微观组织与电性能
(1. 桂林电子科技大学 广西信息材料重点实验室，桂林 541004；
2. 桂林工学院 电子与计算机系，桂林 541004)
摘 要: 采用传统陶瓷制备方法，制备一种新型无铅压电陶瓷 (1−x)Bi0.5(Na0.82K0.18)0.5TiO3-xBiCrO3 (BNKT-BCx)。研究Bi基铁电体BiCrO3对BNKT-BCx陶瓷晶体结构和压电介电性能的影响。结果表明：在所研究的组成范围内，陶瓷材料的主体结构为纯钙钛矿固溶体，微量BiCrO3(x=0~0.02，摩尔分数)不改变陶瓷的晶体结构；当BiCrO3含量x＞0.02时，晶体结构由三方、四方共存转变为伪立方结构，并出现明显的第二相；当x=0.015时，d33=168 pC/N；当x=0.01时，kp=0.32，为该体系压电性能的最大值；随BiCrO3含量的增加，陶瓷的低温介电反常峰向低温移动，高温介电反常峰向高温移动，反铁电相区域增加，弥散指数增加。
关键字: 钛酸铋钠；无铅压电陶瓷；压电性能；钙钛矿结构
（1. Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin 541004, China;
2. Department of Electron and Computer, Guilin University of Technology, Guilin 541004, China）
Abstract:A new (Bi0.5Na0.5)TiO3-based lead-free piezoelectric ceramics, (1−x)Bi0.5(Na0.82K0.18)0.5TiO3-xBiCrO3 (BNKT-BCx), was prepared by a conventional ceramic sintering technique. The effect of Bi-based ferroelectrics of BiCrO3 on the crystal structure, dielectric and piezoelectric properties was investigated. X-ray diffraction patterns indicate that trace BiCrO3 addition(x=0−0.02) causes insignificant change in crystal structure, and an obvious secondary phase is observed in the samples with x＞0.02. The piezoelectric constant d33 and the electromechanical coupling factor kp of the ceramics attain maximum values of 168 pC/N and 0.32 near morphotropic phase boundary (MPB) that co-existence between rhombohedral and tetragonal. With increasing BiCrO3 content, the antiferroelectric phase zone gets broader and the diffuse coefficient increases.
Key words: sodium bismuth titanate; lead-free piezoelectric ceramics；piezoelectric properties; perovskites structure
