High Temperature Piezoelectric Properties of Vanadium Doped Bi₄Ti₃O₁₂ Ceramics with Grain Orientation

Abstract

The grain orientation effects of Bi ₄ Ti_0.98V _0.02 O ₁₂ [HF-BITV-0.02] ceramics were investigated using the hot-forging (HF) method for their piezoelectric properties and the high temperature piezoelectric characteristics were examined. Piezoelectric properties of electromechanical coupling factor, k ₃₃ , piezoelectric strain constant, d ₃₃ , piezoelectric voltage constant, g ₃₃ and mechanical quality factor, Q _m at room temperature were 0.39, 40.1 pC/N, 34.5 × 10^{− 3} Vm/N and 1500, respectively. The HF-BITV-0.02 indicates both high Curie temperature, T _c (= 678°C) and high g ₃₃ value as compared with other high temperature piezoelectric materials. From the measurement of piezoelectric properties after the thermal annealing at 550°C, the k ₃₃ and Q _m are revealed to keep high values of approximately 0.37 and 1300, respectively, without a depolarized degradation up to 550°C. The real time temperature dependences of piezoelectric properties indicate a good resonance and antiresonance curve and the k ₃₃ higher than 0.37 at 400°C. Therefore, the HF-BITV-0.02 ceramics seem to be good candidate for lead-free high-temperature piezoelectric materials.

Keywords:

• Curie temperature
• bismuth titanate
• high temperature piezoelectric properties
• piezoelectric voltage constant
• electromechanical coupling factor
• mechanical quality factor

Acknowledgments

The authors would like to thank TOHO TITANIUM CO., LTD. for providing high purity titanium oxide powder. This work was partially supported by a Grant-in-Aid for Scientific Research (B) (No.17360327 and No. 19360302) from the Japan Society for the Promotion of Science.