Enhanced electrical properties and thermal stability of W/Cr co‐doped BIT-based high‐temperature piezoelectric ceramics

Bi 4 Ti 3 O 12 (BIT), a typical layered-structure ferroelectric with a high Curie temperature ( T C ), is a promising material for high-temperature sensors. Herein, W/Cr co-substitution at the B-site of BIT ceramics (BITWC100 x ) is carried out to investigate the phase structure, domain structure, and electrical properties. The W/Cr addition apparently reduces the concentration of oxygen vacancies , effectively improving the ferroelectric and piezoelectric properties as well as the resistivity of the BIT ceramics. The BITWC2 ceramic exhibits a high piezoelectric coefficient ( d 33 = 31.1 pC/N), a moderate T C (651 °C), a large remnant polarization ( P r = 12.2 μC cm −1 ), and a prominent direct current resistivity (5.49 ×10 6 Ω·cm at 500 °C). Moreover, the BITWC2 ceramic possesses a large d 33 of 26.6 pC/N at an annealing temperature of 600 °C, indicating the excellent thermal stability of the piezoelectric coefficient. Overall, the BITWC100 x ceramics can be used in piezoelectric devices at temperatures up to 500 °C.