Ba（ZrxTi1-x）O3弛豫铁电体的介电性能研究

采用传统的固相反应法制备了0．2％Nb2O3掺杂的Ba（Zr0.15Ti0.85）O3弛豫铁电陶瓷，测量了不同温度下的介电频谱；讨论了介电常数的频率和温度特性；结果表明：由于掺铌BZT陶瓷内部结构的不均匀，导致多种弛豫时间的不对称分布，实际的Cole-Cole图不是理论上的半圆，而是偏离半圆的鼠标形式。BZT陶瓷在Zr质量分数为0．15时仍具有弛豫性；在介温曲线中，由于漏导电流的存在，tgδ-T曲线在高温部分有上翘现象．     

Dielectric Properties of （AgxNa1-x）（NbyTa1-y）O3 System Prepared by Liquid Method

The dielectric properties of （AgxNa1-x）（NbyTa1-y）O3 were investigated, and its dielectric loss and capacitance were measured. The dielectric properties of nanometer （AgxNa1-x）（NbyTa1-y）O3 ceramic prepared by liquid method were better than that by conventional solid method. The average grain size of the nanometer powder（34 nm） obtained by citrate-gel method was small near 500 nm and homogeneous and the microstructure was dense and uniform. In addition, the sintering temperature had a great effect on properties. The dielectric properties of resultant samples were as follows： ε〉500, tgδ〈6 10^-4, αc〈 10 ppm/℃, ρv〉1 012Ω·cm.     

BaxSr1-xTiO3微弧氧化铁电薄膜微观结构及电学性能

用分析纯Ba(OH)2·8H2O和Sr(OH)2·8H2O配制电解液,采用微弧氧化法在工业纯钛板(99.5%)表面原位生成BaxSr(1-x)TiO3铁电薄膜。研究了Ba2+/Sr2+对薄膜晶体结构、物相组成、表面形貌及表面粗糙度的影响,并对薄膜的介电、铁电性能进行了表征。结果表明,Ba2+/Sr2+对薄膜晶体结构无影响,但随Ba2+含量增加,BaxSr(1-x)TiO3薄膜中x值与理论值偏离越大;随电解液浓度及Ba2+/Sr2+增加,薄膜表面变得疏松,散布的颗粒尺寸增大,表面粗糙度值增加。在Ba2+和Sr2+各为0.2 mol/L时所得薄膜表面平整度及致密性最好,表面粗糙度值最小,其在100 Hz条件下的介电常数为454.8,且具有饱和电滞回线,有较好的商业化应用前景。     

在LaNiO3衬底上（Pb,La）TiO3铁电薄膜的制备和研究

首先通过金属有机化合物热分解(MOD)法在Si(100)基片上制备出LaNiO3(LNO)薄膜,再通过溶胶-凝胶(sol-gel)法,在LNO/Si(100)衬底上制备出(PbxLa1-x)TiO3(PLT)铁电薄膜。经XRD分析表明,LNO薄膜具有(100)择优取向的类钙钛矿结构,PLT/LNO/Si薄膜具有四方相钙钛矿结构,同时以(100)择优取向。最后对薄膜的介电性和铁电性进行了测试,发现薄膜介电常数适中,铁电性良好。     

极板间距对反应溅射Ge_xC_(1-x)薄膜的影响

利用射频磁控反应溅射法,以Ar、CH4为原料气体,在较宽的工艺参数范围内制备出了GexC1－x薄膜,研究了极板间距对沉积的影响。结果表明,随极板间距的减小,沉积速率增大,薄膜的均匀性变差,薄膜中Ge／C的原子比增加.     

