Dielectric Property of High Density CaCu3Ti4O12 Ceramics

High density CaCu3Ti4O12 ceramics was prepared by the hot-press sintering technique, and their micro- structure, crystalline structure and dielectric property were investigated. The hot-pressed ceramics exhibit the micro- structure of bimodal grain distribution with a high theoretical relative density of 98.3%. X-ray diffraction analysis shows that there is Cu2O minor phase in the hot-pressed ceramics whereas only CuO secondary phase exists after a further thermal treatment in ambience. Both the hot-pressed ceramics and its further thermally treated one exhibit two dielectric relaxations at room temperature, whereas the conventionally sintered ceramics have only one dielectric re- laxation. Moreover, the hot-pressed CCTO ceramics have an extremely large low-frequency permittivity of 2×10 5 , which further increases to nearly 1×10 6 through the ambient thermal treatment. The relation between microstructure