A.C. conductivity and dielectric properties of TiO2 ceramics

TiO2 is attractive as a dielectric material in integrated electronic applications because it has a high dielectric constant. Conductive TiO2 ceramics have been used as variators, oxygen sensors and current collecting electrodes in NaS batteries. Titanium ceramics are also doped with Nb or Ta to increase the electrical conductivity during the processing of TiO2 variators, it was discovered that Al and Fe contaminants can increase the electrical resistivities. TiO2 ceramic pellets were sintered at 1200 degrees C for two hours and X-ray diffraction, a.c. conductivity, and dielectric properties were measured. It was observed that TiO2 exhibits tetragonal structure and the lattice parameters are a = 4.5962 Angstrom and c = 2.9610 Angstrom. The unit volume of each molecule in TiO2 was 62.551 Angstrom3. The electrical conductivity was 4.47 x 109 (ohm·cm1) and the activation energy was 0.797 eV, in good agreement with literature data. The dielectric constant and dielectric loss are ε = 158 and tan δ = 0.038 respectively. Temperature and frequency variation of dielectric constant ε and dielectric loss tan δ properties were also carried out and explained based on the defect model and relaxation process. The above measured values confirm that the compound was stoichiometric, and shows good dielectric properties. (author)