本论文在固相反应法的基础上结合流延成型制备CaCu3Ti4O12（简称CCTO）陶瓷薄片，研究两步法烧结和Cu不同化学计量比对流延成型CCTO陶瓷致密度、微观结构和电学性能等方面影响；同时对CCTO陶瓷介电机理的表面效应进行初步探讨；成功制备多层CCTO陶瓷基双功能元件，并与铝电解电容器和超级电容器进行性能和充放电特性对比试验。 首先，采用两步法烧结流延成型CCTO陶瓷薄片。第二步保温时间和第二步烧结温度对流延成型CCTO陶瓷的性能都有较大的影响。随着第二步保温时间的延长和第二步烧结温度的升高，CCTO陶瓷的相对密度和电容率都有所提高。在第二步烧结温度1000℃保温72h烧结的CCTO陶瓷，...In this paper, CaCu3Ti4O12, i.e., CCTO, ceramics were prepared by the conventional solid-state reaction combining with tape casting. Effects of two-step sintering and excess of copper on density, micro-structure, and electric properties of the samples were studied. And the surface effect of CCTO ceramics was also investigated. And multilayer CCTO ceramics capacitors with twin functions were manufa...学位：工学硕士院系专业：材料学院_材料学学号：2072011115007

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  学校编码：10384                            分类号        密级         学号：20720111150070                                    UDC             硕  士  学  位  论  文  流延法制备低介电损耗巨电容率CaCu3Ti4O12 陶瓷及其电性能研究 Preparation and Properties of CaCu3Ti4O12 Ceramics with Giant Permittivity and Low Dielectric Loss via Tape Casting   李 伟 指导教师姓名：熊 兆 贤  教授 专  业 名 称：材   料   学 论文提交日期：2014 年 5 月 论文答辩时间：2014 年 6 月 学位授予日期：2014 年   月 答辩委员会主席：               评    阅    人：                   2014 年  月 厦门大学博硕士论文摘要库  厦门大学博硕士论文摘要库  厦门大学学位论文原创性声明  本人呈交的学位论文是本人在导师指导下，独立完成的研究成果。本人在论文写作中参考其他个人或集体已经发表的研究成果，均在文中以适当方式明确标明，并符合法律规范和《厦门大学研究生学术活动规范（试行）》。 另外，该学位论文为（   熊兆贤教授   ）课题（组）的研究成果，获得（   熊兆贤教授   ）课题（组）经费或实验室的资助，在（   熊兆贤教授   ）实验室完成。（请在以上括号内填写课题或课题组负责人或实验室名称，未有此项声明内容的，可以不作特别声明。）  声明人（签名）：                       年   月   日           厦门大学博硕士论文摘要库     厦门大学博硕士论文摘要库  厦门大学学位论文著作权使用声明  本人同意厦门大学根据《中华人民共和国学位条例暂行实施办法》等规定保留和使用此学位论文，并向主管部门或其指定机构送交学位论文（包括纸质版和电子版），允许学位论文进入厦门大学图书馆及其数据库被查阅、借阅。本人同意厦门大学将学位论文加入全国博士、硕士学位论文共建单位数据库进行检索，将学位论文的标题和摘要汇编出版，采用影印、缩印或者其它方式合理复制学位论文。 本学位论文属于： （     ）1.经厦门大学保密委员会审查核定的保密学位论文，于   年  月  日解密，解密后适用上述授权。 （     ）2.不保密，适用上述授权。 （请在以上相应括号内打“√”或填上相应内容。保密学位论文应是已经厦门大学保密委员会审定过的学位论文，未经厦门大学保密委员会审定的学位论文均为公开学位论文。此声明栏不填写的，默认为公开学位论文，均适用上述授权。）                               声明人（签名）： 年   月   日  厦门大学博硕士论文摘要库     厦门大学博硕士论文摘要库摘要  I 摘  要 本论文在固相反应法的基础上结合流延成型制备 CaCu3Ti4O12（简称 CCTO）陶瓷薄片，研究两步法烧结和 Cu 不同化学计量比对流延成型 CCTO 陶瓷致密度、微观结构和电学性能等方面影响；同时对 CCTO 陶瓷介电机理的表面效应进行初步探讨；成功制备多层 CCTO 陶瓷基双功能元件，并与铝电解电容器和超级电容器进行性能和充放电特性对比试验。 首先，采用两步法烧结流延成型 CCTO 陶瓷薄片。第二步保温时间和第二步烧结温度对流延成型 CCTO 陶瓷的性能都有较大的影响。随着第二步保温时间的延长和第二步烧结温度的升高，CCTO 陶瓷的相对密度和电容率都有所提高。在第二步烧结温度 1000℃保温 72 h 烧结的 CCTO 陶瓷，在 f =1kHz 下具有最低的介电损耗 tanδ=0.028，同时保持巨电容率 εr=123,331，其非线性系数和击穿场强分别为 4.29 和 30.1 V/mm。当第二步烧结温度提高到 1080℃保温 72 h 时，在 f =1kHz 下 CCTO 陶瓷的电容率达到最大（εr=245,523），而介电损耗为tanδ=0.043，非线性系数为 4.25 和击穿场强为 8.5V/mm。 其次，采用流延成型和常规烧结制备 Cu 微过量的 CaCu(3+x)Ti4O12 陶瓷样品。XRD 分析表明随着 Cu 含量的增加，样品中开始出现 Cu2O 相和 CaTiO3 相，当 x=0.008 时，存在 TiO2、CuO、Cu2O 和 CaTiO3 第二相，形成多相共存的现象；同时 CCTO 陶瓷的晶粒尺寸随着 Cu 含量的增加逐渐趋向均匀，且气孔减少，致密度增加。