Electrical properties of (Na,K,Li)(Nb,Sb,Ta)O₃ ceramics for multilayer-type piezoelectric actuator

ABSTRACT

In this study, lead free CuO added (Na_0.525K_0.4425Li_0.0375)(Nb_0.8975Sb_0.065Ta_0.0375)O₃ ceramics (NKL-NST) and multilayer actuator using the ceramics were fabricated and their physical and displacement properties investigated. The excellent physical properties of electromechanical coupling factor (k_p) = 0.4159, piezoelectric constant (d₃₃) = 166pC/N and mechanical quality factor (Q_m) = 322 were obtained from the 2.5mol% CuO doped (Na_0.525K_0.4425Li_0.0375)(Nb_0.8975Sb_0.065Ta_0.0375)O₃ ceramics sintered at low temperature of 1,000°C for 3 h.

The multilayer-type piezoelectric actuators (abbreviated as MTPA) were fabricated with NKL-NST + 2.5mol% CuO ceramics with excellent piezoelectric properties by tape casting methods. The density and effective electromechanical coupling factor (k_eff) of manufactured haptic piezoelectric actuator were 4.4 g/cm³ and 0.225, respectively. Total-displacement of central part of the actuator was increased with increasing input voltage. With input voltage and driving frequency of 20 V and 420 Hz, the input current, consumption of electrical power and total-displacement under zero force were 324 µA, 5.405 mW and 36 µm, respectively. Whereas, under 2.8 g force, the input current was 358 µA, and electrical power consumption of 4.554 mW and total-displacement of 18 µm under 20 V and150 Hz appeared, respectively.

KEYWORDS:

• Multilayer-type, piezoelectric actuators
• displacement
• effective electromechanical coupling factor