Optimizing Dielectric Constant in Tetragonal BaTiO3 Via Densification, Tetragonality, and Grain Growth Kinetic with Sintering Temperature

Abstract

Tetragonal BaTiO3 nanopowders with tetragonality (c/a = 1.01), compacted uniaxially at 300 MPa, underwent sintering at temperatures ranging from 900°C to 1200°C for 1 h. Their densification and microstructure evolution were examined to determine the dielectric constant as a function of temperature (25-150°C) and frequency (102-107 Hz). Increasing the sintering temperature enhanced the densification and grain growth of BaTiO3, demonstrating a linear relationship between them. However, the tetragonality remained unaffected by the sintering temperature. The densified BaTiO3 exhibited a high dielectric constant (εr) across temperatures and frequencies. The activation energy for grain growth varied depending on the primary mechanism of lattice and grain boundary diffusion, ranging approximately from 119.1 to 172.5 kJ/mol across the entire sintering range.