发生剧烈化学反应产生的,为避免大量气孔的产生,该阶段在烧制时应减慢升温速率㊂适量ZrO2对网络修饰具有重要意义,填补了网络空隙,并增加骨架的连续程度[14]㊂t-ZrO2含量在4%~6%时,搪玻璃涂层表面的缺陷增多,出现了凸起和凹坑,表面缺陷区域能够达到数百微米,如图1所示㊂粗糙的搪玻璃表面容易导致应力集中,促使微裂纹扩展㊂624㊀玻㊀璃硅酸盐通报㊀㊀㊀㊀㊀㊀第40卷图1㊀加入不同含量t-ZrO2烧制后的搪玻璃表面形貌Fig.1㊀Surface morphology of enamel after firing with different t-ZrO2content2.2㊀三点弯曲试验应变分析对烧制的搪玻璃试样进行三点弯曲试验示意图如图2(a)所示㊂首先,在搪玻璃的下表面粘贴电阻应变片,用于测量试验过程中试样下表面受力而导致的拉伸变形,应变片沿着试样长度方向粘贴㊂图2㊀三点弯曲试验示意图与试验曲线图Fig.2㊀Schematic diagram of three-point bending experiment and experimental curves第2期李志恒等:t-ZrO 2相变提高搪玻璃抗拉强度的研究625㊀三点弯曲试验中搪玻璃表面裂纹出现的最大应变值及其所对应的压力值如图2(b)所示㊂从曲线可以看出,未添加氧化锆的搪玻璃涂层比添加3%㊁4%㊁5%的效果好,承受的弯曲应力更大㊂与未添加相比,添加1%t-ZrO 2的试样应变值有微小提升,提高约5%,承受的三点弯曲压力值基本不变;添加2%t-ZrO 2的试样提升明显,裂纹出现时力值达到11kN,2%t-ZrO 2含量的搪玻璃承受的最大力值提高了7kN,搪玻璃出现断裂的应变值达到7.5ˑ10-3,应变值提高约37%,试样的韧性有大幅度的提高㊂在三点弯曲实验中,初始阶段搪玻璃表面应变值的变化缓慢,试验后期应变值增加迅速,在接近应变的最大值时,能够听到清脆断裂声,此时是搪玻璃涂层所承受的极限力值㊂在搪玻璃下表面拉应力作用下,发生裂纹萌生㊁裂纹稳定扩展和断裂现象㊂相关研究发现,当应力小于临界值时,裂纹在扩展过程中受到化学键的作用,裂纹扩展停止;当应力大于临界值时,搪玻璃会发生破坏性断裂[15]㊂符合脆性材料在拉力作用下瞬间断裂的基本特性㊂2.3㊀XRD 分析t-ZrO 2粉末㊁未烧混合粉末㊁搪玻璃烧制后表面㊁搪玻璃烧制后断裂截面的XRD 测试结果如图3所示㊂t-ZrO 2粉末四方相主峰明显㊂掺入搪玻璃粉后t-ZrO 2峰强减弱,这是由于原始瓷釉粉末中含有大量的氧化硅,减弱了t-ZrO 2的峰强[16]㊂将掺入t-ZrO 2的搪玻璃瓷釉粉末烧制后,检测发现t-ZrO 2未发生相变㊂含有t-ZrO 2的搪玻璃试样三点弯曲试验后受力断裂,其截面XRD 分析如图4所示,分析发现有m-ZrO 2峰出现,表明应力会导致t-ZrO 2发生相变,使其转化为m-ZrO 2㊂氧化锆相变是搪玻璃力学性能提高的主要原因,其机制是t-ZrO 2向m-ZrO 2相变时需要吸收能量,从而抑制微裂纹的扩展㊂图3㊀t-ZrO 2粉末㊁未烧混合粉末㊁搪玻璃烧制后表面㊁搪玻璃烧制后断裂截面的XRD 谱Fig.3㊀XRD patterns of t-ZrO 2powder,unfired mixed powder,enamel surface after firing,fracture section afterfiring 图4㊀添加t-ZrO 2搪玻璃断裂面XRD 谱Fig.4㊀XRD patterns of enamel section with t-ZrO 2added 2.4㊀SEM 分析原始釉搪玻璃瓷釉粉末烧制前的微观形貌如图5(a)所示,粒径普遍在10~30μm 之间㊂加入的t-ZrO 2颗粒如图5(b)所示,球状形貌较好㊂t-ZrO 2在搪玻璃瓷釉粉末中混合后的微观形貌如图5(c)所示,两者分散均匀㊂图5㊀样品粉末SEM 照片Fig.5㊀SEM images of the sample powder626㊀玻㊀璃硅酸盐通报㊀㊀㊀㊀㊀㊀第40卷经过烧制后的搪玻璃截面SEM照片如图6(a)所示,经过氧化钾㊁氧化钠等助熔剂的作用,釉粉在高温作用下发生了熔融,氧化锆颗粒和氧化硅等成分紧密结合,相间分界线明显,但未出现相间微裂纹,搪玻璃釉其他成分形成的区域光滑平整㊂未施加载荷前引入t-ZrO2的搪玻璃SEM照片如图6(b)所示,从图中可以看出t-ZrO2相与基质结合紧密,无间隙或气孔生成㊂经过拉力作用后含有t-ZrO2的搪玻璃截面SEM照片如图6(c)所示,裂纹宽度大约1μm,裂纹扩展沿着t-ZrO2相的边界进行,并且烧制后的搪玻璃与t-ZrO2相有明显的过渡区域,边界过渡有助于扩大搪玻璃原始釉相和t-ZrO2相间接触面积,提高强度㊂t-ZrO2相由于具有较强的力学性能,使得微裂纹发生了相间偏转,延长了裂纹的扩展路径,消耗了促使断裂的能量㊂图6㊀搪玻璃釉烧成后SEM照片Fig.6㊀SEM images of enamel after