Piezoelectric Properties of Rosen-type Piezoelectric Transformer Using 0.01Pb(Ni1/3Nb2/3)O3-0.08Pb(Mn1/3Nb2/3)O3-0.91Pb(Zr0.505Ti0.495)O3 Ceramics

The influences of the sintering temperature on the microstructures, piezoelectric, and dielectric properties of PNN-PMN-PZT ceramics and on the method for fabricating of high-power Rosen-type piezoelectric transformers were investigated. The basic composition of piezoelectric ceramics was ternary 0.01Pb(Ni1/3Nb2/3)O-3 - 0.08Pb(Mn1/3Nb2/3)O-3 - 0.91Pb(Zr0.505Ti0.495)O-3 (abbreviated as PNN-PMN-PZT). The density and the microstructures, dielectric and piezoelectric properties as functions of the sintering temperature were investigated. The results indicated that the optimized properties of the ceramics were obtained at a sintering temperature of 1200 degrees C: d(33) = 273 pC/N, K-p = 0.60, Q(m) = 1585, epsilon(r) = 1454, density = 7.917 g/cm(3) and tan delta = 0.0064. Piezoelectric transformers were manufactured using the PNN-PMN-PZT ceramics. The voltage step-up ratio of the piezoelectric transformers showed maximum values near 81 kHz and increased with increasing load resistance. The piezoelectric transformers sintered at 1200 degrees C also showed favorable characteristics with a higher step-up ratio and a lower temperature rise of 3.2 degrees C at an output power of 5 W.