Thermal Expansion and Electrical Characteristics of Ba(1−x)CaxTi0.92Zr0.08O3 Lead-Free Ceramics Prepared by a Modified Pechini Method

Ba (1− x ) Ca x Ti 0.92 Zr 0.08 O 3 (BTZ- x Ca; x = 0–0.20) lead-free ceramics were prepared at a low temperature of 1210°C using as-synthesized nanoparticles through a modified Pechini method. The structure, permittivity, ferroelectricity, piezoelectricity, and thermal expansion characteristics of the ceramics that were influenced by varying calcium contents were studied in detail. X-ray powder diffraction and Raman results suggested that calcium could not induce the rhombohedral phase transition, and impurity phases were detected with excessive x . The electrical properties were basically elevated firstly in the room temperature direction of the temperature of phase transitions for orthorhombic-to-tetragonal with weaker internal stress, and then they apparently deteriorated with the shrunk octahedron size and strongly distorted structure with an increase of calcium content. The optimum electrical properties, i.e., d 33 , k p , and Q m of the BTZ- x Ca ceramics were 261 pC/N, 24.9%, and 98 were obtained when the calcium content was 0.05, respectively. Additionally, the thermal expansion coefficient was studied for providing guidance on the ceramic materials production and usage.