Grain size dependent electrostrain in Bi1/2Na1/2TiO3-SrTiO3 incipient piezoceramics

The electrical properties and microstructures of (1 - x) Bi1/2Na1/2TiO3-xSrTiO(3) (BNT-ST100x, 0.20 <= x <= 0.30) piezoceramics with different grain size distributions were investigated. The critical region separating the ferroelectric from ergodic relaxor is located around x = 0.26. Strains up to 0.2% could be achieved under a low driving fields (E < 2 kV/mm) in the BNT-ST26 composition resulting in excellent actuating performance of S-max/E-max >1000 pm/V. The electrostrain was largely depended on the grain size and an increment of strain up to similar to 38% can be realized by increasing the grain size from 5 mu m to 13 mu m in the BNT-ST26 samples. The results indicate that the field -induced strain performance of BNT-based incipient piezoelectric ceramics can be tailored via microstructure modifications, an alternative strategy to enhance the electromechanical properties. (C) 2016 Elsevier Ltd. All rights reserved.