Influence of excessive Pb and sintering temperature on the structure and properties of 0.39BS-0.61PT ceramics

Abstract Recently, (1-x)BiScTiO3–xPbTiO3 (BS–xPT) ceramics have attracted extensive research attention owing to their higher Curie temperature and better piezoelectric properties than Pb(Zr,Ti)O3 (PZT) ceramics. The piezoelectric properties of PT-based ceramics are usually improved by adding excessive Pb, which compensates the PbO volatilization during sintering. This study investigates the phase structures and electrical properties of 0.39BS–0.61PT ceramics after introducing 1 wt% excessive PbO and modulating the sintering temperature. Unexpectedly, adding 1 wt% excessive PbO degraded the piezoelectric properties relative to those of 0.39BS–0.61PT ceramics. Above a critical sintering temperature (1150 °C), the rhombohedral phase structure of ceramics changed to a morphotropic phase boundary, resulting in an obvious increase in piezoelectric properties. Excellent electrical properties (piezoelectric constant d33 = 417 pC/N, electromechanical property kp = 53%, dielectric loss tanδ = 0.02) were exhibited by 0.39BS–0.61PT ceramics. All ceramics exhibited a high Curie temperature (Tc ≈ 415 °C) and superior piezoelectric stability from room temperature to 330 °C, suggesting their applicability under high–temperature conditions. Our experimental results provide a new approach for designing materials with the desired electrical properties for low-lead BS–PT ceramics. Keywords: BS–PT ceramics, Electrical properties, Phase structure, Excessive PbO.