Ceramics-Silikáty 57 (3) 215-218 (2013)

THE EFFECT OF DIFFERENT POLYMORPHS TiO₂ RAW MATERIALS ON THE DIELECTRIC PROPERTIES AND MICROSTRUCTURE IN CaCu₃Ti₄O₁₂ CERAMICS

CaCu₃Ti₄O₁₂ ceramics with different polymorphs of TiO₂ as starting materials were prepared by the conventional solid-state reaction technique. Their crystalline structure, microstructure and dielectric properties were systematically investigated. It has been found that all of the ceramic specimens prepared in the present study have a good polycrystalline structure, and no secondary phase is been found by XRD. However, large differences in dielectric properties and microstructure are observed in them: 1) the characteristic frequency of dielectric relaxation around 1 MHz in the CCTO ceramics prepared with rutile TiO₂ is much lower than that in those ceramics prepared with anatase TiO₂; 2) no matter dielectric properties or microstructure, the CCTO ceramics prepared with rutile TiO₂ are more sensitive to the sintering temperature than those ceramics prepared with anatase TiO₂.

Keywords: CaCu₃Ti₄O₁₂ ceramics, Different polymorphs TiO₂ raw materials, Dielectric properties, Microstructure