Improving dielectric properties of Zn₂(Ti_0.88Sn_0.12)O₄ ceramics by using molten-salt method to optimize the microstructure

Zn₂(Ti_0.88Sn_0.12)O₄ samples were synthesized by a mixed-oxide reaction method (abbreviated as MO) and a molten-salt method (abbreviated as MS), respectively. The effects of preparing method on the phase-structures, microstructure, and the dielectric properties were systematically discussed. The results show that the MS ceramics have a cubic spinel structure and the MO ceramics have a tetragonal crystal structure. The MS ceramics are composed of more angular and homogeneous grains compared with that of the MO samples. Grain growth of two kinds of ceramic was studied. The results show that the grain growth of MO ceramics exhibits grain boundary diffusion and surface diffusion mechanisms, while MS ceramics exhibits lattice diffusion or evaporation/condensation mechanisms. The MS ceramics are found to have lower apparent activation energy. Densification and homogeneous microstructure play a more important role in controlling the dielectric properties. Therefore, the MS ceramics exhibit better dielectric properties by optimizing the microstructure. (paper)