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Effects of Donor Doping on microstructure and Electrical Properties of Bismuth Layer-structured Bi4Ti3O12 Ceramics

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Effects of Donor Doping on Microstructure and Electrical Pro...

microstructures of an AlSi_7Mg alloy by near-liquidus casting

The 3～〔rd〕International Conference on High-Performance Ceramics(CICC-3)（1）

作者： Una Zhang Suchuan Zhao Liaoying Zheng Guorong Li and Qingrui YinThe State Key Lab of High Performance Ceramics and Superfine microstructure Shanghai Institute of Ceramics Chinese Academy of Science Shanghai 200050 China

＜正＞ A study was conducted on the effects of donor dopants, Nb2O5 and WO3, on microstructure and electric properties of Bi4Ti3O12 （BIT） ceramics. X-ray diffraction patterns of the materials showed a single orthorhombic phase structure. The microstructure results revealed the appearance of plate-like grain. The donor doping decreased the conductivity of BIT by as much as 3 orders of magnitude. The dielectric and ferroelectric properties of doped-BIT materials were also investigated. The decrease in the electrical conductivity allowed the doped samples to be poled to develop piezoelectricity. Thermal annealing studies of the samples indicated the donor-doped BIT were suitable candidate materials for high-temperature piezoelectric applications.

关键词： Bi4Ti3O12 ceramics Donor doping Electrical conductivity Piezoelectric properties

来源： cnki会议评论

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Rare Metals 2007年第3期26卷 226-229页

作者： GAO Ming WANG Ping LU Guimin CUI Jianzhong School of Physics Science ＆ Technology Shenyang Normal University Shenyang 110034 China Key Laboratory for microstructure ＆ properties of Advanced Materials Education Committee of Liaoning Province Shenyang Normal UniversityShenyang 110034 China Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern University Shenyang 110004 China

Semi-solid ingots of an A1SiTMg alloy were obtained using the method of near liquidus casting. Their microstructures exhibit the characteristics of free, equiaxed, and non-dendrite, which are required for semi-solid forming. The influences of casting temperature, heat preservation time, and cooling rate on the microstructure were also investigated. The results show that in the temperature region near liquidus the grain size becomes small with a decrease in casting temperature. Prolonging the heat preservation time makes grain crassitude at the same temperature. And increasing the cooling rate makes grain fine. The microstructure of the alloy cast with iron mould is freer than that with graphite mould.

关键词： semi-solid near-liquidus casting AlSi7Mg alloy microstructure global grains

Y-α-β Sialon复相陶瓷的显微结构和蠕变行为

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无机材料学报 2001年第6期16卷 1113-1120页

作者：林明通蒋丹宇汪霖阮美玲施剑林中国科学院上海硅酸盐研究所高性能陶瓷和超微结构国家重点实验室上海200050

研究了一种以ＹＡＧ为晶界相和理论初始α／β比率为６５／３５的Ｙ－α－β复相ｓｉａｌｏｎ在温度１２５０～１３５０℃和应力１１０～２９０ＭＰａ的四点弯曲蠕变行为，得出在１２５０、１３００、１３５０℃下的应力指数分别为１．... 详细信息

研究了一种以ＹＡＧ为晶界相和理论初始α／β比率为６５／３５的Ｙ－α－β复相ｓｉａｌｏｎ在温度１２５０～１３５０℃和应力１１０～２９０ＭＰａ的四点弯曲蠕变行为，得出在１２５０、１３００、１３５０℃下的应力指数分别为１．３１、１．４９、１．６２，蠕变激活能为６７７ｋＪ.ｍｏｌ-1，显微结构观察表明几乎所有的空洞都位于多晶界，从而推断伴随着多晶界空洞形成的扩散－滑移耦联机制是蠕变的速率控制机制．Ｍｏｎｋｍａｎ－Ｇｒａｎｔ关系式得出的蠕变速率指数p值为１.６，蠕变断裂是由多三晶界空洞的成核、生长、聚结和连接引起的．

关键词：蠕变显微结构氧化相变蠕变断裂 Y-α-βSialon复相陶瓷蠕变变形

Blue-shift of Nano-Y_2O_3 : Eu^(3+) Emission Spectra Excited by X-ray

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Journal of Materials Science & Technology 1997年第4期13卷 351-353页

作者： Qiang LI Lian GAO and Dongsheng YAN(State Key Lab. of High Performance Ceramics & Superfine microstructure, Shanghai Institute of Ceramics,Chinese Academy of Sciences, Shanghai 200050, China) State Key Lab. of High Performance Ceramics and Superfine microstructure Shanghai Institute of Ceramics Chinese Academy of Sciences Shanghai 200050 China

Nano-Y_2O_3:Eu^(3+) powder was prepared by the homogeneous precipitation. With controlling the conditions of the reaction, nano powders with different grain size were obtained. It is found that the blue-shift phenomena exist in the nano-Y2O3:Eu3+ emission spectra excited by X-ray. The wave lengths of the peak (5D0→7F2) are related with the grain size of the powder

关键词： Eu Nano Emission Spectra Excited by X-ray Blue-shift of Nano-Y2O3

Preparation and Properties of Nano-TiO_2 Powders

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Journal of Materials Science & Technology 1997年第4期13卷 321-323页

