检索结果-南通市图书馆

Electronic Properties of batio3 （110） Polar Terminations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2014年第5期30卷 794-799页

作者： XIE Ying YU Haitao Key Laboratory of Functional Inorganic Material Chemistry Ministry of EducationSchool of Chemistry and Materials Science Heilongjiang University Harbin 150080 P. R. China

The band structures, electron, density differences, and surface energies of five different batio3 （110） ter- minations were investigated by first-principles calculations. According to the calculated results of electron density differences, the bonding characteristics of these considered terminations were discussed. The computational results indicate that the batio-terminated surface is metallic, while the 02-, O-, Ba- and TiO-terminated surfaces are all in- sulative. Furthermore, the computed surface energies suggest that for the considered terminations, the polarity com- pensation achieved through surface reconstruction or surface defect is more effective than by change in surface elec- tronic structure. The defected or reconstructed terminations predominate over cleavage and construction of batio3 crystal along （110） direction.

关键词： batio3 (110) Polar surface Polar termination Polarity compensation

Semi-oxalate synthesis of (1-x)batio3-xM0.5Bi0.5TiO3 (M =Li, Na, K)PTCR materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2016年第2期5卷 117-125页

作者： T.A.PLUTENKO O.I.V'YUNOV A.G.BELOUS O.Z.YANCHEVSKII Vernadskii Institute of General and Inorganic Chemistry of the Ukrainian NAS Prospect Palladina 32/34 Kyiv 142 03680 Ukraine

(1−x)batio3–xM0.5Bi0.5TiO3 (M = Li, Na, K) solid solutions were prepared using batio3 pre-synthesized by oxalate method. The stability limits of (1−x)batio3–xLi0.5Bi0.5TiO3 solid solutions have been established. It was shown that increase in M0.5Bi0.5TiO3 concentration results in reduction of ceramic grain size in the (1−x)batio3−xM0.5Bi0.5TiO3 (M = Li, Na, K) system. It was found that the positive temperature coefficient of resistance (PTCR) effect in lead-free materials is due to the presence of a semiconductor core, which is formed by sintering under reducing atmosphere, and dielectric grain boundaries, formed on additional oxidation in air. The use of barium titanate, pre-synthesized by oxalate method, in the synthesis of solid solutions reduced the sintering temperature of ceramics compared with solid state reaction technique. By comparing the electrical properties of the synthesized lead-containing and lead-free materials, it has been shown that lead-free materials exhibit better electrical properties for practical use compared with lead-containing materials.

关键词： lead-free ceramic batio3 semi-oxalate method positive temperature coefficient of resistance (PTCR) effect

Structure and enhanced dielectric temperature stability of batio3- based ceramics by Ca ion B site-doping

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materiomics 2021年第2期7卷 295-301页

作者： Xuewen Jiang Hua Hao Yang Yang Enhao Zhou Shujun Zhang Ping Wei Minghe Cao Zhonghua Yao Hanxing Liu Foshan Xianhu Laboratory of the Advanced Energy Science and Technology Guangdong Laboratory Xianhu Hydrogen ValleyFoshan528200China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing School of Materials Science and EngineeringWuhan University of TechnologyWuhan430070China State Key Laboratory of Advanced Technology for Materials Synthesis and Processing International School of Material Science and EngineeringWuhan University of TechnologyWuhan430070China Institute for Superconducting and Electronic Materials Australian Institute of Innovative MaterialsUniversity of WollongongWollongongNSW2500Australia Nanostructure Research Centre Wuhan University of TechnologyWuhan430070China

Capacitor is an important part of many electronic devices,so the temperature stability as one key parameter of capacitor needs to be improved constantly for meeting the requirements of various application ***,combined with the X-ray diffraction(XRD),selected area electron diffraction(SAED)and Vienna Ab-initio Simulation Package(VASP)calculation,it was confirmed that Ca ion can substitute the Ti site in the BaTi1-xCaxO3-x[BTC100](0≤x≤0.05)ceramics synthesized by solid-phase method which greatly improved the low-temperature stability of dielectric ***,introducing Bi3þand Zn^(2+) into BTC4 to form(1-y)BaTi0.6Ca0.04O2.96-yBi(Zn_(0.5)Ti_(0.5))O_(3)[(1-y)BTC4-yBZT](0.1≤y≤0.2)ceramics can further improve the dielectric-temperature stability by means of diffused phase transition and core-shell *** importantly,the 0.85BTC4-0.15BZT ceramics with a pseudocubic perovskite structure possessed a temperature coefficient of capacitance at 25℃(TCC25℃)being less than±15%over a wide temperature range of 55℃-200℃and a temperate dielectric constant(ε=1060)and low dielectric loss(tanδ=1.5%),which measure up to the higher standard in the current capacitor industry such as X9R requirements.

