Effects of Li2CO3 and Sm2O3 additives on low-temperature sintering and piezoelectric properties of PZN-PZT ceramics

To assist the development of applications for multilayer piezoelectric devices, the low-temperature sintering piezoelectric ceramics of 0.3Pb(Zn1/3Nb2/3)O3-0.7Pb(Zr0.49Ti0.51)O3 with Li2CO3 and Sm2O3 additives were fabricated by a conventional solid-state reaction, and their structural and piezoelectric properties were studied. With the addition of Li2CO3, the minimum sintering temperature of 0.3Pb(Zn1/3Nb2/3)O3-0.7Pb(Zr0.49Ti0.51)O3 piezoelectric ceramics was reduced from 1125 °C to 950 °C through the formation of a liquid phase and its piezoelectric properties showed almost no degradation. When the sintering temperature was below 950 °C, however, the piezoelectric properties degraded obviously. The additional Sm2O3 resulted in a significant improvement in the piezoelectric properties of 0.3Pb(Zn1/3Nb2/3)O3-0.7Pb(Zr0.49Ti0.51)O3 ceramic with added Li2CO3. When sintered at 900 °C, the optimized properties of the 0.3Pb(Zn1/3Nb2/3)O3-0.7Pb(Zr0.49Ti0.51)O3 piezoelectric ceramic with 0.3 wt% Li2CO3 and 0.3 wt% Sm2O3 were obtained as d33 = 483 pC/N, k31 = 0.376, Qm = 73, ɛr = 2524, tan δ = 0.0178.