Enhancing piezoelectric coefficient with high Curie temperature in BiAlO3-modified BiFeO3–BaTiO3 lead-free ceramics

In this work, the lead-free piezoelectric ceramic (1-x)[0.65Bi1.05FeO3–0.35BaTiO3] – xBiAlO3, (BFBT-xBA) (where x = 0, 0.010, 0.015, 0.020, 0.025, and 0.030), were synthesized by a solid-state reaction method, followed by air quenching process. The effects of BiAlO3 (BA) on the crystal structure, morphology and electrical properties of 0.65Bi1.05FeO3-0.35BaTiO3 (BF-BT) ceramics have been investigated. With the incorporation of BA-content (x = 0.010) the coexistence of rhombohedral and pseudocubic phases were observed. Scanning electron microscope (SEM) micrographs revealed that the average grain size of BF-35BT ceramics increased with the addition of BA. Well-saturated ferroelectric (P–E) hysteresis loops with definite remnant polarization (Pr) and coercive field (Ec) were observed. As a result, improvements in ferroelectric and piezoelectric properties with relative high Curie temperature (TC) were obtained at the optimum composition (x = 0.010). In addition, the static piezoelectric coefficient (d33) was enhanced from 97 pC/N for the base composition (x = 0) to 210 pC/N for the optimum (x = 0.010) composition. Fig. Static piezoelectric constant (d33) at room temperature of (1-x)BFBT-xBA Ceramics and temperature dependence of P-E loop for 0.99BFBT-0.01BA Ceramics. [Display omitted] •BiAlO3-modified 0.65Bi1.05FeO3–0.35BaTiO3 were synthesized by a solid-state reaction method, followed by air-quenching process.•1 mol% BiAlO3 doping led to a large increase in the piezoelectric constant.•Large piezoelectric response, attributed to the combination of grain size effect, densification, and coexistence of two phases.