预烧温度对CaCu3Ti4O12陶瓷结构和介电性能的影响

采用固相反应法在不同温度（950～1100℃）下预烧后烧结制备CaCu3Ti4O12（CCTO）陶瓷。对CCTO陶瓷进行物相分析，并测试了20Hz-1MHz频率范围和25～150℃温度区间的介电性能和阻抗谱，详细研究了预烧温度对CCTO陶瓷烧结性能、晶体结构和介电性能的影响。结果表明，较低的预烧温度有利于CCTO陶瓷的烧结，容易获得介电性能较好的CCTO陶瓷。950℃预烧后，于1120℃烧结的CCTO陶瓷室温1kHz频率下介电常数可达12444。     

Electrical characteristics and microstructures of Pr6O11-doped Bi4Ti3O12 thin films

Pr6O11-doped bismuth titanate (BixPryTi3O12, BPT) thin films with random orientation were fabricated on Pt/Ti/SiO2/Si substrates by rf magnetron sputtering technique, and the structures and ferroelectric properties of the films were investigated. XRD studies indicate that all of BPT films consist of single phase of a bismuth-layered structure with well-developed rod-like grains. For samples with y=0.06 , 0.3, 1.2 and 1.5, I-E characteristics exhibit negative differential resistance behaviors and their ferroelectric hysteresis loops are characterized by large leakage current. Whereas for samples with y=0.6 and 0.9, I-E characteristics are of simple ohmic behaviors and their ferroelectric hysteresis loops are saturated and undistorted. The remanent polarization (Pr) and coercive field (Ec) of the BPT Film with y=0.9 are above 35 μC/cm2 and 80 kV/cm, respectively.     

Mg掺杂InxGa1-xN薄膜的磁控溅射法制备和表征

本文采用磁控溅射法用In2O3靶、Ga2O3靶、Mg靶在Si片上制备出InxGa1-xN薄膜和Mg掺杂的InxGa1-xN薄膜。薄膜中的In组分随着Mg的掺杂而减少,因为Mg的掺杂抑制了In-N键的形成,并增加了Ga进入薄膜的机会。通过EDS对Mg掺杂的InxGa1-xN薄膜的分析表明,有1.4%的Mg组分被成功地注入进InxGa1-xN薄膜。电学性能分析表明 In0.84Ga0.16N 和Mg掺杂的 In0.1Ga0.9N薄膜导电类型由n型转变为p型,而且Mg掺杂的 In0.1Ga0.9N薄膜的空穴浓度和电子迁移率分别为 2.65×1018 cm?3 和3.9 cm2/Vs。     

Preparation and Dielectric Properties of CaCu3Ti4O12 Ceramics with Different Additives

Li₂CO₃, MgCO₃, BaCO₃, and Bi₂O₃ dopants were introduced into CaCu₃Ti₄O₁₂ (CCTO) ceramics in order to improve the dielectric properties. The CCTO ceramics were prepared by conventional solid-state reaction method. The phase structure, microstructure, and dielectric behavior were carefully investigated. The pure structure without any impurity phases can be confirmed by the x-ray diffraction patterns. Scanning Electron Microscopy (SEM) analysis illuminated that the grains of Ca_0.90Li_0.20Cu₃Ti₄O₁₂ ceramics were greater than that of pure CCTO. It was important for the properties of the CCTO ceramics to study the additives in complex impedance spectroscopy. It was found that the Ca_0.90Li_0.20Cu₃Ti₄O₁₂ ceramics had the higher permittivity (>45000), the lower dielectric loss (<0.025) than those of CCTO at 1 kHz at room temperature and good temperature stability from ?30 to 75 °C.     

