Stoichiometry, Stability and Phase Equilibria of CaCu3Ti4O12 (CCTO) High Permittivity Ceramics

CaCu3Ti4O12 (CCTO) 高介电常数陶瓷的化学计量、稳定性和相平衡

• 批准号: EP/E065783/1
• 负责人: Anthony West
• 金额: $ 10.35万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2007
• 资助国家: 英国
• 起止时间: 2007 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FE065783%2F1
• 关键词: Stoichiometry; Stability; Phase; Equilibria; CaCu3Ti4O12

There is much current interest in the electrical properties of CaCu3Ti4O12, CCTO, ceramics, since they are, depending on their method of fabrication, heterogeneous materials with semiconducting grain cores and insulating grain or domain boundaries. This unusual electrical microstructure gives rise to a very high effective permittivity associated with the geometric dimensions of the insulating regions and the possibility of applications in electroceramics as, for instance, a novel capacitor material. Scientific interest in CCTO continues, in particular to gain understanding of the reasons for the electrical heterogeneity and to modify its properties by compositional control or doping. This proposal aims to clarify four basic features of the materials science of CCTO: first its true stoichiometry since there is considerable evidence that it is either non-stoichiometric or exists over a range of cation compositions; second, its high temperature stability and in particular, its melting behaviour and whether or not this is preceded by loss of Cu2O from the crystal lattice; third, its intrinsic electrical properties as a function of temperature and atmosphere, and in particular, the nature of the transition from activated hopping to localised electron motion with decreasing temperature and the dependence of this phenomenon on composition; fourth, the factors that control its ceramic microstructure and in particular, the occurrence of anomalous grain growth leading to a duplex structure on the firing of certain samples. Given the continuing great interest in the properties of CCTO, this fundamental material science study is essential to provide underpinning information to allow the fabrication of CCTO in various forms and to optimise control of its properties.

CaCu 3 Ti4 O 12，CCTO，陶瓷的电性能有很大的电流感兴趣，因为它们取决于它们的制造方法，具有半导体晶粒芯和绝缘晶粒或畴界的异质材料。这种不寻常的电微观结构产生了一个非常高的有效介电常数与绝缘区域的几何尺寸和应用的可能性，例如，一种新型的电容器材料在电瓷。对CCTO的科学兴趣仍在继续，特别是了解电不均匀性的原因，并通过成分控制或掺杂来改变其性质。该提案旨在澄清CCTO材料科学的四个基本特征：第一，真实的化学计量，因为有大量证据表明它不是非化学计量的，就是存在于一系列阳离子组成中;第二，高温稳定性，特别是它的熔融行为，以及在此之前是否会从晶格中损失Cu 2 O;第三，作为温度和大气的函数的其固有电性质，特别是，随着温度降低从激活跳跃到局部电子运动的转变的性质以及这种现象对成分的依赖性;第四，控制其陶瓷微观结构的因素，特别是在某些样品烧制时导致双相结构的异常晶粒生长的发生。鉴于对CCTO性能的持续极大兴趣，这种基础材料科学研究对于提供基础信息以允许以各种形式制造CCTO并优化其性能控制至关重要。

项目成果

Impedance spectroscopy study of single crystal CaCu3Ti4O12

单晶CaCu3Ti4O12的阻抗谱研究

• 发表时间: 2008
• 期刊: In preparation
• 作者: N/a Ferarrelli

Stoichiometry and defect structure of CaCu3Ti4O12 ceramics

CaCu3Ti4O12陶瓷的化学计量和缺陷结构

• 发表时间: 2008
• 期刊: In preparation
• 作者: N/a Schmidt

Low temperature processing of CaCu3Ti4O12 ceramics by spark plasma sintering

放电等离子烧结CaCu3Ti4O12陶瓷的低温加工

• 发表时间: 2008
• 期刊: Journal of the American Ceramic Society
• 影响因子: 3.9
• 作者: N/a Li

Localized electrical characterization of the giant permittivity effect in CaCu3Ti4O12 ceramics

• DOI: 10.1063/1.2919095
• 发表时间: 2008-05-05
• 期刊: APPLIED PHYSICS LETTERS
• 影响因子: 4
• 作者: Fiorenza, Patrick;Lo Nigro, Raffaella;West, Anthony R.
• 通讯作者: West, Anthony R.