Fabrication and electrical characteristics of piezoelectric PMN-PZN-PZT ceramic transformers

For the fabrication as piezoelectric transformers, the density, microstructure, dielectric and piezoelectric properties of Pb(Mg1/3Nb2/3)O3-Pb(Zn1/3Nb2/3)O3-Pb(Zr0.52Ti0.48)O3 (PMN-PZN-PZT) ceramics as a function of calcining temperature and sintering temperature were investigated. In addition, the piezoelectric transformers with the composition of PMN-PZN-PZT were fabricated and the characteristics with various resistance loads were measured. The results indicated that the optimized properties of ceramics were obtained at calcining temperature of 800 deg. C and sintering temperature of 1020 deg. C, which were listed as follows: d 33 = 249 pC/N, K p = 0.57, Q m = 1954, ε r = 1122 and tan δ = 0.0059. Meanwhile, piezoelectric transformers sintered at 1020 deg. C show the favorable characteristics with a higher step-up ratio of 145 and a lower temperature rise of 5 deg. C at 250 kΩ