高介电常数材料CaCu3Ti4O12的溶胶-凝胶制备技术研究

用溶胶-凝胶(Sol-gel)技术及柠檬酸自燃法,成功制备了新型的纳米CaCu3Ti4O12氧化物超细粉体.将得到的超细粉体压块,并在1000℃高温烧结成微晶陶瓷材料.用X射线粉末衍射(X-ray powdef diffraction,XRD)确定了烧结体的晶相,用扫描电镜(Scanning electron microscopy,SEM)观察了晶粒的形貌特征与大小.同时研究了徽晶陶瓷的介电常数和介电损耗.CaCu3Ti4O12室温介电常数达104,接近目前高介电常数复合含Pb钙钛矿系陶瓷;介电损耗低于0.20.因此,Sol-gel工艺技术是一种制备CaCu3Ti4O12超细粉体与高介电常数微晶陶瓷的有效方法.     

CaCu3Ti4O12／NiCuZn铁氧体基磁电复合材料研究

将CCTO（CaCu3Ti4O12）与NiCuZn铁氧体进行复合,系统地研究了组分变化对这种新型磁电复合材料的烧结性能、晶相结构、显微结构和磁电性能的影响。随后,为了实现复合材料的低温烧结以及综合考虑复相陶瓷的磁电性能,选取80％（质量分数,下同）NiCuZn铁氧体／20％CCTO组分,以BBSZ（Bi2O3-H38O3-SiO2-ZnO）玻璃作为助熔剂,研究了CCTO／NiCuZn铁氧体基复合材料的烧结行为和磁电性能。结果表明,掺杂BBSZ后,900℃下烧结的所有样品的密度均达到了复相陶瓷理论密度的95％,且复相陶瓷的介电常数和磁导率在1～30MHz范围内均不依赖于频率的变化。在10MHz的频率下,当BBSZ的含量从0增加到3％时,复相陶瓷磁导率μ从13．2增加到47．9,磁损耗tanδμ从0．022下降到0．017,同时,样品的谐振频率从10^9Hz左右移动到3．2×10^8Hz。相应地,复相陶瓷的介电常数F从9．2增加到16,介电损耗tanδε从0．069下降到0．012。这一优异的整体性能使其有望实际应用。     

Ferroelectric properties of dysprosium-doped Bi4Ti3O12 thin films crystallized in various atmospheres

Dysprosium-doped Bi4Ti3O12 （Bi3.4Dy0.6Ti3O12, BDT） ferroelectric thin films were deposited on Pt（111）/Ti/SiO2/Si（111） substrates by chemical solution deposition （CSD） and crystallized in nitrogen, air and oxygen atmospheres, respectively. X-ray diffraction （XRD） and scanning electron microscopy （SEM） were used to identify the crystal structure, the surface and cross-section morphology of the deposited ferroelectric films. The results show that the crystallization atmosphere has significant effect on determining the crystallization and ferroelectric properties of the BDT films. The film crystallized in nitrogen at a relatively low temperature of 650 ℃, exhibits excellent crystallinity and ferroelectricity with a remanent polarization of 2Pr = 24.9 ℃/cm^2 and a coercive field of 144.5 kV/cm. While the films annealed in air and oxygen at 650 ℃ do not show good crystallinity and ferroelectricity until they are annealed at 700 ℃. The structure evolution and ferroelectric properties of BDT thin films annealed under different temperatures （600-750 ℃） were also investigated. The crystallinity of the BDT films is improved and the average grain size increases when the annealing temperature increases from 600 ℃ to 750 ℃ at an interval of 50 ℃. However, the polarization of the films is not monotonous function of the annealing temperature.     

