Thermally stable large strain in low‐loss (Na_0.2K_0.8)NbO₃‐BaZrO₃for multilayer actuators

Abstract

CuO‐doped (1–x)(Na0.2K0.8)NbO3‐xBaZrO3 ceramics (0.0 ≤ x ≤ 0.06) were densified at 960°C. The ceramic with x = 0 exhibited a large sprout‐shaped strain vs electric‐field (S‐E) curve and a double polarization vs electric‐field (P‐E) hysteresis curve, owing to the defect polarization (PD) developed between Cu2+ ions at Nb5+ sites and oxygen vacancies. The sizes of the S‐E and P‐E loops decreased with increasing x, owing to the decrease in the number of PDs. The ceramic with x = 0.04 displayed small S‐E and P‐E curves, indicating its small dielectric loss. It exhibited large strain (0.19% at 8.0 kV/mm) at room temperature, which was maintained at 200°C. A similar strain was observed after applying 106 cycles of an electric field (3.0 kV/mm). Hence, this specimen exhibited large strain with excellent thermal and fatigue properties. Moreover, the synthesized multilayer actuator using the ceramic with x = 0.04 showed excellent vibrational properties, making it promising for applications in multilayer piezoelectric actuators.

High-performance (K,Na)NbO 3-based multilayer piezoelectric ceramic actuators with nickel inner electrodes

“…results in the depressed strain of MLCA. Similar phenomenon has been found in the other MLCA systems [6,25,31,32].…”

“…Currently, the expensive but chemically stable noble metals or alloys (Ag, Pt, Pd, and Ag/Pd) are usually used as the inner electrode in piezoelectric MLCA devices [6,7]. For reasons of the need to reduce the manufacturing costs and the critical diffusion of Ag elements into ceramic layers [8], the attempts have been made to use the base metals such as Cu and Ni [9].…”

A Review on Piezoelectric Materials and Their Applications

“…For example, pressure or tilt sensor are used in touch pads of the mobile phones. [ 178 ] In general, three main groups of materials are used for piezoelectric sensors, which are piezoelectric ceramics like lead zirconate titanate (PZT), [ 179,180 ] single crystalline materials such as quartz, tourmaline etc., [ 181 ] and thin film piezoelectric materials like aluminum nitride. [ 182 ]…”

Recent Developments in (K, Na)NbO3-Based Lead-Free Piezoceramics

“…Piezoelectric materials can convert mechanical energy into electrical energy or vice versa and have been applied to diverse electronic devices, including piezoelectric actuators, ultrasonic transducers, and piezoelectric energy harvesters [ 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. Until recently, Pb(Zr, Ti)O 3 (PZT)-modified ceramics were widely utilized to fabricate piezoelectric components because of their excellent piezoelectric properties and high Curie temperatures ( T C ), allowing them to control the piezoceramics markets [ 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ].…”