关键词： batio3 Ca substituted X9R capacitors Dielectric properties

固相反应法合成batio3粉末的相变和微观结构的转变

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

稀有金属材料与工程 2020年第2期49卷 476-481页

作者：胡乔宇黄皓温佳鑫张蕾于洪宇深圳市第三代半导体重点实验室广东深圳518055 南方科技大学广东深圳518055 东南大学江苏南京210096

以国产亚微米级BaCO3和TiO2为原料,采用砂磨固相法合成粒径小、四方性高的batio3粉体,同时研究煅烧温度、升温速率及保温时间对batio3平均粒径和四方性的影响。结果表明,通过固相反应合成batio3的反应机理可分为两个阶段:当煅烧温度低于... 详细信息

以国产亚微米级BaCO3和TiO2为原料,采用砂磨固相法合成粒径小、四方性高的batio3粉体,同时研究煅烧温度、升温速率及保温时间对batio3平均粒径和四方性的影响。结果表明,通过固相反应合成batio3的反应机理可分为两个阶段:当煅烧温度低于900℃时,BaCO3和TiO2首先形成立方相的batio3,当煅烧温度升至900℃时,立方相batio3开始向四方相转变。在升温速率为5℃/min,煅烧温度为900℃保温5 h时,制备出粒径为180.7 nm,四方性(c/a)为1.0086的超细batio3粉体。该工作为制备超薄层MLCC用高性能batio3粉体提供了较好的研究思路。

关键词： batio3 固态反应相变微观结构

batio3/gelatin核壳复合粒子的制备及电场响应性能研究

在线全文

学校读者我要写书评

暂无评论

功能材料 2013年第11期44卷 1570-1573,1578页

作者：李丽海金玲谢超高玲香陕西师范大学化学化工学院应用表面与胶体化学教育部重点实验室陕西西安710062

为了提高batio3颗粒在含水弹性体中的电场响应能力,以粒径约为500nm的单分散球型Ba-TiO3颗粒为基础,采用微乳液法成功制备了batio3为核、明胶(gelatin)为壳的batio3/gelatin核壳复合粒子。利用TEM、XRD、FT-IR、TG和光学接触角测量等手... 详细信息

为了提高batio3颗粒在含水弹性体中的电场响应能力,以粒径约为500nm的单分散球型Ba-TiO3颗粒为基础,采用微乳液法成功制备了batio3为核、明胶(gelatin)为壳的batio3/gelatin核壳复合粒子。利用TEM、XRD、FT-IR、TG和光学接触角测量等手段对粒子的组成、结构及表面亲水性能进行了表征和测量。结果表明,在立方相batio3核的表面均匀包覆了1层约40～50nm的gelatin,Gelatin壳层约占粒子总重的4.0%,且粒子表面保持良好的亲水性。将粒子分散到含水胶体体系中,通过测量在无/有电场作用下胶凝得到的含水弹性体的储能模量考察了粒子在此体系中的电场响应性能,发现batio3/gelat-in复合粒子在明胶(或壳聚糖)水凝胶弹性体中的电场响应性能均明显强于纯batio3粒子,而且在明胶水凝胶中的响应性能更强。结果说明,聚合物包覆能够明显提高batio3粒子的电场响应性能,而且粒子表面与分散体系相容性越高,粒子的响应性能越好。

关键词：核壳复合粒子 batio3 gelatin 电场响应含水弹性体

原料预处理对batio3压电陶瓷的物性影响

在线全文

学校读者我要写书评

暂无评论

无机材料学报 2017年第6期32卷 615-620页

作者：孙丹丹张家良武燕庆张仲秋刘大康山东大学物理学院晶体材料国家重点实验室济南250100

BaCO_3微粉原料通常由尺寸较大的棒状颗粒所组成,这些棒状颗粒在一次球磨过程中由于不容易粉碎,从而对经预烧、二次球磨所得到的batio_3陶瓷微粉的化学组分的均匀性和颗粒度产生影响,进而影响后序烧结制备的batio_3陶瓷的微观组织结构... 详细信息

BaCO_3微粉原料通常由尺寸较大的棒状颗粒所组成,这些棒状颗粒在一次球磨过程中由于不容易粉碎,从而对经预烧、二次球磨所得到的batio_3陶瓷微粉的化学组分的均匀性和颗粒度产生影响,进而影响后序烧结制备的batio_3陶瓷的微观组织结构和压电性能。本研究重点探讨了以BaCO_3和Ti O_2为原料、通过固相反应途径制备batio_3陶瓷时,实施原料预处理对所制备的batio_3压电陶瓷物性的影响。研究发现,配料前对BaCO_3原料实施球磨预处理可明显地降低棒状颗粒的尺寸,从而可获得颗粒度细化的batio_3陶瓷微粉,进而制备致密度更高和晶粒尺寸更小而压电性能更高的batio_3陶瓷材料。研究中对BaCO_3微粉进行不同时间的球磨预处理,然后制备钛酸钡陶瓷,考察了其压电性能、介电性质、铁电性能和微观结构等物理性质。利用同样的BaCO_3微粉原料,未经球磨预处理所制备的batio_3陶瓷的压电系数d33最高值为410 p C/N,而实施合适的球磨预处理制备的batio_3陶瓷的压电系数d33最高值可达470 p C/N。

