Achieving superior electrical properties of PZT-PNN piezoelectric ceramics through low-temperature sintering with PbO-CuO eutectic additives

Combinational oxides PbO-CuO are incorporated into the matrix of 0.6451Th(Zr0.41Ti0.59)O-3-0.355Ph(Ni1/3Nb2/3)O-3 (PZT-PNN) in order to realize low-temperature sintering while achieving superior electrical properties, which are used to fabricate ceramic-electrode integrated devices for flat-panel-speakers. Ceramics are prepared using conventional solid-state reaction technique, and the effects of different amounts of sintering additives PbO-CuO on phase structure, grain size, sintering temperature and electrical properties are systematically investigated. On that basis, comprehensive electrical properties are further enhanced via optimizing the PbO (CuO) proportions in PbO-CuO additives. The results show that doping appropriate PbO-CuO decreases the sintering temperature significantly from normally 1250 degrees C for most of PZT-based ceramics by more than 250 degrees C, while superior electrical properties are still achieved. PZT-PNN + 1.5 wt% (0.77PbO-0.23CuO) ceramics sintered at 1000 degrees C exhibit optimal electrical properties of d(33) = 780 pC/N, k(p) = 0.62, epsilon(T)(33)/epsilon(0) = 3982, tan delta = 0.025 and density of 7.87 g/cm(3). Furthermore, ceramics sintered at 950 degrees C even possess over 89% of the optimal piezoelectric properties, with d(33) = 695 pC/N, k(p) = 0.59, epsilon(T)(33)/epsilon(0) = 3690, tan delta = 0.018. This work paves the way for mass production of co-firing ceramic-electrode integrated devices for high performance flat-panel-speaker applications, and inspires the low-temperature sintering strategy in other ceramic materials.