空位掺杂La（1-x）2／3Ca1／3MnO3的结构及磁电阻效应

利用标准的固相反应法在1200℃烧结了La(1-x)2/3Ca1/3MnO3(x=0,0.02,0.04,0.08,0.10)样品,冷却后,取出部分在1350℃进行再烧结。利用X射线衍射(XRD)和扫描电镜(SEM)对其晶体结构及表面微观结构进行了研究。X射线衍射测量分析表明样品均为单相,单胞仍然具有正交对称性结构(空间群为Pnm a),随着掺杂浓度的增加,晶格常数和晶胞体积逐渐减小。通过扫描电镜研究表明,样品随着掺杂浓度增加,晶粒逐渐增大,均匀性变好;样品在1350℃再烧结条件下,平均粒度要大,空隙度变小。样品随着掺杂浓度的增加,电阻在逐渐增大,磁电阻在逐渐减小。     

Zn_(1/3)Nb_(2/3)含量对xPMnS-(1-x)PZN性能的影响

以xPMnS-(1-x)PZN四元系压电陶瓷为研究对象,通过研究Zn1/3Nb2/3含量的变化对0.5PMnS-0.5aPZN材料结构与性能的影响,获得具有高压电活性的0.5PMnS-0.5aPZN陶瓷材料。结果表明,四方相结构的0.5PMnS-0.5aPZN材料压电活性优于三方相结构,性能最好的组成位于MPB(四方相边界)附近靠近四方相含量较高的区域,组成Zn1/3Nb2/3含量的变化影响了MPB的位置。     

Na+掺杂对LiNi1/3Co1/3Mn1/3O2结构和电化学性质的影响

采用高温固相法成功制备了不同Na+掺杂浓度的Li_1-xNa_xNi_1/3Co_1/3Mn_1/3O₂锂离子电池正极材料,探究了Na元素掺杂对层状氧化物正极材料结构以及电化学性能的影响。通过X射线粉末衍射仪和扫描电子显微镜表征了材料的结构和形貌,结果表明,当x≤0.3时,样品不会出现其它杂相;当x＞0.3时,样品中会出现NaNi_1/3Co_1/3Mn_1/3O₂的杂相。同时随着掺杂浓度的增加,样品的阳离子混排度逐渐增加。电化学性能结果表明,少量Na+的掺入可以提高LiNi_1/3Co_1/3Mn_1/3O₂在0.2C,0.5C下的放电比容量并增强其循环稳定性,但会损坏材料的倍率性能。     

急冷Al-Cr合金低温氧化制备自修复α-Al2O3薄膜

为了在750℃下制备自修复α-Al2O3薄膜,对Cr质量分数为8%和18%的急冷Al-Cr合金在大气气氛中670～720℃下进行氧化,并采用X射线衍射(XRD)、扫描电镜(SEM)、透射电镜(TEM)和能谱分析(EDS)对氧化膜进行分析.结果表明,Cr质量分数为8%的急冷Al-Cr合金主要由Cr固溶于Al的单相组织构成,质量分数为18%的急冷Al-Cr合金则为Al上分布Al45Cr7的双相组织.急冷Al-Cr合金可以在720℃的低温下通过氧化制备出薄且致密的α-Al2O3膜,合金的基体组织对氧化结果无明显影响,但Cr质量分数较高时,α-Al2O3膜中固溶有少量的Cr.此外,XRD检测结果表明,试样的表面粗糙度有利于获得α-Al2O3.     

sol-gel法制备WO3薄膜的成膜性研究

用sol-gel法在ITO导电玻璃上制备了WO3电致变色薄膜,用光学显微镜对所有薄膜进行拍照,对比薄膜的成膜情况.经观察发现,薄膜前驱液浓度、拉膜速度和杂质对成膜性均有显著影响.从拉膜的过程方面讨论了出现上述情况的原因.     

Ba(ZrxTi1-x)O3弛豫铁电体的介电性能研究

采用传统的固相反应法制备了0.2% Nb2O5掺杂的Ba(Zr0.15Ti0.85)O3弛豫铁电陶瓷,测量了不同温度下的介电频谱;讨论了介电常数的频率和温度特性;结果表明:由于掺铌BZT陶瓷内部结构的不均匀,导致多种弛豫时间的不对称分布,实际的Cole-Cole图不是理论上的半圆,而是偏离半圆的鼠标形式,BZT陶瓷在Zr质量分数为0.15时仍具有弛豫性;在介温曲线中,由于漏导电流的存在,tgδ-T曲线在高温部分有上翘现象.     

