Wu Yichen, Wang Genshui, Jiao Zheng, Fan Yuzhu, Peng Ping, Dong Xianlin
School of Environmental and Chemical Engineering, Shanghai University Shanghai 200444 China.
Key Laboratory of Inorganic Functional Materials and Devices, Shanghai Institute of Ceramics, Chinese Academy of Sciences Shanghai 200050 China
RSC Adv. 2019 Jul 10;9(37):21355-21362. doi: 10.1039/c9ra04069b. eCollection 2019 Jul 5.
As a promising candidate material replacing Pb(ZrTi)O (PZT), the lead-free BiNaTiO (BNT) system exhibits outstanding piezoelectric and ferroelectric properties. However, the weak thermal stability of these electric properties hampers its practical applications. In this work, we designed and prepared novel Nb-doped 0.76BiNaTiO-0.24BiKTiO (BNT-BKT) ceramics with superior temperature stability of electric properties. Both strain as well as discharging properties of 5% Nb-doped BNT-BKT ceramics varied less than 3% and 12.5% respectively from room temperature to 160 °C, ascribed to the enlarged gap between the depolarized temperature ( or ) and the maximum dielectric temperature ( ). In addition, we investigated the impacts of Nb doping on the phase transition, dielectric, piezoelectric and ferroelectric behaviors of BNT-BKT ceramics in detail. Temperature dependent dielectric spectrums indicated that decreased below room temperature with Nb modifying, revealing that the phase structure transformed from ferroelectric into ergodic relaxor. Accordingly, the maximum strain value of 0.21% and recoverable energy storage of 1.2 J cm were simultaneously acquired at the critical composition of 5% Nb incorporation. Our results provide an effective means of obtaining BNT-based ceramics with simultaneously thermally stable strain and discharge properties for wide temperature actuator and capacitor applications.
作为一种有望替代铅基锆钛酸铅（PZT）的候选材料，无铅铋钠钛酸盐（BNT）体系展现出优异的压电和铁电性能。然而，这些电学性能较弱的热稳定性阻碍了其实际应用。在本工作中，我们设计并制备了具有优异电学性能温度稳定性的新型铌掺杂0.76BiNaTiO-0.24BiKTiO（BNT-BKT）陶瓷。5%铌掺杂的BNT-BKT陶瓷的应变和放电性能从室温到160°C分别变化小于3%和12.5%，这归因于去极化温度（或）与最大介电温度（）之间的间隙增大。此外，我们详细研究了铌掺杂对BNT-BKT陶瓷的相变、介电、压电和铁电行为的影响。温度依赖的介电谱表明，随着铌的改性，在室温以下降低，表明相结构从铁电体转变为遍历弛豫体。相应地，在铌掺入量为5%的临界组成下，同时获得了0.21%的最大应变值和1.2 J cm的可恢复储能。我们的结果提供了一种有效的方法，可获得具有同时热稳定应变和放电性能的BNT基陶瓷，用于宽温度范围的致动器和电容器应用。