实验表明 Cu 含量的适当增加可以增大其电容率并降低其介电损耗，当 x=0.004 时，样品表现出最好的电学性能，在 1 kHz 时电容率 εr=91,536 和介电损耗 tanδ=0.027，同时其非线性系数和击穿场强分别为 4.67 和 31.3V/mm；而且 x=0.002 和 x=0.004 的样品相比纯 CCTO 陶瓷样品还体现出更好的频率和温度稳定性；此外，CaCu(3+x)Ti4O12 陶瓷样品的等效串联电阻（ESR）在 100 kHz 下，随着 Cu 含量的增加呈现下降的趋势，当 x=0.008 时 ESR 值最小(3.49 Ω)。     然后，为了对 CCTO 陶瓷的表面效应进行探讨，将 CaCu3.004Ti4O12 陶瓷样品的上下两表面各磨去 0.05mm，并与表面未抛光的样品进行对比。实验结果表厦门大学博硕士论文摘要库摘要  II 明其陶瓷自然表面对CaCu3.004Ti4O12陶瓷样品的介电性能和压敏性能有着明显的影响：自然表面抛光后的样品与未抛光样品相比，其电容率明显降低，同时抛光后样品的 I-V 非线性特性曲线也明显地向低压方向移动；通过对样品表面抛光前后的化学成分 EDX 分析，可知在 CaCu3.004Ti4O12 陶瓷自然表面的晶界中偏析出富 Cu 相，而抛光后的样品的表面 Cu 的含量略低于 CaCu3.004Ti4O12 陶瓷样品中Cu 的化学计量比；陶瓷样品表面抛光后，银电极与陶瓷表面间的肖特基势垒高度降低，导致样品的非线性系数 α 也随之下降。同时，通过制备不同厚度的陶瓷样品来进一步探讨 CCTO 陶瓷的表面效应，实验表明随着陶瓷样品厚度的减小，样品的电容率逐步增大，样品的击穿场强和非线性系数 α 随着样品厚度的减小而增大。说明 CCTO 陶瓷的巨介电效应和压敏性能是表面阻挡层（SBLC）效应和内部阻挡层（IBLC）效应共同作用的结果。在以上实验基础上，我们首次提出改进的四组 RC 相串联（RgCg、RgbCgb、RdbCdb 和 RbCb）的电学等效电路模型，能够更全面地解释 CCTO 陶瓷介电性能和压敏性能。     最后，利用流延 CaCu3.004Ti4O12 陶瓷薄片成功制备多层 CCTO 陶瓷基双功能元件：在 1 kHz 下电容量为 13.06F、介电损耗 tan δ=0.042、非线性系数为 4.97、压敏电压 26.4V，等效串联电阻 ESR=0.51Ω；该 CCTO 元件与相应电容量的铝电解电容器对比，CCTO 陶瓷电容器在更宽的频率范围内，其电容量和介电损耗更加稳定，且介电损耗值更低，同时显示出更好的温度稳定性和更低的 ESR 值。通过搭建充放电电路，对电容器进行充放电性能测试，多层 CCTO 陶瓷电容器与铝电解电容器表现出相似的充放电特性：重复性充放电实验中，多层 CCTO陶瓷电容器在 4 个月内其电性能和充放电特性稳定性好。此外还成功制备大容量CCTO 陶瓷电容器（约 500F），并与超级电容器和锂电池进行相关对比讨论。  关键词：钛酸铜钙；低介电损耗；流延法；表面效应。   厦门大学博硕士论文摘要库Abstract   III Abstract   In this paper, CaCu3Ti4O12, i.e., CCTO, ceramics were prepared by the conventional solid-state reaction combining with tape casting. Effects of two-step sintering and excess of copper on density, micro-structure, and electric properties of the samples were studied. And the surface effect of CCTO ceramics was also investigated. And multilayer CCTO ceramics capacitors with twin functions were manufactured, and then compared with aluminum electrolytic capacitor and Li-ion battery on performance including charging or discharging behavior.   First of all, CCTO ceramic sheets by tape casting were calcined using two-step sintering. Soaking time and sintering temperature in the second step had a great influence on the properties of CCTO ceramics. Relative density and permittivity of CCTO ceramics were improved, with prolonging of soaking time and rising of sintering temperatures in the second step. When sintering condition in the second step was at 1000℃ for 72h, the minimum dielectric loss (0.028) for this sample was obtained in addition to a giant permittivity of 123,331 at 1 kHz, and the nonlinear coefficient and breakdown electric field were 4.29 and 30.1V/mm, respectively. Meanwhile, when sintering condition in the second step was at 1080℃ for 72h, the maximum permittivity of 245,523 for this sample was reached with dielectric loss of 0.043 at 1 kHz, and the nonlinear coefficient and breakdown electric field were 4.25 and 8.5V/mm, respectively.   