Abstract
This article reports the significantly improved piezoelectric and ferroelectric properties of Cu/W co-doped Ca_2Bi_2Nb_(2-x)(Cu_(1/4)W_(3/4))_xO_9 (CBNCW-x, where 0≤ x ≤ 0.150) high Curie temperature lead-free piezoelectric ceramics. The crystal structure, microstructure, and electric properties of CBNCW-x ceramics have been systematically analyzed. The results show that ceramic samples have a bismuth layered structure of m- 2, which is a single-phase of CBN. The ceramic grains show the typical plate-like structure of the bismuth layer. Cu/W co-doped CBN ceramics increased the distortion of NbO_6 octahedron, and significantly enhanced the piezoelectric constant and the remnant polarization. When x = 0.075, it shows better comprehensive properties with an excellent d_(33) of 13.8 pC/N, a high remnant polarization of 12.10 uC/cm2, the Tc of 918 °C, a dielectric loss value of 0.57%, and the Ωm value of 7099. Moreover, CBNCW-0.075 ceramic simple maintains the d_(33) of 12.7 pC/N after annealing 900 °C for 30 min, which shows good high-temperature stability. It suggests that the Cu/W co-doped CBN ceramics have good application prospects in the high-temperature piezoelectric field.
NSTL
Elsevier