firing裂纹偏转区域的EDS元素分布图如图7所示,通过EDS分析来鉴别搪玻璃中的不同相,锆元素分布均匀,裂纹扩展中既有相界断裂,又有穿过氧化锆相的断裂,相界的接触力小,虽然对搪玻璃性能的提高有一定的提升,但消耗的能量较少,对于材料总体的强度和韧性影响不大[17]㊂加入t-ZrO2的搪玻璃截面EDS能谱如图8所示㊂在搪玻璃断裂截面中,SiO2含量最多,因而O㊁Si元素的峰最明显㊂Zr元素在能谱图中出现,ZrO2相也得到充分证实㊂此外,微量的Na㊁Al㊁K元素均有峰出现㊂㊀第2期李志恒等:t-ZrO2相变提高搪玻璃抗拉强度的研究627图7㊀添加t-ZrO2搪玻璃釉EDS元素分布图Fig.7㊀EDS element mappings of enamel with t-ZrO2added图8㊀添加t-ZrO2的搪玻璃截面EDS谱Fig.8㊀EDS spectrum of enamel section with t-ZrO2added2.5㊀拉曼分析加入到原始釉粉之前的t-ZrO2粉末拉曼谱如图9(a)所示,发现氧化锆曲线与标准曲线一致,t-ZrO2特征峰明显,t-ZrO2没有在正常室温下发生相变㊂含有t-ZrO2搪玻璃试样进行过三点弯曲试验后的断裂截面拉曼谱如图9(b)所示,三点弯曲试验中,搪玻璃表面受到拉力,应力诱导t-ZrO2相变为m-ZrO2,相比没有加入t-ZrO2的搪玻璃试样,加入了t-ZrO2的试样因为相变而提高了搪玻璃的力学性能㊂从拉曼谱中可以看出断裂截面仍有t-ZrO2的存在,这是因为t-ZrO2并没有完全相变,剩余的一部分未相变t-ZrO2被检测出来[18],结合前文SEM照片可以看出,由于应力引起的裂纹极少扩展到晶粒内部,因而氧化锆相内部的t-ZrO2难以发生相变,仪器检测的是断裂截面表面的氧化锆相变状况㊂图9㊀t-ZrO2和掺t-ZrO2搪玻璃的拉曼谱Fig.9㊀Raman spectra of t-ZrO2and enamel with t-ZrO2added628㊀玻㊀璃硅酸盐通报㊀㊀㊀㊀㊀㊀第40卷综上可以发现,在含有t-ZrO2提高搪玻璃力学性能的实验组中,t-ZrO2在应力作用下向m-ZrO2相变和裂纹偏转是提高材料力学性能的主要原因,t-ZrO2在应力作用下向m-ZrO2相变[3],相变过程如图10所示㊂该过程伴随着3%的体积膨胀和6%的剪切应变,t-ZrO2增韧机理主要有应力诱导相变增韧㊁微裂纹增韧和裂纹偏转[19-20]㊂整个过程对裂纹产生挤压效应,抑制了裂纹的扩展[21]㊂图10㊀t-ZrO2相变过程中裂纹扩展示意图Fig.10㊀Schematic diagram of crack growth during t-ZrO2phase transition3㊀结㊀论(1)在搪玻璃中添加2%(质量分数)的t-ZrO2有助于使搪玻璃的表面光滑,气孔大量减少;过高的t-ZrO2含量降低搪玻璃的表面性能和力学性能㊂(2)XRD结果显示搪玻璃烧制时的温度没有导致t-ZrO2向m-ZrO2相变,搪玻璃受到力的作用发生断裂,应力造成了t-ZrO2发生相变,并且t-ZrO2相的边界使微裂纹尖端扩展发生偏转,较长的裂纹路径消耗能量,阻止断裂的提前发生;同时,t-ZrO2向m-ZrO2相变由于产生体积膨胀引起的压应力会抑制裂纹的扩展㊂(3)对未施加力的搪玻璃涂层分析发现没有m-ZrO2出现,拉曼分析发现添加t-ZrO2的搪玻璃断裂截面出现大量m-ZrO2,证明应力是导致t-ZrO2发生相变的根本原因㊂参考文献[1]㊀HARSHA R N,KULKARNI M V,SATISH BABU B.Study of mechanical properties of aluminium/nano-zirconia metal matrix composites[J].Materials Today:Proceedings,2020,26:3100-3106.[2]㊀易中周,单㊀科,翟凤瑞,等.Al2O3包覆ZrO2粉体制备的热障涂层材料的结构与性能[J].硅酸盐学报,2018,46(3):328-332.YI Z Z,SHAN K,ZHAI F R,et al.Structure and properties of thermal barrier coating prepared by alumina coated zirconia composite powder[J].Journal of the Chinese Ceramic Society,2018,46(3):328-332(in Chinese).[3]㊀CUI E Z,ZHAO J,WANG X C.Effects of nano-ZrO2content on microstructure and mechanical properties of GNPs/nano-ZrO2reinforcedAl2O3/Ti(C,N)composite ceramics[J].Journal of the European Ceramic 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Ni/ZrO2梯度镀层高温氧化性能及热应变特性3王宏智,姚素薇,张卫国(天津大学化工学院,杉山表面技术研究室,天津300072)摘　要:　采用复合电沉积法制备Ni/ZrO2梯度镀层。

