Fabrication and characterization of low temperature sintering PMN–PZN–PZT step-down multilayer piezoelectric transformer

For the fabrication as step-down multilayer piezoelectric transformer, piezoelectric properties of Pb(Mg_1/3Nb_2/3)O₃–Pb(Zn_1/3Nb_2/3)O₃–Pb(Zr_0.52Ti_0.48)O₃ (PMN–PZN–PZT) ceramics were optimized by ZnO–Li₂CO₃ (ZL) and Pb₃O₄ content. Effects of the additions on the structure, bulk density and electrical properties of ceramics were investigated. The results revealed that the proper additions of ZL with Pb₃O₄ content could modify the electrical properties of the PMN–PZN–PZT ceramics. The composition sintered at 995 °C with 0. 01 wt.% ZL and 0.10 wt.% Pb₃O₄ content showed higher values, which were listed as follows: d₃₃ = 256 pC/N, K_p = 0.60, Q_m = 1910, _r = 1032, tan δ = 0.0070 and r = 2.09 Ω. In addition, the step-down piezoelectric transformers with optimized PMN–PZN–PZT composites were fabricated and the characteristics as the output power and resistance loads were measured. Meanwhile, the step-down piezoelectric transformers sintered at 995 °C showed the favorable characteristics with a higher gain G of 0.204 and a lower temperature rise of 6 °C when the output power was 5 W, and the driving frequency were approximately constant (≈126 kHz) when the output power was from 5 to 13 W. Moreover, the maximum efficiency (90.2%) was obtained at load resistance of 10 Ω.