Microstructural evolution and enhanced piezoelectric properties of 0.5Pb(Ni_1/3Nb_2/3)O₃-0.16PbZrO₃-0.34PbTiO₃ ceramics textured by two-dimensionally-dispersed template grain growth

A two-dimensionally-dispersed template grain growth (2DD TGG) method is proposed for making piezoelectric 0.5Pb(Ni_1/3Nb_2/3)O₃-0.16PbZrO₃-0.34PbTiO₃ (PNNZT) ceramics, textured using highly equi-aligned BaTiO₃ (BT) templates. Unlike a conventional TGG process, the 2DD TGG utilizes both BT-free and BT-included piezoelectric layers, which are laminated alternately. A significantly high texture degree of 94% was obtained for the PNNZT ceramic textured by the 2DD TGG when sintered at 1000°C for 15 h. The evolved microstructure of the textured PNNZT ceramic led to its outstanding piezoelectric properties of d₃₃=1334 pC/N, k_p=92.4%, g₃₃=38.5 × 10⁻³ V∙m/N, along with a dramatically enhanced large-signal electrostrain of d₃₃^∗ of 1409 pm/V at 1 kV/mm. These values indicate that the PNNZT ceramic textured by 2DD TGG is superior to those textured by conventional TGG. In addition, its fatigue behavior was satisfactory, allowing potential use for application in piezoelectric actuator devices.