The Ag-Pd internal electrode of multilayer piezoelectric ceramics needs to be sintered below 1000°C, and lead wires and components need to be welded with lead-free solder at 260°C. PNN–PMW–PZT–
xSr piezoelectric ceramics with high Curie temperature (
Tc > 260°C) were synthesized at a low sintering temperature (960°C) to meet the requirements of multilayer piezoelectric devices. The relationship between structures (phase, domain, and microstructures) and electrical properties (piezo/ferroelectric properties, and dielectric relaxation) in the Sr
2+ substituted ceramics was investigated. Rietveld refinement and Raman spectra show that Sr
2+ substitution can cause the phase change and increase the force constant of [BO
6] octahedron. The piezoelectric response increases with increasing the content of the tetragonal phase (
CTP) in the rhombohedral-tetragonal (R-T) coexisted ceramics. The ceramics with 0.6 mol% Sr
2+ substitution have minimum activation energy for domain wall movement (
Ea) of 0.0362 eV which favors the formation of nanometer-sized domains, and possess excellent electrical properties (
d33 = 623 pC/N,
d33* =783 pm/V,
Tc =295°C). The higher the
CTP, the lower the
Ea. The lower
Ea favors the rotation of polarization direction and extension, and is beneficial to the generation of the nanometer-size domains, resulting in high piezoelectric properties.
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