作者： Zhe SONG Qing LI and Lian GAO(State Key Lab. of High Performance Ceramics & Superfine microstructure, Shanghai Institute of Ceramics,Chinese Acadmey of Sciences, Shanghai 200050, China) State Key Lab. of High Performance Ceramics and Superfine microstructure Shanghai Institute of Ceramics Chinese Acadmey of Sciences Shanghai 200050 China

This paper reports the preparation of nano-TiO2 (about 10 nm) powder by the method of precipitation. In detail, some breparation conditions were investigated in order to find out how to control the grain size and reduce the agglomeration of powders. Also, the reflex spectra of nano-scale powders with different grain size were studied. It tvas found that the wave length and width of reflex spectra are connected with the grain size of nano-TiO2 powders

关键词： TiO Nano Preparation and Properties of Nano-TiO2 Powders OC

Mid-infrared laser with 1.2 W output power based on PPLT

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Science China(Physics,Mechanics & Astronomy) 2010年第4期53卷 638-642页

作者： Lü XinJie, ZHAO Gang, LI GuiJun, GAO ZhiDa, PAN ShuDi & ZHU ShiNing National Laboratory of Solid State microstructure, Nanjing University, Nanjing 210093, China National Laboratory of Solid State microstructure Nanjing University Nanjing China

The optical parametric oscillator (OPO) based on the periodically poled lithium tantalate (PPLT) crystal (40 mm×5 mm×1 mm) is fabricated. The OPO is pumped by a Q-switched Nd:YAG laser working at 1.064 μm. An average idler output power (around 3.8 μm) of 1.2 W and signal output power (around 1.48 μm) of 3 W are obtained when the pump power is 20 W.

关键词： optical superlattice mid-infrared laser optical parametric oscillator (OPO) periodically poled lithium tantalate (PPLT)

Densification and Sintering Kinetics of Rare Earth(α′+β′)-Sialon Composites

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Journal of Materials Science & Technology 1995年第2期11卷 137-140页

作者： Hao WANG T.S.YEN Hanrui ZHUANG and Weiying SUN (State Key Lab. on High Performance Ceramics and Superfine microstructure, Shanghai Institute of Ceramics,Chinese Academy of Sciences, Shanghai, 200050, China) Shanghai Inst of Ceramics Chinese Acad of Sciences Shanghai China

The sintering processes of Re-(α' + β')-sialon composites (Re=Sm, Dy, Yb) have been investigated by using a specially designed high temperature dilatometer. The initial densification of various samples starts at about 1200℃, and the maximum shrinkage rate of these sialon composites occurs at about 1500℃. The light rare earth sialon has a noticeably tower densification temperature and a higher final shrinkage. The sirtering kinetics of Re-(α' +β')-sialonare much more complex. The Kingery's liquid phase sintering model appears to be applicable,but the mechanism of mass transport in stage two appears to be changeable. The controlling factor shiffs from solution-precipitation to diffusion when densification process proceeds from the earlier part to the later part of this stage.

关键词： Figure Sialon Composites Densification and Sintering Kinetics of Rare Earth Dy

GELCASTING OF NANO-SIZE Y-TZP

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Acta Metallurgica Sinica(English Letters) 1996年第6期9卷 489-492页

作者： J.Sun L. Gao J.K. Guo and D.S. Yan (State Key Lab.of High PerformanceCeramics and Superfine microstructure, Shanghai Institute of Ceram ics, Chinese Academy of Sciences, Shanghai 200050, China ) Shanghai Inst of Ceramics Chinese Acad of Sciences Shanghai China

The green specimens of nano-size Y-TZP are formed by gelcasting method. Using polymer electrolytes NaPAA and NH_4PAA, we have studied the rheological properties of *** optimum pH range is between 8 to 10. The proper amount of dispersant changes with the solid *** rheological measurements of suspension containing NH_4PAA show lower *** theoretical green density has been calculated.

关键词： gelcasting nano-size Y-TZP

Phase reaction of Au/Sn solder bonding for GaN-based vertical structure light emitting diodes

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Science China(Technological Sciences) 2010年第2期53卷 301-305页

作者： TIAN PengFei, SUN YongJian, CHEN ZhiZhong, QI ShengLi, DENG JunJing, YU TongJun, QIN ZhiXin & ZHANG GuoYi State Key Laboratory for Artificial microstructure and Mesoscopic Physics, School of Physics, Peking University, Beijing 100871, China State Key Laboratory for Artificial microstructure and Mesoscopic Physics School of Physics Peking University Beijing China

Au/Sn solder bonding on Si substrates was used to fabricate the GaN-based vertical structure light emitting diodes (VSLEDs). The phase reaction of Au/Sn solder under different bonding conditions was investigated by the measurement of electron back scattering diffraction (EBSD), and the characteristics of VSLED were analyzed by scanning acoustic microscope (SAM), Raman scattering, current-voltage (I-V) and light output-current (L-I) curves. After the bonding process, horizontal stripes of Au/Sn phase (δ phase) and Au5Sn phase (ζ phase) were redirected to vertical stripes, and δ phase tended to move to the solder joint. Sn interstitial diffusion led to the distribution of δ phase and voids in Au/Sn solder, which could be seen in SAM and SEM images. Vertical distribution of the δ phase and ζ phase with proper voids in the Au/Sn bonding layer showed the best bonding quality. Good bonding quality led to little shift of the E2-high mode of Raman spectra peak in GaN after laser lift off (LLO). It also caused more light extraction and forward bias reduction to 2.9 V at 20 mA.

关键词： GaN LED bonding Au/Sn phase