Large Strain in CuO‐added (Na0.2K0.8)NbO3 Ceramic for Use in Piezoelectric Multilayer Actuators. Issue 3 (22nd December 2015)

• Record Type: Journal Article
• Authors: Lee, Ji‐Hyun; Kim, Dae‐Hyeon; Seo, In‐Tae; Kim, Jong‐Hyun; Park, Jong‐Seong; Ryu, Jungho; Han, Seung Ho; Jang, Bo‐yun; Nahm, Sahn
• Editors: Damjanovic, D.
• Is Part Of: Journal of the American Ceramic Society. Volume 99:Issue 3(2016)
• Page Start: 938
• Page End: 945
• Publication Date: 2015-12-22
• Subjects: Ceramics -- Periodicals; 620.1405
• DOI: 10.1111/jace.14031
• Languages: English
• ISSNs: 0002-7820

Abstract

Abstract : In this study, 1.0 mol% CuO‐added (Na x K1− x )NbO3 (CN x K1− x N) ceramics with 0.0 ≤ x ≤ 0.5 were sintered at a relatively low temperature of 960°C. A large Q m value (≥1750) was obtained for the specimens with x ≤ 0.2 owing to the hardening effect of Cu 2+ ions, indicating that a large number of Cu 2+ ions had replaced Nb 5+ ions in these ceramics. The double polarization versus electric field ( P – E ) hysteresis loop was observed for the specimens with x ≤ 0.2, and was explained by the defect polarization ( P d ) formed between Cu 2+ ions and O 2− vacancies. These specimens also exhibited a sprout‐shaped strain versus electric field ( S – E ) curves with a large strain of 0.14%–0.15% at 8.0 kV/mm because of the internal bias field produced by P d . For the CN0.2 K0.8 N ceramic, a double P – E hysteresis loop was maintained at 125°C without remnant polarization. Moreover, this ceramic showed a large strain of 0.175% after 10 4 cycles when a high electric field of 8.0 kV/mm was continuously applied to the specimens during each cycles. Therefore, CN0.2 K0.8 N is a useful lead‐free piezoelectric ceramic for multilayer actuators.