Large strain response in Bi₄Ti₃O₁₂ modified BNT-BT piezoelectric ceramics

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• 作者：Peng Li^a ; Baihui Liu^a ; Bo Shen^a ; ^{shenbo@tongji.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Jiwei Zhai^a ; ^{apzhai@tongji.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Lingyu Li^a ; Huarong Zeng^b
• 关键词：BNT-BT ; Bi4Ti3O12 ; Strain ; Phase transition ; Domain structure
• 刊名：Ceramics International
• 出版年：2017
• 出版时间：January 2017
• 年：2017
• 卷：43
• 期：1
• 页码：1008-1021
• 全文大小：1825 K

文摘

In this paper, a novel system of lead-free piezoelectric ceramics 0.94(Bi_0.5Na_0.5)TiO₃−0.06BaTiO₃-xBi₄Ti₃O₁₂ (abbreviated as BNT-BT-xBiT) were prepared by the solid-state reaction method. The effects of Bi₄Ti₃O₁₂ dopant on the strain behavior, dielectric, ferroelectric and piezoelectric performance of BNT-BT ceramics were systematically investigated. A optimal strain value of ~0.37% was achieved around the critical composition of x=6 wt% which corresponds to a normalized strain (S_max/E_max) of 465 pm/V. The large strain response in this sample is mainly originated from two aspects: one is that BiT addition induced ferroelectric-to-relaxor phase transition evidenced by “pinched” ferroelectric hysteresis loops and vanished negative strain of bipolar strain loops as well as downward shift of T_F-R; the other is that the small-sized nanodomains (or polar nanoregions) facilitate the domain switching and domain wall motion with an applied electric field, which lead to large external contribution to strain response. These results indicate that BNT-BT-xBiT piezoelectric ceramics with large strain response may be a promising lead-free material for actuator application.