Barium Titanate Piezoelectric Ceramics Manufactured by Two-Step Sintering

Two-step sintering was applied to manufacture fine-grain barium titanate (BaTiO3) piezoelectric ceramics from hydrothermally synthesized 100 nm particles. Scanning electron microscopy (SEM) revealed a small and irregular domain structure in the samples. The sintering condition dependences of density, dielectric constants, and piezoelectric properties were investigated. Under the optimal conditions, dense specimens had an average grain size of approximately 1.6 µm, and showed large dielectric constants and excellent piezoelectric properties. The large piezoelectric constant of d33=460 pC/N was measured using a d33 meter. The Curie and orthorhombic-to-tetragonal phase transition temperatures were 126 and 24 °C, respectively. These results indicated the possibility of applying non-lead-based BaTiO3 ceramics manufactured by a low-cost process to ultrasonic generators, actuators, piezoelectric vibrators, and sensors working at room temperature.