Secondly, CaCu(3+x)Ti4O12 ceramics were formed by tape casting. With the increasing of the copper content, it was found that the second phases of TiO2 and CuO appeared in X-ray diffraction patterns. Meanwhile, there were peaks of secondary phases including TiO2, CuO, Cu2O and CaTiO3 for the sample with x=0.008. With the increasing of the content of Cu, the grain sizes of ceramics were gradually tend to uniform, and, the porosity of samples decreased and the density of samples increased. When the x value was 0.004, the best electrical performance were obtained for this 厦门大学博硕士论文摘要库Abstract  IV sample, with εr=91,536 and tanδ= 0.027 at 1 kHz, and the nonlinear coefficient and breakdown electric field were 4.67 and 31.3 V/mm, respectively. In addition, the steady dielectric properties and temperature stability were showed for the x=0.002 and x=0.004 samples in low frequency range, compared with that of other samples. With the increasing of the Cu content, ESR values of samples reduced gradually. When the x value was 0.008, ESR value was minimum, only 3.49Ω.   Thirdly, two sides of nature surfaces for CaCu3.004Ti4O12 ceramics by tape casting were polished for a thickness of 0.05mm compared with the unpolished sample. It was revealed that nature surfaces of CCTO ceramics had a significant impact on dielectric properties and varistor characteristic. Permittivity of the polished sample was significantly lower than the unpolished one. And I-V curve of the polished sample moved to the low voltage. Through EDX analysis, the rich-Cu phase was segregated at the grain boundary on the natural surface of sample, however, stoichiometric ratio of Cu was slightly lack on the surface of the polished sample. Surface schottky barrier between silver electrode and ceramic surface was reduced after the nature surface was polished, and then nonlinear coefficient of sample had a decline. In addition, CCTO samples with different thickness were prepared. The permittivity, nonlinear coefficient and breakdown electric field of samples were all increased gradually, with the decreasing of the thickness of samples. It was showed that giant permittivity and varistor of CCTO were the result of the joint action of SBLC and IBLC. Dielectric behavior and varistor of CCTO ceramics were more comprehensively explained by the electrical equivalent circuit model of the RgCg、RgbCgb、RdbCdb and RbCb series.     Finally, multilayer CCTO ceramics capacitor with twin functions was prepared via CaCu3.004Ti4O12 ceramic sheets with C= 13.06F and tanδ= 0.042, and ESR value was 0.51.Ω at 1 kHz. The nonlinear coefficient and breakdown voltage were 4.97 and 26.4V respectively. Compared with aluminum electrolytic capacitor, the capacitance and dielectric loss of multilayer CCTO ceramics capacitor were more stable in a wide frequency range. At the same time, the multilayer CCTO ceramics capacitor also 厦门大学博硕士论文摘要库Abstract  V exhibited better temperature stability and lower ESR value than the aluminum electrolytic capacitor. Furthermore, the charge-discharge performance of two kinds of capacitors were also tested, showing similar charge-discharge characteristics. And the multilayer CCTO ceramic capacitor displayed a quite good stability of electric properties and charge-discharge characteristics during four months. In addition, the large capacity of CCTO capacitor was prepared (about 500 F), and compared with super capacitor and Li-ion battery.  