Preparation of BaTiO_3-Acetylene Black Composite with a Super High Dielectric Constant

The ceramic composite which has a super high dielectric constant was prepared by compounding and sintering Acetylene Black(AB) and BaTiO3 together in the protective atmosphere. Microstructure and morphology of the composite were measured by XRD and SEM, and the dielectric properties were measured by LCZ meter. The results indicate that the prepared samples, are much difficult to form BaTiO3/AB composites when sintering in air atmosphere and at high temperature, because AB is oxidated and volatilized under that case. But the calcination process is improved due to the formation of liquid phases with decomposition and volatilization of AB in the AB doped BT system, AB can however be distributed in the sintered BaTiO3 matrix perfectly when sintering in the protective atmosphere of N2. The BaTiO3/AB ceramic composite with dense structure is hence formed completely while calcining at the temperature range 1200℃ to 1250℃. The dielectric constant of the BaTiO3/AB composite is increased evidently around the percolation threshold. The super high dielectric constant of 35000 can be obtained in BaTiO3/AB composites when AB content between 0.8wt% and 2.0wt%, which is 12 times more than that of BaTiO3 without AB doping.