Strain properties and piezoelectric constant of lead-free barium titanate ceramics

In this paper, strain and piezoelectric constant of lead-free BaTiO3 ceramics can be modified by the change of sintering temperatures (1300 degrees C similar to 1390 degrees C) in air, and then the enhanced electrical properties can be demonstrated. The phase structure (orthorhombic-tetragonal) of BaTiO3 ceramics almost remains unchanged with the increase of sintering temperatures. However, their microstructure and electrical properties can be influenced by the sintering temperatures. It was found that their relative density and average grain size obviously increase, and then electrical properties can be enhanced. Interestingly, the enhancement of strain properties can be observed, that is, unipolar strain reaches 0.162% and d(33)* gets 405 pm V-1, which is superior to most reported results of pure BT ceramics. Finally, BT ceramics sintered at 1350 degrees C exhibit the optimum electrical properties of d(33) similar to 330 pC N-1, k(p) similar to 38%, epsilon(r) similar to 3300, and tan delta similar to 1.2%. Therefore, the optimization of sintering temperature is a brief way to modulate the structure and property of pure BT ceramics.