Hard piezoelectric properties of lead‐free BiFeO3‐BaTiO3 ceramics
Myang Hwan Lee, Hae In Choi, Da Jeong Kim, Ji Su Kim, Tae Kwon Song- Materials Chemistry
- Ceramics and Composites
Abstract
Hard piezoelectric properties are investigated in lead‐free BiFeO3‐BaTiO3 (BF‐BT) ceramics. Rhombohedral (R) phase ceramics of (1‐x)BF‐xBT (x = 0.20‐0.30) were prepared using a conventional solid‐state reaction and water‐quenching process. The R structure is observed in x = 0.20‐0.275, and the R and tetragonal phases coexist at x = 0.30. The piezoelectric charge sensor coefficient (d33) and electromechanical planar coupling factor (kp) increase with increasing BT content, whereas the mechanical quality factor (Qm) decreases. The x = 0.20 ceramic shows the best hard piezoelectric properties: the highest Qm = 403, and the highest TC = 607°C. In contrast, x = 0.30 ceramic shows soft piezoelectric properties: d33 = 301 pC/N and kp = 0.33 with TC = 510°C. These results show that the BF‐BT system in R‐phase rich region has good hard piezoelectric properties for transducer applications.
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