Effect of BaTiO3 heat treatment on the microstructure and dielectric properties of BaTiO3-based ceramics

We have studied the effect of heat treatment of the starting BaTiO3 powder on the dielectric properties and microstructure of X7R-type BaTiO3-based ceramics. The results demonstrate that annealing of BaTiO3 stabilizes the degree of tetragonality in the crystal lattice of the ceramics. Microstructural analysis shows that the annealing temperature has no effect on the average grain size of the ceramics. Increasing the BaTiO3 annealing temperature increases the dielectric permittivity of the core phase and reduces the temperature coefficient of capacitance (TCC). We obtained an X7R-type BaTiO3-based ceramic material (BaTiO3 annealing temperature, 1150°C; firing temperature, 1160°C) with the following properties: ɛ25°C = 2230, TCC = ±12% (−55 to 125°C), and tanδ25°C = 0.013.