Enhanced torsional actuation and stress coupling in Mn-modified 0.93(Na_0.5Bi_0.5TiO₃)-0.07BaTiO₃ lead-free piezoceramic system

Abstract

This paper is concerned with the development of a piezoelectric d₁₅ shear-induced torsion actuator made of a lead-free piezoceramic material exhibiting giant piezoelectric shear stress coefficient (e₁₅) and piezoelectric transverse shear actuation force comparable to that of lead-based shear-mode piezoceramics. The Mn-modified 0.93(Na_0.5Bi_0.5TiO₃)-0.07BaTiO₃ (NBT-BT-Mn) composition exhibited excellent properties as a torsional transducer with piezoelectric shear stress coefficient on the order of 11.6 C m^–2. The torsional transducer, consisting of two oppositely polarized NBT-BT-Mn d₁₅ mode piezoceramic shear patches, provided a rate of twist of 0.08 mm m^–1 V^–1 under quasi-static 150 V drive. The high value of piezoelectric shear d₁₅ coefficient in NBT-BT-Mn sample further demonstrated its potential in practical applications. These results confirm that the lead-free piezoceramics can be as effective as their lead-based counterparts.

Keywords:

• Lead-free
• piezoceramic
• shear-mode
• torsion
• actuation

Classification:

• 10 Engineering and structural materials; 107 Glass and ceramic materials; 202 Dielectrics/Piezoelectrics/Insulators
• 304 Powder processing/Sintering
• 400 Modeling/Simulations

Acknowledgements

The authors would like to thank Dr Y. Yan for the help with EDS analysis measurement. Currently, the first author is in the Department of Mechanical and Aerospace Engineering at North Carolina State University.