MICROSTRUCTURE EVOLUTION AND DIELECTRIC PROPERTIES OF K₃Li₂Nb₅O₁₅ and BaTiO₃ COMPOSITES

ABSTRACT

Investigations of composite materials with two different crystal structured ferroelectric ceramics were carried out. In this study, phase development, sintering behavior and dielectric characteristics of the composites of tungsten bronze structured ferroelectric K₃Li₂Nb₅O₁₅ (KLN) and perovskite structured BaTiO₃ (BT) were examined as a function of molar ratio x in (1−x) K₃Li₂Nb₅O₁₅−xBaTiO₃. A wide range of solid solution of BT in KLN was observed and the lattice constants of KLN decreased with BT contents. However, the solubility of KLN in BT was very narrow. X-ray analysis revealed that both KLN and BT phases coexisted in the samples from x = 0.4 to x = 0.8. Therefore, two dielectric relaxation peaks were observed in the samples with x = 0.4 ∼0.8, each of which is originated from KLN and BT phase, respectively. The solid solution between KLN and BT decreased the T_C of both KLN and BT to lower temperature.

Keywords:

• Tungsten bronze structure
• perovskite structure
• composites
• ferroelectrics
• K₃Li₂Nb₅O₁₅ (KLN)
• BaTiO₃ (BT)

ACKNOWLEDGMENT

This work was supported by grants No. R01-2003-000-11606-0 from the Basic Research Program of the Korea Science & Engineering Foundation.