Effects of W/Cr Co-doping on the Crystal Structure and Electric Properties of CaBi2Nb2O9 2 Nb 2 O 9 Piezoceramics

Calcium bismuth niobate (CaBi2Nb2O9) 2 Nb 2 O 9 ) is a typical bismuth layered structure piezoelectric material with high Curie temperature (about 943 degree celsius) and high stability, which is an important candidate functional element for high temperature vibration sensors above 600 degree celsius. However, its low piezoelectric coefficient and high temperature resistivity seriously limit the signal acquisition of high-temperature piezoelectric vibration sensor. To improve the comprehensive performance, in this work, W/Cr co-doped CaBi2Nb1.975W0.025O9-x%Cr2O3 2 Nb 1.975 W 0.025 O 9- x %Cr 2 O 3 (CBNW-xCr, x Cr, 00.2) x <= 0.2) Aurivillius phase ceramics were prepared via conventional solid-state sintering route. The effects of W/Cr co-doping on the crystal structure and electrical properties of CBN piezoelectric ceramics were investigated. The results show that co-doping of W/Cr elements transforms crystal structure of the ceramics from orthorhombic to tetragonal crystal system, enhances distortion of the crystal structure, and significantly improves piezoelectric and insulating properties of the piezoelectric ceramics. When x =0.1, the Curie temperature is 931 degree celsius, the piezoelectric coefficient is 15.6 pC/N, the resistivity reaches the order of 106 6 ohm<middle dot>cm at 600 degree celsius, and the dielectric loss is only 0.029, which endows the system an important potential application in the field of high-temperature piezoelectricity.