The impact of co-doping Ce, W, and Mn on the microstructure and piezoelectric performance of high-temperature piezoelectric ceramics based on CaBi2Nb2O9

CaBi2Nb2O9 (CBN) is a bismuth layered ferroelectric material with extremely high Curie temperature and low dielectric loss, which has great application potential in ultra-high temperature field. However, because of its low piezoelectric coefficient, its practical application still faces great challenges. This study successfully prepared Ca1-xCexBi2Nb1.98(W2/3Mn1/3)0.02O9 (x = 0–0.05) two-layer ferroelectric ceramics using direct-reaction sintering method. A pseudo tetragonal structure was successfully constructed near x = 0.02 using the substitution method of Ce4+ at site A, and W6+ and Mn4+ at site B, which altered the crystal structure of CBN based ceramics. The properties of CBN-based piezoelectric ceramics have been significantly improved by this modification. It has a higher piezoelectric constant (d33 = 20.6 pC/N) and Curie temperature (Tc = 950 °C), while having a lower dielectric loss (tanδ = 0.031 at 500 °C). In addition, CaBi2Nb2O9 based piezoelectric ceramics also show excellent thermal stability. After annealing at 900 °C for 2 h, the d33 value remained high at 19.2 pC/N, retaining about 93.2% of its original value. Therefore, these findings indicate that Ca1-xCexBi2Nb1.98(W2/3Mn1/3)0.02O9 is a high-temperature piezoelectric material with great potential.