Calcining temperature dependence on structure and dielectric properties of CaCu3Ti4O12 ceramics

CaCu3Ti4O12 powders were obtained by calcining the precursor, which was synthesized by sol-gel process, at different temperatures, and the ceramics were obtained by dry pressing and sintering using the powders. The dependence of calcining temperature on the microstructure and dielectric properties of the ceramics was studied. The results show that the grain size of the powder grows larger with increasing calcining temperature from 700 to 1000 A degrees C. With increasing the calcining temperature, the grain size of CCTO ceramics increases and then decreases, while the porosity exhibits an opposite trend. The ceramic, obtained by using the powders calcined at 850 A degrees C, shows the largest grain size, and it also shows good dielectric properties with the dielectric constant of 2.61 x 10(4) and the dielectric loss of 0.12 at 1 kHz.