Keywords: CaCu3Ti4O12; Low dielectric loss; Tape Casting; SBLC。 厦门大学博硕士论文摘要库Abstract   VI        厦门大学博硕士论文摘要库目录  VII 目录 摘要 .................................................... I Abstract ............................................... III 目录 .................................................. VII Contents ................................................ XI 第一章 绪论 ............................................. 1 1.1 引言....................................................... 1 1.2 电介质理论概述 ............................................. 1 1.2.1  电介质的极化.......................................... 2 1.2.2  介电损耗.............................................. 3 1.2.3  介电弛豫模型.......................................... 3 1.3 压敏电阻概述 ............................................... 5 1.3.1  压敏电阻的非线性 I-V 特性 .............................. 5 1.3.2  压敏电阻主要特性参数.................................. 7 1.4 钛酸铜钙的基本特性及其研究现状 ............................. 7 1.4.1  钛酸铜钙 CCTO 晶体结构特征 ........................... 7 1.4.2  CCTO 陶瓷的介电性能及其研究现状 ...................... 8 1.4.3  CCTO 陶瓷的压敏性能及其研究现状 ..................... 10 1.5 本论文的主要研究内容 ...................................... 11 第二章 CCTO 陶瓷的制备工艺与表征方法 ................... 13 2.1 引言...................................................... 13 2.2 实验原料 .................................................. 13 2.3 实验仪器设备 .............................................. 14 2.4  样品制备工艺 ............................................. 14 2.4.1 流延成型.............................................. 14 厦门大学博硕士论文摘要库目录  VIII 2.4.2  制备工艺过程......................................... 15 2.5 样品测试技术与表征方法 .................................... 18 2.5.1  陶瓷相对密度和径向收缩率测试方法..................... 18 2.5.2  物相分析技术......................................... 19 2.5.3  微观形貌观察......................................... 19 2.5.4  电性能测试方法....................................... 19 2.6 本章小结 .................................................. 20 第三章  两步烧结法对流延成型 CCTO 陶瓷结构及性能的影响 .. 21 3.1 流延法制备 CCTO 陶瓷 ............................... 21 3.1.1  CCTO 粉体的制备 .................................... 211 3.1.2  CCTO 薄片陶瓷的制备 ................................. 23 3.2 第二步保温时间对流延成型 CCTO 陶瓷结构及电气性能影响 ..... 25 3.2.1  XRD 物相表征结果及其分析 ............................ 25 3.2.2  相对密度与收缩率测试结果及其讨论..................... 25 3.2.3  SEM 观察结果及其讨论 ................................ 26 3.2.4  电气性能测试结果及其讨论............................. 28 3.3 第二步烧结温度对流延成型 CCTO 陶瓷结构及电性能的影响 ..... 31 3.3.1  XRD 物相表征结果及其分析 ............................ 32 3.3.2  相对密度与收缩率测试结果及其讨论..................... 