Effects of sintering atmosphere on piezoelectric properties of 0.75BF-0.25BT ceramic

Abstract

0.75BF-0.25BT ceramics were prepared by sintering at 980 - 1040°C in air or under atmosphere powder. A sample with 1 mole %-excess Bi2O3 was also prepared to compensate for Bi2O3-evaporation. Physical and piezoelectric properties of these three samples were compared. When the sintering temperature increased from 980°C to 1040°C, the density of the sample sintered in air decreased continuously due to Bi-evaporation. Due to the suppression of Bi-evaporation, the sample sintered under atmosphere powder had a higher density at sintering temperatures above 1000°C than did the sample sintered in air. The addition of 1 mole %-excess Bi2O3 successfully compensated for Bi-evaporation and kept the density at the higher value until 1020°C. Grain size increased continuously when the sintering temperature increased from 980 to 1040°C, irrespective of the sintering atmosphere. When the sintering temperature increased, the piezoelectric constant (d33) and the electromechanical coupling factor (kp) increased for all samples. The sample with 1 mole % excess-Bi2O3 showed the highest density and the best piezoelectric properties at sintering temperature of 1020°C.