Large Strain in CuO-added (Na0.2K0.8)NbO3 Ceramic for Use in Piezoelectric Multilayer Actuators

Ji Hyun Lee, Dae Hyeon Kim, In Tae Seo, Jong Hyun Kim, Jong Seong Park, Jungho Ryu, Seung Ho Han, Bo Yun Jang, Sahn Nahm

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15 Citations (Scopus)


In this study, 1.0 mol% CuO-added (NaxK1-x)NbO3 (CNxK1-xN) ceramics with 0.0 ≤ x ≤ 0.5 were sintered at a relatively low temperature of 960°C. A large Qm value (≥1750) was obtained for the specimens with x ≤ 0.2 owing to the hardening effect of Cu2+ ions, indicating that a large number of Cu2+ ions had replaced Nb5+ 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 (Pd) formed between Cu2+ ions and O2- 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 Pd. For the CN0.2K0.8N 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 104 cycles when a high electric field of 8.0 kV/mm was continuously applied to the specimens during each cycles. Therefore, CN0.2K0.8N is a useful lead-free piezoelectric ceramic for multilayer actuators.

Original languageEnglish
Pages (from-to)938-945
Number of pages8
JournalJournal of the American Ceramic Society
Issue number3
Publication statusPublished - 2016 Mar

ASJC Scopus subject areas

  • Ceramics and Composites
  • Materials Chemistry


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