(Li,Na,K)NbO₃-based multilayer piezoceramic with Ag/Pd inner electrodes

Abstract

Lead-free (Li,Na,K)NbO3-based multilayer piezoceramics with Ag/Pd inner electrodes were fabricated. Each multilayer piezoceramic comprised 20 layers, and each layer had a thickness of 13 μm. These multilayer piezoceramics succeeded in driving a high electric field of 16 kV mm−1, while producing a strain of 0.24%. The microstructure was investigated using scanning electron microscopy and scanning transmission electron microscopy. It was found that the grain size was 400 nm and the ceramic layer had high densification. The elemental Ag also diffused uniformly throughout the ceramic layers, as observed by an energy dispersive X-ray spectrometer. This outstanding thin-layer stacking design of the lead-free piezoceramic could result in a displacement property exceeding that of a Pb(Zr,Ti)O3-based multilayer piezoceramic. However, the electric resistance was low (4.2 × 1012 Ω ‧ cm at 100 °C) compared with that of multilayered Pb(Zr,Ti)O3 (1.9 × 1013 Ω ‧ cm at 100 °C). Therefore, the electric resistance must be improved before replacing lead-containing piezoceramics.

Ferroelectric polarization of tetragonal BiFeO3—an approach from DFT calculations for BiFeO3–BaTiO3 superlattices—

“…10,[13][14][15][16][17][18][19][20][21][22] To establish an MBP similar to the PZT system, various lead-free solid solution systems have been investigated and composition-driven variations of crystal structure and properties have been studied. Since the discovery of (K, Na)NbO 3 -based ceramics with properties comparable to PZT, 23) (K, Na)NbO 3 [24][25][26][27][28][29][30] and its related Nb-based materials [31][32][33][34][35][36] have intensively studied with the aim of developing lead-free piezoelectric devices.…”

Fabrication and properties of reduction-resistant lead-free NaNbO3–BaTiO3 piezoelectric ceramics

“…[20][21][22][23][24][25][26] This is difficult to achieve with lead oxidebased compounds. The progress of miniaturization and lowering of the operation voltage of piezoelectric components, which leads to energy savings, has led to the formation of multilayered structures [21][22][23][24][25][26][27][28] since electrode cost becomes an issue, as in the case of multilayer ceramic capacitors. 20) The authors have reported on reduction-resistant BaTiO 3 -based piezoelectric materials with excellent electrical properties.…”