关键词： batio3 压电陶瓷原料预球磨处理微观结构

Structural and electronic properties of Fe-doped batio3 and SrTiO3

在线全文

学校读者我要写书评

暂无评论

Chinese Physics B 2007年第5期16卷 1422-1428页

作者：张超王春雷李吉超杨鲲 School of Physics and Microelectronics State Key Laboratory of Crystal Materials Shandong University Jinan 250100 China

We have performed first principles calculations of Fe-doped batio3 and SrTiO3. Dopant formation energy, structure distortion, band structure and density of states have been computed. The dopant formation energy is found to be 6.8eV and 6.5eV for Fe-doped batio3 and SrTiO3 respectively. The distances between Fe impurity and its nearest O atoms and between Fe atom and Ba or Sr atoms are smaller than those of the corresponding undoped bulk systems. The Fe defect energy band is obtained, which mainly originates from Fe 3d electrons. The band gap is still an indirect one after Fe doping for both batio3 and SrWiO3, but the gap changes from Γ-R point to Γ-X point.

关键词： the first-principles impurity batio3 SrTiO3

Co：batio3／Si(100)纳米复合薄膜制备、微结构及其紫外光电子能谱研究

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

物理学报 2008年第1期57卷 600-606页

作者：吴卫东何英杰王锋詹勇军白黎巨新陈正豪唐永建孙卫国潘海斌四川大学原子与分子物理研究所成都610064 中国工程物理研究院激光聚变研究中心南京大学物理系南京210093 中国科学技术大学国家同步辐射实验室合肥230029

采用脉冲激光气相沉积(PLD)方法,在Si(100)晶面上制备了Co:batio3纳米复合薄膜.采用X射线衍射(XRD)结合透射电镜(TEM)方法研究了两种厚度Co:batio3纳米复合薄膜的晶体结构,当薄膜厚度约为30nm时,薄膜为单一择优取向;当薄膜厚度约为100nm... 详细信息

采用脉冲激光气相沉积(PLD)方法,在Si(100)晶面上制备了Co:batio3纳米复合薄膜.采用X射线衍射(XRD)结合透射电镜(TEM)方法研究了两种厚度Co:batio3纳米复合薄膜的晶体结构,当薄膜厚度约为30nm时,薄膜为单一择优取向;当薄膜厚度约为100nm时,薄膜呈多晶结构.原子力显微镜(AFM)分析表明,当膜厚为30nm时,薄膜呈现明显的方形晶粒.采用紫外光电子能谱(UPS)研究了Co的价态和Co:batio3纳米复合薄膜的价带谱.研究表明:当Co浓度很高时其态密度(DOS)与晶体batio3明显不同.此外,嵌埋纳米Co颗粒的batio3薄膜的能带结构可用纳米颗粒的浓度来调制,从而也可对其光学和电学性质进行改性.

关键词： batio3 纳米复合薄膜紫外光电子能谱

核-壳结构界面对纳米Ag掺杂batio3@PDA/P（VDF-HFP）复合膜介电和储能性能影响

在线全文

学校读者我要写书评

暂无评论

复合材料学报 2019年第9期36卷 2042-2050页

作者：夏卫民张慧慧顾玉娇西安理工大学印刷包装与数字媒体学院

为改善聚偏氟乙烯(PVDF)基复合材料界面相容性,提高其电性能,利用聚多巴胺(PDA)成功包覆了纳米钛酸钡(batio3),并引入纳米Ag离子制备出具有核-壳结构的Ag镶嵌batio3@PDA-Ag颗粒。以介电聚合物聚偏氟乙烯-六氟丙烯(P(VDF-HFP))为基体,采... 详细信息

为改善聚偏氟乙烯(PVDF)基复合材料界面相容性,提高其电性能,利用聚多巴胺(PDA)成功包覆了纳米钛酸钡(batio3),并引入纳米Ag离子制备出具有核-壳结构的Ag镶嵌batio3@PDA-Ag颗粒。以介电聚合物聚偏氟乙烯-六氟丙烯(P(VDF-HFP))为基体,采用溶液流延法制备了batio3@PDA-Ag/P(VDF-HFP)复合材料厚膜。利用FTIR和XPS验证了batio3@PDA-Ag/P(VDF-HFP)复合材料结构和形貌,并用宽频介电频谱仪和铁电测试仪分别比较了PDA包覆前后的不同batio3含量的batio3@PDA-Ag/P(VDF-HFP)复合膜在低电场下的介电性能和高电场下的电极化性能。结果表明,batio3@PDA-Ag质量分数为20wt%的batio3@PDA-Ag/P(VDF-HFP)复合膜在10Hz下介电常数(εr)达到了25,介电损耗(tanδ)仅为0.1,在175MV·m-1电场下电极化强度(Dm)为6.2μC·cm-2,200MV·m-1时储能密度(Ue)达到了6.9J·cm-3,高于其它界面未处理复合膜。以上结果可为此类介电复合材料界面结构处理和电性能研究提供参考。

关键词： batio3 聚偏氟乙烯-六氟丙烯介电储能核-壳结构