Polycrystalline CaCu3Ti4O12 ceramics were prepared by the field-assisted sintering technique. The effects of the dwell time and temperature on structural, microstructural and dielectric properties of CaCu3Ti4O12 ceramics have been investigated. Powder mixtures were calcined at 900 ºC for 18 h before consolidation. The dwell temperatures and times range between 750 and 930 ºC and 1 to 8 min, respectively. Sintered pellets were characterized by X-ray diffraction, scanning electron microscopy and impedance spectroscopy. X-ray diffraction patterns show evidences of a single-phase perovskite-type structure and the calculated lattice parameter is 7.40 Å. The hydrostatic density increases slightly with increasing dwell time and temperature. Scanning electron microscopy observations revealed a heterogeneous microstructure for all samples. The dielectric loss remains constant over a wide temperature range. The obtained permittivity is approximately 10³ at 1 kHz. The increase of the dwell temperature was found to produce a brittle ceramic.
sintering; CCTO; dielectric properties
