非晶相包覆铌酸钾钠基无铅陶瓷介电特性的湿度稳定性研究

项目名称： 非晶相包覆铌酸钾钠基无铅陶瓷介电特性的湿度稳定性研究

项目编号： No.51302319

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： 甄玉花

作者单位： 中国石油大学（华东）

项目金额： 25万元

中文摘要： 铌酸钾钠((K,Na)NbO3,KNN)基陶瓷是目前最受关注的无铅压电体系。但由于其富含亲水基（K-O，Na-O），不同湿度环境下易化学吸附水分子，从而影响其介电特性的稳定性。为了减弱KNN体系对水分子的化学吸附，本项目拟用一层非晶相包覆KNN晶粒，以此隔绝水分子的吸附，降低其介电参数的湿度敏感性。本研究选择易形成非晶相的B2O3基氧化物作为KNN的添加物，通过对比纯KNN和非晶相包覆的KNN体系在宽湿度量程内（10-95%RH）的感湿特性，分析非晶相包覆及其他微观结构（气孔率、晶粒尺寸）对KNN基陶瓷的水分子吸附、极化机制以及载流子变化的影响；结合复阻抗分析，建立等效电路，揭示KNN体系陶瓷在不同湿度环境下的电导机理；并利用电介质物理理论，分析KNN体系陶瓷的微观感湿机理。该项目的顺利进行，可降低KNN体系介电特性的湿度敏感性，并为不同湿度环境下基于KNN体系的应用开发提供科学判据。

中文关键词： 无铅压电；湿度稳定性；介电特性；铌酸钾钠；

英文摘要： Up to date, (K,Na)NbO3 (KNN)-based ceramics are the most promising lead free piezoelectric ceramics. But they show previous instability of dielectric properties under different humidity enviroment, whiched caused by the water molecules polarization due to the reach amount of hydrophilic group K-O and Na-O. To improve the physical absorption and reduce the chemical absorption of water molecules, which would enhance the stability of dielectric properties, we intend to form microstructure of amorphous phase-covered KNN grains. B2O3-based oxides would be used to form amorphous phase. The amorphous phase can be used to block the water chemically-absorbed on KNN grains. Through tailoring the composition and content of the additive oxides as well as main processing parameters, the amorphous phase-covered dense KNN-based materials can be fabricated. Based on this, we need analyze the influence of detailed microstructure (amorphous phase, pore content, and grain size) on water absorption, polarization as well as carrier mobolity of KNN-based ceramics through testing the humidity sensitive properties of pure KNN and B2O3-based oxides doped KNN under broad humidity atmosphere range (10-95%RH); Then, we should build equivalent electric circuit based on the complex impedance, and analyze the effect of amorphous phase on the

英文关键词： lead free；humidity stability；dielectric property；sodium potassium niobate；