High‐Energy Density Ceramic Composition in the System Pb(Zr,Ti)O 3 –Pb[(Zn,Ni) 1/3 Nb 2/3 ]O 3

This study reports a high‐energy density piezoelectric polycrystalline ceramic composition in the system Pb(Zr 1− x Ti x )O 3 –Pb[(Zn 1− y Ni y ) 1/3 Nb 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 0.52 Ti 0.48 )O 3 –0.1Pb(Zn 1/3 Nb 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 0.56 Ti 0.44 )O 3 –0.1Pb[(Zn 0.8 Ni 0.2 ) 1/3 Nb 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 |=ɛ n , where ɛ 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.