Low temperature sintering and microwave dielectric properties of TiO2 ceramics

The TiO2 ceramics were prepared by a solid-state reaction in the temperature range of 920-1100 °C for 2 h and 5 h using TiO2 nano-particles (Degussa-P25 TiO2) as the starting materials. The sinterability and microwave properties of the TiO2 ceramics as a function of the sintering temperature were studied. It was demonstrated that the rutile phase TiO2 ceramics with good compactness could be readily synthesized from the Degussa-P25 TiO2 powder in the temperature range of 920-1100 °C without the addition of any glasses. Moreover, the TiO2 ceramics sintered at 1100 °C/2 h and 920 °C/5 h demonstrated excellent microwave dielectric properties, such as permittivity (Ɛr) value >100, Q × f  > 23,000 GHz and τf ≅ 200 ppm/°C.