NSF: Materials World Network: Nanoscale Structure-Property Relationships in Lead Free Morphotropic Phase Boundary Piezoelectrics

NSF：材料世界网络：无铅同形相边界压电体中的纳米级结构-性能关系

• 批准号: EP/G02586X/1
• 负责人: Pamela Thomas
• 金额: $ 52.91万
• 依托单位: University of Warwick
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2008
• 资助国家: 英国
• 起止时间: 2008 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FG02586X%2F1
• 关键词: NSF; Materials; World; Network; Nanoscale

Ecological restrictions in many parts of the world are demanding the elimination of lead (Pb) from all consumer items, an important environmental context that underlies this research programme. This prohibitive trend places the ceramics industry in a precarious position as it is entirely dependent on Pb-based materials for piezoelectric applications. Piezoelectric materials are widely used in sensors, actuators and other electronic devices. The most popular materials to date are those based on the perovskite PbZrxTi1-xO3 (PZT), in use in over 90% of the piezoelectricity market. There is an urgent need to find alternatives to PZT for piezoelectric applications and in recent years, a number of materials such as Na0.5Bi0.5TiO3 (NBT) and its solid-solutions with BaTiO3 (NBT-BT) or K0.5Bi0.5TiO3 (NBT-KBT), K0.5Na0.5NbO3 (KNN) and its solid solution with LiTaO3 (KNN-LT) have been researched as possible replacements. The newer lead-free materials are united with PZT in that they exhibit a region in their phase diagrams where there appears to be a sudden change in crystal structure, typically from a rhombohedral to a tetragonal phase. This region has been termed the Morphotropic Phase Boundary (MPB) and appears to coincide with the maximum piezo-response of these materials. It is the aim of this programme to obtain a unified scientific understanding of the morphotropic phase boundary (MPB) region and its impact upon piezoelectric properties in lead-free piezoelectric materials, taking as our example the Na0.5Bi0.5TiO3 - BaTiO3 (NBT-BT) solid solution. We aim to investigate the MPB in NBT-BT from the nano-scale science to the macroscopic physical properties thus exploring this material's full potential as a functioning lead-free alternative and providing the most thorough description and understanding of an MPB in a lead-free system to date. To put this aim in context, there is currently much research world-wide addressing the full and proper description of the archetypal MPB system PZT itself, for which several key questions remain unanswered. In particular, is the MPB region truly a new monoclinic crystalline phase (as has generally accepted since the breakthrough crystallographic studies of of Noheda et al in 1999)? Or does it consist of adaptive nano-domains of tetragonal/rhombohedral symmetry? Or should it be explained through the growth and diminution of short-range order driven by correlated atomic displacements? These and further questions about the nature of the MPB must be answered URGENTLY and DIRECTLY in lead-free MPB systems themselves both for a fundamental understanding of the processes that promote high piezoelectric properties and to engineer effective new functional materials. In this materials-worldwide-network (MWN) programme, which combines leading researchers from three continents, we will apply the new and advanced experimental methodologies that have been developed to address the nano-science of the MPB to the lead-free material, NBT/BT, which is the ultimate goal of this proposal. The principal aims can be summarised as:1 To identify the nanoscale domain structure and characterize its piezoelectric response; 2 To determine the structural mechanism (transformational sequences) by which high piezoelectricity is achieved in non-Pb materials, and identify similarities and differences between MPBs in non-Pb and Pb-based systems; 3 To use this understanding to improve piezoelectric properties in NBT-BT and non-Pb systems.4 To provide an enhanced research education/experience for PhD and early-career scientists via UK/US collaborations and exchanges.Total Resource Request by each Organisation: Warwick 489,758 (EPSRC contribution 403,174): Oxford 65,183 (EPSRC contribution 52,147)Total UK resources: 554,941 (455,321 EPSRC contribution)

