Microstructural, dielectric and piezoelectric properties of low-temperature sintering Pb(Co1/2W1/2)O3–Pb(Mn1/2Nb2/3)O3–Pb(Zr,Ti)O3 ceramics with the addition of Li2CO3 and Bi2O3

In this study, in order to develop the low-temperature sintering ceramics for multilayer piezoelectric devices, Pb(Co1/2W1/2)O3–Pb(Mn1/2Nb2/3)O3–Pb(Zr,Ti)O3 (PCW–PMN–PZT) ceramics doped with Li2CO3, Bi2O3 and CuO as sintering aids were manufactured, and their microstructural, dielectric and piezoelectric properties were investigated. When the only CuO was added, specimens could not be sintered below 980 °C. However, when Li2CO3 and Bi2O3 with CuO were simultaneously added to the basic composition ceramics, specimens could be sintered below 980 °C. The addition of Li2CO3 and Bi2O3 were proved to lower sintering temperature of piezoelectric ceramics due to the effect of Li2CO3–Bi2O3 liquid phase. Piezoelectric properties of Li2CO3 and Bi2O3 added specimens showed higher values than those of the only CuO added specimens. At 0.2 wt% Li2CO3 and 0.3 wt% Bi2O3 added specimen sintered at 920 °C, the dielectric constant (ɛr) of 1457, electromechanical coupling factor (kp) of 0.56 and mechanical quality factor (Qm) of 1000 were shown, respectively. It is considered that these values are suitable for piezoelectric device application such as multilayer piezoelectric transformer and ultrasonic vibrator with pure Ag internal electrode.