32 3.3.3  SEM 观察结果及其讨论 ................................ 33 3.3.4  电气性能测试结果及其讨论............................. 36 3.4 本章小结 .................................................. 40 第四章  Cu 微量添加对流延成型 CCTO 陶瓷微观结构及性能影响41 4.1 前言...................................................... 41 4.2 CaCu(3+x)Ti4O12流延样品的制备 ............................... 41 4.3 Cu 微量添加对流延成型 CCTO 陶瓷结构和电性能的影响 ........ 42 4.3.1  XRD 物相表征结果及其分析 ............................ 42 4.3.2  相对密度与收缩率测试结果及其讨论..................... 43 厦门大学博硕士论文摘要库目录  IX 4.3.3  SEM 观察结果及其讨论 ................................ 43 4.3.4  电气性能测试结果及其讨论............................. 46 4.4 本章小结 .................................................. 50 第五章 CCTO 陶瓷介电性质和压敏性质的机理探讨 ........... 53 5.1  前言 ..................................................... 53 5.2  实验步骤 ................................................. 53 5.3  CCTO 陶瓷的表面效应及其讨论 ............................. 54 5.3.1  CaCu3.004Ti4O12陶瓷样品抛光前后的表面形貌及成分分析 ... 54 5.3.2  CCTO 陶瓷样品表面抛光对其电学性能的影响 ............. 55 5.4 改进的 CCTO 陶瓷理论模型的提出 ......................................................... 59 5.5 不同厚度 CCTO 陶瓷样品的电学性能及其讨论 ..................................... 61 5.6 本章小结 .................................................. 63 第六章 CCTO 多层陶瓷双功能元件的制备及性能对比 ......... 65 6.1 前言...................................................... 65 6.2 多层 CCTO 陶瓷双功能元件的制备工艺 ....................... 65 6.3 多层 CCTO 陶瓷双功能元件的电气性能 ....................... 66 6.4 多层 CCTO 陶瓷双功能元件与铝电解电容器对比 ............... 70 6.4.1 电学性能对比实验及其讨论.............................. 70 6.4.2 充放电特性对比实验及其讨论............................ 77 6.5 多层 CCTO 陶瓷双功能元件的时间稳定性实验结果及其讨论 ...... 79 6.6 大容量 CCTO 陶瓷电容器的制备及其讨论 ..................... 82 6.7 本章小结 .................................................. 87 第七章 总结与展望 ...................................... 89 7.1 本论文结论 ................................................ 89 7.2 展望...................................................... 91 参考文献 ............................................... 93 攻读硕士期间科研成果 ................................... 99 致谢 .................................................. 101 厦门大学博硕士论文摘要库目录  X                             厦门大学博硕士论文摘要库Degree papers are in the “Xiamen University Electronic Theses and Dissertations Database”. Fulltexts are available in the following ways: 1. If your library is a CALIS member libraries, please log on http://etd.calis.edu.cn/ and submitrequests online, or consult the interlibrary loan department in your library. 2. For users of non-CALIS member libraries, please mail to etd@xmu.edu.cn for delivery details.厦门大学博硕士论文摘要库

Preparation and Properties of CaCu3Ti4O12 Ceramics with Giant Permittivity and Low Dielectric Loss via Tape Casting

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Preparation and Properties of CaCu3Ti4O12 Ceramics with Giant Permittivity and Low Dielectric Loss via Tape Casting

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