Preparation, characterization and dielectric properties of CaCu3Ti4O12 ceramics

CaCu3Ti4O12 nano-sized powders were successfully prepared by sol-gel technique and calcination at 600-900 degrees C. The thermal decomposition process, phase structures and morphology of synthesized powders were characterized by IR, DSC-TG, XRD, TEM, respectively. It was found that the main weight-loss and decomposition of precursors occurred below 450 degrees C and the complex perovskite phase appeared when the calcination temperature was higher than 700 degrees C. Using above synthesized powders as starting materials, CCTO-based ceramics with excellent dielectric properties (epsilon(25) = 5.9 x 10(4), tan delta = 0.06 at 1.0 kHz) were prepared by sintering at 1125 degrees C. According to the results, a conduction mechanism was proposed to explain the origin of giant dielectric constant in CCTO system. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.