Microstructure, Dielectric, and Piezoelectric Properties of Pb0.92Ba0.08Nb2O6–0.25 wt% TiO2 Ceramics: Effect of Sintering Temperature

Abstract

In order to obtain dense PbNb2O6‐based piezoelectric ceramics with a single orthorhombic ferroelectric phase, Ba, and excess Ti were doped into PbNb2O6 ceramics with the composition of Pb0.92Ba0.08Nb2O6–0.25 wt% TiO2 via a conventional solid‐state reaction method. The ceramics were sintered at 1210°–1300°C. The effects of sintering temperature on the crystallite structure, microstructure, and dielectric and piezoelectric properties were studied in detail. All ceramics had shown a high relative density (>94%) and a single orthorhombic phase. The lattice parameters, grain size, and shape varied with changing sintering temperature. All ceramics exhibited a typical characteristic in ferroelectrics with normal paraelectric–ferroelectric phase transition at the Curie temperature. With increasing sintering temperature from 1210° to 1300°C, the Curie temperature decreased from 554° to 523°C, while the maximum dielectric constant increased. The change in dielectric properties with changing sintering temperature is associated with a competing effect among internal stress, porosity, and grain size. The ceramic sintered at 1260°C possesses an excellent piezoelectric constant (d33=82 pC/N), low mechanical quality factor (Qm=20.52), low dielectric loss (tan δ=0.0062), and high Curie temperature (Tc=535°C), presenting a high potential to be used in high‐temperature applications as piezoelectric transducers.