SEM测试表明,沿镀层生长方向,ZrO2含量由0逐渐增加到21%(体积分数),呈梯度分布;高温氧化实验结果表明,梯度镀层在800℃处理24h后氧化增重仅为纯镍镀层的1/6,氧化处理并未改变镀层中ZrO2微粒的梯度分布。

结构分析表明,ZrO2微粒的掺杂使梯度镀层晶粒细化,结晶细致,可阻止高温氧化时氧原子向金属内部扩散。

弥散分布的ZrO2对金属镍高温氧化时具有活性元素效应,可阻止Ni的短路扩散,降低氧化增重速率。

因此,Ni/ZrO2梯度镀层具有优良的高温氧化性能,可用于高温氧化气氛之中。

热应变特性研究表明,沿镀层厚度方向,热应变变化平缓,有效地缓解了界面处材料热失配,从而降低了材料的热应力。

关键词:　梯度功能材料;复合镀层;热应变中图分类号:　T G174.44文献标识码:A 文章编号:100129731(2006)06209552041　引　言功能梯度材料(f unctionally gradient material,简称F GM)是一种两侧成分完全不同,中间呈梯度过渡的新型材料,例如陶瓷/金属梯度功能材料,一侧具有隔热好,硬度高、耐高温、耐磨损、耐腐蚀、耐辐照等陶瓷的特点,另一侧具有导热性好,强韧性等金属的优点,中间成分呈梯度过渡,无明显界面,不产生应力集中,因此,在航天、化工、电子、机械、生物医学乃至日常生活领域具有广泛的应用[1,2]。

目前F GM制造方法主要有相分布技术(PVD和CVD)、粒子排列、等离子喷镀和自蔓延高温合成(SHS)技术等[3～8]。

这些方法存在高温、高真空及设备昂贵等缺点,如何对这些方法进行改进并开发新的制备技术,对于F GM进一步发展是至关重要的[9]。

复合电沉积法具有控制简单,易于操作,投资少,可处理复杂工件等优点[10],是制备梯度功能材料的重要方法之一。