SrxBa1-xBi4Ti4O15陶瓷及SrBi4Ti4O15／BaBi4Ti4O15复合材料的性能研究

采用固相烧结工艺制备了SrxBa1-xBi4Ti4O15铁电陶瓷和SrBi4Ti4O15／BaBi4Ti4O15铁电复合材料。在固相反应过程中，680℃时SrBi4Ti4O15或BaBi4Ti4O15开始生成：800℃时材料主晶相基本形成，但是还有微量焦绿石相存在；850℃时SrBi4Ti4O15或BaBi4Ti4O15的主要衍射峰全部出现。随着Ba含量的增加，SrxBa1-xBi4Ti4O15陶瓷的居里温度逐渐降低。Sr0.5Ba0.5Bi4Ti4O15，陶瓷的介电常数峰在高频时较宽，在100Hz时，介电常数峰被随温度升高而逐渐增大的介电常数所“屏蔽”，材料介电损耗随温度升高而增大，但在低频下增加得更快，这是高温下由氧空位引起的电子松弛极化造成的。将预烧后的SrBi4Ti4O15和BaBi4Ti4O15粉体分别造粒后冉均匀混合，压片成型，经烧结制得的SrBi4Ti4O15／BaBi4Ti4O15复合陶瓷其相变弥散特性明显优于SrxBa1-xBi4Ti4O15的相变弥散特性。     

磁电复合材料CuFe2O4/PbZr0.53Ti0.47O3的内耗与介电损耗

制备了组分为xCuFe2O4-(1-x)PbZr0.53Ti0.47O3(其中x=0．1，0．2，0．3，1．0)的磁电复合材料，XRD实验表明，样品中只存在着CuFe2O4和PbZr0.53Ti0.4703相．利用多功能摆测量了样品在低频下(0.1--6．4Hz)的内耗，同时利用HP4194A阻抗分析仪测量了样品低频(100Hz--1 MHz)的介电损耗，分析了复合物中CuFe2o4和PZT对内耗及介电损耗分别所作的贡献．     

Effect of annealing temperature on ferroelectric properties of （Bi, Nd）4（Ti, V）3O12 thin films

Thin films of Nd^3＋/V^5＋-cosubstituted bismuth titanate, （Bi3.sNd0.5）（ Ti2.96V0.04）O12 （BNTV）, were fabricated on the Pt（111）/Ti/SiO2/Si（100） substrates by a chemical solution deposition technique and annealed at different temperatures of 650, 700, 750 and 800 ℃. The surface morphology and ferroelectric properties of the samples were studied in detail. The result shows that the film annealed at 800 ℃ indicates excellent ferroelectricity with a remanent polarization of 2Pr=40.9 i.tC/cm^2, a coercive field （Ec） of 114 kV/cm at an applied electrical field of 375 kV/cm. The substitution of Ti-site ion by V^5＋ ions could improve the upper limit of the optimal annealing temperature by decreasing the space charge density in BNT thin film. Additionally, the mechanism concerning the dependence of ferroelectric properties of BNTV thin films on the annealing temperature was discussed.     

Preparation and microstructure characterization of a nano-sized Ti4+-doped AgSnO2 electrical contact material

A Ti4+-doped nano-structured AgSnO2 material was prepared using sol-gel method and characterized by X-ray diffraction (XRD), transmis-sion electron microscopy (TEM), and scanning electron microscopy (SEM). The results show that Ti4+ cations are successfully doped into the crystal lattice of SnO2, and thus significantly improve the electrical conductivity of the sample. Furthermore, the coating of Ag on Ti4+-doped SnO2 nano-sized particles enhances the surface wettability and enables the resulting AgSnO2 material to have better mechanical properties.     

Microstructure and electrical properties of sol–gel derived Ni-doped CaCu3Ti4O12 ceramics

Dielectric properties and varistor performance of sol–gel prepared Ni-doped calcium copper titanate ceramics (CaCu₃Ni_xTi₄O_12+x, x=0, 0.1, 0.2, 0.3) were investigated. SEM and XRD were used in the microstructural studies of the specimens and the electrical properties were investigated for varistors. XRD patterns show that the CCTO ceramics were single phase with no Cu-rich phase. SEM results indicated that the samples had smaller grain sizes than those synthesized by traditional solid-state reaction methods. The experimental results show that the highest dielectric constant and lower dielectric loss occur when x=0.2. When x=0.3, the lowest leakage current is obtained and the maximum value reaches 0.295; meanwhile, the lowest threshold voltage and nonlinear coefficient are found, the minimum values of them are 1326 V/mm and 3.1, respectively.     

