Simultaneously enhanced piezoelectric response and depolarization temperature in BNT-7BT ceramics with simple composition via optimizing sintering temperature

For (Bi 0.5 Na 0.5 )TiO 3 -based ceramics, one of the obstacles limiting their actual application is the incompatibility of a large piezoelectric response d 33 with a low depolarization temperature T d . In this work, a high d 33 of 186 pC/N and a T d of 133 °C are achieved simultaneously in unmodified 0.93(Bi 0.5 Na 0.5 ) TiO 3 –0.07BaTiO 3 (BNT-7BT) ceramics only via optimizing sintering temperature. Structural and microstructural analyses show that grain size and relative content of P4bm and R3c phases in BNT-7BT ceramics can be regulated by tuning the sintering temperature ( T sinter  = 1100  ° C, 1120  ° C, 1140  ° C, 1160  ° C, and 1180  ° C). Thus, high sintering temperature is not only able to increase the grain size to promote the domains switching for higher the piezoelectric response, but also to enhance the ratio of R3c/P4bm phase so as to improve ferroelectric-relaxor transition temperature that defer the depolarization. Hence, the present work provides a simple and effective method for optimizing the piezoelectric properties of (Bi 0.5 Na 0.5 )TiO 3 -based ceramics.