Permittivity properties of thermally treated TiO2

Pure titanium oxide (TiO2) is an environmentally stable material, having interesting dielectric properties that can be practically utilized for microwave applications, and biological tissue simulations. In this study, the permittivity-frequency response of compressed TiO2 being calcined under different conditions, were investigated for the frequency range 20 Hz - 1 MHz, as well as the microwave frequency regime 2.6-3.2 MHz. The calcination effect on the microcrystal structure has been studied by XRD, SEM and microhardness. The acquired complex permittivity values are correlated to the encountered structural changes: The anatase microcrystal structure (maintained for calcination temperatures below 915 degreesC) exhibits significant ionic-relaxation and value-variations in the low frequency regime. The rutile microcrystal structure almost attains relaxation free permittivity response, with low loss characteristics in the examined frequency range. Calcination temperature of 1180 degreesC provides ceramics with a high packing microcrystal density, having stable epsilon(r)' = 12.3 and tandelta = 2.3 x 10(-3) (at 1 MHz). (C) 2003 Elsevier B.V. All rights reserved.