Effect of Sintering Heating Rate on CaCu3Ti4O12 Formation

Abstract

CaCu3Ti4O12 (CCTO) is an electroceramic material with complex cubic perovskite-like oxide. It possessed a giant dielectric constant of about 105 over a wide temperature range (100-600 K). In this work, CCTO was synthesized through solid state method. The effect of different heating rate during sintering process was studied. The raw materials - CaCO3, CuO and TiO2 were wet ball milled for 24 hours and calcined at 900 °C for 10 hours. Then the calcined powder was pressed into pellet shape at 300 MPa. Sintering was done at 1040 °C for 12 hours with different heating rates: 3, 5 and 10 °C/min. The phase formation and surface morphology was investigated by X-Ray Diffraction (XRD) and Field Emission Scanning Electron Microscope (FESEM), respectively. The density was measured by Archimedes Principle. XRD pattern proves the CCTO single phase formation for the calcined powder and sintered pellet. The SEM images show the different grain size for different heating rate. The density of the pellet was found to be reduced when faster sintering heating rate was used.