溶胶-凝胶法制备（Nd,Bi）_4Ti_3O_（12）铁电薄膜

采用溶胶-凝胶法在Pt/Ti/SiO2/Si基片上制备了（Nd,Bi）4Ti3O12薄膜。将薄膜于空气中分别进行每1层、每2层、每3层500℃预退火10 min,最后于氮气氛中680℃退火30 min。结果表明：预退火工艺对薄膜的结构和铁电性能都有影响：每一层预退火处理的薄膜具有较大的剩余极化值和最小的矫顽场（2Pr=47.8μC/cm2,2Ec=254 kV/cm）。所有薄膜都呈现良好的抗疲劳特性。     

Synthesis of MnxZn(1-x)Fe2O4 Nanoparticles by Ball-milling Hydrothermal Method

SMnZn1-xFe2O4 (x=1,0.9,0.8,0.7,0.6,0.5,0.25,0) nanoparticles were prepared by ball-milling hydrothermal and investigated by X-ray diffraction, DTG and TEM, Nanocrystallite grain size was determined by X-ray linewidth to be from 63 (A) to 274 (A). The thermal properties indicate absorbed water still remain at low temperature, crystalline ware will be decomposed from 230 ℃ to 260 ℃, partial Mn2 will be oxidized near 730 ℃. TEM shows the ferrite particles pocess a spherical morphology and uniform nanosize.     

Influence of annealing time on the microstructure and properties of Pb(Zr0.53Ti0.47)O3 thin films

The PZT thin films were prepared on (111)- Pt/Ti/SiO2/Si substrates by sol-gel method, and lead acetate [Pb(CH3COO)2], zirconium nitrate [Zr(NO3)4] were used as raw materials. The X-ray diffractometer (XRD) and scanning electron microscopy (SEM) were used to characterize the phase structure and surface morphology of the films annealed at 650 ℃ but with different holding time. Ferroelectric and dielectric properties of the films were measured by the ferroelectric tester and the precision impedance analyzer, respectively. The PZT thin films were constructed with epoxy resin as a composite structure, and the damping properties of the composite were tested by dynamic mechanical analyzer (DMA). The results show that the films annealed for 90 minutes present a dense and compact crystal arrangement on the surface; moreover, the films also achieve their best electric quality. At the same time, the largest damping loss factor of the composite constructed with the 90 mins-annealed film shows peak value of 0.9, higher than the pure epoxy resin.     

ZnxCd(1-x)S薄膜的制备及其光电性质的研究

用化学池沉积法制备了不同锌含量的 Znx Cd( 1 -x) S薄膜 ,并阐述了不同锌含量对薄膜性能的影响及其原因。通过 X射线衍射、扫描电镜、光谱透过率等测试方法表明 ,在 0 .4相似文献   

(K1-xNax)（Ta（1-y）Nby）O3纳米粉体的水热合成研究

采用水热法合成了不同组分的无铅压电(K1-xNax)(Ta1-yNby)O3(KNTN)纳米粉体。研究结果表明,在高介质碱度条件下可以获得K/Na摩尔比为1的KNTN纳米粉体。随着K含量的增加,产物由单斜向四方晶型转变。产物中的Ta/Nb摩尔比与原料中Ta2O5/Nb2O5摩尔比呈线性关系。随着Ta含量的增加,KNTN由正交→四方→立方晶型转变,其微结构则由长方体逐渐转变为立方体结构。     

Sol－Gel法制备YBa_2Cu_3O_（7－x）超细粉末研究

用柠檬酸盐作螯合剂，用氨水调节溶液的酸度，通过Ｓｏｌ－Ｇｅｌ转变制得了粒径为１００ｎｍ大小的ＹＢａ２Ｃｕ３Ｏ（７－ｘ）超细粉末，对ＹＢａ２Ｃｕ３Ｏ（７－ｘ）在合成反应中溶胶的形成和凝胶聚合过程进行了研究和探讨。Ｓｏｌ－Ｇｅｌ法制得的ＹＢａ２Ｃｕ３Ｏ（７－ｘ）超细粉末在粒度、纯度、烧结特性和超导性能上，均优于固态反应合成方法。     

Microstructural Probing of (1-x) GeS_(2-x)Ga_2S_3 System Glasses By Raman Scattering

1IntroductionFiber amplifiers are of technological interest for ap-plications in optical communications systems.Attentionshas been paidtothe chalcogenide glasses because of theirlower phonon energy and higher quantumefficiency[1-4].Galliumis an essential …