ABSTRACT
In the research, the properties of sodium copper titanate niobate – barium titanate [(1-x)NaCu3Ti3NbO12-(x)BaTiO3: (1-x)NCTNO-(x)BT] ceramics prepared by conventional solid-state reaction method with various molecular weight of BT or x between 0.1, 0.3 and 0.5 were investigated. These ceramics were sintered at 975, 1000, 1025 and 1050 oC for 10 h in ambient atmosphere. The phase structure, microstructure, density, micro-hardness and dielectric properties were examined by x-ray diffraction technique (XRD), scanning electron microscopy (SEM), Archimedes method, Vickers micro-hardness tester and impedance analyzer, respectively. It was found that, the addition of BaTiO3 resulted in the formation of second phase which increased upon increasing the BaTiO3 content. Compared to the base composition, the grain sizes of all the (1-x)NCTNO-(x)BT were significantly reduced. The densities of (1-x)NCTNO-(x)BT ceramics and dielectric properties were improved with the addition of BaTiO3. For the effect of sintering temperatures, no substantial change in the crystal structure and grain growth was found whereas an increase in densities and hardness with increasing temperatures were observed. The (0.7)NCTNO-(0.3)BT ceramics sintered at 1025 oC showed the highest density and dielectric constant (∼80500) at room temperature with 1 kHz measurement.
Acknowledgment
The author would like to thank Prof. Dr. Tawee Tunkasiri for his help in many facilities (Materials Science Research Laboratory (MSRL), Department of Physics and Materials Science, Chiang Mai University).