Enhancement of piezoelectric properties of CaBi2Nb2O9 ceramics by Ce doping and direct reaction sintering

CaBi 2 Nb 2 O 9 (CBN) with the Aurivillius phase has a high Curie temperature ( T C ) and remarkable fatigue resistance , which has great potential for application as high-temperature sensors. However, due to its low piezoelectric properties , its practical application remains a great challenge. In this paper, Ca 1- x Ce x Bi 2 Nb 2 O 9 ceramics were prepared by the direct reaction sintering (DRS) and conventional preparation (CP) methods, respectively. The experimental results indicate that Ce doping can increase the piezoelectric coefficient d 33 of CBN ceramics by about two times. Among them, the grain size of the samples prepared by the DRS method is finer and more uniform, and the d 33 value of DRS samples is about 3.6–9.4 % higher than that of CP samples. The DRS sample Ca 0·97 Ce 0·03 Bi 2 Nb 2 O 9 has a d 33 value of 18.9 pC/N, a T C of 948 °C, and a resistivity of 1.1 × 10 5  Ω cm at 600 °C. This study shows that DRS method is an effective densification method, which can prepare CBN-based ceramics with excellent comprehensive properties, and provides an innovative preparation route to explore CBN-based ceramics with excellent piezoelectric properties.