世界许多地方的生态限制要求从所有消费者项目中消除铅（PB），这是该研究计划的基础的重要环境环境。这种过度的趋势使陶瓷行业处于不稳定的位置，因为它完全取决于用于压电应用的基于PB的材料。压电材料广泛用于传感器，执行器和其他电子设备中。迄今为止，最受欢迎的材料是基于Perovskite PBZRXTI1-XO3（PZT），在压电市场的90％以上。迫切需要找到用于压电应用PZT的替代方案，近年来，许多材料Na0.5bi0.5tio3（NBT）及其使用BATIO3（NBT-BT）或K0.5BI0.5BI0.5BI0.5BI3 （NBT-KBT），K0.5NA0.5NBO3（KNN）及其使用Litao3（KNN-LT）的实心溶液已被研究，作为可能的替换。较新的无铅材料与PZT结合在一起，因为它们在其相图中表现出一个区域，在这些区域中，晶体结构似乎突然发生了变化，通常从菱形到四方相。该区域已称为形态相边界（MPB），似乎与这些材料的最大压电反应一致。该计划的目的是获得对形态相边界（MPB）区域（MPB）区域及其对无铅压电材料中压电特性的影响的统一科学理解，以我们的示例为NA0.5BI0.5TIO3-BATIO3-BATIO3（NBT---T---- BT）实心解决方案。我们的目的是研究NBT-BT中的MPB从纳米级科学到宏观的物理特性，从而探索该材料作为无铅替代方案的全部潜力迄今为止的系统。为了将这个目标置于上下文中，目前在全球范围内有许多研究解决了对原型MPB系统PZT本身的完整和正确描述，为此，几个关键问题仍未得到解决。特别是，MPB区域是否真正是新的单斜晶相（自1999年Noheda等人的突破性晶体学研究以来，人们普遍接受）？还是由四方/菱形对称性的自适应纳米域组成？还是应该通过相关原子位移驱动的短距离顺序的生长和减少来解释？这些关于MPB性质的问题和进一步的问题必须在无铅MPB系统本身中直接回答，以便对促进高压电性能的过程进行基本了解，并设计有效的新功能材料。在结合了来自三大大洲的主要研究人员的材料 - 世界网络网络（MWN）计划中，我们将应用已开发的新的和先进的实验方法来解决MPB的纳米科学，以无铅材料为NBT NBT /bt，这是该提案的最终目标。主要目的可以总结为：1来确定纳米级结构并表征其压电响应； 2确定在非PB材料中实现高压电性的结构机制（变换序列），并确定非PB和基于PB的系统中MPB之间的相似性和差异； 3使用这种理解来改善NBT-BT和非PB系统中的压电性能。4通过英国/美国的合作和交流为博士和早期职业科学家提供增强的研究教育/经验。每个组织的总体资源请求：沃里克489,758（EPSRC贡献403,174）：牛津65,183（EPSRC贡献52,147）英国总资源：554,941（455,321 EPSRC贡献）

项目成果

Investigation of the depolarisation transition in Bi-based relaxor ferroelectrics

• DOI: 10.1063/1.4869132
• 发表时间: 2014-03-21
• 期刊: JOURNAL OF APPLIED PHYSICS
• 影响因子: 3.2
• 作者: Woodward, David I.;Dittmer, Robert;Thomas, Pam A.
• 通讯作者: Thomas, Pam A.

Splitting of the transition to the antiferroelectric state in PbZr 0.95 Ti 0.05 O 3 into polar and antiferrodistortive components

• DOI: 10.1103/physrevb.88.094107
• 发表时间: 2013-09
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: F. Cordero;F. Craciun;F. Trequattrini;C. Galassi;P. Thomas;D. Keeble;A. M. Glazer

Domain Wall Displacement is the Origin of Superior Permittivity and Piezoelectricity in BaTiO 3 at Intermediate Grain Sizes

• DOI: 10.1002/adfm.201301913
• 发表时间: 2014-02-01
• 期刊: ADVANCED FUNCTIONAL MATERIALS
• 影响因子: 19
• 作者: Ghosh, Dipankar;Sakata, Akito;Jones, Jacob L.
• 通讯作者: Jones, Jacob L.