Lithium-modified (K_0.5Na_0.5)NbO₃-BiAlO₃ lead-free piezoelectric ceramics with high Curie temperature

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• 作者：Yi Chen ; ^{mrchenyi@swu.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Dandan Xue ; Zhiqian Chen ; Xianquan Jiang ; Jie Gou ; Gang Liu ; Xiaokui Liu ; Zunping Xu
• 关键词：C. Piezoelectric properties ; C. Dielectric properties ; D. Niobates ; D. Perovskites ; Lead-free ceramics
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：634-640
• 全文大小：1946 K

文摘

Lead-free piezoelectric ceramics based on the perovskite solid solution 0.995(K_0.5Na_0.5)_1−xLi_xNbO₃–0.005BiAlO₃ were prepared using conventional solid-state sintering techniques. According to the analysis of X-ray diffraction patterns, a pure perovskite phase structure could be achieved in the studied composition range of 0≤x≤0.08. As the lithium content increased, the crystal structure gradually transitioned from orthorhombic to tetragonal symmetry. Furthermore, an orthorhombic–tetragonal phase boundary could be observed in ceramics with the compositions of 0.03≤x≤0.05. The ceramics with compositions close to the orthorhombic–tetragonal phase boundary exhibited enhanced piezoelectric activity, possessing the largest values of piezoelectric constant d₃₃, and planar and thickness electromechanical coupling coefficients, of 182 pC/N, 0.375, and 0.460, respectively. Additionally, it was found that these ceramics with excellent piezoelectric properties also possessed a high Curie temperature (~ 450 °C), indicating that they would be suitable for application in elevated-temperature piezoelectric devices.