Piezoelectric and ferroelectric properties of (Bi_{1鈭?span style='font-style: italic'>x}Na_0.8K_0.2La_x)_0.5TiO₃ lead-free ceramics

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• 作者：Baoyin Wang ; Laihui Luo ; ^{luolaihui@nbu.edu.cn} ; Feng Ni ; Peng Du ; Weiping Li ; Hongbing Chen
• 关键词：Lead-free ceramic ; Piezoelectric ; Dielectric ; Depolarization ; Strain
• 刊名：Journal of Alloys and Compounds
• 出版年：2012
• 期刊代码：45_09258388
• 类别：ms
• 出版时间：15 June, 2012
• 卷：526
• 期：Complete
• 页码：79-84
• 文件大小：844 K

摘要

Lead-free piezoelectric ceramics (Bi_1鈭?em>xNa_0.8K_0.2La_x)_0.5TiO₃ were synthesized successfully by conventional solid state reaction method. The piezoelectric, dielectric and ferroelectric characteristics of the ceramics were investigated and discussed. The XRD results show that La³⁺ has diffused into (BiNa_0.8K_0.2)_0.5TiO₃ (BNKT) lattices to form a new solid solution (Bi_1鈭?em>xNa_0.8K_0.2La_x)_0.5TiO₃ with a pure perovskite structure. Partial substitution of La³⁺ for Bi³⁺ in the BNKT ceramics can enhance their piezoelectric, without an obvious decline of ferroelectric properties. The piezoelectric measurements and P-E hysteresis loops reveal that the ceramic with x = 0.005 has the highest piezoelectric performance and strong ferroelectricity. At high La³⁺ level (x > 0.04), the low dielectric anomaly at T_d disappears. A maximum strain of 0.16%is obtained at x = 0.02 for the (Bi_1鈭?em>xNa_0.8K_0.2La_x)_0.5TiO₃ ceramic. The depolarization temperature T_d decreases with x increasing (x = 0-0.08), and the depolarization mechanism is analyzed.