Abstract: CaCu₃Ti₄O₁₂ ceramics with giant dielectric constant were prepared by the traditional ceramic method, in which the oxide powders were mixed and pre-sintered at 850～950℃, and then
sintered at 1050～1090℃, respectively. XRD, SEM and LCR were used to measure the phase structure, the morphology and dielectric properties of the ceramics. The results show that the dielectric
constant and the temperature at which the low dielectric constant typically transforms to special high are seriously controlled by the perfection and the defects of grain boundaries of the crystalline. The
relaxation temperature of the dipole in the sample pre-sintered at 950℃ and sintered at 1090℃ is 70K lower than that of the dipole in the sample pre-sintered at 880℃ and sintered at 1050℃,
and the dielectric constant is 300% enhanced, and simultaneously remains giant in a relative wide temperature range. The better the crystallinity of the ceramic, the faster the transation of the dielectric
constant from low to high.

Key words: CaCu₃Ti₄O₁₂, prepartion, giant dielectric canstant