Electromechanical properties and cycling stability of low-temperature co-fired BNT–ST multilayer piezoactuators

• Published in: Journal of materials science. Materials in electronics 2022-09, Vol.33 (27), p.21482-21496
• Main Authors: Tong, Xing-Ye, Yang, Yu-Ting, Du, Zong-Zheng, Song, Min-Wei, Zhou, Jia-Jun, Liu, Hong, Guan, Chun-Lin
• Format: Article
• Language: English
• Subjects: Actuators; Bismuth titanate; Ceramics; Characterization and Evaluation of Materials; Chemistry and Materials Science; Cycles; Lead free; Lead zirconate titanates; Low temperature; Manganese dioxide; Materials Science; Monolayers; Multilayers; Optical and Electronic Materials; Palladium; Piezoelectric actuators; Rapid prototyping; Silver; Stability; Tape casting; Thickness
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-022-08939-7

Low-temperature co-fired Bi 0.5 Na 0.5 TiO 3 –SrTiO 3 (BNT–ST)/Ag–Pd lead-free multilayer piezoactuators (MLAs) with a large strain and excellent cycling stability were fabricated by tape casting for practical applications. Adding CuO decreased the sintering temperature of (1 −  x )BNT– x ST + 0.05 wt% MnO 2 (BNST100 x ) ceramics from 1190 °C to 960 °C. A BNST25.5 ceramic with 1.2 wt% CuO outputs a large normalized strain (950 pm/V) under an ultra-low driving field (2 kV/mm). Through optimizing the material composition and ceramic layer thickness, a normalized strain of 760 pm/V at 2.5 kV/mm is realized in a BNST24 with 1.2 wt% CuO MLA with a 63 μm single-layer thickness. Fairly good cycling stability is achieved with only ∼5% reduction after 10 7 cycles at 4 kV/mm. At the same time, these MLAs could still deliver over 85% strain at 80 °C. A MLA prototype with commercial size outputs a total strain of 0.112% and a blocking stress of 35.4 MPa at 2.5 kV/mm, demonstrating a better performance than that of traditional commercial lead zirconate titanate (PZT) actuators.