Modulation of electrostriction and strain response in bismuth sodium titanate‐based ceramics

The electrostriction and strain response of lead‐free Bi 0.5 Na 0.5 TiO 3 –BaTiO 3 piezoceramics with La and Nb [(Bi 0.47 Na 0.47 Ba 0.06 ) 1− x La x Ti 1− y Nb y O 3 ] were modified by optimizing the depolarization temperature. The influences of La and Nb on their phase structure and electrical properties were systematically investigated. All the ceramics exhibited a pseudocubic phase, which is independent of the addition of La and Nb. The strain values increased gradually with the addition of La, and a high strain of ~0.5% (80 kV/cm) was attained without any remnant strain when the compositions had a value of x = 0.015. Instead, the piezoelectric constant d 33 dropped down ~20 pC/N due to the shift of the T d (or T f−r ) to room temperature. Interestingly, by establishing the relationship between T d and strain values, it should be feasible to optimize the strain property of Bi 0.5 Na 0.5 TiO 3 ( BNT )‐based ceramics by regulating T d to ambient temperature. In addition, a very high electrostriction coefficient Q 33 of ~0.0758 m 4 C −2 can be found under high temperatures of 125 and 150°C. We believe that the strain and electrostriction behavior of BNT ‐based ceramics can be well modified by the modulation of depolarization temperature.