Ultra-fast synthesis and properties of high dielectric constant calcium copper titanate (CCT) ceramics synthesized by electric discharge assisted mechanical milling in oxygen and argon plasma

Synthesis of high dielectric constant calcium copper titanate (CCT) was carried out using the novel approach of electric discharge assisted mechanical milling (EDAMM) under oxygen and argon atmospheres. X-ray diffraction revealed complex structural changes associated with processing for different periods and under the different atmosphere. Morphology and grain size were investigated by field emission scanning electron microscopy and transmission electron microscopy. CCT was found to form directly by EDAMM processing in oxygen, while EDAMM processing in argon resulted in formation of intermediated nanostructure phases. Both the oxygen and argon EDAMM processed samples were sintered in air at 900 °C, and coarsen to produce CCT microstructures. The oxygen processed samples were found to have the larger grain size. Dielectric properties of the prepared samples were investigated using an LCR meter. The highest reported dielectric constant of CaCu3Ti4O12 (CCT) was found for the oxygen EDAMM processed and annealed sample, a dielectric constant of 48,000 measured at room temperature. This is the highest value ever reported for CCT materials which are not in nano-powder form.