Evolution of microstructure and electrical properties of Aurivillius phase (CaBi4Ti4O15)1-x(Bi4Ti3O12)x ceramics

(CaBi4Ti4O15)1-x(Bi4Ti3O12)x (CBT-xBIT) Aurivillius phase ceramics were synthesized by the conventional solid reaction method. The evolution of the structure and the electrical properties of CBT-xBIT ceramics were systematically investigated. Due to the enhanced spontaneous polarization induced by internal stresses on the Bi2O2 layers in the CBT-xBIT structure, the optimal piezoelectric coefficient (d33 ~ 13 pC/N) was obtained in the ceramics with x = 0.3 while exhibiting a relatively good thermal stability in the temperature range of 20-700 °C. The dc resistivity (ρdc) of the CBT-xBIT ceramics exhibited a higher value (≥ 109 Ω cm) at room temperature, and the tan δ value of CBT-xBIT (x= 0, 0.1 and 0.3) within the temperature range of 20-500 °C maintained stability as a result of the domain structure and point defect concentration in the ceramics. In addition, a distinctive double dielectric peak anomaly was observed in the εr-T curves of the CBT-xBIT (x= 0.3, 0.5 and 0.7) ceramics, and it plays a remarkable role in the thermal stability of the piezoelectricity of CBT-xBIT ceramics. As a result, such research can benefit high temperature practical piezoelectric devices.