High-energy density ceramic composition in the system Pb(Zr,Ti) O ₃-Pb[(Zn,Ni) _1/3Nb _2/3]O ₃

This study reports a high-energy density piezoelectric pol) crystalline ceramic composition in the system Pb(Zr _1-xTi _x) O ₃-Pb[(Zn _1-yNi _y), _1/3Nb _2/3]O ₃ (PZT-PZNN Two different Zr/Ti ratios in the PZT system were investigated: 52/48 corresponding to morphotropic phase boundary (MPB) and 56/44 corresponding to the tetragonal phase. The compositions investigated in this study are represented as: 0.9Pb(Zr _0.52Ti _0.48) O ₃-0.1Pb(Zn _1/3Nb _2/3)O ₃ [0.9PZT (52:48)-0-1PZN]+y wt% MnCO ₃, where y varies from 0 to 0.9 wt% and 0.9Pb (Zr _0.56Ti _0.44)O ₃-0.1Pb[(Zn _0.8Ni _0.2) _1/3Nb _2/3]O ₃ [0.9PZT (56:44)-0.1PZNN] +y mol% MnO ₂, where y varies from 1 to 3 mol%. A high-energy density material is characterized by the large magnitude of the product of the piezoelectric voltage constant (g) and the piezoelectric strain constant (d) given as (dg). The condition for obtaining large magnitude of dg was derived to be as |d| = ε ⁿ, where ε is the permittivity of the material and n is a material constant having a lower limit of 0.5. The d ₃₃·g ₃₃ value of the samples having composition 0.9 PZT (56:44)-0.1 PZNN+2 mol% MnO ₂ (sintered in two steps at 1100°-1000°C) was found to be 18456.2 × 10 ^-15 m ²/N, which, to the knowledge of the authors, is the highest value reported for polycrystalline ceramics. This composition was also found to exhibit a high magnitude of g ₃₃ as 83.1 V · (m · N) ^-1, corresponding to the magnitude of n as 1.126.