Processing parameter influence on BaTiO 3 ceramic fractal microstructure and dielectric characteristics

Abstract

In the process of BaTiO₃ ceramics consolidation, technological parameters like sintering temperature, pressing pressure and additives significantly determine the microstructure and electrical properties. Slight change of a particular sintering parameter can considerably change the microstructure as well as the electrical parameters. Structural complex grain–contact–grain is observed on Ho doped BaTiO₃ ceramics, sintered from 1320 to 1380°C. The new configuration model of ceramic grain contact surfaces is presented in this paper. This model is based on Coble's two-sphere approximation and its generalisation to ellipsoidal geometry. The integral contact surface directly influences the value of the total ceramic capacity. Fractal method is applied for intergrain contact analysis. Ceramic grains are considered to have fractal surface (as it is elsewhere in nature) and, therefore, fractal structure influences on the dielectric properties of BaTiO₃ ceramics. The obtained results give better understanding of ceramic microstructure with the final aim to establish significant interrelation among processing, structural and electrical parameters.