提高三临界无铅压电陶瓷温度稳定性的实验研究与理论模拟

项目名称： 提高三临界无铅压电陶瓷温度稳定性的实验研究与理论模拟

项目编号： No.51302209

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 一般工业技术

项目作者： 薛德祯

作者单位： 西安交通大学

项目金额： 25万元

中文摘要： 目前使用的大多数压电材料都含有对人体及环境有害的铅元素，因此急需实现压电材料的无铅化。文献和申请人前期研究表明，在无铅体系中构建一条始于三临界点的相界，可以在这种相界处获得较高的压电性能。然而，该相界在温度成分相图上较倾斜，且其居里温度较低，导致这种三临界无铅压电陶瓷材料性能的温度稳定性较差，难以满足实用要求。本申请项目拟通过调整三临界相界两侧四方相和三方相的相稳定性，使两相自发极化及自发应变趋于一致，以实现该相界的垂直化，达到提高其性能温度稳定性的目的。拟首先通过实验在钛酸钡基压电陶瓷体系中验证这一思路的可行性与普遍性；进而以实验结合朗道理论模拟的方法，研究相界两侧铁电相稳定性对相界附近相失稳过程的影响，提出设计高温度稳定性三临界无铅压电陶瓷的准则；最后在高居里温度铌酸钾钠体系中应用上述准则，构建垂直三临界相界，为开发较宽温度范围内性能稳定的无铅压电陶瓷材料作有益探索。

中文关键词： 压电陶瓷；准同型相界；相变；材料信息学；材料基因组

英文摘要： The Pb-based piezoelectrics like lead zirconate titanate (PZT) have been the workhorse of piezoelectric devices for half a century. However, Pb has recently been expelled from many applications owing to its toxicity. Thus there is an urgent demand for high performance Pb-free alternatives for the Pb-based piezoelectrics. Recent literatures and our previous studies show that a tricritical-point-type phase boundary in Pb-free systems can lead to equally excellent piezoelectricity as soft PZT at room temperature, owing to a nearly vanishing polarization anisotropy. However, the current tricritical-point-type phase boundaries are highly tilted in the temperature-composition phase diagram of BaTiO3-based systems and also possess fairly low Curie temperatures. Consequently the piezoelectric properties exhibit high temperature sensitivity, largely restricting their applications.In the present project, we proposed an idea to tune the slope of the tricritical-point-type phase boundary by adjusting the phase stability of rhombohedral and tetragonal terminals in the phase diagram through defect doping. It is expected that when the rhombohedral and tetragonal terminals equally compete there will be a vertical phase boundary at which piezoelectric properties show high temperature stability. The project is organized as fol

英文关键词： piezoelectric ceramics；MPB；phase transition；Materials informatics；MGI