在压电材料中，含铅固溶体由于制备工艺简单，成本低，又具有较好的力学性能和稳定的压电性能，在压电元件领域一直占主导地位。但这类压电陶瓷材料的主要成分PbO (或Pb3O4)的含量约占原料总量的70％，其在生产、使用和废弃的过程中都会给人类和自然环境造成严重的伤害。因而，在压电陶瓷领域，无铅压电陶瓷从环保的角度考虑越来越引起人们的重视。而目前开发的无铅压电陶瓷体系仍存在很多方面的问题，有待进一步的研究和探索。
在当前研究的无铅压电陶瓷体系中，钙钛矿结构型陶瓷具有较高的机电耦合系数，被认为是一种有着广泛应用前景的压电材料。在钙钛矿型无铅压电陶瓷中，目前研究得比较多的体系有BaTiO3基、钛酸铋钠（NBT）基和铌酸钾钠（KNN）基。BaTiO3基材料压电性能中等，且难以通过掺杂来大幅度地改变性能；而Na0.5Bi0.5TiO3（NBT）具有较高的压电性能，但去极化相变温度较低；K0.5Bi0.5TiO3（KBT）和KxNa1-xNbO3（KNN）具有较高的去极化温度，但该组分在未掺杂时用传统方法很难烧结致密，且还有易吸潮的缺点。
本实验中采用普通固相烧结法，制备了致密化的掺杂不同稀土元素的KNN基和KBT基陶瓷以及（1－x）BaTiO3-x( K0.5Bi0.5)TiO3（BK100x）复合陶瓷。希望通过对KNN、KBT和BK陶瓷的制备和性能表征，获得具有较好压电性能的无铅压电陶瓷材料。本文工作主要分为以下几个部分：
采用X射线衍射（X-ray diffraction,XRD）分析技术对所制得的压电陶瓷进行相结构分析，以确定所制得样品是否具有钙钛矿结构；通过比较利用原子力显微镜(atomic force microscope,AFM）表征的在不同烧结条件下得到的陶瓷样片的表面形貌，分析了烧结温度与烧结样片表面晶粒大小的关系；严格控制了制备过程中的各个环节，着重分析了KNN和KBT陶瓷的烧结工艺和极化条件中的主要影响因素及影响特征，确定出了较佳的制备工艺参数；研究了BK的介电常数温度谱，测试了在不同频率下该陶瓷的介电性能在升温过程中的变化，并着重分析了1KHz下介电性能和温度的变化关系；较为细致的测定了BK陶瓷的压电性能，比较了在不同烧结温度下所得到的样品的压电性能参数。最终获得了致密度较高，具有良好压电性能的无铅陶瓷BK10。其主要压电性能为：d 33=71pC/N，kp=0.18，tanδ=2.17%，Qm=189。
关键词：无铅，压电陶瓷， KNN，KBT，BK，制备工艺，介电性能，压电性能
THE PREPARATION AND PROPERTIES OF PEROVSKITE-TYPE LEAD-FREE PIEZOCERAMICS
ABSTRACT
Among sorts of piezoelectric material systems, lead-based PZT material has been dominating the market for piezoceramics component due to their excellent piezoelectric properties. Since PZT contains more than 70 %( wt.) lead which is toxic, it is apprehensive that PZT has harmful influence upon environment and our human beings. Through the heightening of the public’s awareness towards global environment protection and sustainable development of the world society, it’s necessary and urgent to replace PZT by those harmless lead-free piezoceramics while maintaining comparable piezoelectric properties and reasonable phase transition temperature.
In lead-free piezoceramics fields, Potassium sodium Niobate (KNN) and bismuth potassium titanate (KBT) reveal improved piezoelectric properties and correspondingly high depolarization temperature. However, their hygroscopicity and sinterability make it difficult to obtain well-densified KNN-based or KBT-based ceramics. The goal of our study is to optimize the sintering and piezoelectric character of KNN and KBT ceramics,especially to obtain ceramics possessing good properties.
The main works are as follows: KNN-based, KBT-based ceramics doped with rare elements and BK ([(1-x) BaTiO3-x (K0.5Bi0.5) TiO3] ceramics were synthesized via traditional solid state reaction, sintered under atmospheric pressure with different additive as sintering aid. In this study, the phase structures of all samples were detected through XRD (X-Ray Diffraction), the microstructures of the samples’ surface were analyzed by AFM (Atomic Force Microscope). And at last, their dielectric and piezoelectric properties were investigated. The KNN-based and KBT-based ceramics in this study performed midding dielectric properties, meanwhile the other compositions BK10(90%BaTiO3-10%(K0.5Bi0.5)TiO3) gave optimized piezoelectric properties(d33=71pC/N，kp=0.18，tanδ=2.17%，Qm=189).