烧结温度对CaCu3Ti4O12陶瓷C波段介电性能的影响

采用固相反应法制备了CaCu3Ti4O12(CCTO)陶瓷,研究了烧结温度对CCTO晶相、微观形貌、致密度以及在C波段(3.95～5.85 GHz)的介电性能的影响。结果表明,在1040℃烧结的试样除了含有CCTO,还存在部分没有反应的TiO2。随着烧结温度的升高,TiO2逐渐消失。与1040℃和1060℃烧结的试样相比,在1080℃烧结的试样晶粒尺寸较大且粒径较均匀,而在1100℃烧结的试样有明显的熔化现象。试样的密度随烧结温度的升高而增加,在1080℃时达到最大值。在1040～1080℃烧结的试样,其介电常数随着烧结温度的升高而增加,而在1100℃烧结的试样的介电常数反而有所降低。不同烧结温度下的CCTO陶瓷的介电常数和介电损耗随频率的增大变化不大。在所得的试样中,在1080℃烧结的CCTO陶瓷介电常数最高,介电损耗最低。     

Hydrogen storage properties of Mg-doped Ti_(1.2)Fe alloys synthesized by mechanical alloying

1　INTRODUCTIONHydrogenstoragematerials ,usedinhydrogensourcesystemsforfuelcellshavebeeninvestigatedduetotheirhighvolumetricdensity ,safety ,easyminiaturizationandconvenientoperation .Consider ingallkindsofhydrogenalloysasawhole ,AB typeTiFealloysareknowntobemuchmoresuitableforusingin portableormobilePEMFCbecauseofitshighreversiblehydrogenstoragecapacity ,whichismuchhigherthanthatofAB5 typealloys.Ontheotherhand ,theactivationpropertiesoftheTiFeal loysare poor .Forexample ,typically ,…     

Li4Ti5O12/TiN复合材料的制备及电化学性能

以尿素为氮源,采用高温热处理方法在Li4Ti5O12表面自生长一层纳米尺寸厚度的TiN导电包覆膜。利用DSC-TG、Raman、TEM、FT-IR、XRD及恒流充放电等测试手段,研究热处理工艺对材料结构、形貌及电化学性能的影响。结果表明:使用适中的尿素原料含量可以获得均匀连续、厚度适中的TiN导电膜,较高的热处理温度有利于促进TiN的生成,而较短的热处理时间可以保持材料物相的纯净和较高结晶度。在尿素含量10%(质量分数)、热处理温度800℃、热处理时间20 min的工艺条件下,所制备的复合材料的容量和倍率性能最优,0.2C和3C初始放电比容量分别达到162.4和130.2 mA.h/g。     

Ba（Sn0．1Ti0．9）O3粉体的熔盐法制备与性质

采用熔盐法研究了Ba（Sn0．1Ti0．9）O3铁电体粉体的制备工艺和粉体性质。探讨了在熔盐催化下，合成温度对Ba（Sn0．1Ti0．9）O3反应完全程度及粉体形态的影响。结果表明，当反应温度达到900℃时，在熔盐环境下即可合成单相固体Ba（Sn0．1Ti0．9）O3，随着反应温度提高，粉体尺寸变化不大，但当温度超过950℃时出现晶粒异常长大趋势。烧结陶瓷的形貌和介电性质显示陶瓷粉体烧结活性好且介电性质优良。     

合成工艺对CaCu3Ti4O12陶瓷介电性能的影响（英文）

利用溶胶凝胶工艺制备CaCu3Ti4O12粉体,经相同压力和时间冷压后,于1000℃下进行烧结,制备CaCu3Ti4O12陶瓷。微观组织观察表明,烧结时间对复合陶瓷的晶粒尺寸有显著的影响;烧结不同时间的复合陶瓷的介电常数和介电损耗在50Hz到100kHz的范围内表现出弱的频率相关性。随着频率的增加,复合材料的介电损耗降低,而介电常数保持在一个较高值。最佳的烧结时间为6h。